The Analysis Of Seismic Response Of Continuous Girder Bridge Under Non-uniform Excitation

With the rapid development of transportation, the southwest region of China where there are more mountains and rivers is widely applied to bridge structure. In the southwest region with ups and downs, the span of the bridge and the height of piers have increased correspondingly, hence when choosing the form of the bridge structure, it is necessary to meet the transport needs and to consider the terrain features. Owing to the earthquake-prone areas in parts of southwest region, the bridge seismic design is particularly important, which means the reasonable selection and scientific design of seismic structures is a favorable way to reduce earthquake.This paper takes Apengjiang left lane of the bridge as the project example, and its total length of the main beam is 253.8m, and span arrangement is(66.9+120+66.9)m, at the same time,it is a prestressed concrete continuous girder bridge. The text uses ANSYS software to build the full-bridge space model, and conduct its full-bridge modal analysis, uniform excitation seismic response analysis and non-uniform excitation seismic response analysis. The contents of this text have a certain reference value for the seismic design of similar bridges, The main contents are as follows :(1)Through the bridge modal analysis, it can be found the change in height of piers and the effect of pile and soil will affect the mode shapes and frequencies, and it needs to consider the pile- soil interaction when conducting seismic response analysis.(2)By entering the E-wave, T-wave and artificial wave of seismic waves, it can be separated to conduct uniform excitation seismic response analysis for model girders and piers, and it can be obtained the displacement of main beams and piers, the shear and the maximum response of bending moment and the corresponding cross-sectional position under three different seismic waves, and it is helpful for bridge seismic design to determine the position of the maximum seismic response.(3) By entering three different operating conditions, it can be to conduct non-uniform excitation seismic response analysis for model girders and piers, and it can be obtained the displacement of main beams and piers, the shear and the maximum response of bending moment and the corresponding cross-sectional position under three different operating conditions.(4)By comparing the result of uniform excitation analysis and non-uniform excitation analysis, It can be found that the maximum response position of main beam is the same under two different excitation, The maximum displacement of the main beam in each non-uniform excitation conditions is less than the maximum displacement of its conditions which includes two kinds of seismic waves under conducting uniform excitation separately; The maximum bending moment and shear under each condition are less than the response in two alone it contains the maximum bending moment or shear the larger. The maximal response positions of piers is the same under two different excitation. The maximum response of piers in each non-uniform excitation conditions are less than the seismic response of its conditions which includes two kinds of seismic waves under conducting uniform excitation separately.