Measuring the Effects of Bridge Deck Replacement Methods on Construction Performance Factors by Mikkel Yuri Watts A thesis submitted to the Graduate Faculty of Auburn University In partial fulfillment of the Requirements for the Degree of Master of Science in Civil Engineering Auburn, Alabama August 6, 2011 Copyright 2011 by Mikkel Yuri Watts Approved by Wesley C. Zech, Chair, Associate Professor of Civil Engineering Rod E. Turochy, Associate Professor of Civil Engineering Hassan H. Abbas, Assistant Professor of Civil Engineering Jeffrey J. LaMondia, Assistant Professor of Civil Engineering ii Abstract The objective of this research was to develop and evaluate a methodology for measuring the effect of various bridge deck replacement methods on the total cost, schedule, and road user costs of a bridge project. Steps are outlined for data collection, normalizing, and nested ANOVA statistical analysis of created construction performance factors: unit cost, production rate, and road user cost. A contractor exit survey was developed to gather vital information on a bridge project that may not be reflected in the raw collected data. A hypothetical example problem was created which demonstrated how the methodology and analysis outlined can be used to aid engineers in justifiably selecting the most viable bridge deck replacement method(s) to use on future projects, based upon regional constraints and agency priorities. iii Acknowledgments The author would like to especially thank Dr. Wesley Zech for his guidance and support during the formulation and writing of this thesis. The author would also like to recognize and thank Dr. Rod Turochy and Dr. Jeff LaMondia for their additional help in the traffic data collection and analysis aspects of this research and Dr. Hassan Abbas for his insight on the construction techniques and sequencing being applied. iv Table of Contents Abstract ........................................................................................................................................... ii Acknowledgements ........................................................................................................................ iii List of Tables ............................................................................................................................... viii List of Figures ................................................................................................................................ xi Chapter One Introduction ................................................................................................................1 1.1 Bridge Deck Replacement Method ................................................................................3 1.1.1 Deck System ...................................................................................................3 1.1.2 Casting Technique ..........................................................................................7 1.1.3 Construction Sequencing ................................................................................7 1.2 Research Objectives .......................................................................................................8 1.3 Organization of Thesis .................................................................................................10 Chapter Two Literature Review .....................................................................................................12 2.1 Introduction ..................................................................................................................12 2.2 Accelerated Bridge Construction (ABC) Methods ......................................................13 2.3 Construction Performance Factors ...............................................................................16 2.4 Project Schedule...........................................................................................................17 2.5 Traffic Monitoring Technologies .................................................................................19 2.5.1 Pneumatic Tubes ...........................................................................................20 2.5.2 Vehicle Magnetic Imaging (VMI) ................................................................21 v 2.5.3 Digital Video Monitoring .............................................................................23 2.5.4 Radar .............................................................................................................25 2.5.5 Summary of Traffic Monitoring Devices .....................................................26 2.6 Road User Cost ............................................................................................................28 2.7 Collection Locations ....................................................................................................29 2.8 Earthcam? Construction Cameras ...............................................................................32 2.9 Analysis Methods.........................................................................................................33 2.10 Summary of Literature Review ..................................................................................34 Chapter Three Methodology & Data Collection ............................................................................36 3.1 Introduction ..................................................................................................................36 3.2 I-59 Bridge Dimensions ...............................................................................................40 3.2.1 Northbound (NB) Bridge Deck Details ........................................................45 3.2.2 Southbound (SB) Bridge Deck Details .........................................................46 3.3 Data Collection Locations ............................................................................................47 3.4 Data Collection ............................................................................................................48 3.4.1 Cost ...............................................................................................................48 3.4.2 Schedule ........................................................................................................54 3.4.3 Traffic Data ...................................................................................................59 3.5 Summary of Methodology & Data Collection .............................................................61 Chapter Four Data Analysis Techniques .......................................................................................64 4.1 Introduction ..................................................................................................................64 4.2 Gantt Charts .................................................................................................................64 4.3 Normalizing Collected Data ........................................................................................67 vi 4.3.1 Unit Cost .......................................................................................................67 4.3.2 Production Rate .............................................................................................68 4.3.3 Road User Cost .............................................................................................69 4.4 Nested ANOVA Statistical Procedure .........................................................................76 4.5 Contractor Exit Survey ................................................................................................80 4.6 Summary of Data Analysis Techniques .......................................................................81 Chapter Five Application of Methodology ....................................................................................83 5.1 Introduction ..................................................................................................................83 5.2 Raw Data Development ...............................................................................................87 5.2.1 Bridge Dimensions........................................................................................87 5.2.2 Cost Estimating .............................................................................................88 5.2.3 Schedule Estimating......................................................................................94 5.3 Data Collection Summary ............................................................................................99 5.4 Analysis Techniques ..................................................................................................101 5.4.1 Gantt Charts ................................................................................................101 5.4.2 Normalizing Collected Data .......................................................................105 5.4.3 Nested ANOVA ..........................................................................................111 5.4.4 Summary of Nested ANOVA .....................................................................135 5.5 Summary of I-59 Example Project ............................................................................137 Chapter Six Conclusions and Recommendations ........................................................................139 6.1 Conclusions ................................................................................................................139 6.2 Recommendations ......................................................................................................141 References....................................................................................................................................144 vii Appendices????????????????????????????????...147 Appendix A: Road User Cost Template .........................................................................148 Appendix B: Contractor Exit Survey ..............................................................................150 Appendix C: ALDOT plan set for Project No. BR-1059................................................153 viii List of Tables Table 2-1. Traffic Monitoring Technologies Summary ............................................................... 27 Table 2-2. Construction Camera Price Comparison Chart .......................................................... 33 Table 3-1. Lane-Span Dimensions for Northbound/Southbound Bridges ................................... 42 Table 3-2. Northbound/Southbound Bridge TCB Cost Data Collection Summary ..................... 52 Table 3-3. Northbound/Southbound Bridge Demolition Cost Data Collection Summary .......... 53 Table 3-4. Northbound/Southbound Bridge Demolition Cost Data Table .................................. 54 Table 3-5. Northbound/Southbound Bridge TCB Schedule Data Collection Summary ............. 56 Table 3-6. Northbound/Southbound Bridge Demolition Schedule Data Collection Summary ... 57 Table 3-7. Northbound/Southbound Bridge Construction Schedule Data Collection Summary 59 Table 3-8. Northbound/Southbound Traffic Data by Work Closure Period ................................ 61 Table 3-9. Northbound/Southbound Bridge Comprehensive Raw Data Summary ..................... 63 Table 4-1. Northbound/Southbound Bridge Construction Performance Factors ......................... 75 Table 4-2. Nested ANOVA Null and Alternative Hypothesis Test for Construction Performance Factors ........................................................................................................................ 79 Table 5-1. Northbound/Southbound Traffic Data by Work Closure Period ................................ 85 Table 5-2. Lane-Span Dimensions for Northbound/Southbound Bridge .................................... 88 Table 5-3. TCB Cost Estimating Summary ................................................................................. 90 Table 5-4. Demolition Cost Development Based on Assumed Learning Curve Cost Reduction 91 Table 5-5. Assumed Deck System Construction Unit Cost ......................................................... 92 ix Table 5-6. Construction Cost Development Based on Assumed Learning Curve Cost Reduction ....................................................................................................................................................... 93 Table 5-7. TCB Schedule Estimating Summary .......................................................................... 95 Table 5-8. Estimated Deck System Construction Schedules ....................................................... 97 Table 5-9. Northbound and Southbound Traffic Data by Work Closure Period ......................... 99 Table 5-10. Northbound/Southbound Bridge Summary Raw Data Table ................................. 100 Table 5-11. Assumed RUC Calculation Values ........................................................................ 106 Table 5-12. Northbound/Southbound Bridge Construction Performance Factors ..................... 110 Table 5-13. Example Nested ANOVA Null and Alternative Hypothesis Test for Construction Performance Factors ................................................................................................................... 111 Table 5-14. TCB Unit Cost ........................................................................................................ 112 Table 5-15. TCB Unit Cost Nested ANOVA Model Report from SAS Software .................... 113 Table 5-16. Demolition Unit Cost ............................................................................................. 116 Table 5-17. Demolition Unit Cost Nested ANOVA Model Report from SAS ......................... 116 Table 5-18. Construction Unit Cost ........................................................................................... 119 Table 5-19. Construction Unit Cost of Nested ANOVA Model Report from SAS ................... 119 Table 5-20. TCB Production Rates ............................................................................................ 122 Table 5-21. TCB Production Rate Nested ANOVA Model Report from SAS ......................... 122 Table 5-22. Demolition Production Rates ................................................................................. 125 Table 5-23. Demolition Production Rate Nested ANOVA Model Report from SAS ............... 125 Table 5-24. Construction Production Rates ............................................................................... 128 Table 5-25. Construction Production Rate Nested ANOVA Model Report from SAS............. 128 Table 5-26. Estimated Road User Cost (RUC) Values per Deck System ................................. 131 x Table 5-27. RUC Nested ANOVA Model Report from SAS .................................................... 131 Table 5-28. I-59 Example Bridge Deck Replacement Methods Effect on Construction Performance Factors P values ................................................................................ 135 xi List of Figures Figure 1-1. Exodermic Deck System (Harvey, 2011). ................................................................... 4 Figure 1-2. Steel Grid Deck System (Harvey, 2011). .................................................................... 5 Figure 1-3. NCHRP Deck System (Badie and Tadros, 2008). ...................................................... 6 Figure 2-1. Deployed Pneumatic Tubes....................................................................................... 21 Figure 2-2. Trax Apollyon Controller Box. ................................................................................. 21 Figure 2-3. Quixote?s NC-200 VMI Device ................................................................................ 22 Figure 2-4. Quixote's G-10 VMI Device ..................................................................................... 22 Figure 2-5. Deployed NC-200 VMI Device. ............................................................................... 23 Figure 2-6. Site Controller Link to VMI Devices ........................................................................ 23 Figure 2-7. Typical Intersection Location. .................................................................................. 24 Figure 2-8. Autoscope Traffic Detection Device. ........................................................................ 24 Figure 2-9. RTMS G4 in Sidefire Position. ................................................................................. 25 Figure 2-10. RTMS G4 Radar Device. ........................................................................................ 25 Figure 2-11. ASTI RTMS G4 Trailer. ......................................................................................... 31 Figure 2-12 Construction Camera Manufactures. ........................................................................ 32 Figure 3-1. Project Flow Chart for Evaluating Bridge Deck Replacement Methods. ................. 37 Figure 3-2. Plan View of I-59 Bridge Project Divided into Lanes and Lane-Spans. .................. 39 Figure 3-3. Elevation Views of Longitudinal Construction Joint. ................................................ 43 Figure 3-4. Traditional Construction Sequence TTC Concrete Barrier Placement. .................... 44 xii Figure 3-5. Accelerated Construction Sequencing TTC Concrete Barrier Placement. ............... 44 Figure 3-6. Northbound Bridge Span Construction Details......................................................... 46 Figure 3-7. Southbound Bridge Span Construction Details......................................................... 47 Figure 3-8. Lane Configuration of TCBs for Traditional Construction Sequence. ..................... 49 Figure 3-9. Lane Configuration of TCBs for Accelerated Construction Sequencing before and After Lane-Span Demolition. ................................................................................... 50 Figure 3-10. RTMS G4 Traffic Collection Locations. ................................................................ 60 Figure 4-1. Typical Traditional Construction Sequence Gantt Chart. ......................................... 65 Figure 4-2. Nested ANOVA Interaction Tree Diagram. .............................................................. 78 Figure 5-1. Plan View of the I-59 Project Divided into Lanes and Lane-Spans. ........................ 84 Figure 5-2. Project Flow Chart For Evaluating Bridge Deck Replacement Methods. ................ 86 Figure 5-3. Summary of Learning Curve Cost Reduction for Each Lane Span. ......................... 94 Figure 5-4. Summary of Learning Curve Time Reduction for Each Lane-Span. ........................ 98 Figure 5-5. Traditional Construction Sequencing Gantt Charts with Weekday Closure. .......... 103 Figure 5-6. Accelerated Construction Sequencing Gantt Charts with Weekend Closure. ........ 104 Figure 5-7. RUC Template For Lane-Span NBI1. ..................................................................... 108 Figure 5-8. TCB Unit Cost Interaction Tree Diagram. .............................................................. 115 Figure 5-9. Demolition Unit Cost Interaction Tree Diagram. ................................................... 118 Figure 5-10. Construction Unit Cost Interaction Tree Diagram. ............................................... 121 Figure 5-11. TCB Production Rate Interaction Tree Diagram. ................................................. 124 Figure 5-12. Demolition Production Rate Interaction Tree Diagram. ....................................... 127 Figure 5-13. Construction Production Rate Interaction Tree Diagram. ..................................... 130 Figure 5-14. RUC Interaction Tree Diagram. ............................................................................ 134 1 Chapter One Introduction 1 Introduction Currently, many elements of the U.S. Highway Infrastructure (e.g., roadways, bridges, culverts, etc.) are approaching design life expectancies, increasing the need for either replacing or rehabilitating deteriorating elements. The Federal Highway Administration (FHWA) estimates that 26 % of bridges, currently in the U.S., are deficient and in need of repair or replacement (Mistry and Mangus, 2006). The birth of the interstate system in the mid 1950?s created an essential infrastructure of roadways and bridges vital to commerce in the U.S. ?In the past two decades, the number of vehicles on U.S. roadways has increased by more than 75% while the total mileage of new highway systems has increased by only 4%? (FHWA, 1992). The continued use of the deteriorating infrastructure in such critical condition comes with an ever- growing risk to the traveling public. This combination of traffic volume growth, user demand, and the current state of the infrastructure has led many engineers to explore new construction methods (e.g., accelerated construction techniques) for replacing or rehabilitating infrastructure elements that minimize construction-related impacts (e.g., traffic delays to road users, increases in fuel consumption, impact to local businesses, etc.). Additionally, the FHWA is emphasizing that future bridge designs have a service lifespan of 100 years, placing additional pressure on the overall performance of accelerated construction techniques (Mistry and Mangus, 2006). 2 A growing concern in the transportation industry is the confounding effect and impact construction schedules have on the traveling public. Longer construction schedules typically result in extended lane closures which lead to traffic congestion and ultimately result in high road user costs (RUCs) absorbed by the motoring public. In addition, if accelerated construction techniques are implemented on projects to reduce RUCs by minimizing traffic related impacts, higher construction costs could be experienced straining a state highway agency?s budget. Cost- benefit analyses must be performed for upcoming projects under consideration to make sound justifiable engineering decisions on whether or not to employ an accelerated construction method(s). For a project being considered for accelerated construction techniques, a decision maker needs to have a fundamental understanding of the interaction between the cost, schedule, and traffic impact in order to perform an effective cost-benefit analysis. From this information engineers can determine, based on the needs and resources of a project under consideration, which accelerated method(s) is the most financially viable option. ?The Alabama Department of Transportation (ALDOT) has over three total miles of major interstate bridges (i.e., 3 to 5 lanes wide with approximately 600,000 ft2 of deck near downtown Birmingham, AL) with significant levels of deck cracking and deterioration? (Ramey and Oliver, 1998). To address the current state of these deteriorating interstate bridges, a combination of accelerated bridge deck replacement methods are being proposed for use in Birmingham, AL. The appropriate accelerated bridge deck replacement method needs to have the ability to reduce overall construction time while simultaneously achieving high quality performance, therefore satisfying both traffic volume and FHWA service life demands. 3 Prior to the actual implementation of accelerated bridge deck replacement methods in Birmingham, testing and evaluation of such methods are needed to determine associated advantages and disadvantages. The testing and evaluation will measure both in-place structural integrity, and construction performance of four different bridge deck replacement methods. A research project is being conducted on a low volume section of I-59 in Collinsville, AL to examine and evaluate the performance of four selected accelerated bridge deck replacement methods. The I-59 bridges were identified for testing and evaluation since the bridges are located in an area where construction related impacts would be minimal since the location has an approximate AADT of 13,420 vehicles (ALDOT, 2011). The lower traffic volume makes the I- 59 bridges an ideal location for this research since impacts to road users will be minimal, and construction activity will not experience delays as a result of construction related traffic disruptions. Monitoring the I-59 project from a constructability standpoint will assist in identifying advantages and disadvantages of these bridge deck replacement methods for consideration by ALDOT engineers on future Birmingham, AL bridge projects. 1.1 Bridge Deck Replacement Methods The I-59 bridge project is unique in the sense that it will employ three different bridge deck systems, two construction sequences, and two different casting techniques for bridge deck reconstruction. Each of the three elements: (1) deck system, (2) construction sequence, and (3) casting technique, will be used to evaluate these accelerated bridge deck replacement methods from a constructability perspective and are defined separately in the following sections. 1.1.1 Deck System The term deck system refers to the design and materials used to construct a modular bridge deck achieving a particular desired structural integrity. The first phase of the I-59 project was to 4 determine: (1) the number of deck systems that could be tested on the I-59 bridges, and (2) which systems were most beneficial for future use. This work was performed by the Auburn University Department of Civil Engineering, led by Dr. Hassan H. Abbas. The three deck systems to be evaluated in this research include: (1) ExodermicTM, (2) Steel Grid (Partial Depth), and (3) NCHRP (Full Depth). Each deck system is described separately in the following sections. 1.1.1.1 Exodermic Deck System An Exodermic? (or ?composite, unfilled steel grid?) deck is comprised of a reinforced concrete slab on top of, and composite with, an unfilled steel grid. This system can be constructed with a cast-in-place (CIP) or precast (PC) casting techniques. The Exodermic system maximizes the use of the compressive strength of concrete and the tensile strength of steel (Exodermic Bridge Deck, 2011). Figure 1-1 shows the typical design of an Exodermic deck system. Figure 1-1. Exodermic Deck System (Harvey, 2011). 1.1.1.2 Steel Grid Deck System Three steel grid deck system combinations exist: open, full, and partial depth. An open steel grid deck system is the lightest system and the easiest to install, however, it also offers the poorest 5 ride quality. A full depth steel grid deck system is the heaviest modular deck system of the three with the relative best ride quality, but it is also the most expensive and difficult to install. A partial depth steel grid deck system is in-between the open and full depth systems in terms of weight, cost, and constructability (Harvey, 2011). Through earlier research conducted by the Auburn University civil engineering department, a partial depth steel grid deck system was selected to be further investigated for its feasibility on the I-59 project. Figure 1-2 shows the design of a typical cast-in-place (CIP) steel grid partial depth deck system. Figure 1-2. Steel Grid Deck System (Harvey, 2011). 