Large Span Structure Under Multidimensional Multi-point Input Of Seismic Analysis Method Research

Due to its large span structure base extension length, span is big, the bearing whenthe earthquake ground motion is not synchronous, earthquake excitation of spatialvariation effect should not be ignored. Conventional seismic response analysis methodis based on consistent earthquake input assumptions, without considering the effect ofspatial variation. For large span structure, if still use consistent incentive calculationmethod of the structure, will be not accurate enough. So based on the analysis ofseismic response calculation of long-span structure, the spatial variation effect ofearthquake excitation is very necessary. In this paper, we study the large span structureunder multidimensional multi-point excitation of earthquake resistant analysis method,mainly focus on is the earthquake excitation is considered the spatial variation effect inthe seismic analysis method, the research content mainly has:(1)Space effect is studied on influence principle of large-span structure seismicresponse calculation.(2) study the long-span structure seismic response calculation, the three mainmethods and the spatial effect is how to think about it.(3) study the stochastic simulation of ground motion field, and study the set of eachmodel is how to consider the spatial effect; Study the coherence function model is seteach factor as well as the scope of their respective practical;(4) on the basis of forefathers’ research on the synthesis of multi-point artificialtime history method and simplified method.(5) through the above research, a Matlab program synthesis to considering theeffect of ground motion space suitable for calculating the earthquake response of thelong-span structure of multi-point ground motion time history, and formedmulti-dimensional multi-point artificial time history, for a three span continuous rigidframe bridge are consistent excitation and traveling wave excitation, unidimensionalmulti-point excitation, the multi-dimensional seismic response under multi-pointexcitation analysis, studies the traveling wave effect, incoherence effect and local siteeffect, as well as the multi-dimensional seismic response of the long-span structure ofmulti-point input, the following conclusions:1) the traveling wave effect in the seismic response of the long-span structurecalculation cannot be ignored. 2) after considering the effect of partially coherent, calculated seismic responsevalue slightly smaller when compared to the consistent excitation.3) when the seismic responses of the long-span structure calculation, tounidimensional input relative to the multidimensional input are unsafe.