摘要
针对大跨斜拉桥空间跨度范围广、局部场地条件差异性大,服役期内可能遭受空间地震动影响的问题,开展了空间地震动作用下大跨斜拉桥振动台台阵试验。研究了地震动空间效应对斜拉桥关键截面动力响应(加速度、位移和应变)的影响规律。研究结果表明:地震动空间效应对斜拉桥的地震动力响应有明显影响,其中行波效应影响较小,考虑行波效应和相干效应时影响次之,同时考虑行波效应、相干效应和局部场地效应时影响最为显著。以主塔为例,与一致激励相比,同时考虑空间地震动的行波效应、相干效应和局部场地效应时,主塔加速度、位移和应变最大增加幅值分别为55.69%、62.37%和67.37%。因此,开展大跨斜拉桥结构抗震设计时,采用一致激励或仅考虑行波效应时可能会低估斜拉桥的实际地震响应,应综合考虑行波效应、相干效应和局部场地效应等地震动空间效应。
This paper investigates the effects of spatial effects of seismic ground motions on the seismic responses of long-span cable-stayed bridges,considering their large range and notable variations in local site conditions.Shaking table tests were conducted on a cable-stayed bridge,and the dynamic responses(acceleration,displacement,and strain)of critical sections of the cable-stayed bridge were compared and analyzed.The results demonstrate the significant influence of spatial effects of ground motion on the dynamic responses of the cable-stayed bridge.Specifically,the analysis reveals that the wave passage effect has the least impact on the dynamic responses of the cable-stayed bridge,followed by the combined effect of the wave passage and coherence,while the combined effects of the wave passage,coherence,and local site conditions exert the largest influence.Taking the main tower as an example,the maximum acceleration,displacement,and strain responses increased by 55.69%,62.37%,and 67.37%,respectively,when spatial seismic motions incorporating the wave passage effect,coherence effect,and local site effects were considered,as compared to uniform excitation.Consequently,the seismic responses of cable-stayed bridges may be underestimated if only uniform excitation or the wave passage effect is considered.It is therefore imperative to comprehensively account for the effects of wave passage,coherence,and local site conditions of the spatial ground motion in the dynamic response analysis of long-span cable-stayed bridges.
作者
郑庆涛
苏俊省
李忠献
ZHENG Qingtao;SU Junsheng;LI Zhongxian(Key Laboratory of Coast Civil Structure Safety of the Ministry of Education,Tianjin University,Tianjin 300350,China;School of Civil Engineering,Tianjin University,Tianjin 300350,China)
出处
《地震工程与工程振动》
CSCD
北大核心
2024年第5期50-60,共11页
Earthquake Engineering and Engineering Dynamics
基金
国家自然科学基金项目(52238012,51427901)。
关键词
大跨斜拉桥
振动台台阵试验
行波效应
相干效应
局部场地效应
long-span cabled-stayed bridge
shaking tables test
wave passage effect
coherence effect
local site effect
