Correlation Analysis between Double-plateau Ground Motion Intensity Index and Frame Structure Response Displacement

The seismic damage caused by the double-plateau ground motion of the large earthquake with multi-fault rupture is much more serious than that of the single-plateau ground motion. At present, it is not clear what kind of intensity index is used to better describe the characteristics of the double-plateau ground motion. Based on the record of the 5.12 Wenchuan earth quake with obvious double-plateau characteristics, the correlation between the recorded intensity index and the maximum seismic response displacement of the frame structure is analyzed. According to the significance of the linear regression equation between various intensity indexes and the maximum seismic response displacement of frame structure, a intensity index that can reasonably describe the characteristic of the double-plateau ground motion is selected. The results show that among the three types of intensity indexes, the correlation between the velocity intensity index and the maximum seismic response displacement of the frame structure is the strongest, the correlation of the displacement intensity index the weakest, and the correlation of acceleration intensity index between the velocity intensity index and the displacement intensity index. Among the speed intensity indexes, the peak velocity has the strongest correlation with the maximum seismic response displacement of the frame structure. There regression results between the peak velocity and the maximum response displacement of the frame structure is the most significant. It is recommended to use the peak velocity as the intensity index for seismic analysis of engineering structures under the double-stationary ground motion.