Parametric analysis of mechanical behavior of steel planar tubular truss under fire

This paper presents experimental and numerical results of steel planar tubular truss, which was exposed to the fire condition. The principal aim is to investigate the critical temperature of the truss under permanent load and the influence of geometric parameter. It is found that both experimental and numerical results demonstrate that the failure of the steel planar tubular trusses is due to the local buckling of the brace members which validates the accuracy of finite element model. In the parametric analysis, it is found that the geometric parameters of the truss have a significant influence on the load bearing capacity of steel planar tubular truss subjected to the fire. The parameters include wall thickness ratio ττ, diameter ratio ββ and chord diameter/thickness ratio γγ. The results demonstrate that the critical temperature of the truss can be improved significantly by the increase of the brace diameter and the wall thickness of the chord while changing the wall thickness of the brace has limited effects. It is indicated from the analysis that at the higher load level, the parameters τ,βτ,β and γγ have a distinct influence on critical temperature of the steel planar tubular truss.