Fire Safety Science Digital Archive

Fire engineering design based on numerical analysis of actual fire behavior of building structures was proposed in Japan as early as 1989. The second author and his colleagues performed a numerical study on fire resistance of steel structures of 48 high-rise buildings exposed to compartment fire, and their results indicate that steel structures that are designed against seismic load exhibit fire resistance up to nearly 600?. Further, they report when a fire occurs in a building of steel structure, steel structural members exposed to fire exhibit large deformations at their ends, derived from thermal elongation, in combination with severe restraint by adjacent structural members. Analysis of thermal stresses and deformation is based on the assumption that beam-column connections do not lead to failure. For proper fire engineering design of steel structure, the bearing strength of joints at elevated temperature must be clarified. It is known that bearing strength of high-tension bolted joints reduce over 350 C and reach to zero over 600 C. Therefore, it is necessary for fire engineering design of steel structures to clarify the shear strength of high-tension bolts at elevated temperature. In this study, tension tests of friction type high-tension bolted joints are conducted at constant temperatures ranging from room temperature to 650 C.