1.1.1.3 NCHRP Deck System The purpose of the National Cooperative Highway Research Program (NCHRP) Report 584 was to establish guidelines and recommendations for creating nonproprietary, full-depth, precast (PC) concrete bridge deck panel systems. The report developed: (1) recommended guidelines for the design, fabrication, and construction of full-depth PC concrete bridge deck panel systems and (2) connection details for new deck panel systems (Badie and Tadros, 2008). The NCHRP deck system that will be tested in Collinsville is CD-1(b), as identified in NCHRP report 584. The PC 6 concrete deck panels use pre-tensioned transverse and conventional longitudinal reinforcement. Transverse panel to panel connections will be accomplished through the use of a splice slot located along the transverse reinforcement of each deck panel system. Once the panels are in place, an additional splice bar will be inserted into the slot and the slot will be filled with grout. Figure 1-3 shows the unfilled NCHRP deck system and transverse panel to panel connections. (a) Plan View of Deck System Showing Reinforcement Location. (b) CD-1(b) Splice Panel to Panel Connection. Figure 1-3. NCHRP Deck System (Badie and Tadros, 2008). 7 1.1.2 Casting Technique Casting technique refers to whether the bridge deck systems were precast (PC) offsite or cast-in- place (CIP) at the project location. PC is defined as a product created in a reusable mold off-site and then transported to the construction location for installation. Often PC concrete is casted in a controlled environment under ideal concrete curing conditions. CIP is defined as concrete that is cast at the project location into a specific form created for one unique project. The environmental conditions are often beyond the contractor?s control during the curing process and equipment like mats and driers are used to aid the curing of concrete if necessary. 1.1.3 Construction Sequencing Construction sequencing refers to the scheduling and staging of bridge deck replacement activities that are employed by the contractor throughout the project duration. The two types of construction sequencing evaluated in this research include: (1) traditional construction sequencing and (2) accelerated construction sequencing. Each type of construction sequencing evaluated as part of the I-59 project is defined below. 1.1.3.1 Traditional Construction Sequencing Traditional construction sequencing is defined as a construction sequence that uses a permanent lane closure to replace the entire length of bridge lane. During this sequencing, temporary concrete barriers (TCB) will be used to establish a lane closure while the adjacent lane is maintained open for vehicle travel. Once demolition and construction is completed for the full length of a lane (i.e., all four lane-spans), the TCB is removed and the closed lane is reopened for use by the motoring public. 8 1.1.3.2 Accelerated Construction Sequencing Accelerated construction sequencing employs intermittent lane closures, as defined by a contractual time-based provision, to perform construction during periods of low traffic volume. This construction sequence employs TCBs to establish a closed lane while maintaining an open lane of travel adjacent to the work space. The purpose of using intermittent lane closures during non-peak travel time periods is to minimize traffic disruption on the motoring public. An intermittent lane closure could be considered a weeknight closure (e.g., 6 p.m. to 6 a.m.) or weekend closure (e.g., Friday at 6 p.m. to Monday at 6 a.m.). During these intermittent lane closure periods, demolition and construction are to occur on a single lane-span or on the amount of bridge decking the contractor can demolish and replace within a given work period. Once construction on the lane-span under consideration is complete, the closed lane is reopened for traffic and both lanes remain operational for traffic movements until work begins on the subsequent lane-span, during the next non-peak travel time period. The lane is then closed once again so demolition and construction can occur on the subsequent lane-span under consideration. This process is repeated until all lane-spans over the entire length of the bridge are completed. After total lane reconstruction work is complete, the TCBs are removed permanently and both lanes on the bridge are reopened to the traveling public. 1.2 Research Objectives The purpose of this research is to develop a framework that will be used to evaluate the impact of different bridge deck replacement methods from a construction perspective based on the total project cost, schedule, and traffic impact. The specific objectives of this research are: 1. Develop a methodology for statistically evaluating the effects that a particular bridge deck?s replacement methods: deck system, construction sequence, and casting technique 9 have on the three specified construction performance factors: (1) unit cost, (2) production rate, and (3) road user cost. 2. Perform a hypothetical case study using the methodology developed to demonstrate the applicability of the method and how the results can be used to select the most viable bridge deck replacement method to use on a future project based upon regional constraints and agency priorities. 3. Develop an exit survey to be administered to and completed by the contractor that gathers important construction feedback of each bridge deck replacement method constructed. To satisfy the research objectives and determine the bridge deck replacement methods effects on the construction performance factors outlined, the following tasks will be performed on the I-59 project: 1. Identify, describe, evaluate, and critically assess pertinent literature on the current deck systems, methods, technologies, and analysis techniques available for assessing bridge deck replacement methods. 2. Outline how the data (i.e., bridge dimensions, cost, schedule, traffic data, and contractor reports) from the Collinsville I-59 project will be collected for each bridge deck replacement method constructed. 3. Describe how construction camera technology can be used to monitor and document the construction effort for each separate lane span. 4. Use Remote Traffic Microwave Sensor (RTMS) G4 devices prior to the construction effort to capture traffic data (i.e., volumes and speeds) to aid in calculating accurate road user costs. 10 5. Create guidelines to perform an analysis of variance (ANOVA) to determine the effect that each bridge deck replacement method has on the construction performance factors (i.e., unit cost, production rate, and road user costs). 6. Develop an example problem to demonstrate the use of the methodology based on a hypothetical scenario of the I-59 project. 1.3 Organization of Thesis This thesis is divided into six chapters that organize, illustrate, and describe the steps taken to satisfy the research objectives outlined above. Chapter 2: Literature Review examines the current state of bridge deck replacement methods in practice. Furthermore, the literature review documents performance factors, scheduling, construction and traffic monitoring techniques, and analysis methods that pertain to performing a comparative analysis. Chapter 3: Methodology and Data Collection will outline the step-by-step procedures, learned and formulated out of the literature review, which will be used in the monitoring and collecting data on the I-59 project. Chapter 4: Data Analysis Techniques will discuss how to develop Gantt charts and normalize the raw data collected to create the selected construction performance factors: unit cost, production rate, and road user cost. After normalization of the data, analysis of variance (ANOVA) tests will be outlined and an exit contractor survey will be described. Chapter 5: Application of Methodology will give a detailed example from start to finish exhibiting in a step-by-step fashion, the data collection process and the application of the statistical analyses. Hypothetical scenarios will be created with fictitious data for analysis as a result of the construction effort being delayed on multiple occasions. This section should be used as a reference during actual construction of the I-59 project. Chapter 6: Conclusion and Recommendations will summarize 11 the work performed in chapters 1 through 5 with lessons learned through the course of this project and make recommendations for future bridge deck replacement research. 12 Chapter Two Literature Review 2 Literature Review 2.1 Introduction To satisfy the research objectives outlined in the previous chapter, a thorough literature review was conducted on several pertinent subjects relating to the I-59 project in Collinsville, AL. The topics that have been examined include: 1. Accelerated Bridge Construction (ABC) methods that exist or have been used and implemented on bridge rehabilitation and reconstruction projects, 2. Construction performance factors that have been measured for quantifying effectiveness of both building and roadway construction projects, 3. Scheduling effects on the overall performance of projects, 4. Traffic monitoring technologies that exist for capturing accurate and reliable vehicular data, 5. Road User Cost (RUC) estimating for bridge projects, 6. Collection locations for monitoring traffic flow, 7. Construction camera monitoring technology, and 8. Analysis methods for measuring construction performance The following sections will discuss the results of the literature review for the abovementioned topics. 13 2.2 Accelerated Bridge Construction (ABC) Methods ABC methods refer to any construction bridge effort that is intended to greatly reduce the typical overall construction schedule. This is a wide all-encompassing term. The I-59 project will be testing a variety of ABC deck systems, construction sequences, and casting techniques. A variety of cast-in-place (CIP) and precast (PC) systems have been experimented with on ABC projects in the past. Each offers its own advantages and disadvantages; a portion of this research will focus on comparing the strengths and weaknesses of each system. One such deck system that will be used on the I-59 project is an Exodermic? system. Exodermic deck panels are comprised of an unfilled steel grid 3 to5 in. (7.63 to 12.7 cm) deep, with a 3 to 5 in. (7.63 to 12.7 cm) reinforced concrete slab on top of a composite with the steel grid. The Exodermic panels can be either PC offsite or CIP at the project location. In 2005, the Georgia Department of Transportation (GDOT) experimented with PC Exodermic deck panels on two bridges. One bridge was the Bells Mill Bridge in Gainesville, GA and the other bridge was the Atlanta I-285 bridge, over US-41. The Bells Mill Bridge was 388 ft (118.26 m) long with a two way, two lane configuration. The bridge was narrow with a total transverse width of 26 ft (7.92 m). The deck spans were replaced on a nightly schedule (Monday ? Friday) 9:00 p.m. to 5:00 a.m. with two PC Exodermic panels with an area of roughly 500 ft2 (46 m2). The Atlanta I-285 bridge over US-41 is an eight lane bridge system (four lanes in each direction) with a total length of 240 ft (73.15 m). Due to the skew of the bridges, Exodermic trapezoidal panels were used. The project schedule for the reconstruction effort consisted of a weekend 14 closure schedule (using partial lane closures starting at Friday 9:00 p.m. and reopening on Monday at 5:00 a.m.) to avoid high periods of traffic. During the construction phase, two lanes of traffic were maintained while the remaining two lanes were repaired at a rate of 2,527 ft2 (235 m2) per weekend. The project was completed in 5 weekend closures, 7 weekends ahead of the allotted 12 weekends provisioned in the GDOT bid for a total of 12,635 ft2 (1174 m2) of bridge decking upon completion. The construction effort of both the Bells Mill bridge and the Atlanta I-285 bridge were a success because ?the bridge decks were replaced using rapid deck replacement techniques during periods of low traffic volume to reduce accident risk and improve public acceptance? (Umphrey et al., 2007). Another ABC bridge project was conducted by the Ohio Department of Transportation (ODOT) in Quaker City, Ohio in 2003. The project used a precast deck system to rapidly replace the bridge deck. Originally the 60 ft (18.29 m) bridge, built in 1952, had been a two span, continuous, reinforced concrete slab bridge with reinforced concrete substructure. Due to time constraints, it was not possible to replace the previous slab with a new continuous concrete slab. Closure of the bridge would result in a 20 mile (32.19 km) detour for automobiles and a 40 mile (64.37 km) detour for trucks and buses (Salem et al., 2006). Another alternative explored for the Quaker City bridge was using a partial lane closure construction sequence. This process was eliminated because the bridge was a major route for school buses and a partial closure posed safety concerns to the large school buses passing through the work zone. The ODOT decided to use a post-tensioned precast system for decking replacement coupled with a compressed work 15 schedule that took advantage of the time between spring and summer semesters of the local Ohio schools. The project was accomplished in 19 days, 3 days behind schedule. Although the project was complete 3 days behind schedule, the project was considered a success because it was completed in a reasonable enough time that school activity was not affected and the structural objectives of the reconstruction were met to satisfactory conditions (Salem et al., 2006). The above mentioned methods of ABC are a more conservative approach to maximizing construction productivity while minimizing traffic delay impacts during rehabilitation. Other less conventional methods exist that have proven quite successful on a number of projects. One project in particular that used innovative techniques to solve a complex problem is the Church Street South Extension project over the New Haven Interlocking and Rail Yard that used one of the world?s largest cranes to complete a bridge section replacement. The Connecticut Department of Transportation (ConnDOT) required that a 320 ft (97.54 m), 850 ton (743 metric ton) span of a 1,280 ft (390.14 m) bridge be replaced in a single weekend. Traditional bridge construction techniques were not possible because of the train yard that existed under the footprint of the project. A compressed construction schedule was used to minimize disruption to train service and shorten worker exposure time to active rail lines. To meet the rigorous demands outlined by the ConnDOT, the Lampson International LLC?s Transilift? LTL-2600 was used to lift the 320 ft (97.54 m), 850 ton (743 metric ton) prebuilt span of bridge section into place in a 3 hour period. On an early morning, May 3rd, 2003 the crane lifted the section 65 ft (19.81 m) into the air and maneuvered it 100 ft (30.48 m) over to its final resting location. The total duration for the move was 3 hours. When the final project was completed in December 16 2003 it was 5 months ahead of schedule and $500,000 under its $32 million dollar budget (Mistry and Mangus, 2006). 2.3 Construction Performance Factors An objective of the I-59 project will be to assess the effect that the bridge deck replacement methods selected has on the construction performance factors: unit cost, production rate, and road user cost. For analysis, data collection will be recorded through the duration of the project and then used to compute construction performance factors. The data collection effort regarding construction performance factors will begin prior to the construction effort, continue through all stages of the actual work, and be continued for a period after the completion of the project. From the literature review, three common measurement factors (i.e., cost, schedule, and quality) appeared many times indicating these factors as important data to be collected to perform a construction performance analysis. ?Project managers like to talk about the three legged stool on which their project sits: project quality, schedule, and cost. Applying rapid bridge construction techniques such as those described here strengthens those legs tremendously? (Capers Jr, 2005). Umphrey et al. (2007) identified similar performance factors in their research of four accelerated bridge projects in Georgia. ?Documentation of the GDOT work included a time sequence, deck replacement square footage per work period, total construction time, typical work period construction tasks, and photographic display/discussion of the deck replacement work? (Umphrey et al., 2007). 17 A method for comparing methods of construction using performance factors is to create index values or ratios of the performance factors in an effort to normalize the data to have the ability to analyze data across different sized projects. Chan and Kumaraswamy (1995) collected index values during their research of Hong Kong building construction projects. Major building construction in Hong Kong has a reputation for being both satisfactory and incredibly quick with accurate completion time forecast (Chan and Kumaraswamy, 1995). In 1995 Chan et al. formulated and tested empirical models to determine if project completion estimates could be predicted based on a set of parameters. For their research they closely examined the relationships between time-cost models, time-floor area models, and time-number of stories models. In all 3 models a linear relationship was determined with a coefficient of determination above 0.60. The results of the research showed that the index values created could be used to make future project predictions based on a known parameter. Although this example is referring to building construction, the applicability of creating performance factors for future project estimating can be used in bridge construction. 2.4 Project Schedule Project scheduling is an important aspect to the success of any construction project. During accelerated construction, scheduling plays a significant role in ensuring the project is completed on time or ahead of schedule. In accelerated construction, scheduling becomes an essential component to ensure that projects are completed successfully on-time or ahead of schedule. Planning and coordinating sequential events keeps productivity rates high by minimizing lost work hours due to lack of material or personnel on the project site. Prior to construction an important task to consider during the scheduling process is to organize a pre-construction meeting amongst the parties involved on the project. The objective of this meeting is to discuss 18 potential problems that could occur during the construction effort. Groups are encouraged to voice their opinions on potential issues or circumstances that could delay the project, while also indicating that they understand their individual responsibilities. This process ensures everyone is working together to successfully complete the accelerated task and finish the project on time. In the Quaker City Bridge project discussed earlier, such a pre-construction meeting was held. Representatives from ODOT, the general contractor, the post tensioning subcontractor, the precast fabricator, and the design engineering firm met six months ahead of construction to discuss any potential delay issues that could be encountered during work. An issue that had been overlooked earlier in the planning phase was a noise ordinance permit required for heavy construction in urban areas. If proper paper work had not been filed before construction, the noise ordinance could have caused serious delays. Due to the short duration of the construction project and the importance of the bridge being replaced, local officials gladly offered a waiver on the noise ordinance (Salem et al., 2006). By bringing a diverse group of individuals together to examine the work of their peers they were able to identify potential problems that had been overlooked in the earlier development phase of planning. Once the sequence of work and possible delay issues had been identified in the pre-construction portion of the project, the next step was to begin the construction phase of the Quaker City Bridge. During construction it is important to keep clear lines of communication open between all parties involved in the project. In the event that work cannot be carried out according to the schedule or setbacks occur that cause delay, rapid communication among key personnel to resolve issues is required to keep work moving forward. ABC requires fast decisions to keep pace with that of accelerated construction. On the Quaker City Bridge project it was noted that a key to success was the 19 project manager?s authority and ability to make tough decisions when the engineers could not be reached immediately (Salem et al. 2006). ?The contractor and contracting agency formed a cordial relationship of partnering that ensured an atmosphere conducive to quality performance? (Salem et al., 2006). Giving confident and qualified individuals authority to make hard decisions rapidly is critical for accelerated projects to be accomplished on a compressed schedule successfully. Periodic monitoring of the project should be performed during construction by comparing work accomplished to work expected at a given time. This process ensures that the project remains on schedule. Following construction, a post construction meeting should be held to analyze the work that was performed. The objectives should be to assess the work performed against the work expected and identify any successes or failures that occurred during the project. Feedback from the contractors is encouraged and should be used to revise plans for future projects. Naoum (1994) used a questionnaire following project completions to evaluate client satisfaction concerning time, cost, and quality. All aspects of the post construction analysis should be integrated into future work based upon the lessons learned to ensure projects operate more smoothly in future construction efforts. 2.5 Traffic Monitoring Technologies To monitor the flow of traffic prior, during, and post construction, a literature review was performed on different vehicular detection technologies. It was identified that the device selected should be capable of the following: (1) nonintrusive data collection means, (2) record accurate and reliable data, (3) easy to install and maintain, and (4) be remotely accessible. Four 20 different types of vehicle detection equipment were compared for use on the I-59 project which included: 1. Pneumatic Tubes 2. Vehicle Magnetic Imaging 3. Traffic Detection Cameras 4. Radar Monitoring Devices The results of this literature review were used to select the traffic monitoring device that was purchased for the I-59 Project. 2.5.1 Pneumatic Tubes Pneumatic tubes work by using a set of air filled tubes placed across a roadway at a set distance apart. When traffic traverses the tubes, an air-pulse is sent to a controller on the side of the road. The control box can calculate, based on the distance of the tubes from each other, the speed, volume, classification, and gap of the vehicles traversing the pneumatic tubes. This system requires that workers enter the traffic lanes to install the rubber tubes and secure them to the pavement. Figure 2-1 below shows the typical deployment of a Trax Apollyon pneumatic tube system on a roadway. Figure 2-2 shows the same Trax Apollyon controller box that would be used to gather traffic data from the pneumatic tubes. 21 Figure 2-1. Deployed Pneumatic Tubes. Figure 2-2. Trax Apollyon Controller Box. Courtesy JAMAR TRAX Apollyon Brochure Courtesy JAMAR TRAX Apollyon Brochure Once data are collected, the controller box must be downloaded to a computer for data analysis and interpretation. This can be accomplished through a series of different connectors. More modern controller boxes use a universal serial bus (USB) connection, which makes data transfer more convenient. The system overall requires very little power, compared to other vehicle movement monitoring technologies. On average, four lanes can be monitored by a single controller and tube system for simple counts, excluding speeds. The biggest drawback to using a tube system in Collinsville was the associated maintenance of the tubes on the roadway. Traffic movements, particularly heavy vehicles, passing over tubes have a tendency to displace the tubes and affect the reliability of the collected data. This requires periodic maintenance of installed tubes to ensure data collection is accurate. According to Smadi et al. (2006) on the use of road tubes, ?they present a number of challenges, including: mixed accuracy for simple axle counts, limited data detail (long recording intervals), difficulty of setup, and potential safety hazards to crew and road traffic? (Smadi et al. 2006). 2.5.2 Vehicle Magnetic Imaging (VMI) VMI devices come in a variety of styles. VMI devices work by measuring disruptions in a magnetic field created by the metal in vehicles passing through the recorder?s magnetic zone. 22 Extreme low temperatures can create unreliability in the accuracy of vehicle counts (Bahler et al. 1998). The speed, vehicle classification, and count of each vehicle can be determined from this field disruption. The recorder is generally placed in the lane of travel for monitoring traffic movements. This requires workers to temporarily enter the traffic lanes to install the VMI device. Figure 2-3 shows a plate style VMI device produced by Quixote Transportation Technologies Inc. The plate is installed on the surface of the roadway for traffic collection. Figure 2-4 shows a close up view of the G-10 VMI device produced by Quixote. A hole is drilled into the roadway and the G-10 is inserted so the top of G-10 is near flush with the road surface. Asphalt is applied to the top of the G-10 to smooth out any differential heights between the road and the G-10. Figure 2-3. Quixote?s NC-200 VMI Device Figure 2-4. Quixote's G-10 VMI Device Courtesy www.qttinc.com Courtesy www.qttinc.com Some VMI devices must be physically removed from the lane of travel and connected to a computer for data retrieval. Other more advanced systems create a wireless link with a nearby site controller that can transfer the information to a remote location. The NC-200 can be seen installed on the roadway in Figure 2-5. For data retrieval, the NC-200 will have to be physically removed from the roadway and brought to a computer for download. The wireless link between two G-10 VMI devices and a site controller can be seen in Figure 2-6. With the G-10, 23 downloading of the data can be accomplished from a remote location and the devices do not need to be removed until their battery life expires. Figure 2-5. Deployed NC-200 VMI Device. Figure 2-6. Site Controller Link to VMI Devices Courtesy nu-metrics NC-200 Brochure Courtesy nu-metrics Groundhog G-10 Brochure Since most market devices require one piece of equipment per lane, the upfront cost of this type of vehicle detection technology can be expensive. The battery life on VMI devices ranges from 21 days to 3 years depending on the type of VMI. Equipment with a longer battery life can be left in place and retrieved months later for continued traffic analysis. 