基于概率地震需求分析的铅芯橡胶支座抗震性能研究

选取谱加速度为地震动强度参数，最大墩底弯矩为工程需求参数,对铅芯橡胶支座隔震简支梁桥和非隔震简支梁桥进行了概率地震需求分析,从概率的角度定量计算研究了铅芯橡胶支座在提高桥梁结构抗震性能上的作用。概率地震需求模型计算结果表明，隔震桥梁结构回归方程的斜率均小于非隔震桥梁结构回归方程的斜率，这反映出隔震结构对地震动强度改变的敏感性小于非隔震结构；场地危险性分析表明，在同一场地上，桥梁结构体系遭遇某水平谱加速度的超越概率，隔震结构小于非隔震结构，隔震支座的应用降低了桥梁结构对应的场地危险性；概率地震需求危险性分析表明，在本文设定的场地和结构参数下，铅芯橡胶支座隔震桥梁结构发生墩底纵筋屈服的年超越概率远小于非隔震结构相应的概率。本文的研究表明，概率地震需求分析方法作为一种基于概率的定量分析方法，可以用于不同结构体系的桥梁结构抗震性能的评价上。

Study on Seismic Performance of LRB Based on Probabilistic Seismic Demand Analysis

By choosing spectral acceleration as Intensity Magnitude parameter and bending moment at pier bottom as Engineering Demand Parameter, Probabilistic Seismic Demand Analyses for seismic isolated simply supported beam bridge with Lead Rubber Bearing (LRB) and non-isolated bridge are presented in this paper, from which the function of LRB is studied with a quantitative analysis method of the probability based. The results of Probabilistic Seismic Demand Model show that the regression slope of isolated bridge is smaller than that of non-isolated bridge. It means bridge installed with LRB is less sensitive to the increase of ground motion intensity. The results of Probabilistic Seismic Hazard Analysis show that the exceeding probability of isolated bridge for encountering a certain spectral acceleration is lower than that of non-isolated bridge, so the using of LRB decreases the bridge’s hazard level. The results of Probabilistic Seismic Demand Hazard Analysis indicate that the LRB can greatly decrease bridge's annual exceeding probability for reaching yield moment at pier bottom with the setting site condition and structure parameters in this paper. The research carried out in this paper shows that Probabilistic Seismic Demand Analysis, as a probability based quantitative analysis method, can be adopted in evaluation of different seismic design methods or seismic devices.