Correlation Between Seismic Intensity Measures and Response of Skewed Bridges

Abstract

This paper investigates the relationship between 23 earthquake intensity measures (IMs) and seismic responses of skewed bridges and then identifies the best IMs of damage of the bridge. A total of 290 ground motion records classified into low- and high-frequency content groups are employed for numerical analyses. A series of nonlinear time-history analyses for the skewed bridges is performed to observe its seismic responses. Seismic responses of the bridges are measured in terms of the drift ratio and shear forces of bridge piers. A series of Pearson’s correlation coefficients are calculated to recognize the correlation between each of the 23 seismic IMs and seismic responses of the bridge. The numerical results show that in the case of low-frequency ground motions the best IMs correlated with the seismic response of bridges are Arias intensity (Ia), characteristic intensity (Ic), spectral acceleration (Sa(T1)), and spectral velocity at the fundamental period (Sv(T1)). For high-frequency motions, the well-correlated IMs with seismic damage of bridge are specific energy density (SED), Arias intensity (Ic), root-mean-square of velocity (Vrms), and characteristic intensity (Ic). Additionally, PGV/PGA ratio, mean period (Tm), and predominant period (Tp) show to be weakly correlated with seismic responses of bridges subjected to both low- and high-frequency motions.