A pile–soil–cable-stayed 1/70-scale bridge model was designed and constructed to represent an extremely long-span cable-stayed bridge with a 1400-m central span. Shaking table tests were conducted to investigate the wave-passage effects on the seismic responses of the pile–soil–cable-stayed bridge model under uniform and non-uniform longitudinal excitations. Additionally, the acceleration frequency spectra and seismic responses of the bridge model were separately evaluated to compare the effects of uniform and non-uniform excitation. Finally, a 3-D finite element model in OpenSees was built for comparison with the test results. The results showed that the longitudinal wave-passage excitations considerably impacted the acceleration frequency spectra in the vertical direction of the girder and the modal participation factor, which resulted in the symmetric vertical bending mode shapes of the girder to increasingly affect the seismic response as the wave-propagation velocity decreased. The longitudinal wave-passage excitations increased the vertical responses at the 1/2-span of the girder, whereas they generally decreased the longitudinal responses of the girder and tower, as compared with uniform excitation. The longitudinal wave-passage excitations had different impacts on the pile–soil interaction effects for the three studied structural systems of the pile–soil–cable-stayed bridge model. Moreover, the dynamic characteristics and seismic responses obtained from the numerical simulations were consistent with the experimental results.

中文翻译：

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波动对桩-土-斜拉桥纵向非均匀激励下地震反应的影响：振动台试验和数值模拟

设计并建造了桩-土-斜拉桥1/70比例桥模型，以代表中心跨距为1400 m的超长跨度斜拉桥。进行了振动台试验，研究了在均匀和非均匀纵向激励下，波通道对桩-土-斜拉桥模型地震响应的影响。另外，分别评估了桥梁模型的加速度频谱和地震响应，以比较均匀和非均匀激励的影响。最后，在OpenSees中建立了一个3-D有限元模型，用于与测试结果进行比较。结果表明，纵向波通过激励极大地影响了大梁垂直方向的加速度频谱和模态参与因子，当波传播速度降低时，导致梁的对称垂直弯曲模式形状越来越影响地震响应。与均匀激励相比，纵向波通过激励增加了梁的1/2跨度的垂直响应，而它们通常降低了梁和塔的纵向响应。对于三个研究的桩-土-斜拉桥模型结构体系，纵向波通过激励对桩-土相互作用的影响有不同的影响。此外，数值模拟得到的动力特性和地震响应与实验结果一致。