橡胶隔震支座性能劣化规律及相应近海隔震结构全寿命周期地震风险分析

The offshore structures with huge investment have great effect on national economy, in order to improve their seismic safety, usually adopt the isolation techonology. The offshore isolated structures are generaly affected by the combined action of complex marine corrosion environment and normal work condition for a long time. As time went on, properties deteriorations of material and isolated bearing may be produced. Under the suddenly occurred earthquake, if the isolated bearing which is link of superstructure and substructure can normally play action, and if the seismic behavior of the total structure system can meet the requirement, are very important. So, the key scientific problems are the deterioration law of mechanical properties of isolated bearing and its influence law on sesimic performance of the offshore isolated structures.. In consideration of complex marine corrosion and earthquake environment, the project takes the isolated rubber bearing and the offshore isolated bridge as research subject, through a large number of tests of the isolated rubber bearings or rubber materials and theory analysis, discovers the properties deterioration law of the isolated rubber bearig and rubber material; research influence of the properties deterioration of the isolated bearing on seismic performance of the offshore isolated bridge; analyse seismic potential risk of damage and failure for the offshore isolated bridge in life-cycle period. This project can benefit to bring the isolated bearing into full play under normal work condition and earthquake enviroment, ensure the offshore isolated bridge normally service in life-cycle period.

近海结构投资巨大，对国民经济和社会发展影响重大，为提高其抗震安全性，多采用隔震技术。但近海隔震结构处于复杂海洋环境和正常使用荷载的长期共同作用，材料及隔震支座性能随时间可能产生劣化甚至失效，在突发地震下，隔震支座是否能正常发挥作用对整体结构抗震性能影响重大。因此隔震支座的性能劣化时变规律及其对近海隔震结构抗震性能的影响规律是需要解决的关键科学问题。本项目以橡胶隔震支座和近海隔震桥梁为研究对象，通过大量试验及理论分析，揭示复杂海洋及地震环境耦合作用下，支座及相应材料性能的劣化及时变规律；分析隔震支座性能劣化对近海隔震桥梁抗震性能的影响规律；探索隔震橡胶支座因复杂海洋环境影响产生的性能劣化造成的近海隔震结构的损伤失效地震风险,对于确保隔震支座及桥梁在寿命周期内正常服役意义重大。

本项目针对复杂近海环境开展了橡胶隔震支座老化、海蚀、干湿循环试验（包括天然橡胶支座、高阻尼橡胶支座），并针对近海隔震结构开展了全寿命性能易损性分析和可靠度分析。.项目组通过老化、海蚀加速劣化试验，研究了考虑老化时间影响的天然隔震支座橡胶材料修正本构Moony-Rivlin模型、不均匀老化对近海桥梁天然橡胶隔震支座性能影响及简易预测方法、基于热老化作用的天然橡胶隔震支座力学性能时变规律；同时，开展了老化及海蚀作用下近海桥梁天然橡胶隔震支座性能劣化试验、橡胶材料性能劣化试验、橡胶本构Moony-Rivlin模型的研究；最后，基于橡胶隔震支座老化时变规律，开展了近海隔震桥梁地震响应时变规律、时变易损性及地震风险可靠度分析。.项目组分别针对天然橡胶支座和高阻尼隔震支座，开展了长达几个月的干湿循环试验，研究了海水干湿循环作用下天然橡胶隔震支座和高阻尼橡胶支座橡胶材料力学性能劣化规律、橡胶本构Mooney-Rivlin模型、支座基本性能时变规律、支座水平刚度的剪应变相关性时变规律、支座拉剪性能时变规律；同时基于高阻尼橡胶支座劣化，开展了近海隔震桥梁抗震性能时变规律研究、并基于中心复合设计响应面法开展了时变地震易损性分析。.通过本项目的研究，揭示了天然橡胶隔震支座和高阻尼橡胶隔震支座在复杂海洋环境及地震共同作用下随着劣化时间增长的性能劣化时变规律；构建了天然橡胶材料考虑近海环境影响的修正橡胶Moony-Rivlin本构模型；分析了隔震支座和墩柱性能劣化对近海隔震桥梁抗震性能的影响规律；探索了隔震橡胶支座因复杂海洋环境影响产生的性能劣化造成的近海隔震桥梁全寿命性能和可靠度。研究结果可为橡胶材料的本构关系变化规律、橡胶隔震支座性能劣化规律研究，以及隔震工程全寿命性能风险评估和基于全寿命的抗震设计打下坚实的基础。