Research On Response Of Restricted Steel Beam Under Elevated Temperature And Blast Loading

Steel structure buildings get used increasingly and widely in ourcountry. The leakage of gas in the kitchens or the combustible liquid insteel chemical plants make the steel structure housings as the multiple zoneof the fire and explosion accidents. Explosion always cause fire, and firesometimes cause explosion. So the research of the influence of the buildingstructure under common effects of fire and explosion has significance.The finite element program ANSYS was used to analyze the behaviorof models, only blast loading and both elevated temperature and blastloading. The changes with elevating temperature of steel elastic modulus,yield strength and other physical properties is considered in the analysis,and also considered the rate effect in this research.The main results list in this paper as follows:(1) The steel material model was determined, which could be used injoint action of fire and explosion, considered the action of hightemperature and the strain rate effect. Fire and explosion load model wasdetermined.(2) The finite element model for the analysis of fire and explosionresponse was determined, referenced to two kinds of tests, one was underonly elevated temperature, and the other was under only blast loading.(3) For one kind of constraint beams, the properties with the fire onlyand the blast only was investigated. To discuss the influence of the fire tothe blast, the response of the steel beam under three different kinds of blastin different temperature was analyzed. To summary the influence of theblast to fire, the response of the steel beam under the fire after different power of blast in different time was analyzed.(4) The reasonable failure mode of the steel beam in the fire andexplosion impact was researched. When the mid deflection was larger thanL/20, the steel beam was defined to reach the failure mode whateverduring the fire or blast.(5) Based on the numerical results, common effect in fire andexplosion of different rotational restraint, axis constraints, load ratio andspan-depth ratio for constraint beam was studied.