Issue 29

W. Guodong, Frattura ed Integrità Strutturale, 29 (2014) 376-384; DOI: 10.3221/IGF-ESIS.29.33 381 (a) The density of displacement response power spectral in main span. (b) The density of displacement response power spectral in main span. (c) The density of displacement response power spectral in main span. (d) The density of displacement response power spectral in bridge’s back span. (e) The density of displacement response power spectral in bridge’s back span. (f) The density of displacement response power spectral in bridge’s back span. Figure 3 T he response power spectral density of main span, mid-span across back in cable-stayed bridge. When comparing the pseudo excitation method directly obtained with absolute displacement and traditional random vibration method, the relative error of its calculation results is shown as Tab. 1. We could derive the following conclusion from the data in table that: (i) the calculation results of two algorithm are basically the same, it demonstrates that after linearization, the pseudo excitation method directly obtained with absolute displacement could replace traditional random vibration method in studying the seismic performance of structure. The excellence of this method has following points: the absolute displacement does not needs to be decomposed into quasi static displacement and dynamic relative displacement during calculating; quasi static modal matrix A does not needs calculation when constructing virtual stimuli for harmonic response analysis, thus it is simple and feasible; its essence does not changes the basic principle of traditional pseudo excitation method, its calculation efficiency is equivalent to traditional pseudo excitation method.