抗震设计中多遇地震的问题和讨论
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摘要
指出作为截面抗震验算标准的"小震"混淆了两种明显不同的概念:其一是对应于50年超越概率63%的地震动参数(以下简称"多遇小震");其二是50年超越概率10%的地震动参数经过折算得到的参数(以下简称"折算小震").上述混淆导致抗震设计中实际上执行着不同的标准.文中讨论了中、小地震动参数之间关系的复杂性,包括从地震危险性分析得到的基岩面中、小地震峰值加速度的离散性,一致概率谱的差异,以及中、小地震由于土层反应非线性影响导致的场地相关谱的系统性差异.指出重大工程的抗震设计以"多遇小震"取代"折算小震"进行截面验算可能导致反应谱特征周期Tg明显低估的问题,并提出了相应建议.
"Small earthquakes" used as the standard of section seismic checking in seismic design confuses two significantly different concepts.One is the ground motion parameters corresponding to 63% exceeding probability in 50 years(hereinafter referred to as "frequent earthquakes"),and the other is the parameters received by reducing that corresponding to 10% exceeding probability in 50 years(hereinafter referred to as "reduction small earthquakes").Above confusion leads to a result that two different standards are actually followed in seismic design.Complexity of the relation of ground motion parameters corresponding to medium and small earthquakes is discussed,such as dispersion of peak acceleration,differences of consistent probability spectra on the bedrock obtained from seismic hazard analysis,and systematic differences of site-related response spectra between medium and small earthquakes by soil non-linear effect.Substitution frequent earthquakes for reduction small earthquakes in section seismic checking for major engineering projects may result in underestimation of response spectrum characteristic period Tg.Some suggestions are put forward.
"Small earthquakes" used as the standard of section seismic checking in seismic design confuses two significantly different concepts.One is the ground motion parameters corresponding to 63% exceeding probability in 50 years(hereinafter referred to as "frequent earthquakes"),and the other is the parameters received by reducing that corresponding to 10% exceeding probability in 50 years(hereinafter referred to as "reduction small earthquakes").Above confusion leads to a result that two different standards are actually followed in seismic design.Complexity of the relation of ground motion parameters corresponding to medium and small earthquakes is discussed,such as dispersion of peak acceleration,differences of consistent probability spectra on the bedrock obtained from seismic hazard analysis,and systematic differences of site-related response spectra between medium and small earthquakes by soil non-linear effect.Substitution frequent earthquakes for reduction small earthquakes in section seismic checking for major engineering projects may result in underestimation of response spectrum characteristic period Tg.Some suggestions are put forward.
引文
高孟潭,韩炜.1992.抗震设计中大、中、小地震的确定[M]∥地震工程研究文集.北京:地震出版社:14--20.
国家质量技术监督局.2001.GB18306—2001中国地震动参数区划图[S].北京:中国标准出版社:1--2.
卢寿德主编.2006.GB17741—2005《工程场地地震安全性评价》宣贯教材[M].北京:中国标准出版社:111--112.
上海市地震局,同济大学.2004.上海市地震带参数区划[M].北京:地震出版社:188--191.
沈建文,石树中.2004.大中小震与抗震设防标准[J].地震学报,26(5):533--538.
吴健,高孟潭.2004.场地相关设计反应谱特征周期的统计分析[J].中国地震,20(3):263--268.
翟长海,谢礼立.2006.抗震规范应用强度折减系数的现状及分析[J].地震工程与工程振动,26(2):1--7.
中华人民共和国城乡建设环境保护部.1989.GBJ11—89建筑抗震设计规范[S].北京:中国建筑工业出版社:18--24.
中华人民共和国建设部.2001.GB50011—2001建筑抗震设计规范[S].北京:中国建筑工业出版社:10--11.
中华人民共和国经济贸易委员会.2001.DL5073—2000水工建筑物抗震设计规范[S].北京:中国电力出版社:274--277.
Nordenson G J P,Bell G R.2000.Seismic design requirements for regions of moderate seismicity[J].Earthquake Spectra,16(1):205--225.
国家质量技术监督局.2001.GB18306—2001中国地震动参数区划图[S].北京:中国标准出版社:1--2.
卢寿德主编.2006.GB17741—2005《工程场地地震安全性评价》宣贯教材[M].北京:中国标准出版社:111--112.
上海市地震局,同济大学.2004.上海市地震带参数区划[M].北京:地震出版社:188--191.
沈建文,石树中.2004.大中小震与抗震设防标准[J].地震学报,26(5):533--538.
吴健,高孟潭.2004.场地相关设计反应谱特征周期的统计分析[J].中国地震,20(3):263--268.
翟长海,谢礼立.2006.抗震规范应用强度折减系数的现状及分析[J].地震工程与工程振动,26(2):1--7.
中华人民共和国城乡建设环境保护部.1989.GBJ11—89建筑抗震设计规范[S].北京:中国建筑工业出版社:18--24.
中华人民共和国建设部.2001.GB50011—2001建筑抗震设计规范[S].北京:中国建筑工业出版社:10--11.
中华人民共和国经济贸易委员会.2001.DL5073—2000水工建筑物抗震设计规范[S].北京:中国电力出版社:274--277.
Nordenson G J P,Bell G R.2000.Seismic design requirements for regions of moderate seismicity[J].Earthquake Spectra,16(1):205--225.