冻融钢筋混凝土框架结构抗震性能研究

Research on seismic performance of freeze-thaw reinforced concrete frame structure

为研究严寒地区冻融钢筋混凝土(RC)框架结构的抗震性能,采用有限元分析平台OpenSees对冻融RC框架进行宏观尺度建模。基于冻融RC构件的试验数据,验证冻融RC梁柱宏观尺度模型及建模方法的正确性。采用宏观尺度模型对5层RC框架结构进行静力推覆分析、弹塑性时程分析及地震易损性分析,对比不同冻融循环次数工况下的结构地震反应和退化规律。结果表明:随着冻融循环次数的增加,RC框架结构的承载能力及刚度明显退化,在地震作用下的位移响应逐渐增大,结构损伤和塑性发展程度不断加深,破坏概率明显提高;当冻融循环次数为50、100和200时,结构的抗侧承载力分别降低2.7%、4.8%及7.8%,结构在罕遇地震作用下的最大层间位移角分别增大7.8%、16.3%及23.9%,结构在峰值加速度为1.0 g下的倒塌概率分别增大14.7%、30.7%及45.6%。研究可为严寒地区RC框架结构的抗震性能评估提供参考。

To investigate the seismic performance of freeze-thawed reinforced concrete(RC) frame structure in cold regions, the finite element platform OpenSees was used to model the freeze-thaw damaged RC frame. The experimental data of frost RC components were used to verify the correctness of the macro model of frost RC beam-column and modeling method. The static pushover analysis, time history analysis, and seismic fragility analysis of a five layer RC frame structure were performed, and the seismic response and degradation law of different freeze-thaw cycles were compared. The results show that with the increase of number of freeze-thaw cycles, the bearing capacity and stiffness of structures are obviously deteriorated. The displacement response,damage extend, plasticity extend, and damage probability under earthquakes are significantly increased. With number of freeze-thaw cycles of 50, 100, and 200, the structure causes a decrease in the lateral bearing capacity of structures by 2.7%, 4.8%, and 7.8%, respectively. The maximum inter-story drift ratio is reduced by 7.8%,16.3%, and 23.9%, respectively, and the structural collapse probability of peak ground acceleration at 1.0 g is increased by 14.7%, 30.7%, and 45.6%, respectively. The study can provide a reference for the evaluation of seismic performance for RC frame structures in cold regions.