曲线高架桥在非一致地震作用下的随机反应分析

Analysis of Stochastic Response of Curve Viaduct under Non-consistent Earthquake Action

考虑行波效应和空间相干效应,利用随机振动的基本理论和分析方法建立了桥梁结构计算模型。对某一曲线高架桥分别进行了地震波单向输入时的一致和非一致地震随机反应分析,分析了不同视波速下的行波效应和不同空间相干程度对曲线桥结构反应量的影响规律。分析结果表明,在随机地震作用下,当考虑行波效应且视波速较小时,曲线桥在地震作用方向的墩顶位移、墩底内力变化较大,且随着视波速减小其反应增加的幅值越大;考虑空间相干效应时,在地震作用方向结构的反应却是减小的,随着相干程度的减弱,其减幅值增加,在完全不相干作用下,其减幅值最大,在30%至60%之间,即使在强相干作用下其值也不可忽略。

With consideration of the traveling wave effect and the spatial coherence effect,a bridge structure calculation model was established through the elementary theory and the analysis method of the random vibration.The stochastic response of a curve viaduct under one-way inputs of both the consistent earthquake action and the non-consistent one were analysed.Influences of the responses to the curve bridge structure due to the traveling wave function with different traveling wave velocity and the different spatial coherence function were discussed.The result shows that(1) the pier top displacement and pier bottom internal force in earthquake direction change remarkably and the response amplitude increases with the velocity decreases with consideration of the traveling wave effect and the wave velocity is smaller under random seismic action;(2) structural response in the earthquake direction reduces and the effect will be larger with the degree of coherence decreases under the effect of spatial coherence;(3) the reduction is the largest which increases between 30%-60% under completely irrelevant and its value cannot be ignored even in the strong coherent.