CATENARY ACTION IN RESTRAINED STEEL BEAMS EXPOSED TO ELEVATED TEMPERATURE

Abstract

Structures are primarily designed for ambient temperature conditions, taking into account the various design limit states, and the flexure mechanism resists the applied load. Increased temperature results in significant deflection, which enables the shift from compressive to tensile or catenary action. At elevated temperature, the catenary system balances the applied load on structural beams. At elevated temperature, creep can be quite significant, and its effects increase significantly as the temperature rises. This shows that disregarding creep may result in very inaccurate structural response estimates for some types of structural fire problems. The study is primarily concerned with creep behaviour and its effect on the load-bearing system at elevated temperatures. A modification is proposed to incorporate creep effects into the simplified analytical procedure. For the numerical simulations, a finite element model is created using the commercial software Abaqus and the creep effect is introduced using a subroutine.