地震动位移反应谱阻尼修正系数研究  

Damping modification factors for displacement response spectra

作　　者：李恒[1,2] 吴建超 雷霆[1] Li Heng;Wu Jianchao;Lei Ting(Hubei Key Laboratory of Earthquake Early Warning, Institute of Seismology, CEA, Wuhan 430071, China;Wuhan Institute of Earthquake Engineering, Wuhan 430071, China)

机构地区：[1]中国地震局地震研究所地震预警湖北省重点实验室,湖北武汉430071 [2]武汉地震工程研究院,湖北武汉430071

出　　处：《土木工程学报》2018年第7期61-69,86,共10页China Civil Engineering Journal

基　　金：地震科技星火计划(XH15027);国家自然科学基金(41474050)

摘　　要：阻尼修正系数(DMF)用于抗震设计规范中校正临界阻尼比高于或低于5%的弹性反应谱。在解耦多参数交叉影响的原则下研究了三个主要地震参数(震级、距离和场地条件)对地震动位移反应谱阻尼修正系数的影响。结果表明,DMF随着结构自振周期增大而逐渐趋近于1;随着震级和距离增大,阻尼比对位移反应谱影响随之增大,DMF曲线更加发散,这意味着通过附加阻尼减小结构地震反应对于大震和远震更加有效;场地条件对DMF的影响仅限于近场范围,但无法归纳出明显的影响规律,且随距离增大,不同场地对应的DMF之间的差异逐渐缩小。通过人工合成地震动数值试验,分析加速度反应谱与位移反应谱DMF曲线,得出结论:地震动频谱分量随频率的相对变化速度,对位移反应谱DMF曲线起控制性作用。最后提出了适宜于抗震设计规范采用的DMF公式,并利用实际强震记录数据拟合了DMF公式中的关键参数。In seismic design codes, damping modification factors （DMF） are used to adjust the elastic response spectral values with those critical damping ratios more than or less than 5%. The effects of earthquake magnitude, source-to-site distance and site conditions on the DMF for displacement response spectra are investigated. The results show that the DMF gradually approaches to 1 with the increase of the natural vibration period of the structure. The effects of magnitude and distance are obvious, and the influence of site class gradually diminishes with increasing distance. For a given period in which the magnitude or distance increases, the effect of damping on the seismic response may also increase, indicating that the response reduction due to the structural damping may become more efficient. Furthermore, the influence mechanism is analyzed. It can be concluded that the relative ratio of the low-frequency components of ground motion controls the DMF. The relative ratio is represented as the attenuation index of the acceleration response spectrum in the long-period range. A larger attenuation index corresponds to a faster approaching of the DMF curve towards unity with increasing the period. Based on these results, it is seen that the formula for DMF proposed in this work is applicable to the seismic design codes.

关 键 词：阻尼修正系数 地震动位移反应谱 减震 衰减指数 抗震设计规范 

分 类 号：TU202[建筑科学—建筑设计及理论]