工程抗震设计思考

The thinking on engineering seismic design

抗震设计规范主要是理论研究与地震工程实践经验的概括和总结。而且它还将随着地震认识的深化和科学的进步,与时俱进,不断地修改、完善。因此,文中就一些理论概念、设防要求、结构分析、抗震措施等问题阐释我们的体会和看法。明确指出,地震烈度的意义应依据应用的不同状况给出合理解释;将地震烈度附上概率的概念,不易于应用;抗震设防的目的在于减轻建筑物地震破坏、避免人员伤亡、减少经济损失;地区抗震设防应以设防烈度为防范对象;工程抗震设计的设防烈度应考虑场地条件的影响;基于弹性反应谱理论,在考虑抗震设防要求的计算分析中,引入重要性系数及结构系数是合理的;重要性系数及结构系数都与地震发生概率无关;没有必要取多条地震时程曲线按所谓多遇地震下进行补充计算;地震作用的准确性有限,除结构计算分析外,采用适当抗震构造措施是必要的;超越设防烈度的地震是抗震设计的风险问题。

Seismic design codes are generalized from theory research and practice of earthquake engineering, mean- while they should be improved with the deepening on the earthquake engineering research and science progress. Some views and opinions about seismic design, such as aseismic concepts, requirement for fortification earthquake, structural analysis, constructional measure for earthquake resistance, are proposed. The meanings of earthquake in- tensity should be understood according to its different application conditions. It is tried for the seismic design to put probability into the earthquake intensity, but no easy to its application. The goals of earthquake fortification are to reduce the damage of building, avoid human casualties and alleviate economic loss. The object of the earthquake fortification in a zone should be earthquake fortification intensity. The site condition should be considered into the fortification intensity of engineering seismic design. It is reasonable to put the importance modified coefficient and structural coefficient into seismic design based on elastic response spectrum. The importance modified coefficient and structural coefficient are not generally relative to earthquake arose probability. It is no necessary to add many earthquake time histories to structural analysis under frequently occurred earthquake. The accurate of earthquake action is limited, so it is necessary to adopt constructional measure for the earthquake resistance besides structural a- nalysis. The earthquake over the fortification intensity is a risk problem.