Experimental study on fire resistance of precast concrete columns with efficient reinforcement

Abstract

In order to improve installation efficiency, construction quality and reduce the cost of monolithic precast concrete frame structures, precast concrete columns reinforced by efficient reinforcement have been proposed in recent years. Their static and seismic behaviors generally meet design expectations, while, to the authors’ best knowledge, their fire resistance has not been properly studied. In this paper, results from fire resistance experiments on full-scale precast concrete columns reinforced by efficient reinforcement under standard fire exposure conditions are presented. The effect of reinforcement forms, load intensity and fire conditions on the fire resistance of the precast concrete columns has been studied. The test results show that fire resistance of the connection zone of the precast concrete column is higher than that of the non-connection zone. The test results also show that precast concrete columns reinforced by cluster reinforcement have a higher fire resistance than columns reinforced by large-diameter reinforcement. On the basis of the test results and the calculation methods current in use, a simplified approach that considers the effect of cross-sectional area reduction and temperature difference caused by spalling is proposed to predict fire resistance of precast concrete columns reinforced by efficient reinforcement.