2.5.3 Digital Video Monitoring Digital video monitoring devices use video imaging to capture traffic data for analysis. This is accomplished through user defined detection zones created with point and click application. Information that can be collected include: speed, count, and vehicle classification. The greatest benefit of this type of technology is that it allows for live streaming video of the monitored location. Due to the power demands of such equipment, most video cameras require a connection to traffic cabinets, making them ideal for intersection locations. Because of the bandwidth requirement needed by streaming video, it is usually typical to integrate the camera into an agency?s IP-based communication network. An advantage of connecting into an IP- based communication network is the ease of monitoring and retrieving data from a remote 24 location. The number of lanes that can be simultaneously monitored is a matter of the camera?s geometry to the viewing area. In general, if the field of vision of the video device is clear, then it can be monitored. Figure 2-7 shows the view of a video detection camera located above an intersection. Figure 2-7. Typical Intersection Location. Figure 2-8. Autoscope Traffic Detection Device. Courtesy www.autoscope.com Courtesy www.autoscope.com The live monitoring technology makes video detection equipment ideal for traffic incident reporting. Current issues with this technology fall into three main categories: (1) monitoring vehicles at night, (2) monitory vehicles in poor weather, and (3) direct sunlight on the camera lens. A study by Bahler et al. (1998) on nonintrusive traffic devices stated, concerning camera technology, ?miscounting was observed during the transition periods, especially the transition from day to night. One video device tended to undercount during the evening transition and the other tended to over count? (Bahler et al. 1998). In terms of poor weather and direct sunlight an overhead hood has been designed for most camera systems that offer minimal protection from the elements. Figure 2-8 shows an image of an Autoscope video traffic detection camera. It can be seen that a hood has been designed over the camera lens minimizing sun glare. It is recommended that the video camera be oriented in such a way as to avoid poor weather and direct sunlight to minimize the potential for inaccurate data collection. 25 2.5.4 Radar Radar monitoring devices work by creating a radar field along the roadway that monitors vehicles entering and exiting the field. Data that can be collected include: speed, class, count, and volume. The radar device can be placed in either an overhead or a sidefire orientation. The setback and elevation should be determined based on the specification of the technologies? manufacturer. The installation process does not require workers to enter the roadway, minimizing exposure to live traffic conditions associated with dangerous work zone environments. The RTMS G4 produced by Image Sensing Inc. (ISS) can be seen in Figure 2-9 in a sidefire orientation along a typical highway capturing bidirectional traffic data. Figure 2-9. RTMS G4 in Sidefire Position. Figure 2-10. RTMS G4 Radar Device. Courtesy Imagesensing.com RTMS G4. Courtesy www.rtms-by-eis.com. Radar technology has proven over time to be both highly reliable and accurate. Bahler et al. (1998) concluded that the use of RTMS G4, seen in Figure 2-10, equipment for freeway applications, ?exhibited good potential for detecting and measuring vehicle speed. The technology also has the advantage of monitoring multiple lanes when mounted from a sidefire location, perpendicular to the direction of traffic? (Bahler et al., 1998). Weather had little effect on the consistency of traffic counts with radar collectors. Radar boxes tend to be small in size and easily installed and calibrated. They can be set-up to store data into memory for later 26 retrieval, or various forms of wireless technology create the capability to access data from the radar device, via a remote location. The power requirements of many radar systems is quite low and most venders offer a solar power option for prolonged traffic monitoring needs. 2.5.5 Summary of Traffic Monitoring Devices The requirements of the traffic monitoring device selected for the I-59 project included: (1) nonintrusive data collection means, (2) record accurate and reliable data, (3) easy to install and maintain, and (4) be remotely accessible. Four traffic monitoring technologies were researched for possible purchase. Of the four technologies, one video detection, two radar, two VMI, and one pneumatic tube were compared. The summary of the four technologies can be seen in Table 2-1. It was determined that the RTMS G4 by ISS fulfilled the traffic monitoring device requirements outlined for the I-59 project. Three RTMS G4 devices were purchased with internal wireless modems and cameras. The wireless modems make it possible to monitor and download traffic data from a remote location without a direct connection to the RTMS device. With the internal cameras the travel lanes can be monitored from a computer remotely. 27 Table 2-1. Traffic Monitoring Technologies Summary Activity Traffic Monitoring Technologies Autoscope Radar Recorder RTMS G4 Trax Apollyon NC-200 G-10 w/Site Controller Installation Method Non-Intrusive Non-Intrusive Non-Intrusive Intrusive Intrusive Intrusive Sensor Type Video Radar Radar Pneumatic VMI VMI Data Collected Speed Yes Yes Yes Yes Yes Yes Volume Class Incident Yes No No No No No Max Setback Distance (ft) 300 400 250 None None 400 ft. to Site Controller Download Interface Wireless Yes No Yes No No Yes Ethernet (IP) Yes No Yes No No Yes Direct connection Yes Yes Yes Yes Yes Yes Number of Simultaneous Monitored Lanes 6-8 2 12 2 1 1 Bi-directional Monitoring Yes Yes Yes Yes No No Memory Capacity N/A 4 MB 8 MB 8 MB 3 MB 5-days Affected By Rain/Snow/Sun None None Stop Go Traffic Power Lines Power Lines Offsite Monitoring and Control Yes No Yes No No Yes 28 2.6 Road User Cost Road user cost (RUC) is a function of the volume and lane conditions at a work zone. To determine how to accurately assess a RUC for the I-59 project the following literature was reviewed. Traditionally, the Highway Capacity Manual (HCM) has been used for predicting freeway capacities. One problem that is encountered from relying on the HCM model for predicting capacities is ?the Highway Capacity Manual (HCM) procedures provide generic estimates for two types of lane closures only, with no guidance as to how these estimates are affected by traffic, geometric, and environmental conditions? (Al-Kaisy and Hall, 2003). The HCM procedure for calculating a freeway capacity is to first determine an ideal base capacity and then modify it by a series of factors. As previously stated, those factors do not account for critical lane closure conditions or environmental issues. In an attempt to create a more accurate model for predicting the capacity of freeways during construction, Al-Kaisy and Hall (2003) experimented with two variations to the HCM model. Both models were built on the principles established in the HCM of determining a base capacity and then modifying it by several factors. The factors chosen by his team as most effecting to the capacity were: percent heavy vehicles, driver population, light conditions, inclement weather, work activity on-site, lane closure configuration, and rain. In the first experiment a nonlinear multiplicative capacity model was derived. The resulting model had a coefficient of determination of 0.63. In the second experiment a linear additive capacity model was created using multivariate linear regression with a coefficient of determination of 0.68. Overall, the authors determined that a model that 29 accounted for critical lane closure conditions or environmental issue was more accurate in terms of predicting the freeway capacity than simply relying on the HCM model. Other factors to consider when estimating a RUC include regional cost values per vehicle. The American Association of State Highway and Transportation Officials (AASHTO) reports three key factors for performing a user benefit analysis to determine a RUC from highway construction projects. The three key factors outlined are the value of time, operating cost, and accident cost per vehicle (AASHTO, 2010). The three factors depend on the lane closure conditions and the average wage and operating cost of the location in question. 2.7 Collection Locations Smadi et al. (2006) stated on set-up requirements concerning vehicle detection technology, ?There are many factors that need to be taken into account as far as setting up the sensors, such as location, complexity of the user interface (software and hardware), the ease of the deployment, and the type of roadway facility being analyzed? (Smadi et al. 2006). Location will dictate the weather and environmental conditions. Complexity of the user interface (i.e,, software and hardware) will determine how remotely accessible the device is. Ease of deployment will control how portable a device is to be used at multiple locations. The type of roadway facility will usually be divided into either free flowing conditions, such as those exhibited on freeways, or stop go conditions, as seen at intersections. These factors will govern the decision on which vehicle detection technology is applicable to a specific situation. The conditions that exist for the I-59 project are a free flowing, two lane, rural highway on level terrain. The project location experiences an average annual daily traffic volume of 13,420 (ALDOT, 2009). The device to be used for data collection will be the RTMS G4, a radar based 30 device. A comparative study by Bahler et al. (1998) tested RTMS G4 units in both overhead and sidefire mounted positions on a freeway test site located on Interstate 394 at Penn Avenue in Minneapolis, Minnesota. The results of the RTMS G4 data were compared to baseline values gathered from both hand and loop counts. In the overhead orientation the RTMS G4 was mounted at 25 ft (7.62 m) in the direction facing departing traffic. The device in the overhead configuration counted vehicular volumes within 3 percent of the baseline values. For the sidefire configuration, the units were mounted to sidefire poles at a setback of 4 to 100 ft (1.22 to 30.48 m) with a height of 15 to 35 ft (4.57 to 10.67 m). The setback and height were determined from manufacturer specifications. The RTMS G4 volumes, in the sidefire orientation, were within 5 percent of the baseline values. For overhead and sidefire positions, the speed data were within 8 percent of the baseline value. A comparative study was performed by the researchers Smadi et al. (2006) using the Wavetronix Smart Sensor and a video vehicle detection system. For this study the devices were mounted to a mobile trailer device that was easy to deploy and completely mobile. The devices were deployed along the side of the roadway in a sidefire position with a setback and height dimensions as outlined by the manufacture. The trailer mounted radar units could be oriented in a forward fire or sidefire position; however, it was noted by Smadi et al. (2006). that sidefire was best suited for temporary data collection. Mounting the radar device to extending mobile trailers did not cause any loss of accuracy or reliability in collected data and proved an excellent method for creating mobile units 31 Based on the above literature review, three solar power trailers for deployment and data collection were purchased to accompany the RTMS G4 devices. The trailers were manufactured by ASTI and were recommended by Blackhawk Enterprise, the local ISS RTMS G4 vendor. The maximum telescoping height of the trailers is 20 ft. The ASTI trailers were purchased to accompany the RTMS G4 devices and can be seen in Figure 2-11. The trailers made the RTMS G4 devices highly mobile and easy to reuse for future traffic monitoring needs. For data collection purposes, the trailers can be placed along the shoulder or adjacent to the roadway in a sidefire position. This orientation keeps the installers from entering the traveled roadway while the RTMS remains non-intrusive. Figure 2-11. ASTI RTMS G4 Trailer. 32 2.8 EarthCam? Construction Cameras To capture construction activity during the I-59 project two construction camera manufactures were researched, those two companies being the OxBlue and EarthCam. Both companies were highly recognized as leaders of construction camera technologies and have been featured in Engineering News Record (ENR) magazines. Figure 2-12 shows the OxBlue and Earthcam construction cameras. (a) OxBlue Camera. (b) EarthCam Camera. Courtesy OxBlue Construction Camera System 2010. Courtesy Earthcam.net. Figure 2-12 Construction Camera Manufactures. The purpose of the cameras on the I-59 project is to monitor day to day construction efforts for later analysis in conjunction with reports documenting work performed. It was required that the construction camera chosen for the I-59 project be a system that includes a fixed camera with remotely controllable digital Pan, Tilt and 5x Zoom (PTZ), and viewable over the internet through a password protected website. The web application for viewing the I-59 project needed to support calendar image selection, as well as image cropping and overlaid effects for image comparisons. The website and server where information would be stored, needed to be controlled locally by the camera manufacturer. It was determined that the manufacturer needed to provide continuous viewable images at a minimum of 2816H x 2112V (or 6 mega pixels) 33 resolution and 1 image per 15 minutes through the host website. This resolution provides the ability to see in detail to the farthest extent of the project without camera movement. At the completion of the I-59 project it is required that a time lapse video be created with the option to maintain the camera website until a predetermined time. While both camera manufacturers provided digital image cameras capable of the resolution and web applications required, the OxBlue company did not locally control the web server as desired. Both companies provided a completed time-lapse video with the option to maintain the website for a predetermined time. Both manufacturers were contacted and asked to provide competitive quotes for the camera requirements outlined above. The quotes were to include the cost of the 6 mega pixel camera with web service for a month and for a year. Table 2-2. Construction Camera Price Comparison Chart Manufacturer MegaPixel Unit Price ($) Monthly Web Charge ($) Monthly Cost($) Yearly Cost ($) OxBlue 6 mp 4,500.00 615.00 5,115.00 11,880.00 EarthCam 6 mp 5,249.20 250.00 5499.20 8,249.20 After price comparison, it was determined that the EarthCam was a better value than the OxBlue construction camera package. The EarthCam had a higher initial cost for the equipment, but offered a lower month to month web service fee. Over one year, the savings for choosing the EarthCam over the OxBlue would be approximately $ 3,600. 2.9 Analysis Methods The I-59 project will evaluate three elements of various bridge deck replacement methods: (1) deck system, (2) construction sequence, and (3) casting technique that exist for each bridge, but are not shared by each bridge. Due to the uniqueness of this project regarding the combinations 34 of bridge deck replacement methods being constructed over all bridge spans, simple linear regression analysis was not considered as the most viable test. Alternatives to simple t-test and linear regression were researched. A nested analysis of variance (ANOVA) test, by definition satisfies the requirements for analysis in regards to the combination of bridge deck replacement methods being proposed for the I-59 project. ?In certain multifactor experiments, the levels of one factor (e.g., factor B) are similar but not identical for different levels of another factor (e.g., factor A). Such an arrangement is called a nested, or hierarchical, design? (Montgomery, 2005). This multifactor design is applied during the organization of the I-59 project, with each of the bridge deck replacement methods be dependent on the results of one another. The nested ANOVA compares the mean value of each level to determine statistical influence of a parameter being tested. The nested ANOVA will be used to determine the effect of each bridge deck replacement method on the outlined construction performance factors. 2.10 Summary of Literature Review A thorough literature review was performed to gain knowledge of construction and bridge projects from previously conducted research. The literature review was divided into six areas that were intended to cover all aspects of the I-59 project. The eight areas covered by this literature review are listed as follows: 1. Accelerated bridge construction (ABC) methods that exist or have been used and implemented on bridge rehabilitation and reconstruction projects, 2. Construction performance factors that have been measured for quantifying effectiveness of both building and roadway construction projects, 3. Scheduling effects on the overall performance of projects, 35 4. Traffic monitory technologies that exist for capturing accurate and reliable vehicular data, 5. Road User Cost estimating for bridge projects, 6. Collection locations for monitoring traffic flow, 7. Construction Camera Monitoring Technology, and 8. Analysis methods for measuring construction performance The lessons learned from the literature review were then applied to create a methodology for collecting data and analyzing it systematically, which satisfy the I-59 research objectives outlined in Chapter 1 of this report. 36 Chapter Three Methodology & Data Collection 3 Methodology & Data Collection 3.1 Introduction The purpose of this chapter is to describe and establish a methodology and procedure for data collection on the I-59 bridges in Collinsville during construction. The I-59 bridges consist of four total lanes, two northbound (NB) lanes and two southbound (SB) lanes. For construction purposes, each bridge has been subdivided into four unique spans. Each span is divided by the two existing lanes: (1) the inside (passing) lane and (2) the outside (travel) lane. In this thesis, a span in a particular lane will be referred to as a lane-span. There are a total of eight lane-spans per bridge and sixteen lane-spans for the entire I-59 project. Figure 3-1 illustrates a flow chart developed to show the sequencing of this research effort for the evaluation of the bridge deck replacement methods. The flow chart begins with the three major components used to evaluate each bridge deck replacement method and continues through the data collection effort, normalizing of collected data, statistical analyses, and results. 37 Note: *WD - Weekday Lane Closure Scenario *WN - Weeknight Lane Closure Scenario *WE - Weekend Lane Closure Scenario Figure 3-1. Project Flow Chart for Evaluating Bridge Deck Replacement Methods. Nested ANOVA RUCProduction RateUnit Cost Dimensions AASHTO Traffic DataScheduleCost Survey Casting Technique Construction Sequence (WD/WN/WE) Deck System Bridge Deck Replacement Methods Results Data Collection Normalizing Analysis Bridge Deck Replacement Methods 38 Data collection for the I-59 project will be performed on each individual lane-span for each bridge deck replacement method. Four unique bridge deck replacement methods are to be constructed and evaluated during the reconstruction of the I-59 NB and SB bridges. The inside lane on both the NB and SB bridges will be constructed using a traditional construction sequence while the outside lanes on both bridges will be constructed using an accelerated construction sequence. The NB bridge will be constructed using cast-in-place (CIP) casting techniques while the SB bridge will be constructed using precast (PC) casting techniques. Figure 3-2 shows the NB and SB bridges? lane orientations and directions of travel. The four spans for each bridge are labeled and identified for each individual lane-span. Lane-spans that are shaded white will be constructed with traditional construction sequencing, while lane-spans that are cross hatched will be constructed with accelerated construction sequencing. Above each bridge, the deck system that corresponds to the lane-span has been identified. For referencing purposes each lane-span has been given an identification number. A particular lane-span?s identification number will be composed of the direction of travel, whether it is the inside or outside lane, and the individual bridge-lane-span number. For example the lane-span on the NB bridge, on the inside lane of span 1 will have an identification number of NBI1. 39 Figure 3-2. Plan View of I-59 Bridge Project Divided into Lanes and Lane-Spans. Data to be collected for each bridge deck replacement method will include (1) lane-span dimensions (i.e., existing and post-construction length of lane-span and area of lane-span), (2) cost, (3) schedule, and (4) traffic data (i.e., lane volumes and speeds). All data collected is considered to be raw data. The raw data will be used to calculate the following three construction performance factors: (1) unit cost, (2) production rate, and (3) road user cost (RUC). A nested analysis of variance (ANOVA) technique will be used to determine the effect that each individual bridge deck replacement method has on the construction performance factors. Southbound Bridge (precast) Northbound Bridge (cast-in-place) NCHRP Exodermic Exodermic Steel Grid Legend Accelerated Construction Sequencing Traditional Construction Sequencing Span 1 Span 2 Span 3 Span 4 SBI1 SBI2 SBI3 SBI4 NBI1 NBI2 NBI3 NBI4 NBO1 NBO2 NBO3 NBO4 SBO1 SBO2 SBO3 SBO4 Inside Lane Outside Lane Outside Lane Inside Lane Direction of Vehicle Travel N 40 References for data collection include reported values from the contractor, inspector project diaries, visual inspection of the project via EarthCam construction camera technology, the ALDOT plans set, and traffic data collected by the RTMS G4. A survey will be administered at the completion of the project to gather feedback from the contractor on their experience with each bridge deck replacement method. This feedback is intended to gather any additional information about the bridge deck replacement methods that were not captured by the data collected. Such information could include ease of construction or factors beyond the contractor?s control that may have had an impact on construction. 3.2 I-59 Bridge Dimensions Dimensions for all lane-spans have been calculated from the ALDOT plan set for Project No. BR-1059 (I-59 Collinsville). Two additional girders will be added to the previous existing four girders for a total of six girders at completion, to accommodate the widening of the bridge. The addition of substructure and superstructure elements associated with the bridge widening is not being considered in this research effort and corresponding data will not be collected. This research is solely focused on data associated with the demolition or construction of the bridge deck. The length of each span was calculated using ALDOT surveying station information from the plan set. The stations were marked along the centerline of each bridge. The deck width was measured from the longitudinal construction joint to the outside edge of the shoulders. Because the construction joint is located off-center, individual outside lane-span deck widths to be demolished and constructed are greater than the deck width of individual inside lane-spans. A 41 typical existing and post-construction inside lane-span deck width is 12.58 ft (3.8 m) and 19.38 ft (5.87 m) respectively. While, a typical existing and post-construction outside lane-span deck width are 20.58 ft (6.24 m) and 27.38 ft (8.3 m) respectively. The total existing lane-span deck width is 33.2 ft (10.1 m) and the total post-construction lane-span deck width is 46.76 ft (14.2 m). The area of the existing lane-span is determined by lane-span width multiplied by the length of the lane-span, calculated from dimensions included in the ALDOT plan set. Similarly, the area of the post-construction lane-span deck has been calculated as the constructed lane-span width multiplied by the length of the lane-span under consideration. Table 3-1 provides a complete summary of all lane-span deck dimensions (i.e., length, width, and area). These values are calculated based on the dimensions shown on ALDOT plan sheets and should be confirmed by the contractor during the course of the construction effort. Lanes identified with an asterisks could have varying areas due to the skew of the bridge. 42 Table 3-1. Lane-Span Dimensions for Northbound/Southbound Bridges Existing Post Construction Lane Span ID Length (ft) Width (ft) Area(ft2) Width(ft) Area(ft2) NBI1 56.83 12.58 714.9 19.38 1101.4 NBI2* 56.00 12.58 704.5 19.38 1085.3 NBI3* 56.00 12.58 704.5 19.38 1085.3 NBI4 56.83 12.58 714.9 19.38 1101.4 NBO1 56.83 20.58 1169.6 27.38 1556.0 NBO2* 56.00 20.58 1152.5 27.38 1533.4 NBO3* 56.00 20.58 1152.5 27.38 1533.4 NBO4 56.83 20.58 1169.6 27.38 1556.0 SBI1 56.83 12.58 714.9 19.38 1101.4 SBI2 56.00 12.58 704.5 19.38 1085.3 SBI3 56.00 12.58 704.5 19.38 1085.3 SBI4 56.83 12.58 714.9 19.38 1101.4 SBO1 56.83 20.58 1169.6 27.38 1556.0 SBO2 56.00 20.58 1152.5 27.38 1533.4 SBO3 56.00 20.58 1152.5 27.38 1533.4 SBO4 56.83 20.58 1169.6 27.38 1556.0 Note: NBI(#) - Northbound inside (lane-span number) NBO(#) ? Northbound outside (lane-span number) SBI(#) - Southbound inside (lane-span number) SBO(#) - Southbound outside (lane-span number) Demolition and construction will occur off-center from the centerline of the bridge, creating inside lane-span dimensions that are smaller than outside lane-span dimensions. By performing construction off-center, the new construction joint of the lane-spans will occur over the center of a girder providing the joint more stability during construction. The longitudinal construction joint is identified as the location where individual lane-spans will join, progressing in the longitudinal direction of travel. Figure 3-3 below shows a typical existing and post-construction cross-section of the longitudinal construction joint over the existing girder. 