State of the Art on Fire Resistance of Steel Structures and Experimental Study on Section Factors in Korea

摘要

To use the concept of section factor is the most useful method for determination of fire protection thickness at the aspects of various steel sections where the structure built with steel element was exposed to fire. In order to establishment of the new method for determination of fire protection method, we adopted the concept of the U.K and have calculated the figure of section factor for the section used in Korea and have conducted several sorts of fire tests and found out the following results. 1) The bigger section factor, there were big different time lag between heating temperature and surface temperature of steel section and the reaching time for a critical temperature and maximum temperature were faster. Therefore smaller section factor of steel element is more efficient than larger section factor with respect to cost of fire protection. 2) When the specimens for beam and column fire test reached the failure conditions defined the KS F 2257-1,4,6,7, the critical temperature showed the range of 558℃ to 720℃. But in order to get safer margin for determination of fire protection thickness we concluded 538℃ as a critical temperature. 3) For the purpose of getting various fire endurance times for several section with small-scale and different fire protection thickness, we could get various fire endurance times. 4) We could deprive the regressive equation for the determination of fire protection thickness through small-scale fire test with three exposed and four exposed conditions, which was FR=0.15+2225.04 t A/Hp + 60.09t. 5) Cost reduction ratios of fire protection were shown 40%, 17% at 1 hour and 2 hours, respectively when compared to those of the conventional ways with representative sizes.