等效阻尼比对基于位移的抗震设计的影响分析

等效阻尼比是基于位移抗震设计中确定等效周期的一个关键参数。通过对不同研究者提出的等效阻尼比模型进行比较研究,重点讨论了滞回模型、延性系数和等效周期对等效阻尼比的影响。结果表明,不同等效阻尼比模型的总体变化趋势是一致的;滞回模型对等效阻尼比有很大影响,Ramberg-Osgood模型的等效阻尼比是Flagshaped模型的2.56倍;等效阻尼比随着延性系数的增大而增大,尤其在μ=2～4范围内变化幅度最大;短周期与中长周期等效阻尼比相差2倍多,故等效周期小于1 s时,必须考虑其对等效阻尼比的影响。

Analysis of Equivalent Damping Ratio on Displacement-based Seismic Design

The equivalent damping ratio is a key factor in determining equivalent period for displacement based seismic design.The equivalent damping ratio models of different researchers are compared.Influences of hysteretic models,ductility factor and equivalent period on equivalent damping ratio are discussed. It is concluded that tendency of equivalent damping ratio in different models is basically identical. The hysteretic models have important influence on equivalent damping ratio.The equivalent damping ratio of Rambcrg-Osgood model is 2.56 times that of Flag shaped model.The equivalent damping ratio becomes large with the increasing of ductility factor,especially whenμis within2,4].The equivalent damping ratio within short vibration periods is 2 times that of moderate or long vibration periods.So when effective period is shorter than 1 second,the influence of effective period on equivalent damping ratio must be taken into account.