Response of restrained stainless steel corrugated web beams at elevated temperature

This paper is focused on the fire behaviour of axially restrained corrugated web beams made from stainless steel. A finite element (FE) model is developed and validated against available fire test results on restrained flat web carbon steel beams, unrestrained stainless steel cellular beams and numerical studies conducted on carbon steel corrugated web beams in fire. The verified FE model is then employed to conduct an extensive parametric study to assess the relative influence of key properties on the response. The behaviour of stainless steel corrugated web beams (SSCWBs) is compared to that of stainless steel flat web beams (SSFWBs) during exposure to a standard fire under axially restrained support conditions. The axial compression developed in an SSCWB is shown to be significantly lower than that of a comparable SSFWB due to the reduced axial stiffness. A number of parameters are examined including the grade of steel, load ratio, presence of axial restraint as well as thicknesses of the flange and web. It is shown that the overall behaviour of SSCWBs is quite similar compared with equivalent carbon steel corrugated web beams (CSCWBs). However, the stainless steel beams also show much improved performance in terms of survival time due to better retention of mechanical properties at elevated temperature compared with carbon steel. An analytical model for predicting the critical parameters related to the axial force-temperature response of SSCWBs is also presented and verified against the results obtained from the FE models.