An Analytical Investigation of Transverse Joints in Precast-Panel Bridge-Deck Replacement Systems by Brian Mark Rhett A Thesis submitted to the Graduate Faculty of Auburn University in partial fulfillment of the requirements for the Degree of Master of Science Auburn, Alabama December 8, 2012 Copyright 2012 by Brian Mark Rhett Approved by Robert Barnes, Chair, Associate Professor of Civil Engineering Anton K. Schindler, Professor Civil Engineering Hassan Abbas, Assistant Professor of Civil Engineering ii Abstract In recent years precast bridge deck panels have offered a solution for rapid bridge deck rehabilitation by minimizing traffic interruption and accelerating construction. Cracking and early deterioration of the connections between these joints is commonplace, and as more rapid rehabilitation is needed in an ever busier world, the demand for more efficient and effective deck replacement connections has arisen. In an effort to implement a rapid rehabilitation system, the Alabama Department of Transportation commissioned an investigation of these systems. In order to select a system that minimized traffic interruption, an extensive study on rehabilitation systems was conducted, with a focus on eliminating timely post-tensioning from precast deck systems. To assess the feasibility of such a system three separate bridges?one simply supported and two continuously supported?were modeled using a finite-element bridge analysis program. The effects that transverse joints would experience under HS-20 fatigue loading were determined. Based on this modeling and the review of previous studies, guidelines for the future testing and implementation of a transverse joint connection between bridge deck panels are given. Through researching previous studies and finite-element modeling, it was determined that the best transverse connection would be a looped-bar joint for locations experiencing negative flexural stresses or an unreinforced shear key or a looped-bar joint for joints under positive flexure. Under negative bending, it was determined that the top fiber of the joint needed to withstand a tensile stress of at least 256 psi. In the positive bending scenario, the model iii generated tensile stresses of 226 psi in the bottom fiber of the transverse joint. Based on these results laboratory testing is recommended that assesses the fatigue life and performance of joints under a conservative stress of 300 psi. iv Table of Contents Abstract ........................................................................................................................................... ii List of Table ................................................................................................................................... vi List of Figures ............................................................................................................................... vii CHAPTER 1: INTRODUCTION ................................................................................................... 1 1.1 Introduction .......................................................................................................................... 1 1.2 Objective and Scope ............................................................................................................. 4 1.3 Organization of Thesis.......................................................................................................... 5 CHAPTER 2: RAPID DECK REPLACEMENT SYSTEMS, CONNECTIONS, AND PREVIOUS RESEARCH ............................................................................................................ 6 2.1 Introduction .......................................................................................................................... 6 2.2 Rapid Deck Replacement Systems ....................................................................................... 6 2.2.1 Full-Depth Precast Concrete Panels .............................................................................. 6 2.2.1.2 Introduction and History ........................................................................................... 6 2.2.1.3 Implementation and Performance ............................................................................. 7 2.2.2 Exodermic Fully Precast Panels .................................................................................... 8 2.2.2.1 Introduction and History ........................................................................................... 8 2.2.2.2 Implementation and Performance ............................................................................. 9 2.3 Comparison of Transverse Connections ............................................................................. 11 2.3.1 Shear Key Transverse Joint ......................................................................................... 12 2.3.2 Reinforcing Bar Joints ................................................................................................. 17 2.4 Experimental Testing of Transverse Joints ........................................................................ 19 2.5 Summary and Conclusions ................................................................................................. 27 CHAPTER 3: MODELING OF THREE ALDOT BRIDGES ..................................................... 29 3.1 Introduction ........................................................................................................................ 29 3.2 Description of Bridges ........................................................................................................ 29 3.3 Modeling ............................................................................................................................. 30 3.4 Loading ............................................................................................................................... 32 CHAPTER 4: MODELING RESULTS AND DISCUSSION ..................................................... 40 4.1 Organization of Results ...................................................................................................... 40 v 4.2 Results from 60-80-60 ft ALDOT Continuous Span Bridge ............................................. 40 4.2.1 Extreme Positive Moment Case .................................................................................. 40 4.2.2 Extreme Negative Moment Case ................................................................................. 49 4.2.3 Shear Evaluation at CL-1 and CL-2 ............................................................................ 55 4.3 Results from 80-100-80 ft ALDOT Continuous Span Bridge ............................................ 59 4.3.1 Extreme Positive Moment Case .................................................................................. 60 4.3.2 Extreme Negative Moment Case ................................................................................. 62 4.4 Results from Collinsville Bridge (Simple Span) ................................................................ 64 4.4.1 Extreme Positive Moment Case .................................................................................. 65 4.5 Summary and Conclusions ................................................................................................. 69 CHAPTER 5: TRANSVERSE JOINT INVESTIGATION ......................................................... 71 5.1 Transverse Joint Selection .................................................................................................. 71 5.2 Testing ................................................................................................................................ 72 5.2.1 Introduction ................................................................................................................... 72 5.2.2 Positive Bending Test.................................................................................................. 723 5.2.1 Negative Bending Test ................................................................................................ 727 5.2.1 Shear Reversal Test ....................................................................................................... 80 6 CHAPTER 6: SUMMARY, CONCLUSION, AND RECOMMENDATIONS ....................... 85 6.1 Summary ............................................................................................................................. 85 6.2 Conclusions from Research and Modeling ......................................................................... 86 6.3 Recommendations for Future Study ................................................................................... 87 APPENDIX A: Max Moment Comparisons ................................................................................. 92 APPENDIX B: Transverse Stress Plots ........................................................................................ 94 APPENDIX C: Bridge Schematics ............................................................................................. 145 vi List of Tables Table 2.1: Initial Joint Concrete P.T. Stress Level Recommendations for Precast Deck Panels . 16 Table 2.2: Tests AnalyzingFull-Depth Precast Concrete Deck Panel Transverse Joints ............. 26 Table 3.1: Comparison of Moments ............................................................................................. 35 Table 4.1: Stresses at CL-2 due to Positive Moment Truck Loading (60-80-60 Bridge) ............. 45 Table 4.2: Positive Moment Service Load Stresses at CL-2 ........................................................ 49 Table 4.3:Stresses at CL-1 due to Negative Moment Truck Loading (60-80-60 Bridge) ............ 52 Table 4.4: Negative Moment Service Load Stresses at CL-1 ....................................................... 53 Table 4.5: Stresses at CL-2 due to Positive Moment Truck Loading (80-100-80 Bridge) .......... 62 Table 4.6: Stresses at CL-1 due to Negative Moment Truck Loading (80-100-80 Bridge) ......... 64 Table 4.7: Stresses at CL-1 due to Truck Loading (Simple Span Bridge) ................................... 67 Table 5.1: Critical Stresses at Worst-Case Joint Locations .......................................................... 73 Table 5.2: Positive Bending Loading Matrix ................................................................................ 75 Table 5.3: Testing Schedule .......................................................................................................... 77 Table 5.4: Negative Bending Loading Matrix .............................................................................. 80 Table 5.5: Critical Stresses and Shear at Worst-Case Joint Location ........................................... 83 Table 5.6: Shear Test Loading Matrix .......................................................................................... 83 vii List of Figures Figure 1.1: Typical Deck Panel with Grouted Transverse Joints (Yamane et al. 1998) ................. 2 Figure 1.2: Revised Exodermic Bridge Deck System (EBDI 2010) .............................................. 3 Figure 2.1: Revised Exodermic Bridge Deck System (EBDI 2011) .............................................. 9 Figure 2.2: Typical Section at Panel Splice (EBDI 1011) ............................................................ 11 Figure 2.3: Typical Deck Panel with Grouted Transverse Joints (Yamane et al. 1998) ............... 12 Figure 2.4: Various Male-to-Female Shear Keys (Swenty 2009) ................................................. 13 Figure 2.5: Typical Female-to-Female Shear Keys (Swenty 2009) ............................................. 14 Figure 2.6: UDOT Standard Connection (Utah Department of Transportation 2008) ................. 14 Figure 2.7: A Typical Reinforcing Bar Joint before Grouting (Swenty 2009) ............................. 18 Figure 2.8: Alternating Looped-Bar Joint (Ryu 2007) ................................................................. 18 Figure 2.9: Embedded Reinforcing Bar Joint (Badie et al. 2006) ................................................ 19 Figure 2.10: Typical Shear Key Tests (Issa 2003) ........................................................................ 21 Figure 2.11: Joints Tested by M. Swenty (2009) .......................................................................... 23 Figure 2.12: Negative Bending Testing Setup (Swenty 2009) ..................................................... 24 Figure 2.13: Negative Flexural Testing conducted by Chapman (2010) ...................................... 25 Figure 3.1: Typical Transverse Cross Section of Bridges ............................................................ 30 Figure 3.2: AASHTO Truck Loading Scenarios (AASHTO 2007) ............................................. 34 Figure 3.3: Top Fiber Stress Comparisons at Midspan (Simple Span Bridge) ............................. 37 Figure 3.4: Transverse Truck Position 0 (TR-0) ........................................................................... 37 Figure 3.5: Transverse Truck Position 18 (TR-18) ....................................................................... 38 Figure 3.6: Loading of Bridge and Direction of Traffic ............................................................... 39 Figure 4.1: Critical Locations for 60-80-60 Continuous Bridge ................................................... 41 Figure 4.2: Longitudinal Plot of the Effects of TR-13 on CL-2 (60-80-60 Bridge) ..................... 41 Figure 4.3: Longitudinal Position for Extreme Positive-Flexure Stresses (60-80-60 Bridge) ..... 42 Figure 4.4: Maximum Stresses per Position due to Positive Flexure (60-80-60 Bridge) ............. 43 Figure 4.5:Transverse Truck Positions TR-3, 5, 11, and 13 Loading Middle Between Girders .. 43 viii Figure 4.6: Transverse Truck Positions TR-1, 7, 9, 15, and 17 Loading the Girders ................... 44 Figure 4.7: Deck Stresses due to TR-13 at Critical Location 2 (60-80-60 Bridge) ...................... 46 Figure 4.8:Deck Stresses due to TR-11 at Critical Location 2 (60-80-60 Bridge) ....................... 47 Figure 4.9: Deck Stresses due to TR-0 at Critical Location 2 (60-80-60 Bridge) ........................ 47 Figure 4.10:Longitudinal Position of Truck for Negative-Flexure Stresses (60-80-60 Bridge)... 50 Figure 4.11: Longitudinal Plot of the Effects of TR-13 on CL-1 (60-80-60 Bridge) ................... 50 Figure 4.12: Stresses per Transverse Position due to Negative Flexure (60-80-60 Bridge)......... 51 Figure 4.13: Deck Stresses due to TR-18 at Critical Location 1 (60-80-60 Bridge) .................... 53 Figure 4.14: Deck Stresses due to TR-13 at Critical Location 1 (60-80-60 Bridge) .................... 54 Figure 4.15: Deck Stresses due to TR-0 at Critical Location 1 (60-80-60 Bridge) ...................... 54 Figure 4.16: Shear experienced at Transverse Cross-Section CL-2 (60-80-60 Bridge) ............... 56 Figure 4.17: Longitudinal Plot of Shear at Transverse Position 16 as TR-13 passes (CL-2) ...... 57 Figure 4.18:Shear experienced at Transverse Cross-Section CL-1 (60-80-60 Bridge) ................ 57 Figure 4.19: Longitudinal Plot of Shear at Transverse Position 12 as TR-13 passes (CL-1) ....... 58 Figure 4.20: Moment and Shear Diagrams for CL-1 .................................................................... 59 Figure 4.21: Moment and Shear Diagrams for CL-2 .................................................................... 59 Figure 4.22: Stresses per Transverse Position due to Positive Flexure (80-100-80 Bridge) ........ 61 Figure 4.23: Deck Stresses due to TR-13 at Critical Location 2 (80-100-80 Bridge) .................. 61 Figure 4.24: Stresses per Transverse Position due to Negative Flexure (80-100-80 Bridge)....... 63 Figure 4.25: Simple Span Bridge Critical Truck Location ........................................................... 65 Figure 4.26: Stresses per Transverse Position due to Positive Flexure (Simple Span Bridge) .... 66 Figure 4.27: Deck Stresses due to TR-13 at Critical Location 1 (Simple Span Bridge) .............. 68 Figure 4.28: Deck Stresses due to TR-18 at Critical Location 1 (Simple Span Bridge) .............. 68 Figure 5.1: Positive Bending Test Setup....................................................................................... 74 Figure 5.2: Strain Gauge Setup ..................................................................................................... 75 Figure 5.3: Stresses Experienced in Critical Joint as Truck Passes Over Bridge ......................... 79 Figure 5.4: Shear Experienced at Critical Joint as Truck Passes Over Bridge ............................. 79 Figure 5.5: Negative Bending Test Setup ..................................................................................... 