43 (a) Existing Deck Conditions (b) Post Construction Deck Conditions Figure 3-3. Elevation Views of Longitudinal Construction Joint. During work activity, the longitudinal construction joint will be protected from vehicular traffic by temporary concrete barriers (TCBs). During traditional construction sequencing, one row of TCBs will be used to divide the lanes into a work space and traffic space to protect the construction joint from vehicular traffic. Figure 3-4 shows the placement of TCBs for an inside lane under traditional construction sequencing. Construction Joint Girder Construction Joint Girder 44 Figure 3-4. Traditional Construction Sequence TTC Concrete Barrier Placement. During accelerated construction sequencing there will be a period during construction that both the inside and outside lanes will be open for travel. To accomplish periods with two travel lanes while continuing to protect the construction joint, three rows of TCB will be used. Figure 3-5 shows the location of TCB being used during accelerated construction sequencing scenarios. Figure 3-5. Accelerated Construction Sequencing TTC Concrete Barrier Placement. At decking completion a permanent guard rail will be installed at the edge of the new decking, reducing the actual lane width by 1.38 ft (0.42 m) as seen in Figure 3-5 Construction Joint Girder Concrete Barrier Girder Construction Joint Temporary Concrete Barriers Concrete Barrier Permanent Guard Rail 45 3.2.1 Northbound (NB) Bridge Deck Details All lane-span construction on the NB bridge will be accomplished with CIP techniques. For NB lane-spans 1 and 2, both the inside and outside lanes will be built with Exodermic deck systems. For NB lane-spans 3 and 4, both the inside and outside lanes will be reconstructed with Steel Grid deck systems. All work performed on the inside lane of the NB bridge will be done with a traditional construction sequence; while all work accomplished on the outside lane will be performed with an accelerated construction sequence. Work accomplished in a traditional construction sequence, will be performed in the direction of travel. Work completed with an accelerated construction sequence on the NB bridge, outside lane, will be performed in the opposing direction of travel. The reason for having work activity progress in the opposing direction of vehicle travel, during accelerated construction sequencing, is so the oncoming end of the permanent existing barrier rail system can stay in place as long as possible. By using the existing barrier rail, the contractor does not have to protect the blunt end of a temporary barrier from oncoming traffic. Figure 3-6 shows the lane-span details for the NB bridge with arrows identify the direction of travel and reconstruction work activity. 46 Figure 3-6. Northbound Bridge Span Construction Details. 3.2.2 Southbound (SB) Bridge Deck Details All bridge deck replacement methods on the SB bridge will use PC techniques. Both SB inside and outside lane-spans 1 and 2 will be built with NCHRP deck systems. Likewise, both SB inside and outside lane-spans 3 and 4 will be constructed with Exodermic deck systems. All inside lane construction sequencing for the SB bridge will employ traditional construction sequencing, while the outside lane will employ accelerated construction sequencing. All work accomplished in a traditional construction sequence, inside lane on the SB bridge, will be performed in the direction of vehicle travel. All work completed in an accelerated construction sequence, outside lane on the SB bridge, will be performed in the opposing direction of vehicle travel. As previously stated, the purpose for working in the direction opposing travel, during the accelerated construction sequence, is to consider motorist safety by maintaining the permanent Northbound Bridge (cast-in-place) Span 1 Span 2 Span 3 Span 4 Exodermic Steel Grid Legend Accelerated Construction Sequence Traditional Construction Sequence Direction of Vehicle Travel Direction of Deck Reconstruction Inside Lane Outside Lane N NBI1 NBI2 NBI3 NBI4 NBO1 NBO2 NBO3 NBO4 47 features of the oncoming end of the existing guard rail as long as possible. Figure 3-7 shows the lane-span details for the SB bridge with arrows indicating the direction of travel and reconstruction work activity. Note: Arrows on bridge lane-spans represent the direction work will progress. Figure 3-7. Southbound Bridge Span Construction Details 3.3 Data Collection Location For data collection purposes, only items that are used during construction, located in the activity area, (e.g., bridge deck materials, equipment, labor, and temporary concrete barrier) will be considered for cost, schedule, and traffic data. For this thesis the activity area is defined to begin at the beginning bridge deck station and end at the end bridge deck station. Span 1 Span 2 Span 3 Span 4 NCHRP Exodermic Legend Accelerated Construction Sequence Traditional Construction Sequence Southbound Bridge (precast) Outside Lane Inside Lane Direction of Vehicle Travel Direction of Deck Reconstruction N SBO1 SBO2 SBO3 SBO4 SBI1 SBI2 SBI3 SBI4 48 3.4 Data Collection The data that will be collected for each bridge deck replacement method will include the cost, schedule, and traffic data. Cost and schedule have been further subdivided into three work activities: (1) TCB, (2) demolition, and (3) construction. These activities have the greatest potential for creating a cost or schedule variance between the bridge deck replacement methods and therefore are being recorded independently. Information on each category and procedures for data collection are given in the following sections. 3.4.1 Cost Cost data will be collected for each bridge deck replacement method constructed. Cost will be collected for each TCB used within the activity area, demolition of existing lane-spans, and construction of each lane-span. This value will represent the total cost of labor, materials, and equipment required to demolish and replace a particular lane-span under consideration. 3.4.1.1 Temporary Concrete Barrier: Cost Cost of temporary concrete barrier (TCB) will include all equipment, material, and labor required to install, rearrange, and remove all TCBs under consideration within the defined activity area. All TCB cost data will be reported in dollars. Because there are four lane-spans per lane, TCB cost assigned to traditional construction sequence lane-spans will be one fourth the total lane cost of initial and final TCB installation and removal. Figure 3-8 shows an example of the installation of TCB along the longitudinal length of the bridge, dividing it into a work space and traffic space. 49 Figure 3-8. Lane Configuration of TCBs for Traditional Construction Sequence. During the accelerated construction sequencing there will be an initial and final TCB installation and deployment with additional TCB rearrangement for each lane-span. To optimize lane closure and open times, TCB will be rearranged continuously as construction advances from one lane-span to the next. The total TCB cost for a lane-span using an accelerated construction sequence will be one fourth the total lane cost, of initial and final TCB installation and removal, plus the TCB rearrangement cost occurring for individual lane-span demolition and construction activities. Figure 3-9(a) shows an image of an accelerated construction sequence lane with initial TCB installed, while Figure 3-9(b) shows the rearrangement of TCBs on lane-span 2 so demolition and construction can be performed. In example Figure 3-9, after construction is complete the TCBs will be rearranged back onto lane-span 2 and work activity will advance onto lane-span 3. Northbound Bridge (cast-in-place) Span 1 Span 2 Span 3 Span 4 Exodermic Steel Grid Legend Accelerated Construction Sequence Traditional Construction Sequence WORK SPACE TRAFFIC SPACE TCBs N NBI1 NBI2 NBI3 NBI4 NBO1 NBO2 NBO3 NBO4 50 (a) Lane Configuration of TCBs for the Accelerated Construction Sequencing. (b) Rearrangement of TCBs for the Accelerated Construction Sequence for Demolition. Figure 3-9. Lane Configuration of TCBs for Accelerated Construction Sequencing before and After Lane-Span Demolition. To keep track of all costs and fees for TCBs, Table 3-2 has been developed. The table is ordered by deck system type, construction sequence, and casting technique with the appropriate lane- Northbound Bridge (cast-in-place) Span 2 Span 3 Span 4 Exodermic Steel Grid TRAFFIC SPACE WORK SPACE 3 Rows of TCBs Span 1 N NBI1 NBI2 NBI3 NBI4 NBO1 NBO2 NBO3 NBO4 Northbound Bridge (cast-in-place) Span 2 Span 3 Span 4 Exodermic Steel Grid Legend Accelerated Construction Sequence Traditional Construction Sequence TRAFFIC SPACE3 Rows of TCBs Span 1 Demolished Deck NBI1 NBI2 NBI3 NBI4 NBO1 NBO3 NBO4 51 span identification. The researcher will record the total cost for initial and final TCB installation and removal for an entire lane in the column title ?Lane TCB?. The ?Lane TCB? cost; will be divided by four and recorded in the column labeled ?? Lane TCB?. This fee represents the shared cost for the initial deployment and removal of TCBs that are common amongst the different bridge deck replacement methods. For traditional construction sequencing the ?Total TCB? cost will be the same as the ?? Lane TCB? cost. For accelerated construction sequencing the cost for TCB rearrangement must be recorded and included in the total TCB cost. The total TCB cost will be the addition of the ?? Lane TCB? and the ?TCB Rearrangement? and will be written in the column titled ?Total TCB?. 52 Table 3-2. Northbound/Southbound Bridge TCB Cost Data Collection Summary NORTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID COST ($) Lane TCB ? Lane TCB TCB Rearrangement Total TCB Exodermic Traditional CIP NBI1 No Rearrangement Required NBI2 Accelerated CIP NBO1 NBO2 Steel Grid Traditional CIP NBI3 No Rearrangement Required NBI4 Accelerated CIP NBO3 NBO4 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID COST ($) Lane TCB ? Lane TCB TCB Rearrangement Total TCB NCHRP Traditional PC SBI1 No Rearrangement Required SBI2 Accelerated PC SBO1 SBO2 Exodermic Traditional PC SBI3 No Rearrangement Required SBI4 Accelerated PC SBO3 SBO4 53 3.4.1.2 Demolition: Cost The demolition cost for each lane-span will be reported by the contractor in dollars. The cost of demolition will include all material, labor, and equipment used in the demolition of each existing lane-span. Only cost associated with actual demolition of the bridge deck should be considered. Any demolition or preparation work performed on the bridge below the deck area is beyond the scope of this research. Table 3-3 has been created to aid researchers in the collection of demolition cost data. Table 3-3. Northbound/Southbound Bridge Demolition Cost Data Collection Summary NORTHBOUND Deck System Construction Sequence Casting Technique Lane-Span ID COST ($) Demolition Exodermic Traditional CIP NBI1 NBI2 Accelerated CIP NBO1 NBO2 Steel Grid Traditional CIP NBI3 NBI4 Accelerated CIP NBO3 NBO4 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane-Span ID COST ($) Demolition NCHRP Traditional PC SBI1 SBI2 Accelerated PC SBO1 SBO2 Exodermic Traditional PC SBI3 SBI4 Accelerated PC SBO3 SBO4 3.4.1.3 Construction: Cost The cost to construct each deck system for each lane -span will be reported by the contractor in dollars. This cost will include all labor, materials, and equipment required to construct the deck 54 system in question. The following Table 3-4 has been provided to collect construction related data for each lane-span. Table 3-4. Northbound/Southbound Bridge Demolition Cost Data Table NORTHBOUND Deck System Construction Sequence Casting Technique Lane-Span ID COST ($) Construction Exodermic Traditional CIP NBI1 NBI2 Accelerated CIP NBO1 NBO2 Steel Grid Traditional CIP NBI3 NBI4 Accelerated CIP NBO3 NBO4 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane-Span ID COST ($) Construction NCHRP Traditional PC SBI1 SBI2 Accelerated PC SBO1 SBO2 Exodermic Traditional PC SBI3 SBI4 Accelerated PC SBO3 SBO4 3.4.2 Schedule Scheduling for all lane-span activities will be recorded in hours. This time will represent the total time required to reproduce the activity under consideration. Scheduling will be recorded independently for TCB, demolition, and construction. Scheduling tables have been provided in each scheduling subsection to aid in the collection of durations. 3.4.2.1 Temporary Concrete Barriers: Schedule The duration or total time of project spent installing and removing TCBs will be recorded in hours. Total lane duration of initial deployment and final removal of TCBs will be shared by all 55 four lane-spans in the activity lane. The duration for installation and removal of TCBs for traditional construction sequence lane-spans will be one fourth the total duration for deployment and removal of TCBs. The previous Figure 3-8 shows the typical lane configuration of TCB deployment for a traditional construction sequence within the activity area. For accelerated construction sequence bride deck replacement methods, the total duration for deployment, rearrangement, and removal of TCBs will be one fourth the total duration of initial deployment and final removal of TCBs, plus the duration required to rearrange TCBs during individual lane-span construction. See Figure 3-9 in the previous section for a typical accelerated construction sequence setup. The start and finish time for all activities will be documented in the ALDOT inspector project diaries. EarthCam construction cameras may be used to verify times reported by the contractor to ensure accuracy. Table 3-5 is provided below for documenting all start and finish times and to calculate total durations for all TCB deployment, rearrangement, and removal activities. Durations will be reported as the period that elapsed between the start and finish time. For traditional construction sequence the lane-span TCB duration is one quarter the total lane TCB duration. There are no TCB rearrangement times in traditional construction sequencing. 56 Table 3-5. Northbound/Southbound Bridge TCB Schedule Data Collection Summary NORTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Lane TCB Rearrangement TCB Total (hrs) Start Time Finish Time Duration (hr) ? Duration (hr) Start Time Finish Time Durations (hrs) Exodermic Traditional CIP NBI1 No Rearrangement Required NBI2 Accelerated CIP NBO1 NBO2 Steel Grid Traditional CIP NBI3 No Rearrangement Required NBI4 Accelerated CIP NBO3 NBO4 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Lane TCB Rearrangement TCB Total (hrs) Start Time Finish Time Duration ? Duration Start Time Finish Time Durations (hrs) NCHRP Traditional PC SBI1 No Rearrangement Required SBI2 Accelerated PC SBO1 SBO2 Exodermic Traditional PC SBI3 No Rearrangement Required SBI4 Accelerated PC SBO3 SBO4 57 3.4.2.2 Demolition: Schedule The duration of time spent demolishing existing decking will be collected by the project inspectors in hours and will be recorded in their diaries for each individual lane-span. This data will be collected by recording the start and finish time of demolition activity for each lane-span. The duration will be reported as the time elapsed between start and finish times. The EarthCam video surveillance equipment may be used to verify all time values recorded. Table 3-6 should be used to collect and document start and finish times and calculate lane-span demolition durations. Table 3-6. Northbound/Southbound Bridge Demolition Schedule Data Collection Summary NORTHBOUND Deck System Construction Sequence Casting Technique Lane- Span ID Demolition Start Time Finish Time Durations (hrs) Exodermic Traditional CIP NBI1 NBI2 Accelerated CIP NBO1 NBO2 Steel Grid Traditional CIP NBI3 NBI4 Accelerated CIP NBO3 NBO4 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane- Span ID Demolition Start Time Start Time Durations (hrs) NCHRP Traditional PC SBI1 SBI2 Accelerated PC SBO1 SBO2 Exodermic Traditional PC SBI3 SBI4 Accelerated PC SBO3 SBO4 58 3.4.2.3 Construction: Schedule Construction duration will follow demolition duration and include all the time required to form, pour, place, and cure each bridge deck replacement method. The construction start time for each lane-span will be recorded by the inspector and reported in their daily inspection reports. Construction will be considered finished once the bridge deck replacement method is identified as structurally capable of sustaining motor vehicle travel. This period may be prior or post permanent guard rail installation. The time that the lane-span is designated as structurally sound will be identified and reported by the inspector as the finish time of construction. The duration of construction for each bridge deck replacement method will be reported as the elapsed time from start to finish of construction activity. Table 3-7 should be used to track the start and finish time of construction activity and to calculate the bridge deck replacement method construction durations. 59 Table 3-7. Northbound/Southbound Bridge Construction Schedule Data Collection Summary NORTHBOUND Deck System Construction Sequence Casting Technique Lane- Span ID Construction Start Time Finish Time Durations (hrs) Exodermic Traditional CIP NBI1 NBI2 Accelerated CIP NBO1 NBO2 Steel Grid Traditional CIP NBI3 NBI4 Accelerated CIP NBO3 NBO4 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane- Span ID Construction Start Time Start Time Durations (hrs) NCHRP Traditional PC SBI1 SBI2 Accelerated PC SBO1 SBO2 Exodermi c Traditional PC SBI3 SBI4 Accelerated PC SBO3 SBO4 3.4.3 Traffic Data Prior to construction activity on the I-59 bridges, ?before? construction traffic values were collected using the RTMS G4 devices. ?Before? construction traffic values included traffic volumes and speeds on the I-59 bridges during normal two lane operating conditions. The RTMS G4 devices were deployed in a sidefire position along the roadway in three locations for traffic data collection. Data were collected over a seven-day week for both the NB and SB bridges. The trailers were deployed twice prior to construction, once for the NB direction and once for the SB direction in advance of the bridges. The traffic collections on the NB bridge were at mile markers 202.1, 204.4, and 204.6. The traffic collections on the SB bridge was 60 located in the vicinity of mile marker 205.3, 205.8, and 207.0. These collection locations were used to capture traffic prior to and in the transition areas. In Figure 3-10 the trailer locations are represented by stars for the NB and SB bridges respectively. The directions of vehicle travel and the orientation of the entrance and exit ramps have been identified. *Not to scale Figure 3-10. RTMS G4 Traffic Collection Locations. The data were separated into two vehicle classifications, passenger vehicles and trucks, for later RUC estimating. The RTMS units identified classification by vehicle length. Passenger vehicle is any vehicle that was less than 46.9ft (14.2m) and truck is any vehicle greater than 46.9ft (14.2m). This vehicle classification was determined from the AASHTO publication ?Geometric Design of Highways and Streets?. From the collected traffic data for the NB and SB bridges, average vehicle volumes and speeds were calculated for three possible closure scenarios. The three possible work closure scenarios are (1) a weekday closure with a full 24 hour closure, (2) a weeknight closure with a 12 hour work period (e.g., closure occurs on Tuesday at 6pm and reopens on Wednesday at 6 am), (3) a weekend closure (i.e. closure occurs on Friday at 6 pm and reopens to traffic Monday at 6 am). The weekend and weeknight closures will be possible with Activity Area N Southbound Bridge Northbound Bridge 202.1 204.4 204.6 205.3 205.8 207.0 205.0 61 TCB rearrangement. The volume and speed data calculated from the RTMS G4 traffic data collection can be seen on Table 3-8. The weekend volume is based on a 60 hour weekend period. The values in Table 3-8 represent a typical weekday, weeknight, and weekend vehicle volumes and speeds for the six individual collection points collected with the RTMS G4 devices. To calculate weekday volumes and speeds, the average vehicle volumes and speeds for Tuesday, Wednesday, and Thursday were used. Likewise, the non-peak vehicle volumes (i.e. 6pm to 6am) were used for Tuesday, Wednesday, and Thursday to calculate weeknight vehicle volumes and speeds. Weekend vehicle volumes and speeds were calculated as the average of the six RTMS G4 collections points for the period of Friday at 6pm to Monday at 6am. Table 3-8. Northbound/Southbound Traffic Data by Work Closure Period Time of Day Vehicle Volume Speed (mph) Passenger Vehicle Truck Total Passenger Vehicle Truck Weekday (24hr) 7,974 4,164 12,138 75 77 Weeknight (12hr) 2,314 1,328 3,644 66 70 Weekend (60hr) 27,120 5,984 33,104 77 79 During the I-59 project the RTMS G4 devices will be deployed again at the predetermined locations to capture traffic data (vehicle volumes and the corresponding traveling speeds). This data will be compared to the before construction values gathered prior to the start of the I-59 project to determine road user costs (RUC). Further details will be provided for calculating RUC in Chapter 4. 3.5 Summary of Methodology & Data Collection For each bridge deck replacement method constructed on the I-59 project, four areas required data to be collected. Those four areas include: (1) lane-span dimensions (length of lane-span, areas of lane-span both existing and post-construction), (2) cost, (3) schedule, (4) traffic data 62 (volumes and speeds). Cost and schedule data have been further subdivided into TCBs, demolition, and construction activity. Using the bridge dimensions and the American Association of State Highway and Transportation Officials (AASHTO) publication ?User Benefit Analysis for Highways Manual? three construction performance factors will be created, those three factors being, (1) unit cost, (2) production rate, and (3) RUC. From the construction performance factors, statistical analyses will be performed using nested analysis of variance (ANOVA) statistical testing. All subsection raw data tables described and found in this chapter should be compiled into one summary table as seen in Table 3-9 below for use in Chapter 4. 63 Table 3-9. Northbound/Southbound Bridge Comprehensive Raw Data Summary NORTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length Construction Area (ft2) Cost ($) Schedule (hrs) T.D. Exist Post TCB Demo Const TCB Demo Const Veh Vol Exodermic Traditional CIP NBI1 56.83 NBI2 56.00 Accelerated CIP NBO1 56.83 NBO2 56.00 Steel Grid Traditional CIP NBI3 56.00 NBI4 56.83 Accelerated CIP NBO3 56.00 NBO4 56.83 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length Construction Area (ft2) Cost ($) Schedule (hrs) T.D. Exist Post TCB Demo Const TCB Demo Const Veh Vol NCHRP Traditional PC SBI1 56.83 SBI2 56.00 Accelerated PC SBO1 56.83 SBO2 56.00 Exodermic Traditional PC SBI3 56.00 SBI4 56.83 Accelerated PC SBO3 56.00 SBO4 56.83 Note: *Exist ? Existing Construction Area *TCB ? Temporary Concrete Barrier *Demo - Demolition *Const ? Construction *T.D. Veh Vol ? Traffic Data Vehicle Volume 64 Chapter Four Data Analysis Techniques 4 Data Analysis Techniques 4.1 Introduction The purpose of this chapter is to develop techniques to be applied to perform data analyses on data collected during the construction of the I-59 bridges in Collinsville. The analysis of the data collected will be used to determine the interaction between bridge deck replacement methods and the construction performance factors being tested. Results will be compiled for the I-59 project that summarizes all analyses performed. From the results it will be possible to infer which bridge deck replacement methods would be most viable on future bridge projects, based on geographic, project specific and monetary constraints. The results will be demonstrated and interpreted in four main sections, (1) Gantt charts, (2) summary of construction performance factors, (3) nested analysis of variance (ANOVA) tests with interaction tree diagrams, and (4) a contractor exit survey. The following sections will outline the steps and analyses required to compile the results mentioned above. 