【摘要】 目前美国的桥梁设计多采用荷载与抗力系数法规范(LRFD),其荷载系数和抗力系数是以概率为基础的极限状态方程的形式求得的。荷载与抗力系数规范(LRFD)主要标定常规荷载和单个极端荷载,没有考虑多个极端荷载的情况,而且LRFD对于单个极端荷载的考虑并没有基于概率基础。该文针对多种极端荷载下荷载系数设计存在的问题,将多种极端荷载视为随机过程,以失效概率为纽带,提出荷载系数设计的分项失效概率概念。基于LRFD极限状态方程的形式,提出解决多种极端荷载作用下的MH-LRFD荷载系数计算方法,并给出当仅有两种极端荷载下,桥梁结构多灾害设计荷载系数的一般计算步骤。更多还原

【Abstract】 LRFD guide specification for bridge design is mostly used in the United States,where the load and resistance factors are based on probability and limit states equations.LRFD guide specification for bridge design mainly calibrates common loads and single extreme load,and does not involve multiple hazards.Besides,it has no probabilistic basis dealing with single extreme loads.This paper presents a concept of partial failure probability for load factor design based on failure probability and random processes,analyzing the problems of multi-hazards load factors design.And a method of MH-LRFD load factors design is brought about on the framework of LRFD limit states equation,and the calculation procedure of load factors for multi-hazard bridge design is given on the basis of two extreme loads subjected to bridges.更多还原