A 1/70-scale soil-pile-bridge model was designed and constructed according to an extremely long-span cable-stayed bridge with a 1400 m-main span. Shaking table tests were performed to estimate the effects of the near-fault earthquake waves on the seismic responses and pile-soil interactions of the bridge model under near-fault and far-field earthquake waves in the longitudinal direction. A three-dimensional analytical model was established to represent the test results and track the response variations resulting from the near-fault earthquake waves. Finally, both control strategies were numerically studied to decrease the effects of the near-fault earthquake waves on the seismic responses of the bridge model. The results showed that the longitudinal near-fault earthquake excitation significantly increased the acceleration and displacement of the towers and girder, and augmented the curvature and strain at the bottom of the towers as compared to the far-field earthquake excitation, resulting in the bridge model suffering from more severe damage. The near-fault earthquake excitation considerably amplified the pile-soil interaction effects on the seismic responses of the towers and piers. Additionally, the analytical model could approximately represent the test results and reliably take the response variations induced by the near-fault earthquake waves. The elastic cables and supporting piers control strategies could effectively mitigate the effects of the near-fault earthquake waves on the seismic responses the bridge model except for the longitudinal acceleration and vertical displacement of the girder, preventing the towers from experiencing more significant damage.

根据主跨为1400 m的超长跨度斜拉桥，设计和构建了1/70比例尺的土桩桥模型。进行了振动台试验，以估计近断层地震波在纵向上近断层地震和远场地震波作用下对桥梁模型的地震响应和桩-土相互作用的影响。建立了三维分析模型来表示测试结果并跟踪由近断层地震波引起的响应变化。最后，对两种控制策略进行了数值研究，以减少近断层地震波对桥梁模型地震响应的影响。结果表明，与远场地震激励相比，纵向近断层地震激励显着增加了塔架和大梁的加速度和位移，并增加了塔架底部的曲率和应变，从而形成了桥梁模型。遭受更严重的损害。近断层地震激励极大地放大了桩-土相互作用对塔和墩地震响应的影响。此外，分析模型可以近似表示测试结果，并可靠地获取由近断层地震波引起的响应变化。