Title: Proposed AASHTO guidelines for adjacent precast concrete box beam bridge systems, part 1: Analytical investigation
Date Published: March - April 2025
Volume: 70
Issue: 2
Page Numbers: 37 - 55
Authors: Abdullah Haroon, Waleed Hamid, Richard Miller, Bahram Shahrooz, and Eric Steinberg
https://doi.org/10.15554/pcij70.2-01

Abstract

Adjacent box-girder bridges are a cost-effective solution for short-span bridges that require a shallow profile. These bridges use precast concrete hollow boxes erected side by side to create a bridge profile with load transfer between the adjacent girders facilitated by shear keys placed near the top of the section. Transverse post-tensioning is also provided along the span to help with load transfer. However, the traditional partial-depth shear keys are susceptible to thermal cracking. Shear-key cracking can cause leakage and loss of load transfer, leading to corrosion and deterioration of the girders. An analytical study with different shear key configurations was performed to investigate joint performance when subjected to thermal and live loads. The effectiveness of post-tensioning and shear key reinforcement in mitigating shear key cracking was assessed. It was concluded that using full-depth or middepth shear keys can potentially improve the performance of adjacent box-girder bridges, whereas post-tensioning or joint reinforcement is ineffective in leakage prevention.