【摘要】 阻尼比是影响反应谱值的一个重要参数。当结构阻尼比发生变化时,会显著地改变反应谱值,从而影响结构所受地震作用的大小。规范设计反应谱均以一个标准阻尼比为基准,当结构主要振型的阻尼比偏离此标准值较多时,通过修正系数对设计反应谱进行修正。本文比较了各国桥梁抗震设计规范地震设计谱阻尼修正公式,并选取3条含有长周期分量的地震波对一长周期单自由度系统进行时程分析,使用瑞利阻尼,阻尼比从0.01～0.10变化,每种阻尼比计算结果取3条地震波的平均值,并与阻尼比为0.05的结果相比得到修正系数。在与各规范公式结果相比较后得出结论:欧洲规范阻尼修正公式更适用于长周期桥梁。更多还原

【Abstract】 Damping ratio is an important parameter of response spectrum,for it can significally change the earthquake force by influencing response spectrum values.Design response spectrum is generally based on an constant damping ratio,when this constant is deviated from the danmping ratio of structural chief modal far away,the spectrum value would be modificated by a factor.In this paper,the damping ratio modification formulas of bridge seismic design codes in domestic and overseas are compared,and a series of time history analysis of long-period single degree of freedom systems is carried out using three earthquake waves including long period component,damping ratio varied from 0.01 to 0.10 increasing by 0.01 using Rayleigh damping.The calculation result of every damping ratio is taken the average value of three waves,dividing the result of 0.05 damping ratio,the modification factor is obtained.Compared with the results of damping ratio modification formula in different bridge seismic design codes,it is concluded that Eurocode formula is more applicable to long-period bridge.更多还原