4.2 Gantt Charts Scheduling data will be used, from the I-59 project, to create Gantt (bar) charts for each lane (i.e., inside or outside lane) under construction. The Gantt charts will show the construciton process from beginning to end and they will be used to compare different construction sequence lane closure strategies. The Gantt charts will graphically depict the total lane closure period(s), work performed during peak and non-peak hours, vehicle volumes, and the flow of the scheduled 65 tasks. This will highlight the advantages and disadvantages of traditional and accelerated construction sequence scenarios. Total lane closure duration will be the period of time that the lane being reconstructed is closed from vehicular traffic until it is reopened. In traditional construction sequencing, this time period will be continuous from the deployment of temporary concrete barriers (TCBs) to final TCB removal. In contrast, accelerated construction sequencing lane closures will occur intermittently as the lane opens and closes for each reconstruction activity to be performed on individual lane- spans. The total lane closure for the accelerated construction sequence will be the sum of the closures and rearrangement of TCBs for all individual lane-spans to be reconstructed, plus the initial and final closures associated with TCB deployment and removal. Figure 4-1 illustrates a typical Gantt chart for a cast-in-place (CIP) traditional construction sequence lane closure for the I-59 project. Note: * The work period for this example is a 12 hour work day * Only work activity is shown, but each day represents a 24 hour lane closure unless noted otherwise * Number in parenthesis in the ?Lane Closure? column are shared TCB values Figure 4-1. Typical Traditional Construction Sequence Gantt Chart. Lane-Span Deck System * TCB Installation 1 1 1 Exodermic 5 7.5 6 18.5 (0.5) 2 Exodermic 4.5 6 17.5 (0.5) 3 Steel Grid 4.5 6 17.5 (0.5) 4 Steel Grid 4 6 16.5 (0.5) * TCB Removal 1 1 Vehicle Volume 55791 Lane Closure (hrs.) 13000 13000 13000 13000 3791 7 6.5 Day 1 Day 2 Day 3 Day 4 Day 5 7 6, 69 6, 69 6,069 6, 69 1, 70 26,046 Legend: TCB Demolition Construction Cure 66 Figure 4-1 illustrates the activities TCB deployment/removal, demolition, construction, and concrete curing time. For CIP casting techniques the curing time will be absorbed into the construction aspect of the performance factors. The number values on the various bars indicate hours spent on that particular work activity. The work schedule developed in this example was for a typical, 12 hour work period during daytime conditions. However, it should be noted that each day interval represents a 24 hour lane closure period when employing traditional construction sequencing. The TCB deployment and TCB removal is a shared value, divided equally among all lane spans in the reconstruction lane. The shared time is indicated in parenthesis next to the lane closure times for each bridge deck replacement method. Directly below the TCB removal activity are the reported average vehicle volumes for each work period. In the above example the weekday traffic volume of 6,069 vehicles from Table 3-8 were used for each 24 hour period. In the example, the final day (Day 5) consisted only of 7 hours of work activity. A ratio of a 24 hour vehicle volume was applied to a 7 hour work period to get a vehicle volume of 1,770. Work activity is considered complete at the end of Day 5 and all TCB have been removed from the bridge no longer affecting the motoring public. Work could occur during weekdays, weekends, or weeknights. The decision as to which work schedule will be used, will be decided by ALDOT and the contractor at the time of actual construction of the I-59 project. Each work scenario will have a different effect on the total lane closure period. An example problem will be created in Chapter 5 that assumes a traditional construction sequence lane, with a weekday closure, and an accelerated construction sequence 67 lane, with a weekend closure, to determine the affect of the bridge deck replacement methods on the construction performance factors of: unit cost, production rate, and RUC. 4.3 Normalizing Collected Data Before analysis, the raw data collected must be normalized into the construction performance factors: unit cost, production rate, and RUC. For this particular project, normalizing is required and is a process which accounts for the slight differences in areas so comparisons can be made between the construction performance factors. Cost and schedule data will be normalized by the lane-span geometry to create unit costs and production rates. RUC will be estimated with the aid of the RTMS G4 data collected and guidelines from the American Association of State Highway and Transportation Officials (AASHTO)?User and Non-User Benefit Analysis For Highways? manual. Normalizing the collected data is performed for two reasons: (1) it accounts for the difference in inside and outside lane areas, and (2) it allows the research to be applicable to similar scale bridge deck replacement projects for future comparisons. As discussed in Chapter 3, due to the location of the construction joint, the inside and outside lane areas are different. On both bridges the inside lane is roughly 8 ft (2.4 m) smaller than the outside lane. If normalizing were not performed it would not be possible to compare the cost and schedule data of each bridge deck replacement method for each individual lane-span. 4.3.1 Unit Cost The unit cost represents the cost in ($/ft or ft2), normalized by the dimensions of the bridge , required to produce a bridge deck replacement method on one lane-span of the I-59 bridges. Unit cost has been independently calculated for TCB, demolition, and construction activity. 68 TCB unit cost is calculated as the total cost spent for concrete barriers for a lane-span divided by the linear length of the lane-span. The TCB unit cost is reported in dollars per foot ($/ft). Equation 4-1 below shows the calculation for determining TCB unit cost. $ TCB Cost ($)TCB Unit Cost ft Lane -Span Length (ft)? ? =? ?? ? (4-1) Demolition unit cost will be calculated as the total cost for demolition of an individual lane-span divided by the area of existing deck of the lane-span under consideration. The demolition unit cost will be reported in dollars per square foot of existing deck ($/ft2). Equation 4-2 will be used to calculate the demolition unit cost. 2 2$ Demolition Cost ($)Demolition Unit Cost ft Existing Lane -Span Area (ft )? ? =? ?? ? (4-2) Construction unit cost will be calculated as the total cost required to construct the lane-span under consideration with the appropriate deck system. This cost will include all labor, materials, and equipment that was required to construct a lane-span that was structurally capable of carrying vehicles. The construction unit cost, seen in equation 4-3, will be reported in dollars per square foot of post lane-span area ($/ft2). 2 2$ Construction Cost ($)Construction Unit Cost ft Post Lane -Span Area (ft )? ? =? ?? ? (4-3) 4.3.2 Production Rate Production rate has been independently calculated for TCB, demolition, and construction activity. The production rate will indicate the amount of the construction performance factor that could be reproduced in a period of time. 69 TCB production rate will be calculated as the linear length of a lane-span divided by the total duration of time spent installing or removing TCB for the lane-span in question. The production rate for TCB will be reported in feet per hour (ft/hr). Equation 4-4 is used to determine a bridge deck replacement method?s TCB production rates. ft Lane -Span Length (ft) TCB Pr oduction Rate hr TCB Duration (hr)? ? =? ?? ? (4-4) Demolition production rate will be determined by dividing the existing lane-span area by the total duration spent on the demolition process of a single lane-span. Demolition production rate will be reported in square feet per hour (ft2/hr). Equation 4-5 is used to calculate demolition production rates. 2 2ft Existing Lane -Span Area (ft ) Demolition Pr oduction Rate hr Demolition Duration (hr)? ? =? ? ? ? (4-5) Construction production rate will be calculated by dividing the post construction area by the total duration of the construction period for each lane-span. Construction production rate will be calculated using equation 4-6 and reported in square feet per hour (ft2/hr). 2 2ft Post Lane -Span Area (ft ) Construction Pr oduction Rate hr Construction Duration (hr)? ? =? ? ? ? (4-6) 4.3.3 Road User Cost The traffic data of volumes and speeds collected with the RTMS G4 will be used to determine a RUC for each lane. RUC is a function of the delay experienced per vehicle that travels through the activity area of the I-59 project. For this methodology only the delay aspect of RUC is being considered. Alternative routes are not a part of the RUC for this research. It was assumed that the construction activity would not divert vehicles from using the I-59 bridges. The ALDOT 70 temporary traffic control plan has the potential to create delay to the motoring public traversing the work zone. This delay typically comes in the form of one or both of the following, (1) enforced lower work zone speed limits, and (2) traffic congestion reducing vehicle flow due to the closure of travel lanes. Since the I-59 project is located on a very low-volume interstate segment, the only delay expected to be experienced will come from an enforced lower work zone speed. In a high-volume road network, delay could be expected from both lower work zone speeds and vehicle congestion from lane closures. RUC is divided into two parts: (1) value of time of the occupants per vehicle and (2) the operating and ownership cost per vehicle. To determine the value of time aspect the researcher must gather average hourly wages by industry type for the geographic location in question. Based on the transportation mode and trip purpose the average hourly wage is adjusted by a percentage factor. Next, the researcher must determine the average vehicle occupancy. This is performed by visual inspection of the vehicles traveling the project location. Average values for the information stated above can be found in Chapter 5 of the AASHTO manual. It is recommended that the AASHTO manual be consulted when estimating all value of time information. The value of time is determined by the product of the average hourly wage, percentage of hourly wage, and average vehicle occupancy and is reported in dollars per vehicle hour ($/veh-hr). Equation 4-7 below can be used to calculate the value of time per vehicle hour. $Value of Time per Hour Wage Percentage Occupancyveh - hr? ? = ? ?? ?? ? (4-7) 71 To calculate the operating and ownership cost the following information is required: finance rate, other operating costs per mile (tires, maintenance, etc.), vehicle service life (years), vehicle cost, salvage value at end of service life, and insurance per year. Again, the AASHTO manual offers guidance for estimating all the operating and ownership cost stated. With this information the amortized vehicle cost per hour and the insurance cost per hour can be calculated. The amortized vehicle cost per vehicle hour ($/veh-hr) or the depreciation value is determined by applying equation 4-8. The value 8,760 is a conversion factor used to convert years to hours. n n $ (i (P(1 i) - F)Amortized Cost per Vehicle Hour / 8,760 veh - hr (1 i) -1) ? ?+? ? = ? ? ? ?+? ? ? ? (4-8) Where: i = Finance rate P =Vehicle Cost ($) F = Salvage Value ($) n = vehicle life in years The insurance cost per hour is calculated by simply dividing the insurance cost per vehicle hour by the number of hours in a year. Equation 4-9 is used to determine insurance cost per vehicle hour ($/veh-hr). $ insurance cos t per yearInsurance Cost per Vehicle Hour veh - hr 8,760? ? =? ?? ? (4-9) Equation 4-10 is used to calculate the total cost per vehicle hour ($/veh-hr) which is the addition of the value of time, amortized value, and the insurance cost per vehicle hour. This value will be multiplied by the travel time before and during lane closures to determine a final RUC. $Total Cost per Vehicle Hour Value of Time Amortized Insuranceveh - hr? ? = + +? ?? ? (4-10) 72 The travel time for the before lane closure is calculated by dividing the segment length, in feet, by the average travel speed before closure, in miles per hour, of the vehicle classification in question. Likewise, the travel time per vehicle during lane closures is calculated by dividing the segment length, in feet, by the average travel speed during closer, in miles per hour, of the vehicle classification in question. It is expected that the before lane closure average travel speed is greater than the during lane closure travel speed. This will be a result of the regulatory reduced work zone speed limit. Therefore it is expected that the travel time before the lane closure will be less than the travel time during the lane closure. Given the low-volume of the I- 59 location, possible delay from queuing will not be considered in this research. Equation 4-11 shows how to calculate the travel time associated with both before and during lane closures. The value 5,280 is a conversion factor used to convert feet to miles, while 3,600 is a conversion factor used to convert hours to seconds. The travel time is reported in seconds. Segment length (ft) 3,600Travel Time (sec) 5,280 Speed (mph)? ?? ?= ?? ?? ?? ? ? ? (4-11) Once travel time has been determined for both before and during lane closures, the cost per vehicle can be calculated. This is accomplished by multiplying the total cost per vehicle hour, determined with equation 4-10, by the before and during travel time values calculated in Equation 4-11. Equation 4-12 is used to calculate cost per vehicle for both before and during lane closure. $ Total Cost per veh - hrCost per Vehicle x Delayveh 3,600? ?? ? =? ? ? ?? ? ? ? (4-12) The realized cost per vehicle is calculated by subtracting the cost per vehicle before the lane closure from the cost per vehicle during the lane closure. The realized cost represents the monetary value, had there been no delay from regulatory reduced work zone speed limits, the 73 motorist incurs as a result of the work zone conditions. Equation 4-13 is used to determine the realized cost per vehicle. $Realized Cost per Vehicle Cost After Lane Closure Cost Before Lane Closure veh ? ? = ?? ? ? ? (4-13) To calculate RUC for each lane and vehicle classification, the volume of vehicles that traversed the lane during the construction effort is multiplied by the realized cost per vehicle and the percentage of vehicle classification. Lane RUC ($) Re alized Cost Volume Class Percentage= ? ? (4-14) The volumes and speeds of the vehicles before construction have already been collected. During the actual I-59 project the RTMS G4 devices will be used to determine the volumes and speeds of vehicles during construction. The RUC will be reported for each lane as a dollar amount ($). Because each lane-span contributes to the total project closure, the total RUC will be shared as a percentage of the total closure for each lane-span. Lane-span closure will be calculated as lane- span duration divided by total lane-span closure multiplied by lane RUC from equation 4-14. See equation 4-15 for lane-span RUC. Lane-Span Duration (hr)Lane -Span RUC ($) Lane RUC ($)Total Lane-Span Duration (hr)? ?= ?? ? ? ? (4-15) A RUC template has been created to aid the researcher in organizing and calculating a RUC for each lane. The template follows the steps detailed in equations 4-7 through 4-14. A blank template is located in Appendix A. In the RUC template, vehicles have been divided into two classifications, passenger vehicles and trucks. Passenger vehicles represent any vehicle shorter than 46.9 ft (14.2m) in length, while trucks are any vehicle greater than 46.9 ft (14.2m) in length. 74 Once the unit cost, production rate, and RUC have been created, a summary table of the construction performance factors will be compiled. Table 4-1 demonstrates how a summary table of the construction performance factors should be organized. 75 Table 4-1. Northbound/Southbound Bridge Construction Performance Factors NORTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length Construction Area (ft2) Unit Cost Production Rate RUC Exist Post TCB ($/ft) Demo ($/ft2) Const ($/ft2) TCB (ft/hr) Demo (ft2/hr) Const (ft2/hr) ($) Exodermic Traditional CIP NBI1 56.83 NBI2 56.00 Accelerated CIP NBO1 56.83 NBO2 56.00 Steel Grid Traditional CIP NBI3 56.00 NBI4 56.83 Accelerated CIP NBO3 56.00 NBO4 56.83 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length Construction Area (ft2) Unit Cost Production Rate RUC Exist Post TCB ($/ft) Demo ($/ft2) Const ($/ft2) TCB (ft/hr) Demo (ft2/hr) Const (ft2/hr) ($) NCHRP Traditional PC SBI1 56.83 SBI2 56.00 Accelerated PC SBO1 56.83 SBO2 56.00 Exodermic Traditional PC SBI3 56.00 SBI4 56.83 Accelerated PC SBO3 56.00 SBO4 56.83 Note: *Exist ? Existing Construction Area *TCB ? Temporary Concrete Barrier *Demo - Demolition *Const ? Construction *RUC ? Road User Cost 76 4.4 Nested ANOVA Statistical Procedure The construction performance factors will be processed with a nested ANOVA statistical test. The ANOVA test will report validity of the model and statistical significance of the bridge deck replacement method on the construction performance factor being tested. From the ANOVA test, interaction tree diagrams will be created. The interaction tree diagrams will graphically explain the model being tested and show the nested location of the construction performance factors in relation to the bridge deck replacement methods. The I-59 project is a mutltifactor project with the bridge deck replacement methods being mixed with both shared and independent structure depending on the method under consideration. Three bridge deck replacement methods will be tested and therefore a three stage nested ANOVA design will be developed and modeled accordingly. The nesting was based on the uniqueness or shared attribute of the method under consideration. Methods that were cleary independent were nested closer to a top level while methods that were hard to independantly define were nested deeper in the model. Casting technique was chosen as the first nested level because it is clearly unique to the northbound and southbound bridges. Construction sequence was nested at the second level of the model. Unlike the casting technique the construction sequences, traditional and accelerated construction sequence, are proposed for both the northbound and southbound bridges. However, there did exist a shared aspect in the fact that each bridge?s inside lane would be constructed with a traditional construction sequence while the outside lane would be constructed with an accelerated construction sequence. Finally, deck system was nested at the third level because it had the least shared amongst each individual method for each bridge. The Exodermic deck system was shared for both the northbound and southbound bridge while each 77 bridge also received an additional deck system that was independent of the other bridge. Those deck systems being the steel grid on the northbound bridge and the NCHRP on the southbound bridge. The model for the three-stage nested design is as follows in equation 4-15. i j(i) k(ij) (ijk)l i 1,2,...,n j 1, 2,..., ny(ijkl) k 1, 2,...,n l 1,2,...,n =? ? =? = ? + ? + ? + ? + ? ? = ? ? =? (4-15) The term uni0079g4666uni0069uni006Auni006Buni006Cg4667g4667 is the dependent factor of: unit cost, production rate, or RUC. The ? is the mean of the 16 values of the performance factor in question and the g1302g4666g2919g2920g2921g4667g2922 is the usual nested identically distributed (NID) g4666uni0030uni002Cg2026g2870g4667 error term. For this model, ?i is the effect of the ith casting technique, ?j(i) is the effect of the jth construction sequence within the ith casting technique, ?k(ij) is the effect of the kth deck system within the jth construction sequence and ith casting technique. An assumption of the nested ANOVA test is that the random effects model of the ?i , ?j(i), and ?k(ij) terms are uni03B1g2919uni0020uni007Euni0020uni004Euni006Funi0072uni006Duni0061uni006Cuni0020g4666uni0030uni002Cg2026g3002g2870g4667, uni03B2g2919g4666g2920g4667uni007Euni0020uni004Euni006Funi0072uni006Duni0061uni006Cuni0020g3435uni0030uni002Cg2026g3003uni007Cg3002g2870 g3439,uni0020uni03B3g2921g4666g2919g2920g4667uni007Euni0020uni004Euni006Funi0072uni006Duni0061uni006Cuni0020g3435uni0030uni002Cg2026g3008uni007Cg3003g2870 g3439 respectively. That is to say that as the analysis moves through the nested levels each set of factors at the level is question is treated as normally distributed. The results of the factors are dependent on the stages in which it is nested. If the arrangement of the levels were changed (i.e. if construction sequence was moved to the first level) it could be expected that the ANOVA test would report different results. To understand the nested nature of the ANOVA Figure 4-2 has been created and shows the typical nested ANOVA interaction tree diagram of the design model being used. 78 Figure 4-2. Nested ANOVA Interaction Tree Diagram. The nested ANOVA test will be performed a total of seven times for the seven unique construction performance factors, from Table 4-1, across the different nested levels. Those seven construction performance factors being: (1) TCB unit cost, (2) demolition unit cost, (3) construction unit cost, (4) TCB production rate, (5) demolition production rate, (6) construction production rate, and (7) RUC. The null hypothesis (H0) will test that the mean value of the construction performance factor in question, regardless of path selected to the deck system level, are equal. This is to say that the bridge deck replacement methods have no statistical significant difference on the mean value of the factor being tested. The alternative hypothesis (Ha) will test that the path selected does result in a statistical significant difference in the mean value of the construction performance factor in question. Table 4-2 summarizes the construction performance factors and the null and alternative hypotheses that will be tested in the nested ANOVA. Deck System (?) Construction Sequence (?) Casting Technique (?) Performance Factor (y) Dependent Factor Cast-In- Place Traditional Exodermic Steel Grid Accelerated Exodermic Steel Grid Precast Traditional Exodermic NCHRP Accelerated Exodermic NCHRP 79 Table 4-2. Nested ANOVA Null and Alternative Hypothesis Test for Construction Performance Factors Construction Performance Factor Null Hypothesis (H0) Alternative Hypothesis (Ha) 1. TCB Unit Cost g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 2. Demolition Unit Cost g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 3. Construction Unit Cost g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 4. TCB Production Rate g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 5. Demolition Production Rate g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 6. Construction Production Rate g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 7. RUC g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C For each test performed, an ANOVA statistical table and an interaction tree diagram will be produced. The ANOVA statistical table will report the p-value for each bridge replacement method and the R2 value for the model being tested. The p-value will identify the effect that a bridge deck replacement method has on the overall construction performance factor being tested. Because of the limited data points for this experiment, a p-value of 0.05 or smaller will be identified as having a statistically significant difference on the mean value of the performance factor. That is to say that if this project was reproduced with the same bridge deck replacement methods on a similar scale project, 95 % of the future construction performance factors would be within ? 1.96 standard deviations of the mean of the construction performance factors that were analyzed in this research. The R2 value reports the goodness-of-fit of the model. A goodness-of-fit statistic is a quantity that measures how well a model explains a given set of data. The acceptable tolerance of the goodness-of-fit for this research is set at a value of 0.60, where any model that results in an R2 value below 0.60 will be classified as an inaccurate model and researchers can not accurately draw any conclusions from the accompanied p-values. The R2 value of 0.60 is generally accepted in 80 statistics as a threshold for goodness-of-fit and was seen in the literature review as used by researchers performing comparison analysis, specifically Chan and Kumaraswamy. Interaction tree diagrams will be created to give a reference for the magnitude of cost in the ANOVA test. Under each node on the interaction tree diagram the mean and standard deviation will be presented. On the far right of the interaction tree diagram the p-value, determined in the ANOVA test, will be reported. ANOVA statistical table and interaction tree diagram will be described in more detail in the hypothetical example problem produced in the following chapter. 4.5 Contractor Exit Survey Upon completion of the I-59 project a survey will be administered to the contractor. The survey will ask specific questions about the construction effort of bridge deck replacement methods that were implemented on the project. The purpose of the survey is to gather vital information about each bridge deck replacement method that may not be directly represented in the raw or normalized data. Such information could include uncontrollable weather conditions that cause excessive delays to a particular lane-span. In such a case, it may be necessary to exclude that particular lane-span from further analyses and treat the data as an outlier. Other important information will include the overall impression that the contractor had of each bridge deck replacement method (i.e., was there a particular method the contractor had difficulty working with). Finally, the exit survey can be used to suggest future research topics in the field of bridge deck replacement methods and construction performance factors interactions. For the full exit survey see Appendix B. 81 4.6 Summary of Data Analysis Techniques To determine the interaction between bridge deck replacement methods and construction performance factors on the I-59 project, steps for analysis have been outlined. From the analyses, results for the bridge deck replacement methods can be compiled. The results will be divided into four main categories (1) Gantt charts, (2) summary of construction performance factors, (3) nested ANOVA tests with interaction tree diagrams, and (4) the feedback from a contractor exit survey. From the results it will be determined if all or any of the bridge deck replacement methods have a statistical significant impact of the mean value of the construction performance factors being tested. Gantt charts will be constructed using scheduling and vehicle volumes collected. No normalizing or transformation of the data will be required at that time. The Gantt charts give a graphical representation of the work activities and help explain the logical order of construction. To develop construction performance factors, the raw data that are to be collected must be normalized before actual analyses can be applied. Normalizing will be accomplished on cost and schedule by using the bridge dimensions. From this we will be able to create a unit cost and a production rate for each of the three subparts: TCB, demolition, and construction. To create the RUC, volumes and speeds must be collected both before and after lane closures. This will be accomplished with the RTMS G4 devices. The previously mentioned AASHTO manual will be referenced with the volume and speed values collected, to determine a final RUC per lane. The RUC per lane-span will be calculated as a ratio of contribution of a lane-span to the total lane closure. 82 Nested ANOVA tests can be performed after the raw data has been normalized into the construction performance factors of unit cost, production rate, and RUC. ANOVA tests will be performed seven times, once for each individual construction performance factor. From the analyses, p-values and R2 values will be reported in conjuction with an interaction tree diagram for each test. The p-value will be used to report whether a bridge deck replacement method has a statistical significant impact on the overall construction performance factor in question. The R2 value will report the goodness-of-fit of the nested ANOVA model. For this research, a p-value of 0.05 or lower will be considered as statistically significant. An R2 value of 0.60 or greater will be seen as a model that fits well enough to use the corresponding p-value to conclude statistical significance. At the completion of the I-59 project a contractor exit survey will be administered. The survey is a subjective analysis by the contractor, intended to gather important feedback that may not be reflected in the collected data. This research was originally intended to be conducted in conjunction with the actual I-59 project. However, due to setbacks beyond the control of this research team, actual construction was not able to be accomplished. To outline in greater detail the methodology detailed in this research an example problem will be produced in the following chapter. The example problem will guide the reader through all the methodologies, data collection, analyses, and results outlined in the previous chapters. 