关于工程结构抗震设防标准的几个问题的讨论

对与工程抗震设防标准有关的几个问题进行了讨论。分析了多级设防目标中存在的一些问题,建议以结构抗震目标可靠度作为设防参数;讨论了影响结构目标可靠度的因素,建议通过对工程结构进行“投资——效益”分析制定结构最佳的抗震设防标准。

Some Problems on Seismic Fortification Criteria of Engineering Structures

In this paper, some problems concerned in the determination of seismic fortification criteria, such as multi-level earthquake-resistant design criteria, seismic reliabilities, optimal design earthquake levels, are discussed for earthquake-resistant structures. It is suggested that the multi-level seismic design criteria should be improved so that performance-based requirements of the structure may be better satisfied. The target reliabilities are proposed to be the seismic design parameters of structures, and the oplimal degree of safety in structural design may be determined on the basis of minimum expected life-cycle cost consisting of initial cost and failure cost of the structure. The relationship between multi-level seismic design criteria and seismic reliability of the structure is discussed, and multi-level target reliabilities are adopted in order that the multi-level earthquake-resistant design criteria can be accomplished. By this operation, it is unnecessary to determine minor, moderate and major earthquakes in seismic design of the structure, so that difficulties for determining these earthquakes may be eliminated. The seismic reliability of the structure can be assessed basd on the analysis of seismic hazard at the structural site and uncertainties in structural system. Finally the cost benefit analysis method is recommended for deciding the optimal seismic fortification criteria of structures.