Bridge Design for Earthquake Fault Crossings: Synthesis of Design Issues and Strategies. Final Report.

摘要

As shown by the bridge damages observed from recent earthquakes, the bridges crossing earthquake faults can be more vulnerable compared with those lying on one side of the earthquake faults. Avoiding building bridges across earthquake fault zones might be the best design strategy; however, it is not always possible to do so in regions of high seismicity such as California. While rigorous nonlinear response history analysis (RHA) using the spatially-varying ground motions generated based on site-specific seismological studies can be conducted for bridges crossing fault ruptures; such a design and analysis process is too onerous, making it less practical for bridge engineers. In response to the observed bridge damages and the absence of practical analysis methods, two approximate procedures, namely, the Fault Rupture-Response Spectrum Analysis (FR-RSA) and Fault Rupture-Linear Static Analysis (FR-LSA) procedures, were recently developed as alternatives to RHA for bridge across fault rupture zones. While there are many favorable features of the two approximate procedures (e.g., requiring significantly reduced modeling and computational efforts), obstacles still exist limiting their widespread acceptance and application.