80 Figure 5.6: Shear Experienced in Critical Joint as Truck Passes Over Bridge ............................. 81 Figure 5.7: Stress Experienced in Critical Joint as Truck Passes Over Bridge ............................ 82 Figure 5.8 Shear Test Setup .......................................................................................................... 83 ix Figure 5.9: Strain Gauge Setup ..................................................................................................... 84 x List of Abbreviations AASHTO?????..American Association of State Highway and Transportation Officials ALDOT??????.Alabama Department of Transpiration ASTM?????...?American Society for Testing and Materials DOT(s)??????..Department(s) of Transportation FHWA??????...Federal Highway Administration PCI????????Precast/Prestressed Concrete Institute NCHRP??????.National Cooperative Highway Research Program 1 1 CHAPTER 1: INTRODUCTION 1.1 Introduction With roughly 80,000 bridges in the United States being rated as structurally deficient, a key issue facing transportation officials today is the rehabilitation of such bridges (FHWA 2007). The Alabama Department of Transportation (ALDOT) maintains over 3 miles, or 600,000 ft 2 , of bridge deck near downtown Birmingham with considerable deck deterioration and cracking. Crowded thoroughfares and roadways such as these have generated great demands for unobtrusive construction techniques that minimize traffic congestion and detours. For the rehabilitation of bridge decks, it is apparent that rapid bridge construction techniques provide a solution to minimize traffic interruptions and meet public demands. There are numerous types of rapid bridge-deck replacement options, and they all provide a new riding surface within a fraction of the time that it would take to conventionally replace a deficient bridge deck. The process is fairly simple: a precast deck panel is formed and cured away from the construction site, and while the units are being installed, they are typically joined with a grouting material between panel joints (Figure 1.1). This off-site fabrication minimizes curing times to that of the cast-in-place grouting materials, which in turn allows bridge construction to be completed with minimal closures or, in many cases, only partial bridge closures. Despite these benefits, a main issue deterring transportation agencies from using these rapid bridge-deck replacement options is the service life of the joints. Many of these deck panel connections, especially the transverse joints, have a history of early deterioration and cracking problems (Biswas et al. 1986; Issa et al. 1995). More elaborate reinforcement methods and improvements to the cold transverse joint have been made in recent years; however, these 2 options tend to complicate construction and can further extend a bridge?s closure time. Additionally, agencies are further pushing for replacement methods that can be used in bridges with more demanding loading and service requirements (Issa et al. 1995a). Figure 1.1: Typical Deck Panel with Grouted Transverse Joints (Yamane et al. 1998) When considering the use of precast panels for high-volume bridges, ALDOT decided to first test the system on bridges with lower traffic volumes. They elected two sister bridges located near Collinsville, Alabama in order to verify the systems effectiveness and assess any issues. Additionally, ALDOT set parameters that the deck panels should meet. ALDOT required that the transverse deck system connection ? Be suited for rapid deck replacement ? Be a proven concept ? Avoid the use of longitudinal post-tensioning ? Provide adequate durability and fatigue life ? Avoid the use of an overlay 3 By following these directives, effort was devoted to two deck replacement options: exodermic fully precast and full-depth precast concrete panels (Figures 1.2 and 1.3). Both of these panel systems meet the listed requirements above, and they both have a variety of transverse panel joint connection options. Figure 1.2: Revised Exodermic Bridge Deck System (EBDI 2010) Figure 1.3: Typical Full-Depth Precast Panel (Culmo 2000) Clearly, the use of a rapid replacement system is a complex and technical issue that requires careful consideration to assess practicality in construction, acceptable serviceability, and minimization of traffic interruption. 4 1.2 Objective and Scope The primary objective of this research was to investigate the feasibility and recommend testing procedures for the laboratory assessment of transverse connection types for precast decks. Through the use of computer modeling and by researching previous studies, testing criteria were developed to assess the durability, performance, and serviceability of a transverse-joint connection type over the expected life of the deck system. Both exodermic and full-depth precast panels offer a variety of connection options. After researching and assessing these connections, three main transverse joint connections were found to meet ALDOT requirements: a standard female-to-female joint, an alternating looped-bar joint, and the reinforced joint based on NCHRP Report 584 (2008). These joints have diverse performance histories, some offer sacrifices in construction speed for better durability, while others are more proprietary and do not have a clear in-field performance record. However each of these joints offer a potential solution to the transverse connection issues, as each has the durability and effective constructability that is vital in rapid deck replacement systems. In order to accurately assess these joints for in-field performance, the Collinsville simple- span bridges were modeled using a finite-element program. From this analysis, the stresses and other key force effects that the deck and the joint might experience were established. Additionally two standard drawings for continuous-span bridges were obtained from ALDOT and modeled to establish what this system might experience in negative flexure. The worst-case truck loading scenarios were established based on AASHTO LRFD, and these stresses were recorded and used to create testing criteria for transverse joints. 5 1.3 Organization of Thesis The first phase of this project, which is documented in Chapter 2, involved a thorough investigation of the deck replacement options, including an investigation of some transverse connection methods and available rapid redecking panels. The performance of these systems in representative projects and also recommended improvements and design concerns were all researched to form conclusions regarding each system?s capacity for constructability and serviceability. Prior methods of laboratory testing for these various joints were also documented in order to recommend appropriate testing procedures. The second part of this study involved a finite-element analysis of the bridge itself. Using SAP2000, the widened Collinsville bridges and two other ALDOT bridges were modeled to determine the effects the joints will likely experience. Chapter 3 outlines the modeling setup and methodology, while Chapter 4 presents the modeling results. As a result of this research, Chapter 5 presents testing procedures and criteria that are recommended for future laboratory assessment of the transverse joining methods for precast deck panels. Various testing systems, their rationale, and general testing procedures are presented. Finally, Chapter 6 summarizes conclusions and recommendation for the whole of this research project. 6 2 CHAPTER 2: RAPID DECK REPLACEMENT SYSTEMS, CONNECTIONS, AND PREVIOUS RESEARCH 2.1 Introduction This chapter is divided into three major sections: the first is an overview of the various rapid deck replacement systems, the second explores the various transverse deck joint options, and the third summarizes past transverse deck joint testing, modeling, and research. In the first two sections a detailed description of either the deck system or joint will be given. These descriptions include the history, implementation, and past performance of the deck system or joint, with the third section providing an overview of relevant testing previously conducted on the transverse joints. The information gained from previous research and performance helped guide the modeling process described in this report. 2.2 Rapid Deck Replacement Systems The advantages of minimizing traffic disruption by implementing a rapid bridge-deck replacement have prompted many transportation agencies to fund studies and further research in hopes of devising more efficient and pragmatic systems. The two rapid deck replacement systems under consideration by the Alabama Department of Transportation are full-depth precast concrete panels and exodermic panels. Their performance, excluding joint connections, is discussed in the following sections. 2.2.1 Full-Depth Precast Concrete Panels 2.2.1.1 Introduction and History Full-depth precast concrete panel systems have seen a dramatic increase in usage since the early 1970?s (Yousif 1998). In this type of system, virtually the entire bridge deck can be cast off-site, minimizing in-field casting to the connection of slabs and closures. These advantages 7 have spurred an increase in full-depth precast panel research beginning with an investigation of feasibility and performance in 1975 (Kluge et al.). In the 1980?s, the PCI Bridge Committee conducted two separate surveys to confirm the growth and analyze the different construction methods for this system (PCI 1987); these results later became the first recommended practice for precast panel construction (PCI 1988). In 1998, ASTM introduced a standard for the laboratory testing of bridge decks, which gave guidelines for the testing of bridge deck modules (ASTM D6275 1998). Although this standard was withdrawn in 2004, many designers are still using the withdrawn standard as a guideline for precast panel design, as commonly recognized bridge standards include little information relevant to these types of deck panels (Higgins 2010). AASHTO LRFD section 9.7.5 (2008) briefly discusses full-depth panels but gives no guidelines on connectors or grouting. New standards and practices for the design and testing of full-depth precast concrete panels continue to be developed; however, the vast majority of these recommend longitudinal post-tensioning, which is not congruent with the stated directives of this research study listed in Section 1.1. 2.2.1.2 Implementation and Performance The most widely implemented precast deck panel system is full-depth precast panel rehabilitation. These panels have been successfully used in a variety of bridge types including bridges with skewed, superelevated, and crowned profiles as well as bridges with different substructures (Issa et al. 1995a). Issa et al. (1995) conducted a survey of the different rapid construction techniques used in the United States and Canada, finding that 13 of the 51 DOTs surveyed reported using full- depth precast concrete panels (Issa et al. 1995a). It was found that the majority of these 8 departments had designed their own precast panels producing many varieties of joint designs. From these designs, Issa et al. concluded that an effective deck panel system included an efficient construction sequence, transverse prestressing, longitudinal post-tensioning, an appropriate connection between the slab and supporting system, and the appropriate grouting of panel to panel joints (Issa et al. 1995b). Issa et al. (1998) later conducted a quantitative study to determine the amount of post-tensioning needed for adequate performance in full-depth precast bridges. They concluded that a minimum average compressive stress of 200 psi from longitudinal post-tensioning was required for simple span bridges, while continuous span bridges required 450 psi at interior supports (negative moment regions) and 200 psi at the bridge?s midspan. These recommended prestress amounts have since been standard in many precast panel bridge designs. 2.2.2 Exodermic Fully Precast Panels 2.2.2.1 Introduction and History An ?exodermic?, or composite unfilled steel grid deck, comprises a thin reinforced concrete slab made composite with a steel grid that remains void of concrete in construction as depicted in Figure 2.1 (EBDI 2011). This design utilizes the compressive strength of concrete while minimizing weight, as the tensile region of the slab is comprised of the unfilled steel grid. Developed in the early 1980?s, this rapid deck replacement option builds on the durable record of steel grids, while introducing the economy of concrete to make a lighter deck when compared to full-depth concrete decks. The first project using exodermic panels was the 1984 widening of the Driscoll Bridge in New Jersey (Bettigole 1997). Earlier projects were cast-in-place, and exodermic decks were later modified from this original design to include a simpler shear transfer mechanism for a more efficient installation and for improved performance of the deck system. 9 More prominent examples of exodermic decks include the 1998 rehabilitation of New York?s Tappan Zee Bridge, which has become a major project in assessing the performance and validity exodermic deck systems (Caltrans 2003). Although this system is said to perform similar to full- depth precast concrete panels, no research has been conducted to assess exodermic transverse joint connection behavior compared to similar connections on full-depth concrete specimens. Figure 2.1: Revised Exodermic Bridge Deck System (EBDI 2011) 2.2.2.2 Implementation and Performance Exodermic deck units have the option of being fully precast or cast-in-place, however only precast exodermic decks are relevant to this study. A precast exodermic deck behaves similar to a full-depth precast concrete panel in installation with the main exception being the connection of the exodermic panels to the girders. A main advantage for exodermic installation is that the typical weight of these panels ranges from 44 to 84 psf, which represent weight reductions up to 60 percent when compared to other deck rehabilitation systems (Bettigole 1997). This weight reduction is significant in that it allows an increase in the load capacity of 10 the bridge and can also help bring an aging bridge substructure into compliance with design code provisions. A typical exodermic unit ranges from 6.5 to 10 inches in thickness, and these units are typically 6 to 10 ft long with some of the longest panels spanning over 18 ft (EBDI 2010). An early project using exodermic decks was the rehabilitation of the Russell Road Bridge in New York. Like most of the earlier exodermic projects, this bridge?s deck was replaced with a cast-in-place exodermic deck system, which performed well and was comparable to full-depth cast-in-place concrete panels in both performance and installation (Darlow et al. 1989). A precast system was implemented in 1998 on the east deck truss of the cantilever Tappan Zee Bridge in New York (Caltrans 2003), and a later study conducted by Caltrans (2003) concluded that the exodermic decks offered all the same advantages of typical precast panels: they permit rapid construction, are lighter, are easy to install and maintain, and permit partial bridge closures . Since the Tappan Zee rehabilitation, exodermic usage began to spread more rapidly out of the New England region. Florida and many Midwestern states like Wisconsin have rehabilitated bridges with this system, and the majority has performed adequately to date (WDOT 2010). Exodermic deck application has been used in many different bridge types ranging from cantilever to bascule bridges. The most common problems experienced are deck panel connection deterioration and concrete shrinkage cracking, often seen when high performance concrete is used in the panel (Kaczinski 2010). Additionally, some structural cracking has been noted, usually occurring in negative moment regions where no additional reinforcement was included in the upper concrete section (Kaczinski 2010). Overall the exodermic system has performed comparable to full-depth precast concrete panels (Caltrans 2003), especially in terms of transverse joint connection issues; however, there are no comparative studies assessing the performance of exodermic transverse joints against full-depth precast joints. Figure 2.2 shows an 11 EBDI recommended transverse joint section, and given the complexity of this configuration when compared to full-depth precast transverse joints, an assessment between this system and an equivalent full-depth precast system should be made. Figure 2.2: Typical Section at Panel Splice (EBDI 1011) 2.3 Comparison of Transverse Connections Individual deck panels can be connected longitudinally (with joint running parallel to the girders, the length of the bridge) or transversely (with joint running across the width of the bridge as shown in Figure 2.3). These connections can be made through closure pours, mechanical connections, or a variety of other options. Joints are designed to protect the connecting panels from relative vertical movement and transfer vehicular loads to the next panel smoothly. Some of the first research conducted on precast deck panel connections was conducted by Biswas et al. (1984), and since then there has been a consistent problem with the construction and performance of these joints. Issa et al. (1995a.) determined from a nationwide 12 survey that one of the major issues deterring DOTs from using rapid bridge deck rehabilitation was cracking and early deterioration of the connecting joints. Since their report, much effort has been made toward finding better connections that can meet acceptable standards of constructability and serviceability. While advancements have been made, most previous research focuses solely on positive bending in simply supported bridges; little research has been done to compare the performance of different transverse joints experiencing negative flexure. Figure 2.3: Typical Deck Panel with Grouted Transverse Joints (Yamane et al. 1998) 2.3.1 Shear Key Transverse Joint Shear keys are typically unreinforced joints that connect two panels together. As shown in Figure 2.4, male-to-female joints, usually involve a male end that mates with another female end to form a connection, which is epoxied closed. These joints are known to experience extreme stress concentrations and can be difficult to mate during construction (Issa et al. 1995b) Furthermore, male-to-female joints require that panels be slid together making an issue as to the connection of the deck panel to the girder. For these reasons, and a poor performance record 13 when compared to female-to-female joints (Sullivan 2007), male-to-female joints are no longer commonly used. Figure 2.4: Various Male-to-Female Shear Keys (Swenty 2009) Female-to-female shear keys are currently the most commonly used unreinforced joint for transverse connections, based on their performance and ease of installation. A female-to- female joint involves two matching female joints that have a grouted gap in between them that creates a cold joint connection as indicated in Figure 2.4. This grout pocket prevents the high stress concentrations that male-to-female joints experience, and this pocket should be grouted with a high-strength, non-shrink grout (Yousif 1998). There are many variations including unreinforced, welded, and post-tensioned connections. Unreinforced connections are fairly common, but they have an unclear performance record, as some of these joints have been known to crack, leak, and have difficulties with the spalling of concrete (Issa et al. 1995b) However, these problems continue to be reduced due to better grouting materials and improved construction standards (Culmo 2003; Swenty 2009). Increased attention paid to the joint and panel interface, such as sand blasting, has also greatly reduced debonding cracking and other joint failures (Issa et al. 2003). Various forms of welded connections have been developed, and the typical design usually involves a plate anchored into each side of the shear key. Once the panels are placed, a joining rod is welded on both sides to join the two separate plates to the rod, thus completing the welded connection so that grout can used to fill the joint. This joint has been known to experience similar issues as unreinforced shear key joints, in that cracking and leaking 14 were found to be common (Issa et al. 1995b). An example of a welded connection successfully used on an I-84 bridge by the Utah Department of Transportation can be seen in Figure 2.6 (Porter 2009). Figure 2.5: Typical Female-to-Female Shear Keys (Swenty 2009) Figure 2.6: UDOT Standard Connection (Utah Department of Transportation 2008) The most proven transverse shear key is the female-to-female longitudinally post- tensioned joint. By post-tensioning a joint, the joint?s connection becomes tighter, and this post- tensioning force helps maintain joint compression and prevents cracking in both the joint and the deck panel, thus improving the overall behavior of the deck panel system (Issa et al. 2000). Through post-tensioning, deck compression can be maintained through a bridge?s entire service life, and thus mitigate cracks and the infiltration of corrosive materials (Swartz 2008). Although 15 the nationwide survey conducted by Issa et al. did find some issues of cracking and leaking, these problems were attributed to poor construction practices and proprietary grouting materials (1995a). Issa et al. (2000) later noted that ?the biggest cause of any adverse effects (for bridge decks) was the lack of post-tensioning in the longitudinal direction of the structure to secure the tightness of the joints." Originally, Issa et al. (1995b.) recommended a minimum of 150 psi of longitudinal post-tensioning to be applied to simply supported bridges while roughly 300 psi should be applied to continuous span bridges. Since Issa et al.?s survey (1995b.), much testing and observation has been conducted to determine adequate longitudinal post-tensioning levels. Ranging from finite-element modeling to full-scale bridge specimens and in-field data, the majority of these findings determined that approximately 200 psi of post-tensioning is required for simple span bridges while 300 psi or more is required for continuous span bridges. A summary of these recommended stresses and the type of research conducted can be seen in Table 2.1. 16 Table 2.1: Initial Joint Concrete Post-Tensioning Stress Level Recommendations for Precast Deck Panels Bridge Type Stress Level Notes Reference Continuous Span* 340 psi Representative bridge (Swenty 2009) Simple Span* 200 psi (Bowers 2007), (Sullivan 2007) Continuous (2 Span) 500 psi Prototype bridge (Issa et al. 2007) Simple/Continuous* 150 psi/ 300 psi After losses (Issa 2002) Continuous (2 Span models) 208 psi & 308 psi (Issa et al. 2000) 1 Span FEM model* 200 psi Did not include losses (Issa et al. 1998) 3 Span FEM model* 450 psi 18 Simple Spans ~150 psi Bridges that performed well over time (Issa et al. 1995b.) 1 Continuous Span 300 psi Continuous (2 Span models)* 290 psi (Shim and Chang 2002) All Spans 200 psi After losses (Precast/Prestressed 2002) 2 Simple Spans 200 psi (Babaei et al. 2001) 3 Bridges 250 psi (Culmo 2000) Simple Span 200 psi (Yamane et al. 1998) Continuous Span 200-800 psi Based on study *Modeled with Finite-Element Program 17 2.3.2 Reinforcing Bar Joints Reinforcing bar joints are typically female-to-female shear keys that are simply spaced farther apart to allow the development of reinforcing bars within the grouted joint as shown in Figure 2.7. They are rarely post-tensioned and therefore crack when loaded in a continuous composite deck (Swenty 2009). The main issue observed with reinforced joints has been durability, especially in the earlier projects from the 1970?s (Biswas 1974). Durability simply refers to a joint's capacity to handle repetitive truck loadings without inappropriate degradation. This degradation can be caused by the truck itself, or by subsequent issues, such as infiltration, due to cracking induced from the truck's loading. Issa et al. (1995b.) confirmed again that durability was a major issue in joints without post-tensioning, by investigating the in-field performance of numerous joints. The most commonly used reinforced joint in practice is the looped joint. They can either be connected in place by tying rebar loops between panels (Figure 2.7) or they can alternate in an offset splice configuration (Figure 2.8). The Ministry of Transportation in Ontario Canada has devised a connection similar to both Figures 2.7 and 2.8. They conducted a number of scaled tests to verify these joints; however, the results only confirmed that these joints perform satisfactorily under positive flexural stresses (Au et al. 2008). Swenty (2009) conducted tests on a looped-bar connection joint and found that it performed satisfactory under the design life specified by the Virginia DOT; however, he did note that the post-tensioned female-to-female key he tested performed much better. He observed that reinforcing bar joints inevitably experience leakage due to noteworthy cracking (Swenty 2009). Furthermore, research at the University of Tennessee investigated alternating looped-bar joints using 4 deck panel specimens and determined that, under both positive and negative bending moments, this type of joint does 18 provide a viable connection option (Zhu 2010). However, some cracking did occur in these joints, and the University of Tennessee joint was not assessed for infiltration of foreign materials. Figure 2.7: A Typical Reinforcing Bar Joint before Grouting (Swenty 2009) Figure 2.8: Alternating Looped-Bar Joint (Ryu 2007) A proprietary reinforcing bar joint system was proposed by Badie et al.(2006 )and was published by NCHRP in 2008 (Badie et al. 2008). A diagram of the NCHRP joint is shown in Figure 2.9. They developed a connection system for full-depth precast concrete bridge deck panels that did not require the use of an overlay or post-tensioning. This system involves elongated joint HSS tubing cast near the joint. The HSS tube has a cut slot that allows a rebar section to be dropped in the tube thus creating a spliced connection when the joint and tubes are 19 grouted. The joints developed were found to not leak water or crack after being tested in high fatigue cyclic tests (Badie et al. 2006). In addition the NCHRP Report 584 joint is fairly simple to construct, especially when compared to looped rebar joints, which can be tedious to connect. Figure 2.9: Embedded Reinforcing Bar Joint (Badie et al. 2006) Other reinforced joints designed through various combinations of the female-to-female shear keys and reinforcing bar joints have been developed in past years and have been implemented somewhat effectively; however, these systems remain proprietary and are limited in wide usage based on constructability issues (Versace 2004). The main challenges in reinforcing bar joints is finding a design that can be installed easily and quickly while still providing adequate reinforcement and performance. While better joint connections are being developed, Reinforcing bar joints will continue to be unreliable until a joint can provide consistent long-term performance (Swenty 2009). 2.4 Experimental Testing of Transverse Joints Transverse joints are primarily subjected to two types of forces: a vertical shear force and a bending moment (Badie et al. 2006). The shear force acts vertically to break the bond between 20 the grout and the panel joint, while the moment places two portions of the joint in compression or tension, depending on the positive or negative flexure. Many tests have been devised to assess these joints over the years, with some testing a connection?s shear, moment, or axial capacities, while other attempt to mimic traffic loading. These tests are tailored to the specific purpose of each investigation; there is not an official recognized standard to validate the methodologies utilized. This section summarizes the progression and current practice for experimental testing of transverse joints, with more attention given to the few studies that analyzed joints without post- tensioning under negative flexure. Some of the earlier tests assessing transverse deck panel connections have assessed a connection under one force effect, instead of a combination of forces as seen in actual truck loading. Pure shear testing is one such a test. A typical way to accomplish this test is through connecting two ?L?-shaped specimens and joining these sections with a shear key as seen in Figure 2.10a. The specimen is then loaded on the top and/or bottom to determine the maximum pure shear capacity of the joint. In order to further assess a joint?s performance a tensile test and a flexural test are usually conducted as seen in Figures 2.10b and 2.10c, respectively. For tensile tests two slabs are connected using the desired joint and then pulled apart until failure. The flexural test involves applying a moment to the joint, without any shear, thus determining a joint?s behavior in bending. These methods have typically been used to assess grouts, although many researchers have used them to also assess the performance of a particular joint (Backhoum 1991; Gulyas 1995; Issa et al. 2003). These tests are effective in the determination of a joint?s capacities; however common problems for transverse joints have historically involved fatigue performance and infiltration of water and other foreign materials (Issa et al. 1995a). Due to this 21 fatigue issue, many researchers have used more comprehensive tests to validate deck connections. Figure 2.10: Typical Shear Key Tests (Issa 2003) 22 Badie et al. (2006) tested a full scale bridge model to assess the performance of the reinforced joint proposed by NCHRP Report 584. By using one axle load of a HS-20 design truck, they applied a positive moment and simultaneous shear to the joint, which experienced this fatigue-level loading for 2,000,000 cycles. Badie et al. (2006) observed no separation between the grout and the vertical surface of the joint, nor was there any tensile cracking on the bottom surface of the joint. Overall this joint performed satisfactorily, and is recommended for use in simply supported structures. Some more recent research on reinforcing bar joint systems has shown promise for designers. Swenty (2009) conducted research at Virginia Polytechnic Institute comparing various types of joints including two different reinforcing bar joints. Swenty?s approach to testing involved a scaled laboratory bridge based on an existing bridge in Southwest Virginia. This continuous bridge was built with transverse joints located directly above the piers of the structure. Under traffic loading, this location produced negative bending behavior in the joints. The resulting tensile stresses have long been known to be detrimental to these joints, so three standard joint systems were devised to assess which joints could perform adequately. Figure 2.11 shows the joints tested: an embedded rebar joint similar to NCHRP 584, a looped reinforcing bar joint, and two post-tensioned female-to-female shear keys. As can be seen in Figure 2.12, Swenty (2009) placed the transverse joints in pure negative flexure. Steel girders were utilized, as previous research indicated that steel girders provide the worst-case situation for deck panel joints (Bowers 2007). The joints were designed to withstand the factored design moments from service loads. Stress levels were calculated using finite-element analysis, and they were designed to be the same as the stress level produced from loading the real bridge. The test consisted of 1,000,000 cycles of fatigue loading, and at various points during these cycles, 23 loading was stopped in order to conduct ponding tests for leakage. A HS-20 truck loading was used for practicality, although it was found that the HL-93 loading, a combination of the HS-20 truck and lane loading produced slightly higher stresses (Swenty 2009). Figure 2.11: Joints Tested by M. Swenty (2009) 24 Figure 2.12: Negative Bending Testing Setup (Swenty 2009) Overall, Swenty's (2009) study found that the two post-tensioned joints performed the best. The 340 psi post-tensioned joint experienced the smallest cracking and no leakage, while the 167 psi post-tensioned joint experienced the second largest cracking with no leakage. The looped-bar joint experienced the second smallest cracking, however when simultaneously loaded and tested with water ponding, 75 percent of the joint leaked water. The only joint to perform unacceptably was the embedded rebar joint, based on NCHRP 584, with large cracking and full leakage. Swenty noted that all joints, except the 340 psi post-tensioned joint, experienced acceptable but immediate cracking under top-fiber tensile loading from negative bending (Swenty 2009). He also observed that shrinkage cracking between the concrete and grout interface of the joint will occur if no surface preparation is used, regardless of the joint. In conclusion, Swenty's (2009) testing found that if longitudinal post-tensioning on a female-to- female shear key is not an option, a looped-bar joint (Figure 2.11b) would perform satisfactory. Researchers at the University of Tennessee conducted another study on negative flexure in reinforced looped-bar transverse joints (Chapman 2010). By testing four separate reinforced looped-bar joints with varying development lengths and spacings, Chapman was able to confirm that some looped-bar joints can perform successfully under negative flexure. Figure 2.13 shows 25 the testing setup utilized. Related testing of the pure tensile capacity under fatigue loading showed promising results for this looped-bar joint (Zhu 2010). Figure 2.13: Negative Flexural Testing conducted by Chapman (2010) Transverse joint tests range from simple shear push-off tests and pure-flexural tests to scale-model bridges with joints experiencing both shear and moment simultaneously. Although extensive testing of transverse joints has been conducted over the years, there are few tests that address negative bending nor are there many tests addressing shear and moment simultaneously applied to a joint. Tests are generally conducted on full-depth precast panels, without any testing exodermic deck connections? behavior. Although the in-service behavior of exodermic deck panels has been consistent with full-depth precast panels (Kaczinski 2010), the lack of studies comparing these deck connections? behaviors is noteworthy. Table 2.2 shows a summary of relevant testing with general notes on how the test was conducted. All of the panels tested were full-depth precast concrete panels, and it can be seen from the table that the vast majority are post-tensioned female-to-female transverse joints. Hardly any of these tests assess different types of joints under the same loading scenarios; most previous tests were conducted to determine the adequacy of a certain joint. 