An Analytical Investigation of Transverse Joints in Precast-Panel Bridge-Deck Replacement Systems

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 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.