Stability of Steel Columns Subjected to Earthquake and Fire Loads

Abstract

Assessing the stability of steel building frames exposed to fire conditions is challenging because of the need to consider the elevated temperature properties of steel, nonuniform heating of structural members, and large deformational demands on the frames. This challenge is further intensified if the stability of the frame is also influenced by the lateral forces of an earthquake that preceded the fire. Although there has been significant progress recently in simulating the response of frames using finite-element methods, there is a need for computationally efficient tools that would minimize the modeling effort and allow for accurate and rapid assessment so that a large number of simulations can be conducted. To this end, the present study aims to develop a framework for conducting a stability analysis of steel columns subjected to demands imposed by lateral loading followed by fire. A nonlinear formulation is proposed to assess the stability of W-shaped steel columns under multihazard loading scenarios. Results from the proposed formulation show good agreement with available strength design equations of steel columns at ambient and elevated temperatures. This computationally efficient tool can be used to investigate the effects of a wide variety of variables on the stability of steel columns subjected to fire and fire following earthquakes.