157 / 2022-04-29 21:20:06

Analytical Investigation of Prestressed Concrete Girders in Chanthaburi Bridge

Assessment,Bridge,Concrete Deterioration,Finite Element Method

This study is aimed to assess the residual structural performance of 25-year-old post-tensioned concrete bridge girders across the Chanthaburi River located in Chanthaburi province, Thailand. Due to the significant increment of traffic volumes in the past decades, this existing bridge's durability and its residual structural performance have become a crucial maintenance issue in the country. Over bridge’s lifetime, small defects such as cracks can lead to major problems, especially when environmental factors are combined with a lack of maintenance. Since the bridge is located near the river mouth connected to the sea, it has a high tendency to deteriorate from an aggressive environment. Furthermore, due to the pre-stress losses in post-tensioned bridge girders, it can induce excessive deflections and crack in PC bridge girders. This causes structural loss of load capacity and affects the stability of the structure, including creating a feeling of insecurity for the user. 

This research aims to analyze the behavior and predict the structural failure patterns of the Post-tensioned Concrete (PC) girder by using 2D Non-linear Finite Element Method (FEM). Two major influenced parameters studied in this paper are the effect of pre-stress losses in pre-stressed strands and the main percentage of reinforcement corrosion. The cases of pre-stressing loss percentage were calculated based on AASHTO 2007 standard, considering the immediate loss and long-term loss. The vehicle loads and load patterns were evaluated based on AASHTO LRFD-2007. Two series of simulation cases were set to study the behaviors of the girder under flexural and shear failures by shifting the loading position. The combined effect between pre-stress loss and corrosion is presented in this study. This analysis results can signify the safety of the bridge.