With the architectonic development, steel structure is used in more and more architectures. Because of the bad fire performance of steel structure, collapse may occur. In the American 911 accidents, the fire caused by airplane crash led to collapse of WTC, mass and personnel loss is huge. Therefore researches of building collapse caused by fire are very necessary. The absence of knowledge regarding fire dynamics linked to the fact that fire can be considered a random phenomenon has led to general use of prescriptive fire regulations all over the world. This paper mainly introduces the research on collapse probability of building.

According to statistical theory and characteristics of building fire, the probability distribution functions of fire load and the fire duration time of office buildings are presented. The influencing factors to the building collapse under the condition of fire are studied. Based on the fire statistic results, fire dynamical theory and characteristics of building fire, an evaluation method of the collapse probability of building caused by fire is developed in this paper.