地震动持时预测方程的最新研究进展

地震动持续时间对震害的影响已不容忽视，超过一定强度的地震动持续时间可能是造成非弹性结构过度破坏和场地震害程度加重的主要原因．然而，由于长期没有公认的持时定义和广泛适用的持时预测方程，目前几乎所有的工程抗震设计中均还没有考虑持续时间的影响．总结了持时定义和预测方程的最新研究进展：介绍了用Heaviside阶梯函数分别表示括号持时、一致持时和重要持时的定义；还介绍了最近提出的全面考虑各类影响因素、更具代表性和适用性的3个持时预测方程；预示不远的将来地震动持续时间的影响必将在地震安全评价和工程抗震设计中予以考虑．

State of Art Review on Earthquake Ground Motion Duration

As an important factor affecting the seismic damage, the influence of the ground motion duration should not be ignored. It has been proved that duration may account for the over-destruction of the inelastic structure and aggravate the seismic damage degree. However, due to the lack of recognized definition of dura- tion and widely applicable prediction equation in long-term, almost all engineering seismic design did not con- sider the impact of the duration. This paper summarizes the latest research progress of the definitions and pre- diction equations of ground motion duration. It is introduced that the definition of bracketed duration, uni- form duration and significant duration are denoted with Heaviside function. Three recently proposed predic- tion equations, full consideration of multiple influencing factors, more representative and applicability, are described. It is envisaged that, in the near future, the effects of earthquake ground-motion duration will be taken into account in the seismic assessment and seismic design.