26 Table 2.2: Tests Analyzing Full-Depth Precast Concrete Deck Panel Transverse Joints SOURCE DECK PANEL JOINT(S ) TES T PONDING TEST Loading Load (kips) Fatigue Cycles (Roberts 2009) Post-tensioned Female-to-Female, curved bolt (2) Negative moment with shear HS-20 (axle) 40 N/A N/A (Swenty 2009) Prestressed, post-tensioned Female-to-female (4), reinforced (2) Negative moment with shear HS-20 (axle) 75.5 1,000,000 Interval and Continuous (Sullivan 2007) Prestressed, post-tensioned Female-to-female (2), male-to-female (2) Positive Moment with/without shear HS-20 (wheel) 37.33 2,000,000* Interval (Olivia 2007) Prestressed, post-tensioned Female-to-female (2) Positive moment with shear HS-20 (axle) 40.4 2,000,000 N/A (Issa et al. 2007) Prestressed, post-tensioned Female-to-female (2) Positive/negative moment with shear HS-20 (2 axles) 92 N/A N/A (Badie et al. 2006) Prestressed Spliced Joints (2) Positive moment with shear HS-20 (axle) 42.56 2,000,000* Continuous (Shim 2001) Prestressed, post-tensioned Female-to-female (2) Positive moment with shear HS-25 (wheel) 28.1 2,000,000 N/A (Yamane et al. 1998) Varying Depth; prestressed, post-tensioned Female-to-female (2) Positive moment with shear HS-25 (wheel) 25 2,000,000 Continuous *Referenced ASTM D6275 as utilized standard LOADING 27 2.5 Summary and Conclusions Rapid bridge-deck replacement options are a feasible and effective means of rehabilitating bridges quickly and with minimal disruption of traffic. One of the key issues impeding the implementation of this system is finding an inter-panel connection system that can be installed quickly with sufficient durability and thus adequate service life. There is an abundance of research pertaining to certain areas of this research, however some newer transverse joints and aspects of certain panel systems have been largely avoided and need validation. Based on in-field performance and laboratory testing, the panel-to-panel joints should: ? Have testing focusing on fatigue life, as the failure of most joints in service and in laboratory testing was primarily due to cracking caused by cyclic, fatigue loading. Under the design-life fatigue testing, be designed for no cracking or only minute cracking that allows minimal infiltration of water. ? Be sanded after production and filled with non-shrink grout to minimize shrinkage cracking and debonding at the joint-panel interface (Issa et al. 2003). ? Have no cracks under repeated service loads and no water leakage (Issa 1995a); however, with no longitudinal post-tensioning, cracking and leakage will likely occur. ? Although it does not satisfy ALDOT requirements, previous performance has shown that joints should preferably be longitudinally post-tensioned, as it is the most effective way to maintain transverse joint compression, despite its prolonging of construction time. ? Be a post-tensioned or looped-bar joint, if it is expected to experience negative flexure, as these are the only joints that have consistently performed well in tension loading. 28 ? For positive flexure, some unreinforced shear keys have shown promise based on laboratory testing. An unreinforced shear key, the NCHRP system, looped-bar joint, or a post- tensioned joint all have several studies suggesting they could be applied to simply supported bridges. ? As there is no previous research comparing exodermic-panel transverse joints to full-depth precast transverse joints, testing should be conducted to compare the behavior between the two deck panel systems? transverse joint systems. This testing should assess identical joints under the same conditions in each panel system. In regard to the selection of a precast deck panel, exodermic and full-depth precast systems behavior proved similar based on in-field data. Both are effective in minimizing the disruption of traffic and both are proven methods backed by years of satisfactory in-field performance. The main advantage of exodermic panels is that they can offer a 40-60 percent weight savings over full-depth precast. The main issues of selecting one of these precast systems is cost, weight savings, and considerations as to whether the transverse joint between the systems will behave the same for both full-depth precast and exodermic panels. 29 3 CHAPTER 3: MODELING OF THREE ALDOT BRIDGES 3.1 Introduction The modeling process of the three Alabama Department of Transportation bridges is discussed in this chapter. One of these bridges was selected as it is simply supported bridge that is going to be rehabilitated in the near future. The other two bridges were chosen based on standard bridge designs circa the mid 1950?s; these continuous-span, steel-girder bridges were selected because they are expected to generate the greatest demand on transverse joints among bridges that are potential candidates for deck replacement. 3.2 Description of Bridges The Collinsville Bridge is two sister bridges running alongside one another on I-59 in Collinsville, Alabama and crossing over State Road 68. This bridge was used as the pilot field study to better understand the feasibility and performance of the previously mentioned rapid deck replacement systems. The two sister bridges each consist of simply supported spans of approximately 56 ft. The existing deck is 33 ft 2 in. wide supported by four W36x150 steel girders; however, since the bridge is going to be widened for the rapid rehabilitation study, the widened 46 ft 9 in. deck was used in the modeling process with six W36x150 steel girders with cover plates. A typical cross-section of the deck for all three bridges can be seen in Figure 3.1. The second bridge modeled was a standard bridge type used ALDOT. Standard bridge type B2807 consists of a three-span (60-80-60 ft) continuous bridge with a superstructure design almost identical to that of the Collinsville Bridge. This continuous span bridge has a two-lane design width that is anticipated to be widened if selected for rapid bridge deck rehabilitation, and therefore the bridge deck model was widened to accommodate three lanes supported by six girders. 30 The final bridge modeled was a three span, 80-100-80 ft continuous span bridge design from ALDOT standard drawing B2806. This bridge utilizes larger steel sections than the other two bridges, with four W36x194 girders with cover plates. Like the other two bridges selected for modeling, the width of the deck has been increased to accommodate current AASHTO standards for three lanes of traffic, under six steel girders. The plans for the simple span Collinsville Bridge and the 60-80-60 ft and 80-100-80 ft continuously supported bridges can be seen in Appendix C. Figure 3.1: Typical Transverse Cross Section of Bridges 3.3 Modeling The three bridges were modeled using the finite-element program SAP2000 (Computer and Structures, Inc. 2011). More specifically, the SAP2000 Bridge Modeler Wizard was used to model the bridge. The following is a basic overview of the modeling process including choices made about model discretization and the type of SAP structural model. This modeling process follows AASHTO LRFD (2007) specifications for refined methods of analysis, using an isotropic plate model for the deck and following the requirements for beam-slab bridges 31 (AASHTO 4.6.3). The SAP2000 program utilized linear-elastic analysis in the calculation of results. First, layout lines were used as the reference lines to define the horizontal and vertical alignment of the bridges. Once the general shape of the structure was established, the deck sections were then modeled to replicate the superstructure of the bridge. The deck, haunches, and steel girders with cover plates were modeled according to design specifications, while the guardrails were excluded, as they were deemed unnecessary for these analysis purposes. The existing steel yield strength of 33 ksi was used in modeling the girders, while the concrete deck?s properties were modeled based on expected values for the replacement deck. The concrete?s compressive strength was set at 4 ksi with a 3,600 ksi modulus of elasticity. The girders were not modeled using area objects, but instead remained full girder solid objects in order to generate more accurate results in the deck elements. The final steps involved assembling the bridge object. The spans were defined, and then deck sections, diaphragms, abutments, and bents were assigned to their appropriate locations in the spans. Support conditions were then assigned to behave as the actual bridges were designed. For the simply supported bridge, a pinned support condition on the south end, with a roller support at the opposite end. Based from the ALDOT design, the continuous bridge had the two interior bents pinned against lateral movement, with the support conditions at the abutments being rollers. The final step in completing the bridge model was the selection of the type of structural model. Initially a spine model was chosen to verify the overall behavior of the bridge to calculated results. A spine model takes the superstructure and models it as frame elements, thus performing a simple, nearly 2-dimensional analysis of the superstructure. As spine model results matched expected behavior, a more complex and thorough modeling process was chosen for the 32 deck analysis. An area object model was chosen for analysis purposes, as this form of model provides a better representation of 3-dimensional behavior and also more accurately accounts for loading eccentricities. Area object modeling provides the most detailed response results for the deck by using shell elements for the girders and deck. The discretization of the deck spans and other elements was chosen to maintain a square element area shape, in order to satisfy aspect ratio limits specified in AASHTO 4.6.3.1. 3.4 Loading After the bridges were modeled the next step in the analytical process involved the vehicular loading of the structure. All of the various lane loading scenarios were defined in accordance with AASHTO design lane and lane loading criteria. Having determined fatigue as the controlling criteria of transverse joint design, the loading was done in accordance to AASHTO 3.6.1.4 Fatigue Load. Figure 3.2 shows this loading; the spacing from the center axle to the rear axle of the HS20 truck is set at 14 ft for fatigue loading. One fatigue design truck was used to investigate the worst possible loading of the deck area objects. All analysis was conducted without the use of dynamic load allowance (IM) per AASHTO LRFD 3.6.2 and also without the application of multiple presence factors (m), Section 3.1.1.2. Dynamic load allowance is meant to account for wheel load impact from moving vehicles, and although the modeler used did not account for wheel load impact, it was determined to apply this factor to the modeled output results. Essentially, all model-produced stresses unless otherwise listed should be increased by 15 percent for fatigue and fracture limit states and by 33 percent for all other limit states. 33 At first influence-based analysis was used to determine the maximum stresses in the deck. This analysis automatically generates worst-case loading scenarios by determining the greatest effect a truck loading can generate within a specified area or lane. By selecting three lanes, this analysis loads each lane individually, then loads all lanes, and then omits each lane from loading in order to establish what the number of trucks and what position of each truck causes a critical loading. A minimum of one and maximum of three trucks were used to load the bridge, and the loading areas (lanes) were established based on engineering judgment and trial and error. Through this analysis, the worst-case effects for each deck element were established thus creating an influence surface that showed the minimum and maximum response quantities for each deck element and girder in the structure. By generating a contour graph showing the largest compressive and tensile forces that could be experienced in the deck, the highest magnitude stresses were located, and thus the critical transverse deck sections for both positive and negative flexural stresses were located for each of the bridges. 34 Figure 3.2: AASHTO Truck Loading Scenarios (AASHTO 2007) In order to verify this influenced-based analysis as well as the model itself, the model- calculated girder moments were compared to girder-line analysis results, based on the approximate method of analysis for beam-slab bridges, AASHTO LRFD section 4.6.2.2. The girder-line analysis simply assumes that vertical traffic loads are applied to one girder, thus giving the total moment that a load will apply to the bridge. By summing the model-generated moments for each girder, the total moment that the bridge experiences in modeling can be established. This model-generated moment can then be compared to the girder-line analysis moment in order to ensure that the model-generated moments are reasonable. As shown in Table 3.1, the girder-line analysis moments were found to be virtually the same as those moments 35 generated from the model with less than a one percent difference for three different loading scenarios. Table 3.1: Comparison of Moments Girder 3 Trucks 2 Trucks 1 Truck M (k-ft) M (k-ft) M (k-ft) West Exterior 26.9 3.5 -6.1 Interior 78.7 35.1 10.1 Interior 178.9 83.5 32.4 Interior 305.2 193.0 75.2 Interior 357.7 333.3 186.3 East Exterior 354.1 372.4 314.7 Model Moments Summed: 1301.5 1020.8 612.6 Girder-Line Moments per AASHTO LRFD: 1306.4 1024.6 614.8 The next validation step involved calculating deck stresses from the girder-line analysis and model-generated moments. Assuming plane sections remain plane, linear-elastic material behavior, and composite action between the girder and the deck, a section modulus was calculated for the interior deck/girder section and for the exterior deck/girder section. The deck stresses were then calculated by dividing the girder-line and model-generated moments by the section modulus. Figure 3.3 shows the results. The x-axis represents a transverse cross section of the bridge at midspan with transverse position 0 (TP-0) being the center of the bridge and positions -24 (TP-24-) and 24 (TP-24) being the transverse edges of the bridge roadway. The orange dotted line represents model-generated stresses from influenced-based analysis, while the flat bar lines represent the uniformly distributed stresses calculated from both model-generated girder moments and girder-line analysis moments. These stresses in the top fiber of the deck due to girder-line and model-generated moments were assumed to be uniformly distributed across the effective flange width of the girder. From this figure it can be seen that the model-generated stresses coincide with the AASHTO girder-line analysis calculated stresses; the discrepancy 36 between the two is mostly due to localized forces acting in the deck between the girders. Overall, the girder-line analysis results indicate that the model-generated stresses are reasonable. After having located the critical transverse cross section(s) in each bridge, a step-by-step analysis was conducted to determine the locations of the trucks causing the maximum stresses in the deck. A step-by-step analysis involves specifying a truck to cross the bridge at a certain transverse point, and with a certain number of discretization points. Choosing a discretization of every 3 inches, this process essentially moved the fatigue truck across the bridge, recording element data for the entire bridge every 3 inches that the truck progressed. Having determined a critical longitudinal location, the transverse location of the truck needed to be determined. In order to determine this transverse location for an extreme loading scenario, the fatigue truck was run across the bridge repeatedly, each time moving transversely by 1 ft. Figure 3.4 and 3.5 illustrate the transverse movement of the truck from position TR-0 to TR-18. 