Comparative study of integral abutment bridge structural analysis methods

The primary goal is to accurately predict long-term integral abutment bridge (IAB) responses under thermal loads by applying available numerical modeling techniques developed on the basis of a long-term monitoring of in-service IABs. Considered methodologies are: (1) free expansion; (2) empirical approximate; (3) two-dimensional (2D) static analysis; (4) 2D time-history; (5) three-dimensional (3D) static analysis; and (6) 3D time-history. Specific IAB responses evaluated for the comparison are: girder axial force and moment, pile shear, moment, and displacement. The results indicate that the substructure responses predicted by all six analyses are reasonably comparable. However, the superstructure responses predicted by a 2D analysis are significantly different than predictions by a 3D analysis. Both 2D and 3D static analysis predictions tended to form boundaries for 2D and 3D time-history analysis. Therefore, this study concludes that a 3D time-history analysis is preferred for long-term, superstructure response predictions; all 2D and 3D static and time-history analyses are acceptable for substructure response predictions.