摘要
首先,简要分析了近断层脉冲型地震动的产生原因及主要特征,讨论了基于峰值-峰值速度脉冲和正则累积平方速度指标的有明显脉冲地震动记录选择方法。进而,选择一榀六层三跨钢筋混凝土框架结构为研究对象,以非线性有限元软件OpenSees为平台,选择20条有明显脉冲的近断层地震动记录,以结构基本周期对应谱加速度S_a(T_1)为强度指标调整原始地震动记录,并对结构进行增量动力分析(Incremental Dynamic Analysis,IDA),以结构最大层间位移角θ_(max)和楼层最大层间位移角θ_(max,i)等为损伤指标,统计分析IDA结果,得到近断层脉冲型地震动记录下的IDA曲线,进而利用IDA结果,评估了结构的抗整体性倒塌能力。同时,也选择20条远场地震动记录进行同样分析以进行比较。结果对比表明:在地震动强度指标相同时,近断层脉冲型地震动更容易引起结构的破坏;近断层脉冲型地震动作用下结构的抗倒塌能力低于远场地震动作用下结构的抗倒塌能力;近断层脉冲型地震动作用下结构底层的塑性变形相对更加集中。
First, the cause and main characteristics of pulse-type ground motion in the near-fault regions were introduced briefly and selection of near-fault pulse-type ground motion records based on Peak-to-Peak Velocity （PPV） and Normalized Cumulative Squared Velocity （NCSV） were discussed. Then, a 6-story reinforced concrete frame with 3 bays was taken as a case study and the analytical model was built via OpenSees. 20 near- fault pulse-type ground motion records were selected and spectral acceleration at the fundamental period of the strueture,Sa （T1 ） was taken as intensity measure to scale the original ground motion records to conduct maximum interstory drift ratio θmax i of each floor were chosen as damage measures to obtain the IDA curves of the structure. Furthermore, the global collapse resistant capacity was derived and the damage distribution of the structure was evaluated based on the IDA results. Meanwhile, the same analysis was conducted under chosen 20 far-field ground motion records for comparison. Comparison of the results shows that with the same intensity measure, near-fauh pulse-type ground motion is more likely to cause damage to the structure. The global collapse resistant capacity of the structure under near-fault pulse-type ground motion is lower than that under far-field ground motion. For a multi-story reinforced concrete frame structure, plastic deformation is concentrated more at the first floor of the structure.
出处
《结构工程师》
北大核心
2017年第1期32-42,共11页
Structural Engineers
基金
国家自然科学基金项目(51268036)
国家自然科学基金项目(51578273)
关键词
近断层地震动
速度脉冲效应
抗整体性倒塌能力
增量动力分析
near-fauh ground motion, velocity pulse, global collapse resistant capacity, incremental dynamicanalysis