37 Figure 3.3: Top Fiber Stress Comparisons at Midspan (Simple Span Bridge) Figure 3.4: Transverse Truck Position 0 (TR-0) -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position at Midspan, ft Girder Truck Position Stresses Calculated from Model Generated Girder Moments Top Fiber Stresses Girder-Line Analysis Stresses 38 Figure 3.5: Transverse Truck Position 18 (TR-18) Starting at position TR-0 (Figure 3.4) the center of the truck is located at the center of the bridge, with the left and right set of the wheels located 3-feet offset from position TR-0. The truck is moved from position TR-0 to TR-1, then to TR-2, and so on until the truck reaches the extreme allowable position TR-18, which places the exterior wheel load one foot away from the edge of the curb (Figure 3.5). In each transverse position, the truck is run along the length of the bridge and then data are compared to determine the extreme case loading scenario for both longitudinal and transverse loading. There are two worst-case loadings for causing tensile stresses in the deck in each of the continuously supported bridges: a top-fiber, negative-moment extreme case; and a bottom-fiber, positive-moment extreme case. Both cases are extreme as they test the tensile capacity of the joint; top fiber stresses refer to the extreme top fiber of the joint, while bottom fiber stresses refer to the extreme bottom fiber of the joint. The compressive forces were found to be well within normal service-load capacities. It must be noted that as these bridges are all transversely symmetrical, the transverse truck position movement was only 39 conducted for one half of the transverse deck section, and data will be reported for loading the transverse eastern portion of the bridge (Figure 3.6). Figure 3.6: Loading of Bridge and Direction of Traffic After determining the extreme tensile effects for top and bottom fibers, a step-by-step analysis was used to determine shear effects. The trucks were located at the worst-case position previously found for bending stress, and shear was recorded at those critical deck locations. Additionally, the model also analyzed the truck?s passing of the bridge to find the largest magnitude shear force that occurs in critical location CL-1 and CL-2. The results from these stress and shear modeling processes are discussed in further detail in the following chapter. 40 4 CHAPTER 4: MODELING RESULTS AND DISCUSSION 4.1 Organization of Results The results from the modeling of three bridges are discussed in this section, with attention being given to extreme case scenarios. The stresses and shears are expected to represent the modeled load effects that a transverse joint would experience, and therefore these forces should be considered in the testing and selection of a transverse joint connection. 4.2 Results from 60-80-60 ft ALDOT Continuous Span Bridge As a continuous span bridge is subject to both positive and negative bending moment, there are multiple extreme loading scenarios for the 80-60-80 ft bridge. The results from the positive bending worst case scenario will be discussed first, followed by the negative bending extreme loading results, and finally the shear loading results will be shown. 4.2.1 Extreme Positive-Flexure Stress Using a step-by-step analysis, the AASHTO HS-20 fatigue design truck was run along the length bridge in all transverse truck positions TR-0 through TR-18 (Figure 3.4 and 3.6). The critical location for positive-flexure stresses (across a transverse joint) was already known from influence-based analysis; it occurs approximately 5 feet past the first interior bent and is referred to as CL-2 for convenience. Figure 4.1 illustrates this critical transverse location. Having located CL-2, a graph of each transverse position was made to determine the longitudinal extreme case truck position. For TR-13, the extreme positive-flexure stress occurred when the front 8 kip axle of the truck was positioned 19 ft 3 in. past the first bent with the trailing 32 kip axles located 5 ft 3 in. past the bent and 24 ft 9 in. before the bent. Figure 4.2 shows the effect, at CL-2, of the truck as it moved across the bridge. By locating the peak top fiber stress, the critical longitudinal 41 truck position was located, as shown in Figure 4.3. This longitudinal position resulted in extreme joint stresses for all transverse positions TR-0 through TR-18. Figure 4.1: Critical Locations for 60-80-60 Continuous Bridge Figure 4.2: Longitudinal Plot of the Effects of TR-13 on CL-2 (60-80-60 Bridge) -0.20 -0.10 0.00 0.10 0.20 0.30 0 60 120 180 240 S t r e s s ( k si ) Front Axle of Truck Position (ft) Top Fiber Bottom Fiber Bent 42 Figure 4.3: Longitudinal Position of Truck for Extreme Positive-Flexure Stresses (60-80-60 Bridge) From this extreme positive-flexure stress loading, Figure 4.4 summarizes the values generated by the SAP2000 model. This graph represents the greatest stresses normal to a transverse deck joint for each transverse truck position at the critical longitudinal location. It can be seen from Figure 4.4 that the higher stresses are reached when the truck is positioned at transverse positions TR-3, 5, 11, and 13. These loadings are seen in black in the figure, and they represent trucks having either their left or right side wheels located on the deck exactly between two lines of girders (Figure 4.5). Conversely, the smallest stresses occur when half of the truck loading was located directly above a girder, as seen in truck positions TR-1, 7, 9, 15, and 17. Figure 4.6 illustrates this loading of the girder. It can be seen from Figure 4.4 that the stresses in the panels showed a decreasing trend, as truck tires were moved from the middle between girders to on top of the girders. Furthermore, stresses increased as the truck position was moved into the extreme transverse position at the edge of the bridge roadway. These results show that the extreme case for positive-flexure stress across a transverse joint occurs when a set of wheel loads is placed midway between girder lines. 43 Figure 4.4: Maximum Stresses per Transverse Position due to Positive Flexure (60-80-60 Bridge) Figure 4.5:Transverse Truck Positions TR-3, 5, 11, and 13 Loading the Exact Middle Between Girders -0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 0.25 TR 0 TR 1 TR 2 TR 3 TR 4 TR 5 TR 6 TR 7 TR 8 TR 9 T R 10 T R 11 T R 12 T R 13 T R 14 T R 15 T R 16 T R 17 T R 18 S t r e ss, k s i Transverse Truck Position TOP FIBER STRESS BOTTOM FIBER STRESS 44 Figure 4.6: Transverse Truck Positions TR-1, 7, 9, 15, and 17 Loading the Girders Table 4.1 shows the values generated during this extreme positive-flexure stress scenario graphed in Figure 4.4. These values do not include dynamic load allowance and are simply the effects of the design fatigue truck on the bridge deck. Furthermore, this table shows the truck loading scenario, bottom and top fiber stresses, the transverse location of the critical stress, and the modulus of rupture. The modulus of rupture (MR) was calculated using ?? = 7.5?? ? ?, with the compressive strength of concrete being 4000 psi. The transverse location column is based off the scale seen in Figure 4.6, and it can be seen from this column that all the critical locations for each deck panel fall exactly between girders at transverse positions 0, 8, and 16. This signifies that the highest bottom fiber tensile stresses occur in the portion of the deck that is transversely centered between girders. Consistent with expected positive flexural behavior, the bottom fiber of the deck is in tension while the top fiber remains in compression under these maximum stress cases. 45 Table 4.1: Stresses at CL-2 due to Positive-Flexure Truck Loading (60-80-60 Bridge) Truck Transverse Position Transverse Location of Critical Stress Stress, Bottom Fiber Stress, Top Fiber (ft) (ft) (ksi) (ksi) TR 0 0 0.128 -0.094 TR 1 0 0.127 -0.094 TR 2 0 0.174 -0.142 TR 3 0 0.221 -0.189 TR 4 8 0.166 -0.134 TR 5 8 0.221 -0.189 TR 6 8 0.174 -0.141 TR 7 8 0.127 -0.093 TR 8 8 0.128 -0.093 TR 9 8 0.128 -0.093 TR 10 8 0.174 -0.140 TR 11 8 0.221 -0.187 TR 12 16 0.171 -0.130 TR 13 16 0.226 -0.184 TR 14 16 0.18 -0.134 TR 15 16 0.133 -0.085 TR 16 16 0.134 -0.083 TR 17 16 0.134 -0.081 TR 18 16 0.175 -0.117 Extreme Tensile- Stress Case: 16 0.226 -0.184 After determining the stresses in Table 4.1, they were compared to the modulus of rupture. It must be noted that the modulus of rupture is not representative of any joint's capacity; the modulus is simply a benchmark with which the tensile stresses can be referenced. The extreme fatigue stress found at TR-13 was only 0.226 ksi, less than half of the modulus of rupture, which showed significant capacity in the joints to handle fatigue loading. Graphs of the full transverse cross section at Critical Location 2 can be seen in Figure 4.7, Figure 4.8, and Figure 4.9. These figures illustrate the maximum tensile stress that occurs in the deck between 46 girders, and they also show how the force effects due to truck loading are largely localized at the location of the wheels. The localized high stresses normal to a transverse deck joint from truck loading dissipate significantly after the deck panel crosses over a girder support. Figure 4.7: Deck Stresses due to TR-13 at Critical Location 2 (60-80-60 Bridge) -0.20 -0.10 0.00 0.10 0.20 0.30 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft Girder Truck Bottom Fiber Top Fiber 47 Figure 4.8:Deck Stresses due to TR-11 at Critical Location 2 (60-80-60 Bridge) Figure 4.9: Deck Stresses due to TR-0 at Critical Location 2 (60-80-60 Bridge) -0.20 -0.10 0.00 0.10 0.20 0.30 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft Girder Truck Bottom Fiber Top Fiber -0.20 -0.10 0.00 0.10 0.20 0.30 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft Girder Truck Bottom Fiber Top Fiber 48 To further assess the extreme effects for the deck panels, other truck scenarios were analyzed and then compared to the worst case stress of 0.226 ksi from the fatigue design truck. As stated in AASHTO LRFD (2007) Article 3.6.2.2, a dynamic load allowance of 1.15 should be multiplied by this fatigue stress, making the fatigue design stress 0.260 ksi. When analyzing the bridge under AASHTO limit states other than fatigue, different dynamic load allowances must be included and a multiple presence factor should be applied to determine maximum stresses. Further modeling included adding multiple trucks in critical configurations and also changing the truck?s rear axle spacing from 30 ft to 14 ft. Scenarios involving one, two, and three trucks were conducted. The single truck analysis validated the fatigue loading scenarios as the critical loading occurred over transverse truck position 13. After numerous analyses, the worst-case conditions for multiple truck loadings was found to occur when the trucks were positioned as close to the eastern edge as permissible. Table 4.2 shows the modeled extreme service load values that can be expected to be experienced in the deck. By multiplying the truck effects by the appropriate AASHTO multiple presence factor and the 1.33 dynamic load allowance, this table shows the results of loading the bridge with a service load. The extreme effect of 0.361 ksi occurred due to single fatigue truck loading. 49 Table 4.2: Extreme Service Load Stresses at CL-2 Truck Transverse Position Rear Axle Spacing Multiple Presence Factor, m Dynamic Load Allowance, IM Transverse Location of Critical Stress Stress, Top Fiber (including m & IM) (ft) (ft) (ft) (ksi) TR 13 30 1.20 1.33 16 0.361 TR 13 14 1.20 1.33 16 0.354 TR 7 & 17 30 1.00 1.33 16 0.190 TR 7 & 17 14 1.00 1.33 16 0.176 TR (-1),7, & 17 30 0.85 1.33 16 0.162 TR (-1),7, & 17 14 0.85 1.33 16 0.150 Extreme Case: TR-13 @ 30ft 16 0.361 4.2.2 Extreme Negative-Flexure Stress Case As with the extreme positive-flexure stress investigation, the AASHTO HS-20 fatigue design truck was run along the bridge length in all transverse positions TR-0 through TR-18. A plot of the reaction at the critical location as these trucks crossed the bridge showed the critical locations for each transverse truck position. Figure 4.11 shows this type of plot for transverse truck position TR-13. The controlling negative-flexure stress scenario occurred when the front 8 kip axle of the truck was positioned 29 ft 3 in. past the first bent with the trailing 32 kip axles located 15 ft 3 in. past the bent and 14 ft 9 in. before the bent (Figure 4.10). This longitudinal truck location was the extreme case position of the truck for all transverse positions TR-0 through TR-18, causing the largest tensile forces in the top fiber of the deck at the first bent. This tensile stress is largely consistent with the maximum girder-line negative moment stresses that would be expected over the bent. This critical location at the first bent, seen in Figure 4.1, will be referred to as CL-1. 50 Figure 4.10:Longitudinal Position of Truck for Extreme Negative-Flexure Stresses (60-80- 60 Bridge) Figure 4.11: Longitudinal Plot of the Effects of TR-13 on CL-1 (60-80-60 Bridge) The maximum tensile stresses found for each transverse truck position can be seen in Figure 4.12 and Table 4.3. As the trucks moved towards the outer eastern edge of the bridge, top -0.20 -0.10 0.00 0.10 0.20 0.30 0 60 120 180 240 S t r e ss , k si Front Axle of Truck Position along the Length of the Bridge (ft) Top Fiber Bottom Fiber Bent 51 fiber tensile stresses increased. The general trend followed the same pattern as for the extreme positive-flexure stress case; truck positions centered directly over or within a foot of the girder created the highest interior deck stresses. Correspondingly, stresses were lowest at TR-0 and TR-8, as the trucks were centered over the midpoint between the girders, thus placing their tires near portions of the panel directly above the girders. The difference between this case and the positive-flexure stress scenario is that these transverse truck positions caused higher tensile stresses in the deck directly above the girder, as opposed to in between girders. This is because the deck is acting as a tension flange for composite girder bending at these locations. The negative-flexure stresses in the deck were critical at these above girder locations. Another difference in the extreme negative-flexure stress case was that the edge of the deck experienced the highest tensile stresses, with tensile stresses growing rapidly as the truck was moved to the exterior most position TR-18. Figure 4.12: Maximum Stresses per Transverse Position due to Negative Flexure (60-80-60 Bridge) -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.30 TR 0 TR 1 TR 2 TR 3 TR 4 TR 5 TR 6 TR 7 TR 8 TR 9 T R 10 T R 11 T R 12 T R 13 T R 14 T R 15 T R 16 T R 17 T R 18 S t r e ss, k s i Transverse Truck Position, ft BOTTOM FIBER STRESS TOP FIBER STRESS 52 Table 4.3: Stresses at CL-1 due to Negative-Flexure Truck Loading (60-80-60 Bridge) Truck Transverse Position Transverse Location of Critical Stress Stress, Top Fiber Stress, Bottom Fiber (ft) (ft) (ksi) (ksi) TR 0 4 0.151 -0.059 TR 1 4 0.168 -0.067 TR 2 4 0.172 -0.069 TR 3 4 0.175 -0.071 TR 4 4 0.175 -0.071 TR 5 4 0.176 -0.071 TR 6 4 0.173 -0.070 TR 7 4 0.171 -0.068 TR 8 12 0.157 -0.061 TR 9 12 0.175 -0.069 TR 10 12 0.179 -0.071 TR 11 12 0.184 -0.073 TR 12 12 0.185 -0.073 TR 13 12 0.187 -0.074 TR 14 12 0.185 -0.072 TR 15 12 0.183 -0.070 TR 16 20 0.196 -0.059 TR 17 20 0.226 -0.071 TR 18 20 0.255 -0.084 Extreme Tensile- Stress Case: 20 0.255 -0.084 Overall these stresses are well below the 0.474 ksi modulus of rupture. Even when the AASHTO dynamic load allowance of 1.15 is included, a maximum fatigue stress of only 0.293 ksi occurs. As with the extreme positive-flexure stress scenario, multiple trucks were run at various spacings to determine the worst tensile stresses at CL-1 for service loading. Appropriate AASHTO multiple presence factors and dynamic load allowances were applied for service loading; Table 4.4 shows these results. Truck critical transverse loading