An experimental investigation of the fire behaviour of demountable composite beams with profiled steel decking

Abstract

This paper presents the results of a detailed experimental investigation of the fire behaviour of prefabricated demountable composite beams (PDCBs) with bolted shear connectors. Four full–scale standard fire resistance tests were conducted to evaluate the performance of PDCBs with varying degrees of shear connection (65% and 33%) at ambient temperature and different durations of fire exposure (without fire protection and with fire protection to achieve a nominal 60 min’ fire resistance). The experimental results indicate that the Eurocode 4 Part 1.2 simplified approximations to obtain equivalent shear stud and concrete temperatures for the calculation of shear connector resistance in fire are still applicable to demountable shear connectors for different fire exposure durations despite different heat transfer conditions from conventional welded shear connectors. The lower shear connector and concrete temperatures enable the shear connector to enhance its relative resistance to the steel section that has much higher temperatures, thereby greatly increasing the degree of shear connection in fire design. The design calculation method in Eurocode EN1994–1-2 can be applied to composite beams with demountable shear connectors. The experimental observations also confirm that the concrete grouting between different composite slab segments performed well.