Abstract
The purpose of this study is to illustrate the 3-D modeling of typical bridges by using the N215-W210 connector bridge in San Bernardino, California as an example structure. The bridge was analyzed with a 3-D model and also with a 2-D spine analysis that is more commonly used in practice. Internal force and moment demand from imposed dead and live loads in the superstructure and substructure were compared between the 2-D and 3-D analyses. The results focus on a comparison between shear forces and bending moments along the entire length of the bridge superstructure, at the bent caps, and axial loads and moments in the bridge columns. For the superstructure, the analysis results were reviewed for the entire bridge length at each span, while the substructure, only two bents and two columns were selected in this study. The two bents that were considered – Bent 8 is on the curved alignment of the bridge and Bent 9 is on a straight alignment. The 2-D spine analyses were performed with CT-bridge and CT-bent, while the 3D analyses were performed with CSI-Bridge. All loads are based on AASHTO LRFD specifications. The results illustrate that spine analysis may be highly conservative, especially when considering substructure demands.