83 Chapter Five Application of Methodology 5 Application of Methodology 5.1 Introduction A hypothetical example scenario has been created to demonstrate the applicability of the methodology and statistical analysis outlined in Chapters 3 and 4 of this report. The following example will be applied to the proposed I-59 project using hypothetical construction schedules, durations, and construction costs, as a result of the actual I-59 project being delayed. The purpose of the example is to demonstrate the application of the analytical procedures developed which are used to determine the effect, using statistical testing, that the bridge deck replacement methods have on the three selected construction performance factors: (1) unit cost, (2) production rate, and (3) road user cost (RUC). The elements of each bridge deck replacement method that are being used in the analyses include: type of deck system, construction sequence, and casting technique. The bridge dimensions and lane-span identification numbers used throughout the example are identical to the actual I-59 project to be constructed in the future. Figure 5-1 shows the details of the northbound (NB) and southbound (SB) bridges used in this example. The deck system, construction sequence, casting technique, direction of vehicle travel, and lane-span identification numbers have been labeled for each bridge and are shown on Figure 5-1. 84 Figure 5-1. Plan View of the I-59 Project Divided into Lanes and Lane-Spans. For traditional construction sequence lane reconstruction, all durations values are based on an assumed 12 hour, daytime work period. For accelerated construction sequence lane reconstruction, a work closure period of Friday night at 6pm to Monday morning at 6am was assumed. The weekend vehicle volumes are based off a typical 60 hour weekend work period and will be adjusted accordingly. Table 5-1 shows volumes and speeds of both passenger vehicles and trucks that were collected using the RTMS G4 devices. Southbound Bridge (precast) Northbound Bridge (cast-in-place) NCHRP Exodermic Exodermic Steel Grid Legend Accelerated Construction Sequencing Traditional Construction Sequencing Span 1 Span 2 Span 3 Span 4 SBI1 SBI2 SBI3 SBI4 NBI1 NBI2 NBI3 NBI4 NBO1 NBO2 NBO3 NBO4 SBO1 SBO2 SBO3 SBO4 Inside Lane Outside Lane Inside Lane Outside Lane Direction of Vehicle Travel N 85 Table 5-1. Northbound/Southbound Traffic Data by Work Closure Period Time of Day Vehicle Volume Speed (mph) Passenger Vehicle Truck Total Passenger Vehicle Truck Weekday (24hr) 7,974 4,164 12,138 75 77 Weeknight (12hr) 2,314 1,328 3,644 66 70 Weekend (60hr) 27,120 5,984 33,104 77 79 Figure 5-2 is the project flow chart that will be followed throughout the example problem. Since this is a hypothetical example problem, the first step will be to develop raw, hypothetical cost, schedule, and traffic data. After the establishment of the hypothetical raw data, the data analysis procedures outlined in the thesis will be followed for data collection, data normalization, statistical analyses, and reporting of results. The report containing the results of the analyses will state the effect that each bridge deck replacement method has on the construction performance factors. The following is a detailed example problem showcasing the applicability of the methodology described above. 86 Note: *WD - Weekday Lane Closure Scenario *WN - Weeknight Lane Closure Scenario *WE ? Weekend Lane Closure Scenario Figure 5-2. Project Flow Chart For Evaluating Bridge Deck Replacement Methods. Nested ANOVA RUCProduction RateUnit Cost Dimensions AASHTO Traffic DataScheduleCost Survey Casting Technique Construction Sequence (WD/WN/WE) Deck System Bridge Deck Replacement Methods Results Data Collection Normalizing Analysis Bridge Deck Replacement Methods 87 5.2 Raw Data Development To perform an example problem, hypothetical raw data had to be developed for cost, schedule, and traffic data. Actual bridge dimensions from the I-59 project have been used in the following example. Any other similarities that exist between this example data and actual data collected in the future at the time of the I-59 project are purely coincidental. All assumptions for cost, schedule, and traffic data will be describe in the following sections. Average bid prices for TCB, demolition, and construction activities on bridge projects were researched to determine the project cost data to use for the example. 5.2.1 Bridge Dimensions As previously stated the bridge dimensions for the I-59 project were determined from the ALDOT plan set for Project No. BR-1059 (I-59 Collinsville). These dimensions were used to calculate individual lane-span dimensions (i.e. length, width, and area). A summary of the lane- span dimensions by lane span ID can be seen in Table 5-2. 88 Table 5-2. Lane-Span Dimensions for Northbound/Southbound Bridge Existing Post Construction Lane Span ID Length (ft) Width (ft) Area(ft2) Width(ft) Area(ft2) NBI1 56.83 12.58 714.9 19.38 1101.4 NBI2 56.00 12.58 704.5 19.38 1085.3 NBI3 56.00 12.58 704.5 19.38 1085.3 NBI4 56.83 12.58 714.9 19.38 1101.4 NBO1 56.83 20.58 1169.6 27.38 1556.0 NBO2 56.00 20.58 1152.5 27.38 1533.4 NBO3 56.00 20.58 1152.5 27.38 1533.4 NBO4 56.83 20.58 1169.6 27.38 1556.0 SBI1 56.83 12.58 714.9 19.38 1101.4 SBI2 56.00 12.58 704.5 19.38 1085.3 SBI3 56.00 12.58 704.5 19.38 1085.3 SBI4 56.83 12.58 714.9 19.38 1101.4 SBO1 56.83 20.58 1169.6 27.38 1556.0 SBO2 56.00 20.58 1152.5 27.38 1533.4 SBO3 56.00 20.58 1152.5 27.38 1533.4 SBO4 56.83 20.58 1169.6 27.38 1556.0 Note: NBI(#) - Northbound inside (lane-span number) NBO(#) - Northbound outside (lane-span number) SBI(#) - Southbound inside (lane-span number) SBO(#) - Southbound outside (lane-span number) 5.2.2 Cost Estimating Cost estimating was performed for TCB, demolition, and construction. Bid prices and average values were used as a reference point for hypothetical cost values. Actual cost data collected on the I-59 project once constructed, most likely will vary from estimated bid pricing submitted by the contractor during project letting. All cost values reported herein, unless otherwise noted, include all material, labor, and equipment required to perform the activity under consideration. The cost values are not intended to predict the actual I-59 project costs, but rather give guidance as to how to process the actual values collected during the I-59 project for analysis. 89 For demolition and construction activities, the concept of a learning curve will be applied where appropriate for each bridge lane. ?Many repetitive construction field operations exhibit a learning curve, over which the time or cost per cycle decreases as the cycle number increases?(Everett and Farghal 1994). As construction continues the estimated cost of subsequent lane-spans are expected to lower due to an understood learning curve concept. 5.2.2.1 Temporary Concrete Barrier: Cost Estimating To estimate temporary concrete barrier (TCB) cost, the overall bridge length was first calculated to be 225.6 ft (67.7 m). The price of a new ten foot concrete barrier was researched and determined to be $350 by the concrete barrier vendor DCC. To estimate the number of barriers required per row the bridge length was divided by the ten foot concrete barrier. It was determined that a single row of TCB required 23 concrete barriers. By multipling the number of barriers by the cost per barrier, the cost per row of TCB was determined to be $8,050/row. In traditional construction sequencing only one row of TCB is required to create a work space and a traffic space for each bridge. The cost for installing and removing the total TCB row was estimated as $8,050. Each lane-span that is in a traditional construction sequence lane shares an equal portion of the $8,050. The actual cost for each lane-span being construction under traditional construction sequence is reported as $2,013. In an accelerated construction sequence lane there are three rows of TCB required to separate the bridge into a work space and traffic space. Multiply the TCB cost per row of $8,050/row by the three rows of TCB equals a value of $24,150. This value is shared by each lane-span in the construction sequence lane. The actual cost reported for each lane-span in an accelerated 90 construction sequence lane is $6,038. Table 5-3 summarizes the TCB cost estimation for the example problem. Table 5-3. TCB Cost Estimating Summary Construction Sequence Lane TCB Cost Lane-Span TCB Cost Traditional (1 Row of TCB) $8,050 $2,013 Accelerated (3 Rows of TCB) $24,150 $6,038 5.2.2.2 Demolition: Cost Estimating From the report ?Life-Cycle Cost Survey of Concrete Bridge Decks?, ?the average cost of removal and disposal of concrete decks is $9.19 per square foot? (Anido 2001). This value was used as a reference for estimating each lane-span?s demolition cost. The assumed demolition cost is $9.19/ft2 ($100.08/m2) multiplied by the area of the lane span. An assumed learning curve will be applied for a reduction in cost of the subsequent lane-span. The second and third lane-spans? construction will receive a 5% cost reduction, while the fourth construction lane span will receive a 10% reduction. In accelerated construction sequence lanes, a reduction in cost will also be applied to each subsequent lane-span. However, it has been assumed that on a weekend closure only two lane- spans will be demolished in one weekend. Therefore, only the second constructed lane-span on each weekend will receive a 5% cost reduction from the learning curve. Table 5-4 summarizes the demolition cost values developed for each lane-span by applying the average cost per square foot of $9.19/ft2 ($100.08/m2) and the appropriate learning curve percent cost reduction. 91 Table 5-4. Demolition Cost Development Based on Assumed Learning Curve Cost Reduction NORTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length (ft) Existing Construction Area (ft2) Estimated ($/ft2) Learning Curve Reduction Demolition Cost ($) Exodermic Traditional CIP NBI1 56.83 714.9 9.19 0% 6,570 NBI2 56.00 704.5 9.19 5% 6,151 Accelerated CIP NBO1 56.83 1169.6 9.19 5% 10,211 NBO2 56.00 1152.5 9.19 0% 10,591 Steel Grid Traditional CIP NBI3 56.00 704.5 9.19 5% 6,151 NBI4 56.83 714.9 9.19 10% 5,913 Accelerated CIP NBO3 56.00 1152.5 9.19 5% 10,062 NBO4 56.83 1169.6 9.19 0% 10,749 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length (ft) Existing Construction Area (ft2) Estimated ($/ft2) Learning Curve Reduction Demolition Cost ($) NCHRP Traditional PC SBI1 56.83 714.9 9.19 10% 5,913 SBI2 56.00 704.5 9.19 5% 6,151 Accelerated PC SBO1 56.83 1169.6 9.19 0% 10,749 SBO2 56.00 1152.5 9.19 5% 10,062 Exodermic Traditional PC SBI3 56.00 704.5 9.19 5% 6,151 SBI4 56.83 714.9 9.19 0% 6,570 Accelerated PC SBO3 56.00 1152.5 9.19 0% 10,591 SBO4 56.83 1169.6 9.19 5% 10,211 92 5.2.2.3 Construction: Cost Estimating Construction cost for concrete deck systems were research and ?the average concrete deck cost was reported by twelve Department of Transportation?s (DOT?s) was $29.50 per square foot. The minimum cost reported was $20.00 per square foot and the maximum was $55.00 per square foot? (Anido 2001). When comparing the price of cast-in-place (CIP) to precast (PC) deck panels, it was found that PC panels can have an initial price 75% higher than CIP panel (Menard 2010). This information was used to estimate construction cost for the example problem. Because no actual bid prices have been given for each deck system the following unit cost were assumed from the literature. Exodermic CIP decks were estimated at the average cost of $29.50 per square foot. Steel grid was assumed at the minimum cost of $20.00 per square foot. NCHRP was priced at the maximum cost of $55.00 per square foot. The Exodermic PC deck was estimated at a price of 75% higher than the Exodermic CIP deck with a value of $52.00 per square foot. This data is hypothetical and only intended to outline how real I-59 data should be collected and processed. Table 5-5 summarizes the assumed unit cost of each deck system. Table 5-5. Assumed Deck System Construction Unit Cost Deck System Casting Technique Construction Unit Cost ($/ft2) Exodermic CIP 29.50 Steel Grid CIP 20.00 NCHRP PC 55.00 Exodermic PC 52.50 Following unit cost estimation, the learning curve principle was again applied to develop construction cost for each lane-span. The learning curve reductions for each lane-span are the same for the construction cost as they were for the demolition cost. Table 5-6 summarizes the construction cost developed, based on the assumed unit cost and learning curve reduction. 93 Table 5-6. Construction Cost Development Based on Assumed Learning Curve Cost Reduction NORTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length (ft) Post Construction Area (ft2) Estimated ($/ft2) Learning Curve Reduction Construction Cost ($) Exodermic Traditional CIP NBI1 56.83 1101.4 29.50 0% 32,491 NBI2 56.00 1085.3 29.50 5% 30,416 Accelerated CIP NBO1 56.83 1556.0 29.50 5% 43,607 NBO2 56.00 1533.4 29.50 0% 45,232 Steel Grid Traditional CIP NBI3 56.00 1085.3 20.00 5% 20,621 NBI4 56.83 1101.4 20.00 10% 19,825 Accelerated CIP NBO3 56.00 1533.4 20.00 5% 29,133 NBO4 56.83 1556.0 20.00 0% 31,120 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length (ft) Post Construction Area (ft2) Estimated ($/ft2) Learning Curve Reduction Construction Cost ($) NCHRP Traditional PC SBI1 56.83 1101.4 55.00 10% 54,519 SBI2 56.00 1085.3 55.00 5% 56,707 Accelerated PC SBO1 56.83 1556.0 55.00 0% 85,580 SBO2 56.00 1533.4 55.00 5% 80,115 Exodermic Traditional PC SBI3 56.00 1085.3 52.50 5% 54,129 SBI4 56.83 1101.4 52.50 0% 57,824 Accelerated PC SBO3 56.00 1533.4 52.50 0% 80,498 SBO4 56.83 1556.0 52.50 5% 77,606 94 Figure 5-3 summarizes the learning curve reduction percent for each lane-span for demolition and construction activity. Figure 5-3. Summary of Learning Curve Cost Reduction for Each Lane Span. 5.2.3 Schedule Estimating Reasonable average activity durations for installation/rearrangement/removal of TCB, demolition, and construction were assumed for each bridge, lane-span, and deck system. Lane span-dimensions from Table 5-2 were used as the estimating tool for calculating total time required for completing a particular activity. Southbound Bridge (precast) Northbound Bridge (cast-in-place) NCHRP Exodermic Exodermic Steel Grid Legend Accelerated Construction Sequencing Traditional Construction Sequencing Span 1 Span 2 Span 3 Span 4 N 5% 5% 0%10%Demolition Construction 5% 0% 5%0% Demolition Construction 0% 5% 0%5%Demolition Construction 5% 5% 10%0% Demolition Construction Direction of Deck Reconstruction 95 5.2.3.1 Temporary Concrete Barrier: Schedule Estimating TCB schedules were estimated for the time required to install, rearrange, and remove one row of TCBs. It was estimated that each activity: installation, rearrangement, and removal, would require 1 hour. In traditional construction sequencing only one row of TCB is required. For installation and removal it is estimated to take 2 total hours (e.g., 1 hour installation, 1 hour removal). This time will be shared by all four lane-spans equally and the reported TCB lane- span time will equal 0.5 hours. During weekend accelerated construction sequencing three rows of TCB will be required, as well as rearrangements for individual lane-spans. The weekend closure scenario assumes that there is only one rearrangement for each lane-span constructed. Therefore, 4 total hours of rearrangement for the entire lane will be required. The total estimated TCB schedule for accelerated weekend scenarios is 10 hours (6 hours for installation/removal and 4 hours for rearrangement). The lane-span TCB duration reported will be ? the total lane TCB duration (i.e. 10 divided by 4 equals 2.5 hours per lane-span). Table 5-7. TCB Schedule Estimating Summary Construction Sequence Lane TCB hours Lane-Span TCB hours Traditional (1 Row of TCB) 2 0.5 Accelerated (3 Rows of TCB) 10 2.5 5.2.3.2 Demolition: Schedule Estimating The outside lane, using accelerated construction sequencing, of both the NB and SB bridges has larger areas than the inside lane areas, using traditional construction sequencing. The initial demolition time required for an inside lane-span using traditional construction sequencing was 96 assumed to be 5 hours. This time included all cutting, jack hammering, and debris removal to prepare the lane-span for reconstruction. A learning curve of 0.5 hours was applied for the following two lane-spans for durations of 4.5 hours. The learning curve assumes that as the contractor repeats an operation he or she will become more efficient at that operation which results in requiring less time to complete the same activity. For the fourth lane-span an additional learning curve of 0.5 hours was applied, giving the fourth inside lane-span a demolition duration of 4 hours. A learning curve was also applied to the outside lanes using weekend accelerated construction sequencing. During the weekend scenario it was estimated that only two lane-spans could be demolished over this period. For this reason, additional reduction in time from the learning curve will not be applied to the third and fourth lane-span. Each weekend will start the learning curve process over. The durations required for the first and second lane-spans, of weekend accelerated construction sequence lanes, are 9 and 8.5 hours respectively. The durations for the third and fourth lane-spans, which will occur on the second weekend, are also 9 and 8.5 hours respectively. 5.2.3.3 Construction: Schedule Estimating Construction schedule estimating was accomplished by calculating the time needed for each deck system. Cast-In-Place (CIP) deck systems will require additional curing time after pouring concrete, while precast (PC) systems will not. The pour or placement time for each deck system was estimated in hours for both the traditional and accelerated construction sequence lanes. A ratio of the outside lane-span areas to the inside lane-span areas was used to estimate all pour or 97 place times. The curing time regardless of deck system and lane-span was estimated at 6 hours. Table 5-8 shows all estimated construction times. Table 5-8. Estimated Deck System Construction Schedules Deck System Casting Technique Pour or Place Time (hrs) Cure Time (hrs) Traditional Accelerated Exodermic CIP 7.5 10.5 6 Steel Grid CIP 7 10 6 NCHRP PC 6 9 Exodermic PC 7 10 Figure 5-4 displays all schedule estimates calculated in this section by lane-span in a bridge plan view format. On the NB bridge the value of construction has two numbers. The first number indicates the pour time while the second number represents the curing time. The SB bridge is all PC and therefore does not have a curing time for any of the lane-spans. The arrows on the lane- spans identify the direction that work will progress. 98 Note: construction times reported for CIP methods is formatted as: (pour time/cure time) Figure 5-4. Summary of Learning Curve Time Reduction for Each Lane-Span. 5.2.3.4 Traffic Data: Value Estimating Before construction, traffic data volumes and speeds will be used in the example problem. The vehicle classification has been divided into passenger vehicles and trucks. Passenger vehicles represent a vehicle below 46.9 ft (14.2 m) in length while trucks represent a vehicle above 46.9 ft. (14.2 m) in length. These lengths were classified from the American Association of State Highway and Tranportation Officials (AASHTO) ?Geometric Design of Highways and Streets? manual. Southbound Bridge (precast) Northbound Bridge (cast-in-place) NCHRP Exodermic Exodermic Steel Grid Legend Accelerated Construction Sequencing Traditional Construction Sequencing Span 1 Span 2 Span 3 Span 4 N 4.5 6 4.5 6.5 5 7 4 5.5 Demolition Construction 8.5 8.5 9 10 8.5 9.5 9 9 Demolition Construction 9 10.5 / 6 8.5 9.5 / 6 9 10 / 6 8.5 10 / 6 Demolition Construction 4.5 7 / 6 4.5 7 / 6 4 6.5 / 6 5 7.5 / 6 Demolition Construction Direction of Deck Reconstruction 99 During construction it is assumed that there will be no reduction in flow due to the low volumes experience on the I-59 roadway. However, an enforced work zone speed of 45 mph will be used to determine additional RUC. Volumes and speeds that will be used for traditional construction sequence lanes, that will have weekday closures, and accelerated construction sequence lanes, that will have weekend closures, can be seen on Table 5-9. The weekday value is estimated from a 24 hour period, while the weekend value is based on a 60 hour period. Table 5-9. Northbound and Southbound Traffic Data by Work Closure Period Vehicle Volume Speed (mph) Passenger Vehicle Truck Total Passenger Vehicle Truck Before Construction Weekday 3,987 2,082 6,069 75 77 Weekend 13,560 2,992 16,552 77 79 During Construction Weekday 3,987 2,082 6,069 45 45 Weekend 13,560 2,992 16,552 45 45 5.3 Data Collection Summary The values estimated in the previous section for the example will be consolidated, summarized, and shown in Table 5-10. On the actual I-59 project these values will represent actual values collected over the course of the bridge reconstruction effort and no schedule or cost estimating will be required. Table 5-10 shows the bridge dimensions, cost, schedule, and traffic data for the example. The duration information will be used to develop hypothetical Gantt charts to be used throughout the example. The construction performance factors to be evaluated will also be developed from the data seen on Table 5-10. 10 0 Table 5-10. Northbound/Southbound Bridge Summary Raw Data Table NORTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length (ft) Construction Area (ft2) Cost ($) Schedule (hrs) Traffic Data Exist Post TCB Demo Const TCB Demo Const Vehicle Volume Exodermic Traditional CIP NBI1 56.83 714.9 1101.4 2,013 6,570 32,491 0.50 5.00 13.50 6,512 NBI2 56.00 704.5 1085.3 2,013 6,151 30,416 0.50 4.50 13.00 6,512 Accelerated CIP NBO1 56.83 1169.6 1556.0 6,038 10,211 43,607 2.50 8.50 16.00 7,518 NBO2 56.00 1152.5 1533.3 6,038 10,591 45,232 2.50 9.00 16.50 7,518 Steel Grid Traditional CIP NBI3 56.00 704.5 1085.3 2,013 6,151 20,621 0.50 4.50 13.00 6,512 NBI4 56.83 714.9 1101.4 2,013 5,913 19,825 0.50 4.00 12.50 6,512 Accelerated CIP NBO3 56.00 1152.5 1533.3 6,038 10,062 29,133 2.50 8.50 15.50 7,518 NBO4 56.83 1169.6 1556.0 6,038 10,749 31,120 2.50 9.00 16.00 7,518 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length (ft) Construction Area (ft2) Cost ($) Schedule (hrs) Traffic Data Exist Post TCB Demo Const TCB Demo Const Vehicle Volume NCHRP Traditional PC SBI1 56.83 714.9 1101.4 2,013 5,913 54,519 0.50 4.00 5.50 5,153 SBI2 56.00 704.5 1085.3 2,013 6,151 56,707 0.50 4.50 6.00 5,153 Accelerated PC SBO1 56.83 1169.6 1556.0 6,038 10,749 85,580 2.50 9.00 9.00 5,655 SBO2 56.00 1152.5 1533.3 6,038 10,062 80,115 2.50 8.50 8.50 5,655 Exodermic Traditional PC SBI3 56.00 704.5 1085.3 2,013 6,151 54,129 0.50 4.50 6.50 5,153 SBI4 56.83 714.9 1101.4 2,013 6,570 57,824 0.50 5.00 7.00 5,153 Accelerated PC SBO3 56.00 1152.5 1533.3 6,038 10,591 80,498 2.50 9.00 10.00 5,655 SBO4 56.83 1169.6 1556.0 6,038 10,211 77,606 2.50 8.50 9.50 5,655 Note: *Exist ? Existing Construction Area *TCB ? Temporary Concrete Barrier *Demo = Demolition *Const = Construction 101 5.4 Analysis Techniques The raw data summarized in Table 5-10 will be used to compute the construction performance factors to be analyzed. Gantt charts will be created from the scheduling information to help understand and evaluate the different closure scenarios that will be examined. The inside lanes using traditional construction sequencing will be under construction during a typical weekday closure schedule. The outside lanes being constructed under accelerated construction sequencing will be evaluated with a weekend closure scenario. The formulas and methodology for creating the Gantt charts and construction performance factors have been described in detail in Chapter 4. 5.4.1 Gantt Charts For the construction schedule developed in the raw data for this example problem Gantt charts have been created. Traditional construction sequencing was assumed to occur on weekdays using a closure from the beginning of the project until the finish of the project. Accelerated construction sequencing was assumed to be performed on weekends and uses non-peak travel periods to intermittently close lanes for reconstruction while reopening lanes during peak travel periods. A 12 hour work period during the week and a 24 hour work period on the weekends were assumed. One of the limiting factors to the work schedule was the casting technique. Cast-in- place (CIP) construction techniques require a 6 hour cure time. This additional cure time limited the ability of the accelerated construction sequence to be performed during any other closure period other than weekends. 102 From the raw data on Table 5-10 the following Gantt charts were created. The charts highlight the effect that different bridge deck replacement methods have on the total project schedule. The numbers displayed on the bars represent the scheduled time required to complete the activity under consideration. The far right column indicates the lane closure time for each lane-span in hours. The number in parenthesis next to the lane closure time is the shared time for TCB installation and removal. On the bottom of each chart the corresponding vehicle volume is reported for each work period. For traditional construction sequencing on the inside lanes, the work period is 12 hours, however the lane closure is for 24 hours. For accelerated construction sequencing on the outside lanes, the work period and the lane closure period are the same since the lane is reopened to traffic once construction is completed on a lane-span. Figure 5-5 shows the Gantt charts for the traditional construction sequence lanes of the example problem. Figure 5-6 show the Gantt charts for the accelerated construction sequence lanes of the example problem. 