近断层地震动考虑能量损伤效应的非弹性强度需求

Inelastic Strength Demand of Near-fault Ground Motions Considering Energy Damage Effect

由于靠近断层处地震地面运动中速度脉冲作用的存在,导致传统的基于瞬时加速度反应谱的抗震设计,不能有效考虑由此带来的巨大能量耗散和位移需求。笔者采用代表性的脉冲型实际近场地震记录和人工模拟三角函数地震动时程,在分析累积输入地震动耗能和结构位移间关系基础上,提出了等效速度比的表达式;给出了近场地震动的等效变形需求表达式;提出了等价延性系数的概念,来考虑由于地震动能量耗散对结构的强度需求;经非线性时程分析方法对其稳定性进行了验证比较,有利于增强结构的安全性。

Due to the tremendous energy input of earthquake ground motions near the faults, the traditional inelastic seismic design based on transient acceleration response could not take into account effectively the effect of pulse-type energy and displacement demand. With some typical near-fault ground motion records and artificial earthquake waves by trigonometric function simulation, the relationship between the accumulative input energy and the maximum structural deformation was discussed. An index of equivalent velocity ratio was proposed to reflect the steady relation between these two parameters. Based on this expression, the equivalent displacement demand of near-fault earthquake was brought forward. An equivalent ductility coefficient was introduced to consider the structure strength demand from seismic energy dissipation, and the method supposed here was verified through nonlinear time-history analysis to enlarge the structure safety capacity.