近断层高墩桥梁强震破坏机理及其抗倒塌性能研究

With consideration of the damage potential and uncertainty of shallow earthquakes, this research focuses on the high pier bridges constructed on the near-fault region (including bridges crisscross the fault). Combining the theoretical analysis, numerical simulation and experimental test, this project researches the influence factors and response characteristic of high pier bridges accounting for the near-fault high seismic risks, analyses the damage effect of near-fault spatial ground motions, reveals the damage pattern and collapse mechanism of high pier bridges settled on the near-fault region. This project will establish the spatial multi-point multi-dimensional seismic excitation model and generation method of the artificial ground motion for near-fault sites, propose the seismic excitation input method considering the foundation-structural dynamic interaction effects, reproduce the structure damage, system failure and progressive collapse procedure of the high pier bridges on the near-fault region, indicate the failure mode and collapse mechanism of high pier bridges subjecting near-fault seismic excitation, illuminate the collapse prevention performance of high pier bridges in the near-fault region, set up the control theory and method for collapse pattern of high pier bridges in the environment with high seismic risks. The achievements of this project are of great scientific significance and economic value for the seismic resistant design and safety evaluation of high pier bridges subjecting near-fault seismic excitation, it also provide scientific advices on the further exploration for improving the safety of major bridge structures under near-fault seismic excitations.

针对浅源地震发生的极不确定性和强破坏性，以我国近断层（含跨越断层）高墩桥梁为研究对象，采用理论分析、数值仿真和试验研究相结合的方法，考虑近断层强震高风险环境中，高墩桥结构动力非线性反应规律及其影响因素，分析近断层空间地震动的破坏性效应，揭示近断层场地上高墩桥的强震破坏规律和倒塌机制。项目预期将建立近断层地区空间多点、多维地震动场模型和生成方法，提出地基－桥梁基础动力相互作用的子结构分析模型及区域分解高效算法，再现近断层高墩桥梁强震作用下结构破坏、体系失效和倒塌全过程，阐明近断层强震作用下高墩桥梁的失效模式和倒塌机制，揭示近断层区高墩桥梁强震作用下抗倒塌性能，建立近断层高地震风险性环境下高墩桥结构倒塌模式控制理论与方法。预期研究成果对近断层场地上高墩桥梁抗震设计与安全性评价具有极其重要的科学意义和经济价值，也为进一步探索重大桥梁工程考虑近断层（含跨越断层）强震作用的抗震设防提供科学建议。

以近断层高地震风险地区建设的高墩桥梁结构为研究对象，针对强地震动场模型和近断层破坏性效应，高墩桥强震损伤破坏机理，抗倒塌性能评估，以及高墩桥的减震措施和基于延性的抗震设防方法等，进行了一系列深入的研究。提出了近断层空间多点、多维地震动场人工模拟方法，建立了近断层脉冲型地震动定量提取和合成方法，揭示了近断层潜在破坏性效应及其对高墩桥的影响规律；提出了考虑地基－桥梁基础动力相互作用的分析模型，对高墩桥强震作用下破坏、体系失效和倒塌进行分析，阐明了近断层高墩桥的失效模式和倒塌机制；基于IDA和易损性分析方法，揭示近断层区高墩桥梁强震作用下抗倒塌性能，提出基于等效延性的抗倒塌优化设计方法，建立了近断层高地震风险性环境下高墩桥结构倒塌模式控制方法。部分研究成果对近断层地区高墩桥抗震设计与安全性提升具有极其重要的科学意义和经济价值，为“一带一路”沿线桥梁生命线工程的建设与抗震设防提供科学建议。