103 (a) Northbound Bridge, Inside Lane, Cast-in-place. (b) Southbound Bridge, Inside Lane, Precast. Note: * The work period for this example is a 12 hour work day * Only work activity is shown, but each day represents a 24 hour lane closure unless noted otherwise * Number in parenthesis in the ?Lane Closure? column are shared TCB values Figure 5-5. Traditional Construction Sequencing Gantt Charts with Weekday Closure. Lane-Span Deck System * TCB Installation 1 1 1 Exodermic 5 7.5 6 18.5 (0.5) 2 Exodermic 4.5 6 17.5 (0.5) 3 Steel Grid 4.5 6 17.5 (0.5) 4 Steel Grid 4 6 16.5 (0.5) * TCB Removal 1 1 Vehicle Volume 55791 Lane Closure (hrs.) 13000 13000 13000 13000 3791 7 6.5 Day 1 Day 2 Day 3 Day 4 Day 5 7 6, 69 6, 69 6,069 6, 69 1, 70 26,046 Lane-Span Deck System * TCB Deployment 1 1 4 Exodermic 5 5 2 12.0 (0.5) 3 Exodermic 4.5 6.5 11.0 (0.5) 2 NCHRP 2 2.5 3 3 10.5 (0.5) 1 NCHRP 4 5.5 9.5 (0.5) * TCB Removal 1 1 Vehicle Volume 44146 Day 1 Day 2 Day 3 Day 4 Lane Closure (hrs.) 13000 13000 13000 5146 Legend: TTC Demolition Construction Cure 6,069 6, 69 6,069 2,403 20,610 10 4 (a) Northbound, Outside Lane, Cast-in-place. (b) Southbound, Outside Lane, Precast. Note: * The work period for this example is an around the clock schedule * Only work activity is shown, but each day represents a 24 hour lane closure unless noted otherwise * Number in parenthesis in the ?Lane Closure? column are shared TCB values Figure 5-6. Accelerated Construction Sequencing Gantt Charts with Weekend Closure. Lane-Span Deck System * TCB Deployment 3 3 4 Steel Grid 9 10 6 26.0 (1.5) 3 Steel Grid 9.5 6 25.0 (1.5) 2 Exodermic 9 10.5 26.5 (1.5) 1 Exodermic 10 6 25.5 (1.5) * TCB Removal 3 3 Vehicle Volume 43063 Weekend 1 Weekend 2 8.5 8.5 6 Lane Closure (hrs.) 21938 2112514,897 15,173 30,070 Lane-Span Deck System * TCB Installation 3 3 1 NCHRP 9 9 19 (1.5) 2 NCHRP 8.5 8.5 18 (1.5) 3 Exodermic 9 10 20.0 (1.5) 4 Exodermic 8.5 9.5 19 (1.5) * TCB Removal 3 3 Weekend 2 Vehicle Volumes Lane Closure (hrs.)Weekend 1 Legend: TTC Rearrangement Demolition Construction Cure 11,586 22,62111,035 105 On Figure 5-5 and Figure 5-6 the effect of the additional curing time of the CIP casting techniques can be seen on the total project duration. It is important to remember that the accelerated lane-spans have a slightly larger area than the traditional lane-spans and therefore have a larger scheduled time. The production rates calculated in the following section will provide a better indication as to the effect that construction sequence had on the total lane closure and schedule. 5.4.2 Normalizing Collected Data The compiled raw data on Table 5-10 must be normalized for nested analysis of variance (ANOVA) statistical testing. Using the bridge dimensions and values found in the American Association of State Highway and Tranportation Officals (AASHTO) publication,?User and Non-User Benefit Analysis For Highways? the construction performance factors: (1) unit cost, (2) production rate, and (3) RUC were calculated. For the example problem the following values were assumed from ?User and Non-User Benefit Analysis For Highways? for passenger vehicles and trucks and can be seen on Table 5-11. These values are hypothetical and may not be appropriate for the actual I-59 project. 106 Table 5-11. Assumed RUC Calculation Values Passenger Vehicle Truck Finance Rate 0.10 0.10 Percentage of Hourly Wage 50% 100% Average Hourly Wage($) 18.56 20.23 Average Vehicle Occupancy 1.3 1.05 Speed Before Closure (mph) Weekday 75 77 Weekend 77 79 Speed After Closure (mph) 45 45 Other Operating Cost per Mile($/mile) 0.04 0.05 Vehicle Life (years) 10 8 Vehicle Cost ($) 20,000 60,000 Salvage Value at End of Life ($) 2,000 5,000 Insurance per Year ($) 1,000 1,500 Cargo Value($) 200,000 All equations, 4-1 through 4-15, used to calculate the construction performance factors can be found in in Chapter 4. Example calculation for the Exodermic Traditional CIP bridge deck replacment method with lane-span ID NBI1 have been provided and are shown below. The TCB unit cost was calculated using equation 4-1 seen below: $ TCB Cost ($) 2,013TCB Unit Cost = 35.42ft Lane -Span Length (ft) 56.83? ? = =? ?? ? (4-1) Demolition unit cost will be calculated as the total cost for demolition of an individual lane-span divided by the area of existing deck of the lane-span under consideration. Demolition unit cost was calculated with equation 4-2 below: 2 2$ Demolition Cost ($) 6,750Demolition Unit Cost 9.19ft Existing Lane -Span Area (ft ) 714.9? ? = = =? ?? ? (4-2) Construction unit cost will be calculated as the total cost required to construct the lane-span under consideration with the appropriate deck system and can be seen in equation 4-3 below: 107 2 2$ Construction Cost ($) 32,491Construction Unit Cost 29.50ft Post Lane -Span Area (ft ) 1101.4? ? = = =? ?? ? (3) TCB production rate was calculated as the linear length of a lane-span divided by the total duration of time spent installing or removing TCB for the lane-span in question and is shown in equation 4-4 below: ft Lane -Span Length (ft) 56.83TCB Pr oduction Rate 113.7hr TCB Duration (hr) 0.50? ? = = =? ?? ? (4-4) Demolition production rate will be determined by dividing the existing lane-span area by the total duration spent on the demolition process of a single lane-span. Demolition production rate can be seen in equation 4-5 below: 2 2ft Existing Lane -Span Area (ft ) 714.9 Demolition Pr oduction Rate = =143.0 hr Demolition Duration (hr) 5.00? ? =? ? ? ? (4-5) Construction production rate is calculated by dividing the post construction area by the total duration of the construction period for each lane-span and is shown in equation 4-6 below: 2 2ft Post Lane -Span Area (ft ) 1101.4 Construction Pr oduction Rate 81.6hr Construction Duration (hr) 13.50? ? = = =? ? ? ? (4-6) The RUC was calculated using equations 4-7 through 4-14. The following template, shown in Figure 5-7, demonstrates how the equations were used to calculate a lane-span RUC for the lane- span ID NBI1. Table number on the RUC template refer to the ?User and Non-User Benefit Analysis for Highways? AASHTO publication. 108 Figure 5-7. RUC Template For Lane-Span NBI1. 50% 100% $18.56 $20.23 1.3 1.05 77 79 45 45 0.040 0.050 10 8 $20,000 $60,000 $2,000 $5,000 $200,000 $1,000 $1,500 $12.06 $21.24 $0.357 $1.234 $0.114 $0.1712 (Insurance per year / 8760) (Insurance per year / 8760) $2.2831 $12.54 $24.9298 1.998 1.948 3.419 3.419 $0.0070 $0.0135 $0.0119 $0.0237 $0.0049 $0.0102 RUC from Autos for lane($) $73.87 RUC Trucks for lane ($) $78.37 Cost per vehicle during closure($) Inventory cost per vehicle hour($/veh-hr): (Total cost per vehicle hour / 3600)*(delay) (Total cost per vehicle hour / 3600)*(delay) Travel time before closure (sec) Total cost per vehicle hour ( $/veh-hr):Total cost per vehicle hour ( $/veh-hr): (Cargo value X finance rate / 8760) Travel time before closure (sec) Travel time during closure (sec) Amortized cost per vehicle hour ($/veh-hr): A = (i*(P*(1+i)^n)-F)/((1+i)^n)-1)/8760 Insurance cost per vehicle hour($/veh-hr): A = (i*(P*(1+i)^n)-F)/((1+i)^n)-1)/8760 Insurance cost per vehicle hour($/veh-hr): Amortized cost per vehicle hour ($/veh-hr): (wage X percentage X occupancy) (wage X percentage X occupancy) Insurance per Year (Table 5-4): Calculations Autos Trucks Value of time per vehicle hour ($/veh-hr): Value of time per vehicle hour ($/veh-hr): Average hourly wage (Table 5-2) Average hourly wage (Table 5-2) Average vehicle occupancy Average vehicle occupancy Speed before closure (mph) Speed before closure (mph) Speed during closure (mph) Speed during closure (mph) Other Operating Costs per Mile (Table 5-4) Other Operating Costs per Mile (Table 5-4) Cargo Value (tires, maintenance, etc.) (tires, maintenance, etc.) Vehicle Life (years) Vehicle Life (years) Vehicle Cost ($) Vehicle Cost ($) Salvage Value at End of Life Salvage Value at End of Life Inputs Finance Rate: 0.10 Percentage of hourly wage (Table 5-1) Percentage of hourly Wage (Table 5-1) Date 24-Feb Period of Closure Weekday Passenger Vehicles Trucks Analysis Year 2011 Volume (veh) 22,621 Percent Passenger Cars (%) 66.0% Percent Heavy Vehicles (%) 34.0% Road User Cost Estimating General Information Site Information Project I-59 Project Segment (ft) 225.66 (Realized Cost X Volume X Percentage) (Realized Cost X Volume X Percentage) $152.24Total RUC for Lane ($) Insurance per Year (Table 5-4): Results Travel time during closure (sec) (Segment / 5280) X (3600 / Speed) (Segment / 5280) X (3600 / Speed) Realized cost per vehicle ($/veh) Realized cost per vehicle ($/veh) (cost after closure - cost before closure) (cost after closure - cost before closure) Cost per vehicle before closure ($/veh) Cost per vehicle before closure ($) Cost per vehicle during closure($/veh) 109 It is shown in Figure 5-7 that the total lane RUC was determined to be $175.29. To calculate the RUC for the lane-span we will apply equation 4-15. Lane -Span Duration (hr)Lane -Span RUC ($) Lane RUC ($)Total Lane Span Duration (hr)? ?= ?? ?? ? ? (4-15) 19Lane-Span RUC ($) 175.29 46.2672? ?= ? =? ?? ? All calculated construction performance factors for all bridge deck replacement methods have been summarized in Table 5-12 11 0 Table 5-12. Northbound/Southbound Bridge Construction Performance Factors NORTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length (ft) Construction Area (ft2) Unit Cost Production Rate RUC Exist Post TCB ($/ft) Demo ($/ft2) Const ($/ft2) TCB (ft/hr) Demo (ft2/hr) Const (ft2/hr) ($) Exodermic Traditional CIP NBI1 56.83 714.9 1101.4 35.42 9.19 29.50 113.7 143.0 81.6 46.26 NBI2 56.00 704.5 1085.3 35.95 8.73 28.03 112.0 156.6 83.5 43.82 Accelerated CIP NBO1 56.83 1169.6 1556.0 106.25 8.73 28.03 22.7 137.6 97.3 50.13 NBO2 56.00 1152.5 1533.3 107.82 9.19 29.50 22.4 128.1 92.9 51.99 Steel Grid Traditional CIP NBI3 56.00 704.5 1085.3 35.95 8.73 19.00 112.0 156.6 83.5 43.82 NBI4 56.83 714.9 1101.4 35.42 8.27 18.00 113.7 178.7 88.1 41.39 Accelerated CIP NBO3 56.00 1152.5 1533.3 107.82 8.73 19.00 22.4 135.6 98.9 49.20 NBO4 56.83 1169.6 1556.0 106.25 9.19 20.00 22.7 130.0 97.3 51.06 SOUTHBOUND Deck System Construction Sequence Casting Technique Lane Span ID Span Length (ft) Construction Area (ft2) Unit Cost Production Rate RUC Exist Post TCB ($/ft) Demo ($/ft2) Const ($/ft2) TCB (ft/hr) Demo (ft2/hr) Const (ft2/hr) ($) NCHRP Traditional PC SBI1 56.83 714.9 1101.4 35.42 8.27 49.50 113.7 178.7 200.3 30.82 SBI2 56.00 704.5 1085.3 35.95 8.73 52.25 112.0 156.6 180.9 33.91 Accelerated PC SBO1 56.83 1169.6 1556.0 106.25 9.19 55.00 22.7 130.0 172.9 37.81 SBO2 56.00 1152.5 1533.3 107.82 8.73 52.25 22.4 135.6 180.4 35.97 Exodermic Traditional PC SBI3 56.00 704.5 1085.3 35.95 8.73 49.87 112.0 156.6 167.0 35.45 SBI4 56.83 714.9 1101.4 35.42 9.19 52.50 113.7 143.0 157.3 38.53 Accelerated PC SBO3 56.00 1152.5 1533.3 107.82 9.19 52.50 22.4 128.1 153.3 39.65 SBO4 56.83 1169.6 1556.0 106.25 8.73 49.88 22.7 137.6 163.8 37.81 Note: *Exist ? Existing Construction Area *TCB ? Temporary Concrete Barrier *Demo - Demolition *Const - Construction 111 5.4.3 Nested ANOVA Nested ANOVA was performed on each of the seven construction performance factors in Table 5-12. There are three sub-factors in unit cost: TCB unit cost, demolition unit cost, and construction unit cost; three sub-factors in production rate: TCB production rate, demolition production rate, and construction production rate; and one cost factor in RUC. The null hypotheses (H0) tested that the mean value of the construction performance factor in question, regardless of path selected to the deck system level, was equal. This is to say that the bridge deck replacement methods had no statistical significant effect on the mean value of the factor being tested and either method could be selected for similar results. The alternative hypothesis (Ha) tested that the path selected does result in a statistical significant difference in the mean value of the construction performance factor in question. P-values were used to prove or fail to prove the hypotheses. A p-value of 0.05 or smaller was identified as having a statistical significant difference on the mean value of the performance factor. An R2 value of 0.60 or larger was an acceptable goodness-of-fit of the model. Table 5-13 shows the hypotheses and construction performance factors that were tested with a nested ANOVA. Table 5-13. Example Nested ANOVA Null and Alternative Hypothesis Test for Construction Performance Factors Construction Performance Factor Null Hypothesis (H0) Alternative Hypothesis (Ha) 1. TCB Unit Cost g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 2. Demolition Unit Cost g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 3. Construction Unit Cost g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 4. TCB Production Rate g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 5. Demolition Production Rate g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 6. Construction Production Rate g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 7. RUC g2020g2869 g3404g1710g3404g2020g2876 uni006Euni006Funi0074uni0020uni0061uni006Cuni006Cuni0020g2020g3036uni0020uni0061uni0072uni0065uni0020uni0065uni0071uni0075uni0061uni006C 112 Each test produced an ANOVA model report with an interaction tree diagram. From the results, conclusions were drawn to the effect that a bridge deck replacement method had on the overall mean of the construction performance factor being tested. 5.4.3.1 TCB: Unit Cost The construction performance values that were tested in a nested ANOVA for TCB unit cost have been summarized on Table 5-14. These values were taken directly from Table 5-12. Table 5-14. TCB Unit Cost Deck System Construction Sequence Casting Technique Lane-span ID TCB Unit Cost ($/ft) Exodermic Traditional CIP NBI1 35.42 NBI2 35.95 Accelerated CIP NBO1 106.25 NBO2 107.82 Steel Grid Traditional CIP NBI3 35.95 NBI4 35.42 Accelerated CIP NBO3 107.82 NBO4 106.25 NCHRP Traditional PC SBI1 714.9 SBI2 704.5 Accelerated PC SBO1 1169.6 SBO2 1152.5 Exodermic Traditional PC SBI3 704.5 SBI4 714.9 Accelerated PC SBO3 1152.5 SBO4 1169.6 From the ANOVA test the following model report, Table 5-15, was created. 113 Table 5-15. TCB Unit Cost Nested ANOVA Model Report from SAS Software Source DF Sum of Squares Mean Square F-Value P-value Model 7 20365.4309 2909.3473 4274.56 <.0001 Error 8 5.4450 0.6806 Corrected Total 15 20370.8758 R2 Coeff Var Root MSE Mean 0.9997 1.1561 0.8250 71.36 Source DF Type I SS Mean Square F-value P-value Casting Technique 1 0.0001 0.0001 0.00 0.9930 Construction Sequence 2 20365.4306 10182.7153 14961.0 <.0001 Deck System 4 0.00023 0.0001 0.00 1.0000 The ANOVA test fails to prove that the casting technique and deck system selected have a statistically significant impact on the TCB unit cost. The test proves that construction sequence has a statistical significant impact on the mean value of the TCB unit cost, with a reported p- value of <.0001. The R2 value is very high at 0.9997, suggesting that the statistical model explains the given data well. For the 16 TCB unit cost values tested, the overall mean reported was $71.36/ft ($235.49/m). An interaction tree diagram, Figure 5-8, was created to give reference to the magnitude of values being reported by the ANOVA test. The test suggests that the strongest impact on TCB unit cost comes from the construction sequence selected. In Figure 5-8 we see at the construction sequence level that the average mean value of TCB unit cost for a traditional construction sequence lane is $35.68/ft ($117.74/m). The average mean value of the accelerated construction sequence lane at the same level is $107.03/ft ($353.20/m. The accelerated construction sequence TCB unit cost is on average $71.35/ft ($235.46/m) higher than the traditional construction sequence. ). The ratio of accelerated TCB unit cost to traditional TCB unit cost is 3:1, which is 114 to be expected because the accelerated construction sequence lane requires three TCB rows to perform intermittent lane closures, while traditional construction sequencing only uses one row of TCB. 11 5 Figure 5-8. TCB Unit Cost Interaction Tree Diagram. ? ? ? ? 71.36 38.14 71.36 38.14 ? ? ? ? ? ? ? ? 35.68 0.30 107.03 0.91 35.68 0.30 107.03 0.91 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 35.68 0.37 35.68 0.37 107.03 1.11 107.03 1.11 35.68 0.37 35.68 0.37 107.03 1.11 107.03 1.11 0.9930 <.0001 1.0000 Cast-In-Place Precast Traditional Accelerated NCHRP ExodermicExodermic Pvalue Exodermic Traditional Accelerated NCHRP Parameter Steel Grid Exodermic Steel Grid TCB Unit Cost ($ / ft) Casting Technique Construction Sequence Deck System 116 5.4.3.2 Demolition: Unit Cost The values used for demolition unit cost are drawn directly from Table 5-12 which is the summary of the construction performance factors. Table 5-16 shows only the demolition unit costs. Table 5-16. Demolition Unit Cost Deck System Construction Sequence Casting Technique Lane-span ID Demolition Unit Cost ($/ft2) Exodermic Traditional CIP NBI1 9.19 NBI2 8.73 Accelerated CIP NBO1 8.73 NBO2 9.19 Steel Grid Traditional CIP NBI3 8.73 NBI4 8.27 Accelerated CIP NBO3 8.73 NBO4 9.19 NCHRP Traditional PC SBI1 8.27 SBI2 8.73 Accelerated PC SBO1 9.19 SBO2 8.73 Exodermic Traditional PC SBI3 8.73 SBI4 9.19 Accelerated PC SBO3 9.19 SBO4 8.73 From the ANOVA test the following model report, Table 5-17, was generated. Table 5-17. Demolition Unit Cost Nested ANOVA Model Report from SAS Source DF Sum of Squares Mean Square F-Value P-value Model 7 0.6348 0.0907 0.86 0.5741 Error 8 0.8464 0.1058 Corrected Total 15 1.4812 R2 Coeff Var Root MSE Mean 0.4286 3.6774 0.3253 8.85 Source DF Type I SS Mean Square F-value P-value Casting Technique 1 0.0000 0.0000 0.00 1.0000 Construction Sequence 2 0.2116 0.1058 1.00 0.4096 Deck System 4 0.4232 0.158 1.00 0.4609 117 At a p-value threshold of 0.05 the ANOVA model fails to prove that any of the bridge deck replacement methods have a statistically significant impact on the demolition unit cost. This model may be explained from the low learning curve factors applied to the lanes. In real construction a higher reduction learning curve may occur that will result in greater deviation to the demolition unit cost. It can also be seen in this example that the demolition unit cost is completely insensitive to the replacement method casting technique with a p-value of 1.0000. The demolition unit cost interaction tree diagram can be seen in Figure 5-9. 11 8 Figure 5-9. Demolition Unit Cost Interaction Tree Diagram. ? ? ? ? 8.85 0.32 8.85 0.32 ? ? ? ? ? ? ? ? 8.73 0.38 8.96 0.27 8.73 0.38 8.96 0.27 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 8.96 0.32 8.50 0.33 8.96 0.32 8.96 0.33 8.50 0.33 8.96 0.32 8.96 0.33 8.96 0.32 0.4609 0.4096 Deck System Exodermic Steel Grid Exodermic Steel Grid NCHRP Exodermic NCHRP Exodermic 1.0000 Construction Sequence Traditional Accelerated Traditional Accelerated Parameter Pvalue Casting Technique Cast-In-Place Precast Demolition Unit Cost ($ / ft2) 119 5.4.3.3 Construction: Unit cost Table 5-12, construction unit cost were used for nested ANOVA. The construction unit costs have been summarized on Table 5-18. Table 5-18. Construction Unit Cost Deck System Construction Sequence Casting Technique Lane-span ID Construction Unit Cost ($/ft2) Exodermic Traditional CIP NBI1 29.50 NBI2 28.03 Accelerated CIP NBO1 28.03 NBO2 29.50 Steel Grid Traditional CIP NBI3 19.00 NBI4 18.00 Accelerated CIP NBO3 19.00 NBO4 20.00 NCHRP Traditional PC SBI1 49.50 SBI2 52.25 Accelerated PC SBO1 55.00 SBO2 52.25 Exodermic Traditional PC SBI3 49.87 SBI4 52.50 Accelerated PC SBO3 52.50 SBO4 49.88 The ANOVA model report, Table 5-19, for construction unit cost was created from the ANOVA analysis. Table 5-19. Construction Unit Cost of Nested ANOVA Model Report from SAS Source DF Sum of Squares Mean Square F-Value P-value Model 7 3300.9580 471.5654 214.18 <.0001 Error 8 17.6141 2.2018 Corrected Total 15 3318.5721 R2 Coeff Var Root MSE Mean 0.9947 3.9254 1.4384 37.80 Source DF Type I SS Mean Square F-value P-value Casting Technique 1 3099.4273 3099.4273 1407.71 <.0001 Construction Sequence 2 4.2950 2.1475 0.98 0.4178 Deck System 4 197.236 49.3089 22.40 0.0002 120 The ANOVA test fails to prove that construction sequence has a statistically significant impact on the construction unit cost. The test does prove that the casting technique and deck system have statistically significant impacts on the construction unit cost with a p-value of <.0001 and 0.002 respectively. The R2 value is 0.9947, which indicates the model represents the given data well. The mean value for the 16 construction unit costs tested was $37.80/ft2 ($411.64/m2). The construction unit cost interaction tree diagram was created from the analysis and can be seen in Figure 5-10. At the casting level the calculated mean construction unit cost for CIP and PC is $23.88/ft2 ($260.05/m2) and $51.72/ft2 ($563.23/m2) respectively. These results support the cost estimating for this example problem. It was initially assumed that PC had a higher unit cost, 75% mark up, than CIP and it should be expected that the ANOVA supports this assumption. Likewise, the estimated unit costs for the deck systems are reflected in the ANOVA output. It was assumed that the lowest unit cost deck system was a steel grid, followed by the moderately priced Exodermic, and final the most expensive NCHRP. 12 1 Figure 5-10. Construction Unit Cost Interaction Tree Diagram. ? ? ? ? 23.88 5.28 51.72 1.86 ? ? ? ? ? ? ? ? 23.63 5.97 24.13 5.40 51.03 1.56 52.41 2.09 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 28.76 1.04 18.50 0.71 28.76 1.04 19.50 0.71 50.87 1.94 51.19 1.86 53.63 1.94 51.19 1.86 0.0002 0.4178 Deck System Exodermic Steel Grid Exodermic Steel Grid NCHRP Exodermic NCHRP Exodermic <.0001 Construction Sequence Traditional Accelerated Traditional Accelerated Parameter Pvalue Casting Technique Cast-In-Place Precast Construction Unit Cost ($ / ft2) 122 5.4.3.4 TCB: Production Rate The TCB production rate values in Table 5-12 were analyzed in the nested ANOVA. A summary of theses TCB production rate values are shown in Table 5-20. Table 5-20. TCB Production Rates Deck System Construction Sequence Casting Technique Lane-span ID TCB Production Rate (ft/hr) Exodermic Traditional CIP NBI1 113.7 NBI2 112.0 Accelerated CIP NBO1 22.7 NBO2 22.4 Steel Grid Traditional CIP NBI3 112.0 NBI4 113.7 Accelerated CIP NBO3 22.4 NBO4 22.7 NCHRP Traditional PC SBI1 113.7 SBI2 112.0 Accelerated PC SBO1 22.7 SBO2 22.4 Exodermic Traditional PC SBI3 112.0 SBI4 113.7 Accelerated PC SBO3 22.4 SBO4 22.7 The ANOVA model report can be seen in Table 5-21. Table 5-21. TCB Production Rate Nested ANOVA Model Report from SAS Source DF Sum of Squares Mean Square F-Value P-value Model 7 32616.3600 4659.4800 6254.34 <.0001 Error 8 5.9600 0.7450 Corrected Total 15 32622.3200 R2 Coeff Var Root MSE Mean 0.9998 1.2749 0.8631 67.7 Source DF Type I SS Mean Square F-value P-value Casting Technique 1 0.0000 0.0000 0.00 1.0000 Construction Sequence 2 32616.3600 16308.1800 21890.2 <.0001 Deck System 4 0.0000 0.0000 0.00 1.0000 123 The ANOVA model report fails to prove that the casting technique and deck system methods have a statistically significant impact on the TCB production rate. The results suggest that the construction sequence does have a statistically significant effect on the mean TCB production rate. The R2 value of 0.9998, suggest a model that represents the given data well. The reported mean value for the 16 TCB production rate values is 67.7 ft/hr (20.5 m/hr). The magnitude of the TCB production rates can be seen on the interaction tree diagram displayed in Figure 5-11. The TCB production rate at the construction sequence level is 112.8 and 22.6 ft/hr (34.2 and 6.8 m/hr) for traditional and accelerated construction sequencing, respectively. The traditional construction sequence mean TCB production rate is 90.2 ft/hr (27.3 m/hr) greater than the accelerated construction sequence. These results are expected because, by design the TCB production rates are insensitive to, not a function of, casting technique and deck system. The production rates are dependant only on the construction sequence which uses one row of TCB for traditional and three rows of TCB for accelerated construction sequencing. 12 4 Figure 5-11. TCB Production Rate Interaction Tree Diagram. ? ? ? ? 67.7 48.3 67.7 48.3 ? ? ? ? ? ? ? ? 112.8 1.0 22.6 0.2 112.8 1.0 22.6 0.2 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 112.8 1.2 112.8 1.2 22.6 0.2 22.6 0.2 112.8 1.2 112.8 1.2 22.6 0.2 22.6 0.2 1.0000 TCB Production Rate (ft / hr) <.0001 NCHRP Exodermic NCHRP Exodermic 1.0000 Deck System Exodermic Steel Grid Exodermic Steel Grid Construction Sequence Traditional Accelerated Traditional Accelerated Parameter Pvalue Casting Technique Cast-In-Place Precast 125 5.4.3.5 Demolition: Production Rate Demolition production rate values that were used for nested ANOVA testing can be seen in Table 5-22. These values have been taken directly from Table 5-12. Table 5-22. Demolition Production Rates Deck System Construction Sequence Casting Technique Lane-span ID Demolition Production Rate (ft2/hr) Exodermic Traditional CIP NBI1 143.0 NBI2 156.6 Accelerated CIP NBO1 137.6 NBO2 128.1 Steel Grid Traditional CIP NBI3 156.6 NBI4 178.7 Accelerated CIP NBO3 135.6 NBO4 130.0 NCHRP Traditional PC SBI1 178.7 SBI2 156.6 Accelerated PC SBO1 130.0 SBO2 135.6 Exodermic Traditional PC SBI3 156.6 SBI4 143.0 Accelerated PC SBO3 128.1 SBO4 137.6 Table 5-23 shows the ANOVA model report and statistics for the demolition production rates. Table 5-23. Demolition Production Rate Nested ANOVA Model Report from SAS Source DF Sum of Squares Mean Square F-Value P-value Model 7 3320.4900 474.3557 4.77 0.0215 Error 8 794.9800 99.3725 Corrected Total 15 4115.4700 R2 Coeff Var Root MSE Mean 0.8068 6.8383 9.9686 145.7 Source DF Type I SS Mean Square F-value P-value Casting Technique 1 0.0000 0.0000 0.00 1.0000 Construction Sequence 2 2683.2400 1341.6200 13.50 0.0027 Deck System 4 637.2500 159.3125 1.60 0.2639 126 The ANOVA fails to prove that casting technique and deck system has a statistically significant effect on the mean demolition production rate. Only the construction sequence has a statistically significant effect on the mean of the demolition production rate. The R2 value of 0.8068, suggests the model represents the given data well. The overall mean demolition production rate for the 16 values analyzed was reported as 145.7 ft2/hr (13.4 m2/hr). The interaction tree diagram, illustrated in Figure 5-12, shows the magnitude of the mean demolition production rates at each bridge deck replacement method?s level. The mean demolition production rate at the construction sequence level is 158.7 and 132.8 ft2/hr ( 14.6 and 12.2 m2/hr) for traditional and accelerated construction sequences, respectively. It should be expected that the traditional construction sequence lane would have a higher production rate than the accelerated construction sequence lane, because of the assumed learning curve and the sequential progression of demolition activities. In the traditional construction sequence lane, demolition occurs from the first lane-span to the fourth lane-span reaching a maximum demolition cost reduction of 10% from the learning curve. In the accelerated construction sequence, the learning curve only allows the cost reduction to reach a maximum of 5%, because of the intermittent closures. 