Title: System Modeling for Seismic Performance Assessment and Evaluation of Reinforced Concrete Bridge Columns

Author(s): T. L. T. Nguyen, P. F. Silva, M. T. Manzari, and A. Belarbi

Publication: Symposium Paper

Volume: 271

Issue:

Appears on pages(s): 125-146

Keywords: bridge systems; displacement ductility; seismic performance; shear keys; soil-structure interaction

Date: 5/24/2010

Abstract:
In the last two decades, seismic design of reinforced concrete bridges has shifted from a purely “life-prevention” design approach to a broader approach that also addresses “damage control” and “loss reduction” issues. This shift in philosophy requires the use of numerical tools that more accurately simulate the response of various bridge components. As importantly, a greater emphasis is placed on understanding the effects that these bridge components have on the overall seismic response of bridges. This paper presents the results of a series of nonlinear time history analyses of a RC bridge that was simulated under various modeling conditions using a finite element program called Opensees. These time history analyses were performed according to the following 16 modeling conditions: (a) two options for the nonlinear modeling of the columns, (b) two modeling conditions at the bridge columns’ foundation, and (c) four types of modeling conditions at the bridge abutments. Additionally, these modeling conditions were evaluated under two design earthquake levels that characterize the maximum considered earthquake and the frequent earthquake. To enforce the analysis, two more earthquake records were used: Inca-Peru and Northridge. Analytical results confirm that the various modeling options have significant influence on the seismic response of bridge systems, especially when nonlinear response of the abutment shear keys are included in the analyses. The different modeling runs were numerically evaluated and compared to each other in terms of the displacement ductility imposed on the columns. Within a performance-based design methodology, detailed results from these analyses are presented and discussed in further detail in the paper.