Endurance time analysis of seismic performances of long-span continuous rigid-frame bridges with corrugated steel webs

Abstract

The seismic performances of continuous rigid-frame bridges must be evaluated efficiently and accurately using simplified methods during their design and strengthening. As a simplified method to evaluate the seismic performances of bridges, the endurance time method can be used to simulate the complete process of the collapse of an intact bridge via nonlinear time history analysis. The endurance time method is a novel approach of generating seismic acceleration time steps, which allow engineers and researchers to obtain maximal information from the states of the structures with the lowest computational cost. The Fei-Long Bridge—a long-span continuous rigid-frame bridge with corrugated steel webs—has the largest span of this kind in the world and is situated in a medium-risk seismic zone. In this study, we investigated the applicability and accuracy of the endurance time method to estimate the seismic performance of the bridge. Three endurance time accelerograms were generated as seismic inputs based on the design response spectrum provided by the Chinese specifications for the seismic design of highway bridges. In addition, 16 natural far-field and 16 natural near-fault ground motions were selected for incremental dynamic analysis. The seismic response characteristics of the bridge obtained by the endurance time method and incremental dynamic analysis were compared. The results of the endurance time method are observed to be within the envelope of the incremental dynamic analysis results, with an average error lower than 5%, and the median value of the endurance time method agrees well with the mean curve of the incremental dynamic analysis results. Therefore, the endurance time method can be used as a novel simplified and efficient method to evaluate the seismic performances of continuous rigid-frame bridges with corrugated steel webs.