考虑地震动空间效应的斜拉桥风险分析及减震策略研究

Duo to the stochasticity and spatial variability of ground motion, the seismic response mechanism of cable-stayed bridge is extremely complex. However, the relevant theoretical research and numerical analysis are not enough. At present, the research on seismic response is mostly based on the assumption of deterministic earthquake and uniform excitation. Therefore, by accounting for the spatial variability effects of ground motions, the project is armed at investigating the seismic mitigation strategy on cable-stayed bridges by probability and risk analysis. The main contents include: (1) Modelling the acceleration and displacement time histories conditioned on the recorded ground motion arrays, incorporating the effects of incoherence, wave passage, and differential site-response; (2) Establishing the FEM of a cable-stayed bridge by incorporating the various uncertainties, carrying out the multi-support time history analysis; (3) Establishing probabilistic seismic demand model of cable-stayed bridges for multi-support seismic excitations (MSPSDM) by “cloud method”; (4) Deriving seismic risk of cable-stayed bridge by setting resilience (repair time) as an indicator. The risk is derived using the Total Probability Method by combining with seismic hazard model, MSPSDM, probabilistic seismic capacity model and loss model; (5) Optimizing the seismic mitigation strategy and its parameters to achieve the goal of the minimum seismic risk. This project would provide reference for the seismic analysis and seismic mitigation design of cable-stayed bridges. The results could be of great value theoretically and practically.

由于地震动的随机性和空间变异性，地震作用下斜拉桥的响应机理异常复杂，然而相关的理论研究和数值分析还不够充分，目前多是基于一致激励的确定性地震响应研究。因此，本项目基于理论和数值模拟两个方面，考虑地震动空间效应，从概率风险的角度开展斜拉桥减隔震设计与优化研究。主要内容包括：（1）基于实测地震波，模拟能同时考虑行波效应、失相干效应、局部场地效应的多点激励地震波时程；（2）建立考虑多种不确定因素的斜拉桥OpenSEES有限元模拟，进行多点激励非线性时程分析；（3）利用“云图法”建立多点激励作用下的斜拉桥概率需求地震模型；（4）结合地震危险性模型、概率性的抗震能力模型、损失模型，以灾后易修复为性能指标，通过全概率方法计算斜拉桥的地震风险；（5）以体系风险最低为目标，开展多点地震输入下斜拉桥减震装置选择与优化的研究。研究成果为斜拉桥风险评估及减隔震设计提供依据，具有较大的理论意义和工程实用价值。

由于地震动的随机性和空间变异性，地震作用下斜拉桥的响应机理异常复杂，然而相关的理论研究和数值分析还不够充分，目前多是基于一致激励的确定性地震响应研究。因此，本项目基于理论和数值模拟两个方面，考虑地震动空间效应，从概率风险的角度开展斜拉桥减隔震设计与优化研究。（1）基于实测地震波，提出了能同时考虑行波效应、失相干效应、局部场地效应的多点激励地震波时程方法；（2）利用“云图法”建立多点激励作用下的斜拉桥概率需求地震模型；（3）结合地震危险性模型、概率性的抗震能力模型、损失模型，以灾后易修复为性能指标，通过全概率方法计算斜拉桥的地震风险；（4）开发了应用于斜拉桥的多向阻尼体系，并通过试验验证了其抗震行了（5）以体系风险最低为目标，开展了多点地震输入下斜拉桥减震装置选择与优化的研究。研究成果为斜拉桥风险评估及减隔震设计提供依据，具有较大的理论意义和工程实用价值。