positions were the same as in the positive-flexure stress case for both truck loading scenarios involving two or three trucks; however, the worst case scenario for a single truck occurred at TR-18, not TR-13. The 53 maximum tensile stress from these extreme negative-flexure stress cases was found to be 0.407 ksi due to truck loading TR-18, about 13 percent greater than the critical stress from the positive- flexure stress cases. Table 4.4: Negative-Flexure Service Load Stresses at CL-1 Truck Transverse Position Rear Axle Spacing Multiple Presence Factor, m Dynamic Load Allowance, IM Transverse Location of Critical Stress Stress, Top Fiber (including m & IM) (ft) (ft) (ft) (ksi) TR 18 30 1.20 1.33 20 0.407 TR 18 14 1.20 1.33 20 0.402 TR 7 & 17 30 1.00 1.33 20 0.398 TR 7 & 17 14 1.00 1.33 20 0.389 TR (-1),7, & 17 30 0.85 1.33 20 0.338 TR (-1),7, & 17 14 0.85 1.33 20 0.331 Extreme Case: TR-18 @ 30ft 20 0.407 Figure 4.13: Deck Stresses due to TR-18 at Critical Location 1 (60-80-60 Bridge) -0.20 -0.10 0.00 0.10 0.20 0.30 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft Girder Truck Bottom Fiber Top Fiber 54 Figure 4.14: Deck Stresses due to TR-13 at Critical Location 1 (60-80-60 Bridge) Figure 4.15: Deck Stresses due to TR-0 at Critical Location 1 (60-80-60 Bridge) -0.20 -0.10 0.00 0.10 0.20 0.30 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.20 -0.10 0.00 0.10 0.20 0.30 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 55 4.2.3 Shear Evaluation at CL-1 and CL-2 This section addresses the vertical shear forces that occur at the critical locations for both positive- and negative-flexure stresses. For the positive-flexural stress scenario, at CL-2, Figure 4.16 shows the stresses occurring just before (south of the cross section) and just after (north of the cross section) the transverse cross-section at CL-2. These stresses occur when a fatigue truck is loaded at the exact same longitudinal position that causes the extreme positive-flexure stress; this is not the extreme case for shear force. A longitudinal plot of the shear forces that occur at the critical deck transverse location, located at transverse position 16, can be seen in Figure 4.17. This graph represents the critical truck, TR-13, passing across the bridge, and shows the shear force effects that truck causes in the deck at transverse position 16, longitudinal position CL-2. The critical location of the front axle of the TR-13 is at position 79.25 ft, which is coincidentally a peak shear value, close to the maximum shear value. Figure 4.16 shows that the peak shear force per unit width is -0.634 kips/ft before and 0.728 kips/ft after CL-2. Having an 8 in. thick deck, these unit shear forces cause average shear stresses over the uncracked deck cross section of approximately 7?8 psi. Using ACI 318-08 Section 22.5.4, this shear force can be related to the nominal shear strength of the concrete. Shown below, Equation 4.1 can be used to determine this relationship. By applying the appropriate 0.55 strength reduction factor, using an 8 in. thick deck, 1 ft unit width, and a concrete strength of 4000 psi, the nominal shear strength can be found to be approximately 4.45 kips/ft. The 0.728 kips/ft shear force per unit width is thus approximately 15 percent of the design shear strength of monolithic unreinforced concrete. Thus, the shear stresses do not appear to be critical relative to the flexural stresses. These shear stresses are relatively small because the composite deck transfers the majority of the truck-induced vertical forces directly into the supporting girders, rather than through shearing of the joints. 56 ?? ? = ? 4 3 ???? ? ?? (Eq. 4.1) For the extreme negative-flexure stress cases, transverse deck position 12 was chosen over TP-20, despite TP-20 having the highest stresses due to worst-case fatigue loading. Deck position TP-12 was chosen as it did have a localized critical fatigue stresses, and therefore TP-12 was deemed a representative joint location for this shear analysis. The critical negative-flexural stress location in the deck was at TP-12. This critical flexural stress occurred as a truck was positioned at transverse truck position 13 and longitudinally located 89 ft 3 in. north of the first, southern abutment. As can be seen in the longitudinal plot of shear (Figure 4.19), a maximum shear does not occur at this point. When taking a look at the cross section at CL-1 (Figure 4.18), the shear can be seen to be somewhat less than the shears from the positive-flexural stress case. This is most likely due to the girders being located directly below transverse deck position 12. Figure 4.18 shows that the shear force per unit width occurring at TR-12 are 0.439 and -.479 kips/ft before and after the joint, respectively. Figure 4.16: Shear experienced at Transverse Cross-Section CL-2 (60-80-60 Bridge) -0.80 -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 0.80 -25 -20 -15 -10 -5 0 5 10 15 20 25 Sh e a r , k / ft Transverse Location, ft V Before Girder V After 57 Figure 4.17: Longitudinal Plot of Shear Experienced at Transverse Position 16 as TR-13 passes (CL-2) Figure 4.18: Shear experienced at Transverse Cross-Section CL-1 (60-80-60 Bridge) -0.80 -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 0.80 0 60 120 180 240 Sh e a r , k / ft Front Axle of Truck Position, ft Before Jt After Jt. Bent -0.70 -0.50 -0.30 -0.10 0.10 0.30 0.50 0.70 -25 -20 -15 -10 -5 0 5 10 15 20 25 Sh e a r , k / ft Transverse Location, ft Plot of Shear experienced at Transverse Cross Section V Before Girder V After 58 Figure 4.19: Longitudinal Plot of Shear Experienced at Transverse Position 12 as TR-13 passes (CL-1) The significance of this shear behavior is best shown through combining a longitudinal plot of unit shear force with a longitudinal plot of bending moment. Through this combination, the forces that the deck experiences at positions CL-1 and CL-2 during each truck passage can be better understood. By juxtaposing the negative moment and shear at position CL-1, Figure 4.20 shows a crude interpretation of the shear and moment cycle that this transverse cross section experiences with every truck passage. The bending moment increases parabolically to a peak, while the shear increases somewhat linearly, and, at the peak bending moment, the shear reverses and then decreases while the moment reduces to zero. For the positive moment loading at CL-2, Figure 4.21 shows a much different relation between shear and moment, which shows sharp loading and unloading of both forces effects. -0.80 -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 0.80 0 60 120 180 240 Sh e a r , k / ft Front Axle of Truck Position , ft Before Jt After Jt. Bent 59 (a) Shear (b) Moment Figure 4.20: Moment and Shear Diagrams for CL-1 (a) Shear (b) Moment Figure 4.21: Moment and Shear Diagrams for CL-2 4.3 Results from 80-100-80 ft ALDOT Continuous Span Bridge As with the 60-80-60 continuous span bridge, the 80-100-80 has multiple extreme loading scenarios. These data coincide with the 60-80-60 bridge?s data and give a perspective as to the effect of span length on the deck stresses. The results from the positive bending extreme case scenario will be discussed first, followed by the negative bending extreme loading results. -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 V , k / f t Load passing over joint at CL-1 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 M , k - in / f t Load passing over joint at CL-1 -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 V , k / f t Load passing over joint at CL-1 -0.05 0.00 0.05 0.10 0.15 0.20 0.25 M , k - in / f t Load passing over joint at CL-1 60 4.3.1 Extreme Positive-Flexure Stress Case Using the same analysis process from the 60-80-60 bridge, fatigue trucks were run from positions TR-0 through TR-18. The critical location for positive-flexure stress occurred 5 feet past the bent and will be referred to as CL-2. For all transverse truck positions, the extreme positive-flexure stress occurred when the front 8 kip axle of the truck was positioned 19 ft 3 in. past the first bent with the trailing 32 kip axles located 5 ft 3 in. past the bent and 24 ft 9 in. before the bent. When referenced from the first bent, this truck location is identical to the truck locations for the 60-80-60 bridge. From this positive-flexure loading, Figure 4.22 and Table 4.5 summarize the values generated by the SAP2000 model. This graph represents the highest possible stresses in the deck for each transverse truck position at the critical longitudinal location. These stresses behave nearly the same as the 60-80-60 bridge except that the critical stress point in the deck is at position 8 for truck loading at TR-3, instead of at position 0, as seen underlined in Table 4.5. In general truck locations loading the center of a deck between girders cause the highest stresses, and overall the stresses from this case are only slightly less than the 60-80-60 bridge, most likely attributed to the larger girders used in this 80-100-80 bridge. A transverse plot of the truck loading at TR-13 is also shown in Figure 4.23 to further illustrate the related behavior between the two continuous span bridges. 61 Figure 4.22: Maximum Stresses per Transverse Position due to Positive Flexure (80-100-80 Bridge) Figure 4.23: Deck Stresses due to TR-13 at Critical Location 2 (80-100-80 Bridge) -0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 0.25 TR 0 TR 1 TR 2 TR 3 TR 4 TR 5 TR 6 TR 7 TR 8 TR 9 T R 10 T R 11 T R 12 T R 13 T R 14 T R 15 T R 16 T R 17 T R 18 S t r e ss, k s i Transverse Truck Position, ft TOP FIBER STRESSES BOTTOM FIBER STRESSES -0.20 -0.10 0.00 0.10 0.20 0.30 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft Girder Truck Bottom Fiber Top Fiber 62 Table 4.5: Stresses at CL-2 due to Positive-Flexure Truck Loading (80-100-80 Bridge) Truck Transverse Position Transverse Location of Critical Stress Stress, Bottom Fiber Stress, Top Fiber (ft) (ft) (ksi) (ksi) TR 0 0 0.123 -0.087 TR 1 0 0.123 -0.087 TR 2 0 0.170 -0.134 TR 3 8 0.164 -0.128 TR 4 8 0.164 -0.128 TR 5 8 0.217 -0.180 TR 6 8 0.171 -0.133 TR 7 8 0.124 -0.085 TR 8 8 0.125 -0.085 TR 9 8 0.125 -0.084 TR 10 8 0.171 -0.131 TR 11 8 0.218 -0.178 TR 12 16 0.170 -0.121 TR 13 16 0.224 -0.173 TR 14 16 0.178 -0.124 TR 15 16 0.132 -0.074 TR 16 16 0.133 -0.072 TR 17 16 0.133 -0.079 TR 18 16 0.176 -0.109 Extreme Tensile- Stress Case: 16 0.224 -0.173 4.3.2 Extreme Negative-Flexure Stress Case The extreme negative-flexure stress case had consistent behavior with the data from the 60-80-60 bridge. The controlling negative-flexure stress truck placement occurred when the front 8 kip axle of the truck was positioned 29 ft 3 in. past the first bent with the trailing 32 kip axles located 15 ft 3 in. past the bent and 14 ft 9 in. before the bent. This truck location caused critical 63 effects at the first bent, CL-1. Figure 4.24 and Table 4.6 summarizes the values generated by the SAP2000 model. Behavior coincided with that of the 60-80-60 bridge, as truck locations that loaded the center between girders causing higher deck stresses. Additionally, as the truck moved towards the eastern edge, stress values increased greatly. The maximum stress 0.223 ksi was well below the modulus of rupture, 0.474 ksi. As with the positive-flexure stress case, negative-flexure stresses were also slightly less than the 60-80-60 bridge. Shear effects were the same magnitude as the for the positive-flexure stress case; however less shear force occurred in the critical negative-flexure stress joint as this joint is located above the bent and directly on top of a girder. Transverse plots of each truck position for both positive- and negative-flexural stress can be seen in Appendix B. Figure 4.24: Maximum Stresses per Transverse Position due to Negative Flexure (80-100- 80 Bridge) -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.30 TR 0 TR 1 TR 2 TR 3 TR 4 TR 5 TR 6 TR 7 TR 8 TR 9 T R 10 T R 11 T R 12 T R 13 T R 14 T R 15 T R 16 T R 17 T R 18 S t r e ss, k s i Transverse Truck Position, ft BOTTOM FIBER STRESS TOP FIBER STRESS 64 Table 4.6: Stresses at CL-1 due to Negative-Flexure Truck Loading (80-100-80 Bridge) Truck Transverse Position Transverse Location of Critical Stress Stress, Top Fiber Stress, Bottom Fiber (ft) (ft) (ksi) (ksi) TR 0 4 0.132 -0.037 TR 1 4 0.147 -0.043 TR 2 4 0.150 -0.044 TR 3 4 0.154 -0.045 TR 4 4 0.154 -0.045 TR 5 4 0.154 -0.045 TR 6 4 0.152 -0.045 TR 7 4 0.150 -0.044 TR 8 12 0.139 -0.038 TR 9 12 0.155 -0.044 TR 10 12 0.159 -0.045 TR 11 12 0.164 -0.046 TR 12 12 0.165 -0.046 TR 13 12 0.166 -0.045 TR 14 12 0.164 -0.044 TR 15 12 0.147 -0.027 TR 16 20 0.173 -0.030 TR 17 20 0.199 -0.037 TR 18 20 0.223 -0.045 Extreme Tensile- Stress Case: 20 0.223 -0.045 4.4 Results from Collinsville Bridge (Simple Span) The simple span bridge has only one extreme loading scenario for positive-flexure stresses. This data coincides with the continuously supported bridges? positive-flexure stress behavior data and demonstrates the behavior expected to occur in the Collinsville Bridge. 65 4.4.1 Extreme Positive-Flexure Stress Case Fatigue trucks were run across the structure in all transverse positions, causing a critical location for stress at the midspan of the bridge, CL-1. For all transverse truck positions, the extreme positive-flexure stress occurred when the front 8 kip axle of the truck was positioned 43 ft north of the abutment with the trailing 32 kip axles located 29 ft past the bent and before the abutment. Essentially, this location loads the midspan of the bridge with a 32 kip axle. Figure 4.25 shows the bridge?s dimensions and critical truck placement. Figure 4.25: Simple Span Bridge Critical Truck Location Figure 4.26 and Table 4.7 show the critical values from the step-by-step analysis. For the most part, the tensile stresses can be seen to be significantly less than the tensile stresses from the two continuously supported bridges, however the critical stress of 0.209 ksi is still close to the maximum tensile value of 0.226 ksi, from the 60-80-60 bridge. Additionally, the compressive top fiber stresses ranged from 40 to 65 percent greater than those from the continuously supported bridges; however these compressive stresses are well under the service-load compressive capacity of the concrete, and are most likely higher as the critical tensile location 66 for the Collinsville Bridge coincides with the critical compressive location. The critical truck location is located at TR-3, which is somewhat consistent with other data, as this position loads the center between two girders at position 0. Additionally, since the span of this bridge is only 56 ft 10 in., trucks with 14? rear axle spacing were run to determine the amount of stress increase expected. The results showed a negligible increase of less than 1 percent in most cases. It should also be noted that when this bridge is loaded on the eastern edge, a small tensile force is created on the other edge in the bottom and top fibers (Figures 4.27 and 4.28). This tensile stress is well below the modulus of rupture, but could pose durability issues in a joint. Furthermore, joint shear forces were of the same magnitude as for the positive-flexure stress case of the continuous span bridges, and well within limits. Figure 4.26: Maximum Stresses per Transverse Position due to Positive Flexure (Simple Span Bridge) -0.35 -0.25 -0.15 -0.05 0.05 0.15 0.25 TR 0 TR 1 TR 2 TR 3 TR 4 TR 5 TR 6 TR 7 TR 8 TR 9 T R 10 T R 11 T R 12 T R 13 T R 14 T R 15 T R 16 T R 17 T R 18 S t r e ss, k s i Transverse Truck Position, ft TOP FIBER STRESS BOTTOM FIBER STRESS 67 Table 4.7: Stresses at CL-1 due to Positive-Flexure Truck Loading (Simple Span Bridge) Truck Transverse Position Transverse Location of Critical Stress Stress, Bottom Fiber Stress, Top Fiber (ft) (ft) (ksi) (ksi) TR 0 0 0.112 -0.209 TR 1 0 0.112 -0.209 TR 2 0 0.161 -0.256 TR 3 0 0.209 -0.303 TR 4 0 0.151 -0.241 TR 5 8 0.208 -0.305 TR 6 8 0.159 -0.259 TR 7 8 0.110 -0.212 TR 8 8 0.110 -0.212 TR 9 8 0.109 -0.213 TR 10 8 0.157 -0.261 TR 11 8 0.204 -0.308 TR 12 8 0.145 -0.247 TR 13 16 0.193 -0.325 TR 14 16 0.141 -0.278 TR 15 16 0.089 -0.232 TR 16 16 0.085 -0.233 TR 17 16 0.081 -0.234 TR 18 16 0.119 -0.276 Extreme Tensile- Stress Case: 0 0.209 -0.303 68 Figure 4.27: Deck Stresses due to TR-13 at Critical Location 1 (Simple Span Bridge) Figure 4.28: Deck Stresses due to TR-18 at Critical Location 1 (Simple Span Bridge) -0.40 -0.30 -0.20 -0.10 0.00 0.10 0.20 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft Girder Truck Bottom Fiber Top Fiber -0.40 -0.30 -0.20 -0.10 0.00 0.10 0.20 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft Girder Truck Bottom Fiber Top Fiber 69 4.5 Summary and Conclusions The modeling of the two continuously supported bridges and the simply supported bridge gives better understanding of the behavior of bridge decks under truck loading. Through this modeling process several conclusions can be made as to the design and testing of transverse shear keys. For all bridges 1. Loading of the deck on the transverse center between girder lines generally produces the largest tensile flexural stresses across transverse joints. These tensile stresses occur in the deck at that center point between girders if experiencing positive flexure. Under a negative flexure, the larger deck tensile stresses occur in the deck directly above the girder that is straddled by the truck. Without relation to the positive-flexure regions, negative-flexure regions experienced the largest tensile stresses as truck loadings were moved towards the edge of the bridge deck. 2. The loading causing the smallest flexural tensile and shear stresses for both positive and negative flexure occurred when a wheel loaded the deck exactly over a girder. 