Method of load factor determination for multi-hazards bridge design

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.