基于系统可靠度指标的建筑框架结构设计

现行建筑结构设计规范是基于结构构件的可靠度计算,没有很好的考虑结构的系统性,不能准确地反映结构整体的可靠性.为此,本文提出了结构体系抗力调整法.该方法把结构体系可靠性分析和结构体系可靠度调整分2步来完成,根据结构各失效模式的可靠指标和相应的目标可靠指标的比值作为确定抗力调整的主要依据,进行结构各失效模式可靠度的分配和调整,从而以结构体系可靠度指标为参数直接进行建筑结构设计.该方法有效克服了结构设计调整过程中的盲目性,简化了可靠度的计算方法,是一种比较简便实用的结构可靠性设计方法.通过对框架结构体系的可靠性进行分析可以看出,只需要少数主失效模式就能计算出该体系的失效概率,计算结果误差小,能够满足工程设计要求.

System Reliability Index Based Structural Design for building Frames

Current architecture specifications for structural design is based on reliability calculation of structural members, which considers little systematic characters of structure and cannot reflect integrated structural reliability. Therefore, a method of resistance adjustment for structural system was put forward in this article, which consisted of two steps, i.e. reliability analysis of structural system and reliability adjustment to structural system. The main reference for resistance adjustment to structural system is that according to ratio of reliability index for every failure mode to responding target reliability index, we can distribute and adjust reliabilities for every failure mode. So that reliability index of structural system could be used as parameters in architecture structural design, which is a simple and practical way of structural reliability design. It is concluded through the reliability analysis of structural system of a double layer and twin spans frame that it needs a few major failure modes to work out the failure probability of frame structure system with limited calculation error, which can meet the requirement for engineering design.