FIRE-SAFE DESIGN OF MODERN STEEL BUILDINGS IN JAPAN

This paper presents fire-safe design of buildings using fire-resistant (FR) steel. Because of the elements contained, FR steel retains strength at high temperatures compared with conventional structural steels for buildings. Through the use of FR steel and fire-safe design calculating fire intensity, steel temperature and deformation of a frame at high temperature, FR steel can reduce thickness of fire protection materials compared with conventional structural steels and also can be used in steel buildings without any protection in cases where the steel temperature would not exceed 600-degrees-C. In this paper, the fire-safe design of Yokohama Sogo warehouse and Tobihata Building are presented together with the mechanical properties of FR steel and the design method of buildings using FR steel. Yokohama Sogo warehouse employs FR steel for its interior columns and beams by reducing the thickness of sprayed ceramic-cement protection according to required fire resistance in hours. In the Tobihata building, unprotected FR steel was used for its external frames since it was confirmed that the temperature of the frame heated by projecting flame would not exceed 600-degrees-C.