The aim of this research is to understand and quantify the modeling differences
between CSiBridge and OpenSees, and to determine sensitive model parameters.
When designing bridges for the high seismic region of California, the California
Department of Transportation (Caltrans) performs nonlinear time history analysis
of their bridge models. For three-dimensional models, the bridge response generated
from CSiBridge/SAP2000 differs from the bridge response generated from
OpenSees. For this research, Caltrans provided four Ordinary Standard Bridge designs
and their corresponding three-dimensional CSiBridge input files. These files,
along with three-dimensional models created in OpenSees, are employed to understand
the differences in modeling assumptions between the two software packages.
To validate OpenSees as a modeling tool, mode shapes and pushover results in
OpenSees were compared to CSiBridge results. Next, to validate OpenSees in sensitivity analysis, elastic materials were used to model the bridge structure. Next, a
sensitivity analysis is performed in OpenSees, and sensitive input parameters are
identified. Future work includes the implementation of nonlinear material properties
and modeling recommendations.