建筑结构抗震设防等级个数的研究

明确的多级抗震设防思想被国内外工程抗震界广为接受,目的就是结构抗震设计不仅要保护生命的安全,同时也要做到经济合理。但是究竟采用几个设防水平是足够的,才能实现既安全又经济的设防目标,目前还没有一个理论的解释。本文就是针对这一问题,以能否实现明确多级设防的基本目的为原则,把采用连续化思想确定的经济损失作为精确值,用不同设防等级情况下确定的经济损失与之比较,两者之间相差在一定精度范围内的最小设防个数被认为是合理的设防等级个数。根据实例研究表明,目前三水平设防等级还不足以控制结构未来的经济损失,而设防水平达到5个等级时,两种方法给出的经济损失估计值才比较接近。

A study on seismic performance levels of building structures

Definite multi-performance levels seismic design is broadly accepted in earthquake engineering,with the objective of not only protecting human life but also making seismic designs economical.However,there is not yet a theoretical method to determine the sufficient numbers of performance levels to meet the design objective.A new method,based on theoretical analysis,is presented for determining the number of seismic performance levels.An index is calculated as the ratio of the economic loss estimated by using the continuity method and the economic loss calculated by using the discrete method with different seismic performance levels.The minimum number of performance levels is considered as the rational result when the index is within a prescribed small range.The analysis indicates that five performance levels are adequate to control economic loss,whereas three performance levels are not.