李宇 李琛 赵福志 李钊

摘   要：选取139条长周期地震动记录作为输入，研究了恢复力模型参数（恢复力模型、刚度比η、阻尼比ξ、位移延性比μ）和地震动特性（周期T、震级MW、场地、PGA）对长周期地震的输入能量谱SEI、滞回耗能谱SEH和阻尼耗能谱SED的影响. 研究表明：1）恢复力模型对长周期（常规）地震能量谱的影响很大（小）;η对长周期和常规的地震动的能量谱的影响都很小;随着ξ增加，长周期（常规）地震的SEI的长周期段谱值增大（减小）;随着μ增加，长周期（常规）地震的SEH的峰值平台段延长（缩短）且峰值降低（增大）. 2）MW越大，结构损伤越大;场地土越软，能量谱值越大;若已知基准PGAref的能量谱，其他PGAoth的能量谱可由（PGAoth /PGAref）2调整得到. 基于以上的參数影响研究，采用三段式拟合函数，建立了长周期地震弹性输入能量设计谱，并拟合了μ和ξ对长周期地震能量谱的影响公式，进而得到长周期地震非弹性输入能量设计谱.

关键词：长周期地震动;输入能量谱;滞回耗能谱;阻尼耗能谱;设计谱

中图分类号：U448.27                            文献标志码：A

Abstract：A total of 139 long-period ground motion（GM） records are selected to study the effects of the parameters of restoring force models（restoring force models， stiffness ratio η，damping ratio ξ，displacement ductility ratio μ） and GM characteristics （period T，earthquake magnitude MW，site，PGA） on the input energy spectra SEI，hysteretic energy spectra SEH and damping energy spectra SED of the long-period GMs. Therefore， it can be found that： 1） there is a significant（slight） influence of the restoring force model on the long-period （conventional） seismic energy spectra， while there is a slight influence of the restoring force model on the conventional one; there is a slight influence of η on the long-period and conventional seismic energy spectra; with the increase of ξ，the spectral values in the long-period region of the long-period  SEI increases， but for the conventional one it decreases; with the increase of μ，the peak platform and peak value of the long-period SEH is prolonged and decreases， but for the conventional one they are shortened and increases，respectively. 2）the larger MW results in the greater structural damage，while the softer site soil leads to the larger energy spectra value;the seismic energy spectra with other PGAoth can be obtained by multiplying the known seismic energy spectra with the reference PGAref by the equation of （PGAoth /PGAref）2. Then，based on the above parametric studies，the elastic long-period input energy design spectra are established by using a three-segment fitting function， and the influence formulas of μ and ξ on the long-period spectra are fitted. And then the inelastic long-period input energy design spectra are obtained.

Key words：long-period ground motions（GM）;input energy spectra;hysteretic energy spectra;damping energy spectra;design spectra

2003年，在日本十胜冲地震中，苫小牧地区（震中距约225 km，PGA = 89.2 gal）的储油罐被破坏并引发火灾;北海道许多桥梁也发生破坏，如Rekifune Bridge跨中竖向位移达12 cm. 2011年，在东日本大地震中，东京都办公大楼（震中距约300 km）地下3层的最大加速度仅为74 gal，而顶部（48层）最大位移却达65 cm;大阪府办公大楼（震中距约700 km）顶部（52层）最大加速度仅为131 gal，而最大位移却达132 cm. 可见，长周期地震动（远场卓越周期偏大型地震动）对长周期结构有较大影响. 此后，学者们开始真……