Probabilistic evaluation of the seismic performance of a concrete highway bridge in Queensland

Abstract

Being intraplate, the Australian continent has shown low seismicity in its recorded history. However, Australia has been acknowledged as not completely free from seismic hazard. Performance-based earthquake engineering (PBEE) methodology has been widely developed during the past two decades, and has become a key approach for seismic analysis and design. Yet such an approach has not been implemented in Australian structural codes. Therefore, further research is required to develop a domestic approach for Australian applications. In this study, the seismic capacity of a concrete highway bridge is evaluated through a probabilistic method. For this purpose, an analytical model of a typical highway bridge in Queensland was built in OpenSees. The important seismic responses to be considered include the curvature ductility of columns, and the deformations in bearings and abutments. The main uncertainties are related to the source and ground motion models for potential Australian earthquakes. A set of synthetic intraplate ground motions, which was provided by the GeoscienceAustralian, is anticipated to be used in the generation of future probabilistic ground motion maps for Australia, and is presently used for nonlinear incremental dynamic analyses (IDA). The results of this study in the form of seismic capacity limit-states can be further employed for developing performance-based seismic design and/or seismic risk and fragility analyses of Queensland highway bridges.