隔震建筑结构的强震观测与初步分析
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摘要
福建省防灾减灾隔震大楼自2005年8月架设强震观测结构台阵以来,已多次记录到大楼地震动力反应,这些宝贵的结构反应资料对于评价隔震效果、分析结构反应特性具有十分重要的价值。本文从中选取了震级在3.7~7.6、震中距在189~3 595km的24次地震的台阵资料,对大楼的振动特性和隔震效果进行了初步分析,得到的结论是:(1)大楼场地土层的特征周期在0.63~0.68 s;(2)中心大楼在小地震作用下表现的振动卓越频率分别为4.7Hz(垂直向)、1.31Hz(南北向)、1.40Hz(东西向),大楼水平向第一阶振型的频率分别为1.41Hz(南北向)、1.59Hz(东西向),即自振周期为0.70 s(南北向)、0.63 s(东西向);(3)大楼在小地震时隔震效果不明显,其南北向隔震效果比东西向好;随着地下室记录峰值的增大,顶层放大倍数有所降低,大楼卓越频率也有所降低;(4)初步分析表明大楼在小震时仍有扭转效应,其扭转周期为0.5 s,有待进一步分析。
Strong motion network records,which are obtained from the base-isolated building of Fujian Province Earthquake Administration in many earthquakes since August 2005,are quite valuable to understand the vibration characteristics of base-isolated building and assess the effect of base-isolation during earthquakes.Therefore,We primarily analyses 24 seismic records,the magnitudes of which are between 3.7 and 7.6 and the epicentral distances are from 189 to 3595 kilometers.The conclusions are drawn as follows:(1)the predominate period of building site is about 0.63 to 0.68 second;(2)the predominate frequencies of acceleration Fourier spectra in UD,NS and EW directions are 4.7,1.31and 1.40Hz respectively and the structure first-mode predominant periods in NS and EW directions,are about 0.70 and 0.63 second respectively;(3) The isolation devices of high base-isolated building is not effectively performed during these 24 earthquakes.The effect in south-north direction better than that in east-weat direction;the larger the peak acceleration of the basement floor is,the less the vibration peak value of the top floor is magnified and the more drastically the first natural frequency of building decreases;(4)in the high base-isolated building the torsional behavior at low earthquake intensity is revealed and the torsional predominant period of structure is about 0.5 second,but this result needs more verification.
Strong motion network records,which are obtained from the base-isolated building of Fujian Province Earthquake Administration in many earthquakes since August 2005,are quite valuable to understand the vibration characteristics of base-isolated building and assess the effect of base-isolation during earthquakes.Therefore,We primarily analyses 24 seismic records,the magnitudes of which are between 3.7 and 7.6 and the epicentral distances are from 189 to 3595 kilometers.The conclusions are drawn as follows:(1)the predominate period of building site is about 0.63 to 0.68 second;(2)the predominate frequencies of acceleration Fourier spectra in UD,NS and EW directions are 4.7,1.31and 1.40Hz respectively and the structure first-mode predominant periods in NS and EW directions,are about 0.70 and 0.63 second respectively;(3) The isolation devices of high base-isolated building is not effectively performed during these 24 earthquakes.The effect in south-north direction better than that in east-weat direction;the larger the peak acceleration of the basement floor is,the less the vibration peak value of the top floor is magnified and the more drastically the first natural frequency of building decreases;(4)in the high base-isolated building the torsional behavior at low earthquake intensity is revealed and the torsional predominant period of structure is about 0.5 second,but this result needs more verification.
引文
[1]胡聿贤.地震工程学[M].北京:地震出版社,1988:368-394.
[2]郑治真.波谱分析基础[M].北京:地震出版社,1983:1-238
[3]R W克拉夫,J彭津,著,王光远,等译,结构动力学[M].北京:科学出版社,1983.
[4]谢礼立,于双久,等编著.强震观测与分析原理[M].北京:地震出版社,1982:149-164.
[5]周福霖.工程结构隔震减震研究进展[M].北京:地震出版社,2004:1-8.
[6]韦永祥.基于强震和风振记录分析隔震结构的动力特性[D].哈尔滨:中国地震局工程力学研究所,2007.
[7]马强,金星,李山有.单自由度系统地震动力反应的实时计算方法[J].地震工程与工程振动,2003,23(5):61-68.
[8]李鸿晶,Celebi M.一幢钢筋混凝土建筑结构的强地震反应观测[J].地震工程与工程振动,2001,21(4):35-39.
[9]Celebi M.Identification of site frequencies from building records[J].Earthquake Spectra,2003,19(1):1-23.
[10]Toshihide Kashima,Akihiro Itou,Hisashi Fujita.Dynamic behavior of a 9-story base-isolatedbuilding during the 2003 Off Tokachi Earthquake,Japan[C]//Proceedings Third UJNR Workshop on Soil-Structure Interaction,March 29-30,2004,Menlo Park,California,USA.
[2]郑治真.波谱分析基础[M].北京:地震出版社,1983:1-238
[3]R W克拉夫,J彭津,著,王光远,等译,结构动力学[M].北京:科学出版社,1983.
[4]谢礼立,于双久,等编著.强震观测与分析原理[M].北京:地震出版社,1982:149-164.
[5]周福霖.工程结构隔震减震研究进展[M].北京:地震出版社,2004:1-8.
[6]韦永祥.基于强震和风振记录分析隔震结构的动力特性[D].哈尔滨:中国地震局工程力学研究所,2007.
[7]马强,金星,李山有.单自由度系统地震动力反应的实时计算方法[J].地震工程与工程振动,2003,23(5):61-68.
[8]李鸿晶,Celebi M.一幢钢筋混凝土建筑结构的强地震反应观测[J].地震工程与工程振动,2001,21(4):35-39.
[9]Celebi M.Identification of site frequencies from building records[J].Earthquake Spectra,2003,19(1):1-23.
[10]Toshihide Kashima,Akihiro Itou,Hisashi Fujita.Dynamic behavior of a 9-story base-isolatedbuilding during the 2003 Off Tokachi Earthquake,Japan[C]//Proceedings Third UJNR Workshop on Soil-Structure Interaction,March 29-30,2004,Menlo Park,California,USA.
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