Ground motion attenuation characteristics of Wenchuan earthquake and seismic response law of long-span continuous rigid frame bridge with high-rise pier
Shan Deshan Zhang Erhua Dong Jun Guo Shan
Southwest Jiaotong University, Chengdu 610031, China
Abstract：In order to analyze the evolution law for the action effects of long-span continuous rigid frame bridges with high-rise piers under the actions of Wenchuan ground motions with different fault distances, mainshock records of Wenchuan earthquake from 129 national seismic stations were collected. Attenuation characteristics for the intensity magnitudes of Wenchuan ground motion records were analyzed from the viewpoint of engineering seismology, and then the attenuation laws of PGA, PGV and response spectrum were summarized. With the main bridge of Miaoziping bridge taken as the example, two kinds of sample groups for long-span continuous rigid frame bridges with different pier heights were produced, and the representative values for natural periods of these two kinds of bridges were compared and discussed subsequently. Based on the response spectrum analysis, the peak response surfaces, which changed with different fault distances for the response spectra of these two kinds of bridges, were fitted, and then the response characteristics of the long-span continuous rigid frame bridges with high-rise piers for different fault distances were discussed. The results show that for different fault distances, the seismic responses of long-span continuous rigid frame bridges with high-rise piers are significantly different, and the seismic responses of these two kinds of bridges under the action of the near fault ground motions are obviously strong. The research results provide the guidance and reference for the layout of piers and the selection of bridge site for the long-span continuous rigid frame bridge with high-rise piers.
