Fire Resistance of Steel Composite Beams without Fire Protection

In this study, the fire resistance of steel composite beams typically used in building structures was investigated through standard fire and loading tests. For the tests, fire-exposure conditions depending on the steel section shape and load ratio applied to the beams were considered as the test parameters. Based on the test results, the applicability of fire design methods for composite beams recommended in current domestic and overseas fire design codes was analyzed. The results indicate that the current temperature-based design method and reduced flexural capacity method specified by the American Institute of Steel Construction may lead to the conservative fire design of steel composite beams owing to the underestimation of the effects of the fire-exposure conditions and load ratios.