摘要
为明确近断层地震反应谱的特征及其与抗震设计规范中标准反应谱的差异,以此指导近断层地区桥梁的抗震设计,通过统计分析与对比,开展近断层地震特性的研究,选取126条具有典型脉冲特征的近断层地震波,并按照断层类型分为3类,分别计算地震反应谱,并求得平均谱值。将结果与我国规范反应谱及39条ATC63远场地震波反应谱进行对比分析。研究结果表明:长周期范围(1.5~9 s)脉冲型地震波的反应谱明显高于我国现行规范的规定和ATC63远场地震波,最大可达3.7倍。我国规范规定的反应谱用于近断层结构设计时偏于不安全;在3类脉冲型地震波中,正逆断层的脉冲反应谱最大,近断层桥梁抗震分析应输入正逆断层脉冲型地震;对长周期结构抗震分析,应考虑近断层因素的影响。
In order to guide the seismic design of bridge structures located in near-fault area, the response spectrum characteristics of near-fault seismic waves and its difference from the standard response spectrum in the code for seismic design are made clear through statistical analysis and comparison.126 near-fault seismic waves with typical pulse-like characteristics are selected and classified into three groups according to the fault types. The average seismic response spectrum values of these waves are evaluated and compared with the standard response spectrum in the code for seismic design and the results calculated based on 39 ATC63 far-field seismic waves. The research shows that: The average response spectrum of near-fault seismic waves in the long-period(1.5~9 s) are larger than the suggested values in the current Chinese code and those of ATC63 far-field seismic waves. The maximum can reach to 3.7 times of the former one. It may be unsafety to make seismic design of the structure located in near-fault area based on the current code. Among the three types of pulse-like seismic waves, the response spectrum of normal/reversed fault is the maximum one. The pulse-like seismic waves of normal/reversed fault should be used in seismic analysis of the bridges located in near-fault areas. The effect of near-fault should be considered in seismic analysis, especially for the structures, which have long natural vibration period.
引文
[1]YANG D,PAN J,LI G.Non-structure-specific intensity measure parameters and characteristic period of nearfault ground motions[J].Earthquake Engineering&Structural Dynamics,2009,38(11):1257-1280.
[2]陈令坤,张楠,蒋丽忠,等.高速铁路桥梁方向脉冲型近断层地震反应分析[J].铁道工程学报,2013(9):40-46.CHEN Lingkun,ZHANG Nan,JIANG Lizhong,et al.Analysis of seismic response of directivity pulse-like near-fault ground motion to bridge of high-speed railway[J].Journal of Railway Engineering Society,2013(9):40-46.
[3]GB 50011—2010,建筑抗震设计规范[S].GB 50011—2010,Code for seismic design of buildings[S].
[4]GB 50111—2006,铁路工程抗震设计规范[S].GB 50111—2006 Code for seismic design of railway engineering[S].
[5]韦韬,赵凤新,张郁山.近断层速度脉冲的地震动特性研究[J].地震学报,2006(6):629-637.WEI Tao,ZHAO Fengxin,ZHANG Yushan.Characteristics of near-fault ground motion containing velocity pulses[J].Acta Seismologica Sinica,2006(6):629-637.
[6]江辉,李新乐,窦慧娟.近断层长周期脉冲型地震动对竖向反应谱的影响研究[J].振动与冲击,2012(16):56-61.JIANG Hui,LI Xinle,DOU Huijuan.Influence of nearfault long-period pulse-type earthquake ground motions on vertical response spectra[J].Journal of Vibration and Shock,2012(16):56-61.
[7]杜永峰,徐天妮,王亚楠,等.近断层地震动作用下设计速度反应谱研究[J].地震工程学报,2014(4):997-1002.DU Yongfeng,XU Tianni,WANG Yanan,et al.Analysis of designed velocity response spectra subjected to nearfault ground motion[J].China Earthquake Engineering Journal,2014(4):997-1002.
[8]宋廷苏,管庆松,周宝峰,等.美国UBC97与中国建筑抗震设计规范近断层系数对比[J].地震工程与工程振动,2016(5):55-64.SONG Tingsu,GUAN Qingsong,ZHOU Baofeng,et al.Comparison of the near fault factor between Chinese building seismic design code and American Uniform Building Code[J].Earthquake Engineering and Engineering Dynamic,2016(5):55-64.
[9]张莹,孙广俊,李鸿晶.近断层强地震地面运动特征参数分析[J].南京工业大学学报(自然科学版),2017(1):85-92.ZHANG Ying,SUN Guangjun,LI Hongjing.Characteristic parameters analysis of near-fault earthquake-induced ground motions[J].Journal of Nanjing Tech University(Natural Science Edition),2017(1):85-92.
[10]贾俊峰,杜修力,韩强.近断层地震动特征及其对工程结构影响的研究进展[J].建筑结构学报,2015(1):1-12.JIA Junfeng,DU Xiuli,HAN Qiang.A state-of-the-art review of near-fault earthquake ground motion characteristics and effects on engineering structures[J].Journal of Building Structures,2015(1):1-12.
[11]Somerville P G,Smith N F,Graves R W,et al.Modification of empirical strong ground motion attenuation relations to include the amplitude and duration effects of rupture directivity[J].Seismological Research Letters,1997,68(1):199-222.
[12]李明.近断层地震动对结构抗震设计的影响研究[D].北京:中国地震局工程力学研究所,2010.LI Ming.Study on the effect of near-fault ground motion on structural seismic design[D].Beijing:Institute of Engineering Mechanics,China earthquake administration,2010.