This study investigated the deflection behaviour of a composite beam with a glulam beam and an RC slab in a fire. Load-bearing fire tests were conducted on a simply supported glulam beam and a composite beam. Connecting the glulam beam and the RC slab extended the fire resistance period by 20 minutes compared to the glulam beam. This paper proposes a method for calculating the degree of composite effect in a fire. Change in the degree of composite effect is one of the factors that determine the deflection behaviour of composite beams.
