近断层地震地面运动的能量与位移延性需求

Energy And Displacement Ductility Demand Imposed by Near-fault Earthquake Ground Motions

针对脉冲型近断层地震动考虑了位移延性和阻尼因素对结构输入能量谱的影响,指出输入能量谱是表征地震动累积破坏能力的稳定指标,分析了地震动输入能量和单自由度结构响应最大位移之间关系,提出了等效速度比的简化解析表达式.基于Park-Ang双参数损伤模型分析了损失指标和最大位移延性之间的关系,并和文献[12]建议公式进行了比较,指出对于确定的损伤指标,近场地震动相对集中的能量输入会导致更高的位移变形需求,和相对较小的累积损伤需求。因而有必要考虑增强结构瞬时耗能能力以减小其变形。

In this paper, taking into account the effects of displacement ductility and structure damping, input energy spectra is firstly studied for near-fauh earthquake motions containing impulses. Input energy is found to be a credible index to characterize the cumulative damaging potential of such kind of earthquake ground motions. After analyzing the stable relationship between input energy and ultimate inelastic displacement, a simplified formula with equivalent velocity ratio to denote these two parameters is proposed. Based on Park ＆ Ang dualparameter damage model, the relation of damage index and ultimate displacement ductility are discussed and compared with expression from ref.[12]. For certain damage index, more displacement demands are required because of higher concentrated energy input of pulse-type earthquake motions than far-field. So it＇s especially necessary to strengthen energy consuming capacity and reduce structure deformation for the aim of strengthening structure safety.