Comparison and Evaluation of Displacement-based Methods and Modeling Assumptions for Design of Ordinary Bridges in High Seismic Regions Using Various Computer Software
The main objective of this research is to evaluate the effectiveness of three different displacement-based methods for seismic design of ordinary standard bridges. Two bridges previously designed by the Tennessee Department of Transportation (TDOT) engineersfollowing the American Association of State Highway and Transportation Officials (AASHTO) Guide Specifications for LRFD Seismic Bridge Design are selected and investigated in this study. Two different support conditions are considered, one employing seat-type abutments with rigid bent foundations; and the second employing stub wallabutment with flexible bent foundations (Nonlinear Spring Support Configuration). In addition to the AASHTO Specifications, the analysis methods include the capacity-demand-diagram method, as an inelastic demand Capacity Demand Method (CSM), andFederal Emergency Management Agency (FEMA) 440 Procedure C as an equivalent linearization CSM. Pushover analysis methods are used to construct the capacity diagram of the system. Furthermore, the usability of the three most widely used software programs(SAP2000, ADINA, and OpenSees) for performing the displacement-based seismic analysis is studied.This research will provide TDOT engineers with the necessary information on which procedure is the best approach to use for design of highway bridges. Also, it provides information on how well previously designed bridges response when analyzed with the new displacement-based procedures. And finally, it will provide the TDOT engineers with information on capabilities and limitations of various software packages