3. Trucks with the longest (30 ft) rear axle spacing caused the largest stresses in the deck. The simply supported bridge was an exception; it had nearly identical results from loading with the longest and shortest axle spacings. 4. There was little difference in both behavior and stresses in the two continuous span bridges. Based on the correlation between girder sizes and span, stresses from truck loads do not seem to increase dramatically as span changes, assuming girder design is adequate for the spans considered. 70 5. As the factored tensile stresses for both positive and negative flexure ranged from 0.293 to 0.260 ksi, it is recommended that any transverse joint be able to handle repeated loadings that induce a bending stress of at least 0.300 ksi (when computed on the basis of uncracked- section analysis). 6. In fatigue testing either of the positive- or negative-flexure scenarios, consideration should be given to the relation between the moment and shear that the deck section experiences under each truck passage. For the bottom fiber, a typical ratio for shear stress to flexural stress is 1:7. The top fiber has a ratio of 1:11 for shear stress to flexural stress. 71 5 CHAPTER 5: TRANSVERSE JOINT INVESTIGATION 5.1 Transverse Joint Selection Based on previous research and performance of transverse joints, three transverse joint systems meet the criteria set by ALDOT for the Collinsville simply supported bridge. The NCHRP Project 584, female-to-female shear key, and reinforced looped-bar joints all have sufficient testing or in-field history to suggest that they could provide a durable and lasting connection for this rapid bridge deck replacement. However, when a joint experiences negative flexure, these options become even more limited. Testing conducted by Virginia Polytechnic Institute showed poor performance of the NCHRP reinforced joint design, with large deformations and cracking (Swenty 2009). Additionally, several tests have shown that without longitudinal post-tensioning, a female-to-female shear key cannot handle negative flexure (Issa et al. 2007; Swenty 2009). There are tests supporting the use of reinforced looped-bar joints for negative flexure, as well as several newer bridges showing adequate performance of this type of joint, at least for the early life of the bridge (Au et al. 2008; Swenty 2009). When developing these tests it was important to consider that the goal was to test numerous types of joints. Testing which were relatively simple and cost-effective were needed, as the proposal includes testing three types of joints (NCHRP ? 584, looped bar, and female-to- female) under six scenarios (positive and negative bending, shear reversal; with fatigue and monotonic-until-failure testing for all three). Additionally, a proposal to test each joint in both exodermic and full-depth precast concrete panels is included thus bringing the total number of panels to be constructed and tested to 38 panels. Simplistic testing that still provided representative data was a must. 72 This testing will illustrate the comparative behavior between different joints in different types of deck panels. Tests were devised to rigorously address the effects of bending and shear action. However, the stresses experienced in the joint are not completely representative of actual stresses experienced by the joints in a bridge; only primary one-way action is addressed. The stresses are a 2-dimensional representation used to simply the 3-dimensional effects that the joint might experience, and these 2-dimensional stresses are meant to provide a practical, cost- effective assessment of fatigue effects. A primary objective is to provide comparative results that can be used to evaluate each joint and panel?s performance when compared to one another. 5.2 Testing 5.2.1 Introduction In order to fully assess the available transverse joint options, testing should be conducted to evaluate the performance of each joint under expected conditions. As previous research has indicated, the primary cause of failures in these connection types is caused by fatigue from repeated load cycles (Issa et al. 1995a). Fatigue loading produces heavy cracking in the joints, which leads to infiltration and the degradation of the riding surface. For this reason, fatigue assessment should be a primary concern, followed by the joint?s performance under critical static loading. Because the deck panels are typically designed for one-way flexure spanning between the girders, strength limit state loading is not critical unless the reinforcement (if any) crossing the transverse joints is used for the composite girder/slab negative-moment flexural capacity. For these reasons, several tests were devised to assess a transverse joint?s response to the critical stresses determined from the analysis reported in Chapter 4. Two flexural tests, one for positive bending and another for negative bending, are proposed to assess the joint?s behavior under repeated shear and flexural loading cycles. Additionally, a third shear reversal test is 73 recommended to evaluate how the cyclic reversal of shear loading from passage of truck axle loads across the transverse joint affects a type of joint over numerous loadings. Firstly, these tests are to be conducted with fatigue-level loadings; cyclic loading that replicate expected in-field conditions to assess the degradation resistance of the transverse joints. Additionally, monotonic tests to failure are proposed to determine the total strength of these joints in respect to expected loadings. This loading is done to establish whether there is a correlation between the static ultimate strength of a joint and its fatigue degradation resistance. The ultimate goal of this testing is to determine the most practical type of testing that should be performed to prequalify a type of transverse joint for use in rapid bridge construction. A summary of the critical loads, locations, stresses, and shear forces resulting from the analyses described in Chapter 4 can be seen in Table 5.1. As the critical stresses occurred in the 60-80-60 ft continuous bridge model, these values correspond to what that model experienced. Positive Bending stresses occurred due to positive flexure (M+) and shear, while M- represents negative- flexure stresses due negative moment and shear. Table 5.1: Critical Stresses at Worst-Case Joint Locations for 60-80-60 ft Bridge Joint Location Truck Position Stress (ksi) Shear (k/ft) Critical Stress Longitudinal Transverse Transverse Longitudinal (Front Axle) Top Fiber Bottom Fiber Shear Reversal M+ Near Bent TP-16 (Between GRDR) TR-13 79.25' -0.184 0.226 0.728 Yes (-0.425) M- At Bent TP-12 (Over GRDR) TR-13 91.5' 0.187 -0.074 -0.442 No At Bent TP-20 (Over GRDR) TR-18 91.5' 0.256 -0.084 -0.452 No 74 5.2.2 Positive Bending Test In order to accurately account for the critical one-way stresses from bending, a positive bending test must reproduce the flexural stresses and shear that the joint experiences as a HS-20 truck passes over the critical location for a bridge. For this reason, it is suggested to test precast panel decks without girder support, as replicating the necessary shear and moment produced stresses within the joint would be difficult without a full-scale bridge model. By applying the load as shown in Figure 5.1, the joint experiences the appropriate flexural tensile stress and corresponding shear stress. However, due to the symmetry of the section, the elastic neutral axis will cause the critical bottom fiber tensile stresses to be the same magnitude as the top fiber compressive stresses. This does not replicate the computer analysis results seen in Table 5.1, but as transverse joints have shown large capacity and excellent behavior under compression (Issa et al. 1995), this inconsistency is acceptable. Figure 5.1: Positive Bending Test Setup As seen in Figure 5.1, the joint is positioned at a 40 in. offset. This offset creates the appropriate ratio of shear and moment in the joint as the load is applied at position P. For testing purposes the 60-80-60 continuous bridge case was selected, as its deck experienced the highest stresses out of the three bridges modeled. However, as there is expected to be variance in these stresses due to different girder size to span ratios, it is proposed to conservatively increase the 75 critical tensile stress from 226 psi to 300 psi. Shear and flexural stresses from moment were then calculated and increased to be proportionally sized from 226 psi to the prescribed 300 psi, and the loading matrix given in Table 5.2 was created for various test panel joint widths. Table 5.2: Positive Bending Loading Matrix Panel Width Total Peak Load, P P per Panel Width Unit Joint Effects Moment Shear Stress (in.) (kips) (kips/ft) (kip-in/ft) (kips/ft) (ksi) 24 6.4 3.2 38.4 0.960 0.300 48 12.8 96 25.6 PLAN ELEVATION Figure 5.2: Strain Gauge Setup 76 Based on previous studies, fatigue testing for positive bending should be conducted for 2- million cycles. Though shear reversal is experienced by the actual joint, focus will be only on increasing the loading at point P from near 0 kips to a loading that gives 3.2 kips per foot of the joint specimen width. Shear reversal effects will be evaluated in the shear test. It is proposed to maintain a minimum load of 250 lbs per foot to ensure the stability of the testing setup. Loading from this minimum load to 3.2 kips/ft and back to the minimum load should be considered one complete cycle. At appropriate intervals the joint and the deck should be statically loaded to the 3.2 kips/ft and inspected for cracking; detailed notes and observations should be made. Additionally, water ponding tests are proposed at certain loading cycles to assess each joint's leakage and subsequent acceptability to infiltration. Water ponding generally consists of applying a 1.0 in. column of water over the joint for an hour to analyze leakage. Good joint behavior is considered little cracking, no visible water leakage, and a linear strain distribution through the depth of the joint (Swenty 2009). A proposed testing schedule is shown below in Table 5.3. Additionally, Figure 5.2 shows proposed strain gauge setup for the joint system. Again, during the analysis of this and the other tests, focus should be aimed at the comparative behavior of the joints. 77 Table 5.3: Testing Schedule Loading Cycles Ponding Test Static Load Test/Inspection 0 x x 1 x x 1,000 x 5,000 x 10,000 x x 20,000 x 30,000 x 40,000 x 50,000 x x 100,000 x x 200,000 x 300,000 x 400,000 x 500,000 x x 600,000 x 700,000 x 800,000 x 900,000 x 1,000,000 x x 1,250,000 x 1,500,000 x 1,750,000 x 2,000,000 x x Assuming the joint behaves adequately, upon the completion of the 2-million cycles it is proposed to test the panels monotonically to failure. The panel should be loaded at point P until the specimen refuses to resist additional load. Strains and crack widths, deflection values and other observations should be recorded at appropriate intervals as the loading increases in order to fully assess the joint?s bending capacity. Furthermore, another specimen can be tested monotonically to failure without prior cyclic loading. These results can be compared to determine the 2-million fatigue cycle loads effect on the ultimate strength of the system. 78 Information may also be gained about whether short-term monotonic tests offer useful information about long-term, cyclic performance. 5.2.3 Negative Bending Test The negative bending test was designed utilizing the same principles with which the positive bending test was designed. The critical tensile stresses from the 60-80-60 continuous bridge were used to determine loading, but the critical tensile stress was also conservatively increased to 300 psi from the analytically determined worst-case stress of 256 psi. Additionally, as these stresses occur over the bent (Table 5.1), the shear forces experience no reversal as the truck passed over the bridge; therefore this test accurately reproduces expected critical conditions. Figures 5.3 and 5.4 show the truck-induced shear forces and bending stresses experienced at transverse position 12 over the bent. Figure 5.5 shows the proposed loading and support configuration. By applying the load as shown, the joint experiences the appropriate ratio of moment-induced tensile stress to shear stress; however it may be an easier setup to turn the specimen and loading setup upside down. As with the positive bending test, compressive stresses are larger than indicated from the analysis, but testing tensile capacity remains the primary concern of these investigations. 79 Figure 5.3: Stresses Experienced in Critical Joint as Truck Passes Over Bridge Figure 5.4: Shear Experienced at Critical Joint as Truck Passes Over Bridge -0.200 -0.100 0.000 0.100 0.200 0.300 0 60 120 180 240 S t r e s s ( k si ) Front Axle of Truck Position (ft) Longitudinal Plot of Stress experienced at joint Top Fiber Bottom Fiber Bent -0.800 -0.600 -0.400 -0.200 0.000 0.200 0.400 0.600 0.800 0 60 120 180 240 Sh e a r , k / ft Front Axle of Truck Position , ft Longitudinal Plot of Shear experienced at joint Before Jt After Jt. Bent 80 Figure 5.5: Negative Bending Test Setup Table 5.4: Negative Bending Loading Matrix Deck Width Total Distributed Load, P P per foot of width At Joint Moment Shear Stress (in) (kips) (k/ft) (k-in/ft) (k/ft) (ksi) 24 4.75 2.37 38.4 0.710 0.300 48 9.50 96 19.00 Figure 5.5 shows that the joint is positioned at a 52 in. offset in order to provide the appropriate ratio of shear and moment in the joint. In order to achieve a 300 psi stress, the loading matrix in Table 5.4 shows loadings for various deck section widths. Testing should be conducted in the same manner as with the positive bending test, with a 2-million cycle fatigue testing followed by a monolithic until failure test. Ponding and static load tests should be conducted in accordance to the positive bending proposed schedule (Table 5.3), and the deck will have the same strain gauge and potentiometer orientation as with the positive bending test (Figure 5.2). The main difference is that the loading at P will be decreased to 2.37 kips per foot of deck width. Again, good joint behavior is considered little cracking, no water leakage, and linear strain distribution through the depth of the joint. 