Fire resistance performance of L-section fireproof board and thin concrete encased skeleton steel column

Abstract

To investigate the fire resistance of L-section fireproof board and thin concrete encased steel (L-FBTCES) column, four columns were tested under constant axial compression and ISO-834 standard fire, varying the load ratio and concrete encasement thickness. The failure modes, thermal response, deformation response, and fire resistance time were obtained. The thermal response curve of the steel exhibited three stages, and the maximum temperature of the steel was below 600°C during the test. The fire resistance time for all specimens exceeded 120 minutes. The resistance time decreased with the increase of the load ratio and slightly increased with the increase of the concrete encasement. The thermo-mechanical coupling models were established, and the numerical parametrical analysis was conducted. Based on the existing specifications for composite columns and considering the adjusted load ratio and fireproof board thickness, a modified calculation method for L-FBTCES columns was proposed and validated by the numerical analysis results.