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Abstract
A parametric study of single-span integral abutment bridge (IAB) was conducted using finite element analysis to explore the effects of various load conditions, bridge geometries, and soil properties. This study investigated the difference between the live load distribution of traditional jointed bridges and integral abutment bridges (IABs) under HL-93 truck component load. The results showed that AASHTO live load distribution factors (LLDFs) were overly conservative by up to 50% to use for IABs. LLDFs for IABs proposed by Dicleli and Erhan (2008) matched well for interior girder moment, but they were unconservative for exterior girder moment by up to 20% for the bridges studied. The study further investigated the effects of various parameters on the IAB responses under dead, live, and thermal loads and load combinations specified by AASHTO. The results of this study are limited to short to moderate single-span straight bridges under dead, live, and thermal loads. Due to a fixity of superstructure and abutments in IABs, the bridge response to each loading is influenced by the relative stiffness of superstructure to substructure. Under combined loads, the amount of each load effect varied depending on superstructure and substructure stiffness, but the critical load combination for each bridge response was determined in this study. Yielding of piles seems unavoidable for IABs built on sand under combined loads even after the change of pile size or pile orientation, but replacing the soil around top 3m (10ft) of piles with softer material is effective to reduce the significant amount of pile moment for IABs built on sand foundation soil. This thesis includes some design recommendations based on the findings of this study.
Type
thesis
Date
2021-05