12 7 Figure 5-12. Demolition Production Rate Interaction Tree Diagram. ? ? ? ? 145.8 17.2 145.8 17.2 ? ? ? ? ? ? ? ? 158.7 14.8 132.8 4.5 158.7 14.8 132.8 4.5 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 149.8 9.6 167.6 15.7 132.8 6.7 132.8 4.0 167.6 15.7 149.8 9.6 132.8 4.0 132.8 6.7 0.2639 0.0027 Deck System Exodermic Steel Grid Exodermic Steel Grid NCHRP Exodermic NCHRP Exodermic 1.0000 Construction Sequence Traditional Accelerated Traditional Accelerated Parameter Demolition Production Rate (ft2 / hr) Pvalue Casting Technique Cast-In-Place Precast 128 5.4.3.6 Construction: Production Rate The construction production rate values that were analyzed in this section were gathered from Table 5-12. The values analyzed have been displayed in Table 5-24. Table 5-24. Construction Production Rates Deck System Construction Sequence Casting Technique Lane-span ID Construction Production Rate (ft2/hr) Exodermic Traditional CIP NBI1 81.6 NBI2 83.5 Accelerated CIP NBO1 97.3 NBO2 92.9 Steel Grid Traditional CIP NBI3 83.5 NBI4 88.1 Accelerated CIP NBO3 98.9 NBO4 97.3 NCHRP Traditional PC SBI1 200.3 SBI2 180.9 Accelerated PC SBO1 172.9 SBO2 180.4 Exodermic Traditional PC SBI3 167.0 SBI4 157.3 Accelerated PC SBO3 153.3 SBO4 163.8 From the nested ANOVA test the following model information was reported. Table 5-25. Construction Production Rate Nested ANOVA Model Report from SAS Source DF Sum of Squares Mean Square F-Value P-value Model 7 28253.5775 4036.2254 94.46 <.0001 Error 8 341.8200 42.7275 Corrected Total 15 28595.3975 R2 Coeff Var Root MSE Mean 0.9880 4.9827 6.5366 131.19 Source DF Type I SS Mean Square F-value P-value Casting Technique 1 26634.2400 26634.2400 623.35 <.0001 Construction Sequence 2 462.7625 231.3813 5.42 0.0326 Deck System 4 1156.5750 289.1438 6.77 0.0111 129 The results show that the construction production rate is statistically affected by all of the bridge deck replacement methods. The overall mean of the 16 construction production rates analyzed for the given data is 131.9 ft2/hr (12.1 m2/hr). The interaction tree diagram was created from the construction production rates on Table 5-24 and can be seen on Figure 5-13. The lowest p-value was seen at the casting technique level with a value of <0.0001. The mean value of the construction production rates, at the casting technique level, is 90.4 and 172.0 ft2/hr (8.3 and 15.8 m2/hr) for CIP and PC respectively. PC lane-spans were built on average at a rate of 81.6 ft2/hr (7.5 m2/hr) faster than CIP lane-spans. It is expected that the PC casting technique would have a higher production rate than the CIP casting technique because of the assumed 6 hour curing time for CIP methods. The deck system with the highest construction production rate is a NCHRP deck system built with a traditional construction sequence using a PC casting technique with a production rate of 190.6 ft2/hr (18.0 m2/hr). The deck system with the lowest construction production rate is the Exodermic deck system built with a traditional construction sequence using a CIP casting technique with a production rate of 82.5 ft2/hr (7.8 m2/hr). The results of the ANOVA test support the schedule estimating assumptions. It was assumed that the NCHRP deck system had the lowest total duration of 6 and 9 hours, for the traditional and accelerated lanes respectively. The Exodermic deck system was assumed to require the longest duration with a CIP casting technique of 7.5 and 10.5 hours respectively. 13 0 Figure 5-13. Construction Production Rate Interaction Tree Diagram. ? ? ? ? 90.4 7.1 172.0 15.1 ? ? ? ? ? ? ? ? 84.2 2.8 96.6 2.6 176.4 18.6 167.6 11.7 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 82.5 1.3 85.8 3.3 95.1 3.1 98.1 1.2 190.6 13.7 162.2 6.8 176.7 5.3 158.6 7.4 Parameter Construction Production Rate (ft2 / hr) Pvalue Casting Technique Cast-In-Place Precast <.0001 Construction Sequence Traditional Accelerated Traditional Accelerated 0.0111 0.0326 Deck System Exodermic Steel Grid Exodermic Steel Grid NCHRP Exodermic NCHRP Exodermic 131 5.4.3.7 Road User Cost RUC values that were used for nested ANOVA testing can be seen in Table 5-26. These values have been taken directly from Table 5-12 which summarized the calculated RUC for each lane- span. Table 5-26. Estimated Road User Cost (RUC) Values per Deck System Deck System Construction Sequence Casting Technique Lane-span ID RUC ($) Exodermic Traditional CIP NBI1 46.26 NBI2 43.82 Accelerated CIP NBO1 50.13 NBO2 51.99 Steel Grid Traditional CIP NBI3 43.82 NBI4 41.39 Accelerated CIP NBO3 49.20 NBO4 51.06 NCHRP Traditional PC SBI1 30.82 SBI2 33.91 Accelerated PC SBO1 37.81 SBO2 35.97 Exodermic Traditional PC SBI3 35.45 SBI4 38.53 Accelerated PC SBO3 39.65 SBO4 37.81 Table 5-27 shows the ANOVA model report and statistics for the RUC. Table 5-27. RUC Nested ANOVA Model Report from SAS Source DF Sum of Squares Mean Square F-Value P-value Model 7 623.8538 89.1219 31.98 <.0001 Error 8 22.2917 2.7864 Corrected Total 15 646.1455 R2 Coeff Var Root MSE Mean 0.9655 4.0005 1.6692 41.7262 Source DF Type I SS Mean Square F-value P-value Casting Technique 1 480.9249 480.9249 172.59 <.0001 Construction Sequence 2 111.3586 55.6793 19.98 0.0008 Deck System 4 28.1279 7.8925 2.83 0.0981 132 The analysis fails to prove that the deck system selected has a statistically significant impact on the RUC with a confidence interval of 95%. The ANOVA does prove that the casting technique and the construction sequence does statistically affect the total RUC. The R2 value for the model was 0.9655 suggesting that the model fits the given data well. From the RUC values on Table 5-26 the following RUC interaction tree diagram was created and can be seen in Figure 5-14. The largest RUC, $50.60, was associated with an accelerated construction sequence and a CIP casting technique. The traditional construction sequence was performed on weekdays, while the accelerated construction sequence was performed on weekends. From the RTMS G4 data it was determined that weekdays have an average lower vehicle volume than weekends for this example location. In some rural locations passenger vehicle volumes can increase on weekends while truck volumes decrease (Hallenbeck, 1997). Being that I-59 is a rural location higher vehicle volumes were experienced on the expected lower vehicle volume weekends. This result suggests that regional factors must be accounted for when selecting the period to apply accelerated construction sequences. In rural locations weeknights may be a better option for accelerated construction sequencing than weekends, because of the higher weekend vehicle volume attributed to an a rural area. The CIP casting technique required longer total lane closure duration than the PC casting technique because of the additional 6 hour curing time. This additional time resulted in more vehicles that experienced delay due to the construction effort, which results in a higher RUC. 133 13 4 Figure 5-14. RUC Interaction Tree Diagram. ? ? ? ? 47.21 3.93 36.24 2.86 ? ? ? ? ? ? ? ? 43.82 1.99 50.60 1.20 34.68 3.21 37.81 1.50 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 45.04 1.73 42.61 1.72 51.06 1.32 50.13 1.32 32.37 2.18 36.99 2.18 36.89 1.30 38.73 1.30 0.0981 0.0008 Deck System Exodermic Steel Grid Exodermic Steel Grid NCHRP Exodermic NCHRP Exodermic <.0001 Construction Sequence Traditional Accelerated Traditional Accelerated Parameter Road User Cost ($) Pvalue Casting Technique Cast-In-Place Precast 135 5.4.4 Summary of Nested ANOVA A summary of the p-values for each construction performance factor tested can be seen in Table 5-28. A p-value of 0.05 or less was used to determine if a bridge deck replacement method had a statistically significant impact on the mean of the construction performance factor in question. Table 5-28. I-59 Example Bridge Deck Replacement Methods Effect on Construction Performance Factors P values P-Values Unit Cost Production Rate RUC Bridge Deck Replacement Method TCB Demo Const TCB Demo Const Casting Technique 0.9930 1.0000 <.0001 1.0000 1.0000 <.0001 <.0001 Construction Sequence <.0001 0.4096 0.4178 <.0001 0.0027 0.0326 0.0008 Deck System 1.0000 0.4609 0.0002 1.0000 0.2639 0.0111 0.0981 Note: *P value of 0.05 or less indicates a statistically significant effect on the mean value. From the nested ANOVA results, unit cost of the TCB was only affected by the construction sequence. It required three rows of TCB for accelerated construction sequence, while in traditional construction sequence it only required one row of TCB. The demolition unit cost was mostly unaffected by all three of the bridge deck replacement methods. The construction unit cost was affected by the casting technique and the deck system selected. The production rates of TCB and demolition were controlled by the construction sequence. This was a result of the assumed learning curves for the example project. The traditional construction sequence was allowed to reach a maximum cost reduction of 10%, while the accelerated construction sequence only reached 5%. The construction production rate was affected by all three bridge deck replacement methods. The results of the ANOVA reflected the assumed schedule of each deck system and the learning curve applied for raw data estimation. 136 RUC was affected by the casting technique and construction sequence. CIP casting techniques had higher RUC than PC, because it required a longer lane closure period for the curing time. The traditional construction sequence had a lower RUC than the accelerated construction sequence because weekend vehicle volumes were typically higher than weekday volumes for this rural location. Based on the results of this hypothetical I-59 example problem, as a practitioner selecting the most viable bridge deck replacement method for this location, one could suggest that a steel grid cast-in-place traditional method would be best for construction. The steel grid deck system had the lowest unit cost of construction of the 3 deck systems with a moderate production rate. The CIP casting technique had a lower production rate than the PC casting technique but also a lower unit cost. The traditional construction sequence overall had a higher production rate and a lower RUC than the accelerated construction sequence. The traditional construction sequence having a lower RUC than the accelerated construction sequence was due to the attribute of a rural bridge having higher weekend vehicle volumes than the weekday. In some cases, rural location may have higher vehicle volumes on the weekend than on the weekday, opposed to urban locations that typically have lower vehicle volumes on the weekends. The deciding factor between selecting a traditional or accelerated construction sequence and a CIP or PC casting technique would be based on the relative vehicle volume and length of the bridge under consideration, along with regional attributes of the project location. The example problem used a rather small bridge, 225.6 ft (68.4 m), with very low vehicle volumes located in a rural location. Because the I-59 location was rural the benefits of using accelerated construction 137 sequencing on a weekend work schedule were not realized and the traditional construction sequence resulted in a lower traffic impact and lower RUC. 5.5 Summary of I-59 Example Project For the example problem, hypothetical data was created to outline the steps created in the methodology and analysis of this thesis. Using the hypothetical data, with the methodology created, it was demonstrated how the effects of bridge deck replacement methods on construction performance factors could be analyzed. From the ANOVA model reports and interaction tree diagrams, inferences were made to highlight the strengths and weakness of each bridge deck replacement method. The analysis will be used to help determine the most viable bridge deck replacement methods to be used on future bridge projects. The primary variables, from the example results, were the regional location, vehicle volume, and length of the bridge under consideration. Rural location may have higher vehicle volumes on a weekend, which make accelerated construction sequencing with weekend scheduling ineffective at alleviating associated traffic impacts. Alternatively, urban locations typically have lower vehicle volume weekend periods and accelerated construction sequences performed over that period has the potential to result in a lower traffic impacts and RUCs. Longer bridges with overall higher vehicle volumes will result in a high RUC and methods with higher production rates that come with higher unit cost could be more beneficial. Shorter bridges with low vehicle volumes will result in a lower RUC and methods with lower production rates that come with lower unit cost can also be considered. As a practitioner, bridge deck replacement method selection must be determined on the total project cost, schedule, and traffic impact. Low vehicle volume projects will not always warrant 138 accelerated construction methods that come with a higher cost of construction. However, high vehicle volume projects can have a high RUC that could offset the associated cost of construction and accelerated construction methods may be more beneficial where applicable based on regional attributes of the project (i.e. rural or urban). 139 Chapter Six Conclusions and Recommendations 6 6.1 Conclusions Deteriorating U.S. bridge infrastructure combined with traffic volume growth and increased user demand has led many engineers to explore new construction methods for replacing or rehabilitating infrastructure elements that minimize construction related impacts (i.e., travel time delays, congestion, and increases in road user costs (RUCs)). A better understanding is needed of the interaction of accelerated construction techniques on the overall cost, schedule and related traffic impacts. This information will allow practitioners to make sound engineering decisions on which accelerated bridge construction techniques should be employed on future bridge project A bridge deck replacement project has been proposed for I-59 in Collinsville, AL. The bridge is 225.6 ft (68.4 m) in length with an AADT of 13,420 (ALDOT, 2011). The purpose of this research was to develop a framework that will be used to evaluate the impact of different accelerated bridge deck replacement methods from a construction perspective based on the total project cost, schedule, and traffic impact on the I-59 projects. Before formulating a methodology for measuring the effects of bridge deck replacement methods on the construction performance factors: unit cost, production rate, and RUC, a thorough literature review was performed. The literature review identified, described, evaluated, and 140 critically assessed pertinent literature on the current deck systems, methods, technologies, and analysis techniques available for assessing bridge deck replacement methods. The knowledge gleaned from the literature review was applied to create a methodology for statistically evaluating the effects that a particular bridge deck replacement method?s deck system, construction sequence, and casting technique have on the three specified construction performance factors: (1) unit cost, (2) production rate, and (3) RUC. Steps for data collection, normalizing the data, and analysis of the data were outlined. Tables were developed to aid in the collecting and organizing of the data. Delays associated with the development of the plan set, bid package, and unforeseen site conditions on the I-59 project prevented the methodology from being applied to the actual project. As a result, a hypothetical example problem of the I-59 project was developed to demonstrate the applicability of the methodology. The results of the analyses performed are reported to showcase how the methodology could be used to select the most viable bridge deck replacement method to use on a future project based upon regional constraints and agency priorities. This example problem assumed hypothetical data and should only be used as a reference that demonstrates the analysis framework for the actual I-59 project. Based on the hypothetical data in the example problem, it was identified that regional classification, vehicle volume, and bridge length are large contributing factors to the overall RUC and selection of a bridge deck replacement method. In the example it was demonstrated that accelerated construction sequence on a weekend schedule may not be a viable selection for 141 rural location. Urban locations typically have lower weekend vehicle volumes than weekday vehicle volumes and could benefit from weekend accelerated construction sequencing. For ideal urban location such as Birmingham, AL, with lower weekend vehicle volumes, one disadvantage of using accelerated construction sequencing with PC casting techniques is that while it achieves a shorter total project duration, which keeps RUC low, it comes with an average higher overall unit cost for the project. It may not be financially justifiable to select accelerated construction methods to keep RUC low on all projects. If a project does not have high vehicle volumes traditional construction methods may be a better option. Traditional methods on low vehicle volume roadways can keep the overall project cost low with little impact to the RUC. As a practitioner the most critical components to use during decision making are the RUC and the construction cost. Determining when RUC offsets the cost of construction will enable proper bridge deck replacement method selection for a project based on project specific contraints. In addition, an exit survey was developed that will be administered to and completed by the contractor at the I-59 project completion. The purpose of the survey is to gather important construction feedback on each bridge deck replacement method constructed that may not be captured by raw data. 6.2 Recommendations This research only considered direct RUCs such as value of time, and operating and ownership cost. Depending on the location, there are many more factors that can contribute to the overall 142 RUC. Such examples include additional wear and tear of detour roadways from vehicles selecting alternative routes or the monetary loss businesses experience from exposure, due to new route selection by vehicles, increased crash risk associated with the presence of the work zone, and health cost due to increased emissions. These factors have the potential to increase the total RUC of a construction project and research should be conducted into adding these elements into the total RUC. From the results of the example problem and knowledge gained from this thesis, future research should be conducted in the area of RUC on different vehicle volumes and length bridges. Because the vehicle volume and length of the bridge plays such an important part in determining the overall RUC and therefore when that cost is justifiable for selecting accelerated construction methods, better understanding of the vehicle volumes and bridge length is required. A sensitivity analysis study should be conducted comparing the effect of vehicle volumes against RUC to determine at what magnitude of vehicle volume, RUC offsets the increased unit cost accompanied with accelerated construction methods. Likewise, a study comparing the bridge length to the RUC would show at what bridge length accelerated construction methods become an alternative to justifiably keep RUC low. In the example RUC values were estimated from the AASHTO publication (i.e. value of time, amortized cost, insurance cost). These values may not apply to future bridge projects in different regions. Research should be performed to determine appropriate values for a project based on region or site specific attributes. Then a sensitivity analysis should be performed to determine the effects of the assumed values on the overall result of the RUC. 143 To model the nested ANOVA, the bridge deck replacement methods had to be assigned to three levels. The results of the ANOVA test are unique to the design of the levels. Future research can be conducted on similar projects by assigning the bridge deck replacement methods to different levels in the model and seeing how the results are affected. By having a set of results for various models the information will be more transferable to future projects. From the results of the contractor exit survey on the actual I-59 project, the exit survey should be expanded upon. More questions can be formulated that better represent conditions that are experienced during construction. This may lead to considering additional categories associated with the cost, schedule, and traffic data other than temporary concrete barriers (TCB), demolition, and construction. The future research with the methodology outlined throughout this report would help in creating a more accurate model for predicting the effects that bridge deck replacement methods will have on the total project cost, schedule, and traffic impact. This will give practitioners an effective tool to use during the decision making process when selecting accelerated bridge deck replacement methods on future bridge projects. 144 References 1. AASHTO (2010). 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Hallenbeck, M., Rice, M., Smith, B., Cornell-Martinez, C., Wilkinson, J (1997). ?Vehicle Volume Distributions by Classifications.? Washington State Transportation Center. July 1997 14.Harvey, B.. (2011). ?Design & Construction of Rapid Bridge Deck Replacement Systems?. MS thesis. Auburn University, 2011. 15. Menard, R. Why Precast Cost Less. 2010. 18 April 2011. 16. Mistry, V. and A. R. Mangus (2006). "Get in, stay in, get out, stay out." Public Roads 70(Compendex): 1. 17. Montgomery, D.C. (2005) Design and Analysis of Experiments. 6th ed. Hoboken, NJ: John Wiley & Sons, Inc. 18. Naoum, S. G. (1994). "Critical analysis of time and cost of management and traditional contracts." Journal of Construction Engineering and Management 120(Compendex): 687- 705. 146 19. Ramey, D. G. E. and R. S. Oliver (1998). "Rapid Rehabilitation/Replacement of Bridge Decks". Montgomery Auburn University. 20. Salem, O., B. Basu, Miller, R., Randall, J., Swanson, J., and R. Engel. (2006). 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Practice Periodical on Structural Design and Construction 12(Compendex): 48-58. 147 Appendices Appendix A: Road User Cost Template Appendix B: Contractor Exit Survey Appendix C: ALDOT plan set for Project No. BR-1059 148 Appendix A Road User Cost Template 149 (Insurance per year / 8760) (Insurance per year / 8760) RUC from Autos for lane($) RUC Trucks for lane ($) Note: *i = Finance Rate *P = Vehicle Cost *n = Vehicle Life *F = Salvage Value at End of Life *8760 = Number of hours in one year Results (Realized Cost X Volume X Percentage) (Realized Cost X Volume X Percentage) Total RUC for Lane ($) (Total cost per vehicle hour / 3600)*(delay) (Total cost per vehicle hour / 3600)*(delay) Realized cost per vehicle ($/veh) Realized cost per vehicle ($/veh) (cost after closure - cost before closure) (cost after closure - cost before closure) (Segment / 5280) X (3600 / Speed) (Segment / 5280) X (3600 / Speed) Cost per vehicle before closure ($/veh) Cost per vehicle before closure ($) Cost per vehicle during closure($/veh) Cost per vehicle during closure($) (Cargo value X finance rate / 8760) Total cost per vehicle hour ( $/veh-hr): Total cost per vehicle hour ( $/veh-hr): Travel time before closure (sec) Travel time before closure (sec) Travel time during closure (sec) Travel time during closure (sec) A = (i*(P*(1+i)^n)-F)/((1+i)^n)-1)/8760 A = (i*(P*(1+i)^n)-F)/((1+i)^n)-1)/8760 Insurance cost per vehicle hour($/veh-hr): Insurance cost per vehicle hour($/veh-hr): Inventory cost per vehicle hour($/veh-hr): Value of time per vehicle hour ($/veh-hr): Value of time per vehicle hour ($/veh-hr): (wage X percentage X occupancy) (wage X percentage X occupancy) Amortized cost per vehicle hour ($/veh-hr): Amortized cost per vehicle hour ($/veh-hr): Cargo Value Insurance per Year (Table 5-4): Insurance per Year (Table 5-4): Calculations Autos Trucks Vehicle Life (years) Vehicle Life (years) Vehicle Cost ($) Vehicle Cost ($) Salvage Value at End of Life Salvage Value at End of Life Speed during closure (mph) Speed during closure (mph) Other Operating Costs per Mile (Table 5-4) Other Operating Costs per Mile (Table 5-4) (tires, maintenance, etc.) (tires, maintenance, etc.) Average hourly wage (Table 5-2) Average hourly wage (Table 5-2) Average vehicle occupancy Average vehicle occupancy Speed before closure (mph) Speed before closure (mph) Inputs Finance Rate: Passenger Vehicles Trucks Percentage of hourly wage (Table 5-1) Percentage of hourly Wage (Table 5-1) Percent Passenger Cars (%) Percent Heavy Vehicles (%) Date Period of Closure Analysis Year Volume (veh) Road User Cost Estimating General Information Site Information Project Segment (ft) 150 Appendix B Contractor Exit Survey 151 Were you able to reconstruct the lane span with the following required bridge deck replacement methods in the time period allotted in the contract? Yes No Exodermic Cast In Place Steel Grid Cast In Place NCHRP Pre Cast Exodermic Pre Cast *If No please explain a short description below as to why. (Weather delay, broken equipment, etc?) Rate the learning curve that was required for the bridge deck replacement systems that were constructed. 1 = very difficult to learn 5 = very easy to learn (the second lane span went must faster) 1 2 3 4 5 Exodermic Cast In Place Traditional Method Steel Grid Cast In Place Traditional Method NCHRP Pre Cast Accelerated Method Exodermic Pre Cast Accelerated Method Rate the ease of constructability of each bridge deck replacement method independently. 1 = very difficult to construct a lane-span using this method 5 = very easy to construct a lane-span using this method 1 2 3 4 5 Casting Technique Cast in place Pre Cast Construction Sequence Traditional ( full lane closures) 152 Accelerated (intermittent lane closures) Deck System Exodermic Steel Grid NCHRP Would the contractor prefer working with any particular set of bridge deck replacement methods on future bridge projects? Yes No *if yes please provide the methods or method and a short explanation. Would the contractor oppose working with any particular set of bridge deck replacement methods on future bridge projects? Yes No *if yes please provide the methods or method and a short explanation. 153 Appendix C ALDOT Plan Set for Project No. BR-105 15 4 15 5 15 6 15 7 15 8 15 9 16 0 16 1 16 2 16 3 16 4 16 5 16 6 16 7 16 8 16 9 17 0 17 1 17 2 17 3 17 4 17 5 17 6 17 7 17 8 17 9 18 0 18 1 18 2 18 3 18 4 18 5 18 6 18 7 18 8 18 9 19 0 19 1 19 2 19 3 19 4 19 5 19 6 19 7 19 8 19 9 20 0 20 1 20 2 20 3