81 5.2.4 Shear Reversal Test The shear reversal experienced by the positive moment critical joint can be seen in Figure 5.6 below. Additionally the corresponding stresses experienced as the HS-20 truck passes the bridge can be seen in Figure 5.7. Based on the variations seen in these graphs, the shear reversal test was designed to produce similar shear loadings as well as the corresponding, simultaneously occurring tensile stresses. Figure 5.6: Shear Experienced in Critical Joint as Truck Passes Over Bridge -0.800 -0.600 -0.400 -0.200 0.000 0.200 0.400 0.600 0.800 0 60 120 180 240 Sh e a r , k / ft Front Axle of Truck Position, ft Longitudinal Plot of Shear experienced at joint Before Jt After Jt. Bent 82 Figure 5.7: Stress Experienced in Critical Joint as Truck Passes Over Bridge Table 5.5 summarizes the stresses in the critical joint from the computer analyses. As with the bending tests, the bottom fiber stress of 226 psi was increased to 300 psi. The top fiber critical tensile stress was increased proportionally from 99 psi to 130 psi; however, it was found that this did not produce a large enough negative shear. In order to ensure the maximum negative shear of 505 lb/ft was assessed, the shear reversal load was increased to -560 lb/ft thus creating a top fiber tensile load stress of 175 psi. Table 5.6 shows the appropriate loading for various deck widths. The discrepancy between 130 psi tensile stress in the top fiber and 175 psi is noteworthy and could result in quicker degradation of the joint. -0.200 -0.100 0.000 0.100 0.200 0.300 0 60 120 180 240 S t r e s s ( k si ) Front Axle of Truck Position (ft) Longitudinal Plot of Stress experienced at joint Top Fiber Bottom Fiber Bent 83 Table 5.5: Critical Stresses and Shear at Worst-Case Joint Location for 60-80-60 ft Bridge Joint Location Truck Position Stress (ksi) Shear (k/ft) Critical Stress Longitudinal Transverse Transverse Longitudinal (Front Axle) Top Fiber Bottom Fiber Shear Reversal V Near Bent TP-16 (Between GRDR) TR-13 79.25' -0.184 0.226 0.728 Yes (-0.425) TR-13 74.25' 0.099 -0.052 0.505 Yes (-0.646) Table 5.6: Shear Test Loading Matrix Deck Width Load Range, P P per foot of width At Joint Moment Shear Stress (in) (kips) (k/ft) (k-in/ft) (k/ft) (ksi) 24 1.92 to -1.12 0.960 to -0.560 38.4 to -22.4 0.960 to -0.560 0.300 to -0.175 48 3.84 to -2.24 96 7.68 to -4.48 Figure 5.8 Shear Test Setup Figure 5.8 shows a testing proposal for the shear reversal test. In the cantilever configuration, the joint experiences direct shear from the loading, and thus this system provides a simple, yet accurate way to reproduce model results in the testing joint. As with the bending 84 tests, testing with a 2-million cycle fatigue loading, followed by a monolithic until failure test should be conducted. A cycle should range with loading P from 0 lbs to 960 lbs, to -560 lbs, and back to 0 lbs to complete a cycle. Ponding and static load tests should be conducted in accordance to the positive bending test proposed schedule in Table 5.3. A proposed layout for gauges is shown in Figure 5.9. As with the other tests, good joint behavior is considered little cracking, no water leakage, and linear strain distribution through the depth of the joint. PLAN ELEVATION Figure 5.9: Strain Gauge Setup 85 6 CHAPTER 6: SUMMARY, CONCLUSION, AND RECOMMENDATIONS 6.1 Summary The rapid rehabilitation of bridge decks continues to provide a way to restore reliable highway structures while minimizing traffic closures and congestion. For these systems to be effective, rehabilitation must be quick while having an adequate service life to prevent premature degradation. A critical component in both constructability and structural integrity is the transverse joint between deck panels. This study consisted of an intensive review of rapid bridge deck replacement systems and their transverse joints. History, performances, advantages, and difficulties were all noted in order to make recommendations and suggestions for the implementation of an effective transverse joining system in Alabama. In addition, the Collinsville I-59 simply supported bridge and two continuously supported bridges were modeled using a finite-element analysis program to better understand the forces that a transverse joint would be likely to experience. From this review and modeling, guidelines for the testing and selection of a transverse joint were made. In order to assess the selected joints, it is proposed to have three tests: positive and negative bending, and shear. These tests, described in Chapter 5, can accurately reproduce service loading stresses and determine the practicality of transverse joint options. 86 6.2 Conclusions from Research and Modeling The conclusions and observations from the research and modeling of transverse joints are summarized as follows: ? A female-to-female shear key, NCHRP Report-584, or looped-bar joint are all suitable transverse joints in the simply supported bridge. ? A looped-bar joint or a longitudinally post-tensioned female-to-female shear key are recommended for use in bridges that experience negative flexure. ? The NCHRP system is largely proprietary; it should be tested extensively to further validate its performance. ? There is a lack of data comparing transverse joints in exodermic panels to those same joints in full-depth precast panels; all studies found were conducted on full-depth precast panels. Testing should be conducted for each joint in both a full-depth precast and exodermic panel. ? Joint failure induced from cyclic fatigue loading was the primary cause of failure in reviewed cases of laboratory testing and actual construction. ? Fatigue load modeling produced stresses 38 to 45 percent lower than cracking stress, while strength loading produced stresses 15 to 25 percent lower than the cracking stress of concrete. ? Maximum transverse joint flexural stresses were largely insensitive to the span length of the bridge. 87 6.3 Recommendations for Future Study In this study, deck stresses from modeling were found to be within reason for transverse joints. Despite not analyzing actual transverse joints themselves, this research provides the parameters within which transverse joints should be tested. Future research to better assess which joints are suitable in rapid bridge deck replacement should be conducted in the following areas: ? Research should compare the performance of identical transverse joints cast in exodermic and full-depth precast panels to further validate exodermic panel performance. ? Future testing should consider the effects of shear reversal in combination with the implementation of flexural loading of a joint. ? Fatigue load testing with up to 2-million cycles should be conducted with water ponding and service load tests being done at several points during this cyclic loading. 88 REFERENCES American Association of State Highway and Transportation Officials. 2007. AASHTO LRFD Bridge Design Specifications. 4th Edition. Washington, D.C. ACI Committee 318. 2008. Building Code Requirements for Structural Concrete and Commentary (ACI 318-08). American Concrete Institute, Farmington Hills, MI. American Society for Testing and Materials. 1998. ASTM Standard D6275-98: Standard Practice for Laboratory Testing of Bridge Decks. Au, A., C. Lam, and B. Tharmabala. 2008. "Investigation of Prefabricated Bridges Using Reduced?Scale Models." Journal of the Prestressed Concrete Institute Nov.-Dec: 67?95. Babei, K., A. Fouladagar, and R. Nicholson. 2001. ?Nightime Bridge Deck Replacement with Full Depth Precast Concrete Panels at Route 7 over Route 50, Fairfax Country, Virginia.? 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University of Illinois at Chicago, Chicago, Illinois. 1998. 92 7 APPENDIX A: Max Moment Comparisons Figure A.1: Max Moment Comparisons for 3 Trucks Loading Simple Span Bridge Figure A.2: Max Moment Comparisons for 2 Trucks Loading Simple Span Bridge -0.50 -0.40 -0.30 -0.20 -0.10 0.00 0.10 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position at Midspan Girder Truck Position Model Moment Stresses Top Fiber Stresses Girder-Line Analysis Stresses -0.50 -0.40 -0.30 -0.20 -0.10 0.00 0.10 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position at Midspan Girder Truck Position Model Moment Stresses Top Fiber Stresses Girder-Line Analysis Stresses 93 Figure A.3: Max Moment Comparisons for 1 Truck Loading Simple Span Bridge -0.50 -0.40 -0.30 -0.20 -0.10 0.00 0.10 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position at Midspan Girder Truck Position Model Moment Stresses Top Fiber Stresses Girder-Line Analysis Stresses 94 8 APPENDIX B: Transverse Stress Plots B.1 Transverse Stress Plots of Positive Moment Extreme Case for 60-80-60 Bridge Figure B.1: Deck Stresses due to TR-0 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 95 Figure B.2:Deck Stresses due to TR-1at Critical Location 2 (60-80-60 Bridge) Figure B.3: Deck Stresses due to TR-2 at Critical Location 2 (60-80-60 Bridge) Figure B.4: Deck Stresses due to TR-3 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 96 Figure B.5: Deck Stresses due to TR-4 at Critical Location 2 (60-80-60 Bridge) Figure B.6: Deck Stresses due to TR-5 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 97 Figure B.7: Deck Stresses due to TR-6 at Critical Location 2 (60-80-60 Bridge) Figure B.8: Deck Stresses due to TR-7 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 98 Figure B.9: Deck Stresses due to TR-8 at Critical Location 2 (60-80-60 Bridge) Figure B.10: Deck Stresses due to TR-9 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 99 Figure B.11: Deck Stresses due to TR-10 at Critical Location 2 (60-80-60 Bridge) Figure B.12: Deck Stresses due to TR-11 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 100 Figure B.13: Deck Stresses due to TR-12 at Critical Location 2 (60-80-60 Bridge) Figure B.14: Deck Stresses due to TR-13 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 101 Figure B.15: Deck Stresses due to TR-14 at Critical Location 2 (60-80-60 Bridge) Figure B.16: Deck Stresses due to TR-15 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 102 Figure B.17: Deck Stresses due to TR-16 at Critical Location 2 (60-80-60 Bridge) Figure B.18: Deck Stresses due to TR-17 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 103 Figure B.19: Deck Stresses due to TR-18 at Critical Location 2 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 104 B.2 Transverse Stress Plots for Positive-Flexure Extreme Case for 60-80-60 Bridge Figure B.20: Deck Stresses due to TR-0 at Critical Location 1 (60-80-60 Bridge) Figure B.21:Deck Stresses due to TR-1at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 105 Figure B.22: Deck Stresses due to TR-2 at Critical Location 1 (60-80-60 Bridge) Figure B.23: Deck Stresses due to TR-3 at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 106 Figure B.24: Deck Stresses due to TR-4 at Critical Location 1 (60-80-60 Bridge) Figure B.25: Deck Stresses due to TR-5 at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 107 Figure B.26: Deck Stresses due to TR-6 at Critical Location 1 (60-80-60 Bridge) Figure B.27: Deck Stresses due to TR-7 at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 108 Figure B.28: Deck Stresses due to TR-8 at Critical Location 1 (60-80-60 Bridge) Figure B.29: Deck Stresses due to TR-9 at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 109 Figure B.30: Deck Stresses due to TR-10 at Critical Location 1 (60-80-60 Bridge) Figure B.31: Deck Stresses due to TR-11 at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 110 Figure B.32: Deck Stresses due to TR-12 at Critical Location 1 (60-80-60 Bridge) Figure B.33: Deck Stresses due to TR-13 at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 111 Figure B.34: Deck Stresses due to TR-14 at Critical Location 1 (60-80-60 Bridge) Figure B.35: Deck Stresses due to TR-15 at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 112 Figure B.36: Deck Stresses due to TR-16 at Critical Location 1 (60-80-60 Bridge) Figure B.37: Deck Stresses due to TR-17 at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 113 Figure B.38: Deck Stresses due to TR-18 at Critical Location 1 (60-80-60 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -20 -15 -10 -5 0 5 10 15 20 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 114 B.3 Transverse Stress Plots for Positive-Flexure Extreme Case for 80-100-80 Bridge Figure B.39: Deck Stresses due to TR-0 at Critical Location 2 (80-100-80 Bridge) Figure B.40:Deck Stresses due to TR-1at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 115 Figure B.41: Deck Stresses due to TR-2 at Critical Location 2 (80-100-80 Bridge) Figure B.42: Deck Stresses due to TR-3 at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 116 Figure B.43: Deck Stresses due to TR-4 at Critical Location 2 (80-100-80 Bridge) Figure B.44: Deck Stresses due to TR-5 at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 117 Figure B.45: Deck Stresses due to TR-6 at Critical Location 2 (80-100-80 Bridge) Figure B.46: Deck Stresses due to TR-7 at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 118 Figure B.47: Deck Stresses due to TR-8 at Critical Location 2 (80-100-80 Bridge) Figure B.48: Deck Stresses due to TR-9 at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 119 Figure B.49: Deck Stresses due to TR-10 at Critical Location 2 (80-100-80 Bridge) Figure B.50: Deck Stresses due to TR-11 at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 120 Figure B.51: Deck Stresses due to TR-12 at Critical Location 2 (80-100-80 Bridge) Figure B.52: Deck Stresses due to TR-13 at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 121 Figure B.53: Deck Stresses due to TR-14 at Critical Location 2 (80-100-80 Bridge) Figure B.54: Deck Stresses due to TR-15 at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 122 Figure B.55: Deck Stresses due to TR-16 at Critical Location 2 (80-100-80 Bridge) Figure B.56: Deck Stresses due to TR-17 at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 123 Figure B.57: Deck Stresses due to TR-18 at Critical Location 2 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 124 A.1 Transverse Stress Plots of Negative Moment Extreme Case for 80-100-80 Bridge Figure B.58: Deck Stresses due to TR-0 at Critical Location 1 (80-100-80 Bridge) Figure B.59:Deck Stresses due to TR-1at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 125 Figure B.60: Deck Stresses due to TR-2 at Critical Location 1 (80-100-80 Bridge) Figure B.61: Deck Stresses due to TR-3 at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 126 Figure B.62: Deck Stresses due to TR-4 at Critical Location 1 (80-100-80 Bridge) Figure B.63: Deck Stresses due to TR-5 at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 127 Figure B.64: Deck Stresses due to TR-6 at Critical Location 1 (80-100-80 Bridge) Figure B.65: Deck Stresses due to TR-7 at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 128 Figure B.66: Deck Stresses due to TR-8 at Critical Location 1 (80-100-80 Bridge) Figure B.67: Deck Stresses due to TR-9 at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 129 Figure B.68: Deck Stresses due to TR-10 at Critical Location 1 (80-100-80 Bridge) Figure B.69: Deck Stresses due to TR-11 at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 130 Figure B.70: Deck Stresses due to TR-12 at Critical Location 1 (80-100-80 Bridge) Figure B.71: Deck Stresses due to TR-13 at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 131 Figure B.72: Deck Stresses due to TR-14 at Critical Location 1 (80-100-80 Bridge) Figure B.73: Deck Stresses due to TR-15 at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 132 Figure B.74: Deck Stresses due to TR-16 at Critical Location 1 (80-100-80 Bridge) Figure B.75: Deck Stresses due to TR-17 at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 133 Figure B.76: Deck Stresses due to TR-18 at Critical Location 1 (80-100-80 Bridge) -0.2 -0.1 0 0.1 0.2 0.3 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 134 A.2 Transverse Stress Plots for Positive-Flexure Extreme Case for Simple Span Bridge Figure B.77: Deck Stresses due to TR-0 at Critical Location 1(Simple Span Bridge) Figure B.78: Deck Stresses due to TR-1at Critical Location 1(Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 135 Figure B.79: Deck Stresses due to TR-2 at Critical Location 1 (Simple Span Bridge) Figure B.80: Deck Stresses due to TR-3 at Critical Location 1 (Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 136 Figure B.81: Deck Stresses due to TR-4 at Critical Location 1 (Simple Span Bridge) Figure B.82: Deck Stresses due to TR-5 at Critical Location 1 (Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 137 Figure B.83: Deck Stresses due to TR-6 at Critical Location 1 (Simple Span Bridge) Figure B.84: Deck Stresses due to TR-7 at Critical Location 1 (Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 138 Figure B.85: Deck Stresses due to TR-8 at Critical Location 1 (Simple Span Bridge) Figure B.86: Deck Stresses due to TR-9 at Critical Location 1 (Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 139 Figure B.87: Deck Stresses due to TR-10 at Critical Location 1 (Simple Span Bridge) Figure B.88: Deck Stresses due to TR-11 at Critical Location 1 (Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 140 Figure B.89: Deck Stresses due to TR-12 at Critical Location 1 (Simple Span Bridge) Figure B.90: Deck Stresses due to TR-13 at Critical Location 1 (Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 141 Figure B.91: Deck Stresses due to TR-14 at Critical Location 1 (Simple Span Bridge) Figure B.92: Deck Stresses due to TR-15 at Critical Location 1 (Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 142 Figure B.93: Deck Stresses due to TR-16 at Critical Location 1 (Simple Span Bridge) Figure B.94: Deck Stresses due to TR-17 at Critical Location 1 (Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 143 Figure B.95: Deck Stresses due to TR-18 at Critical Location 1 (Simple Span Bridge) -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 -25 -15 -5 5 15 25 S t r e ss, k s i Transverse Position, ft. Girder Truck Bottom Fiber Top Fiber 144 APPENDIX C: Bridge Plan 145