Non-discretisation formulation for the non-linear analysis of semi-rigid steel frames at elevated temperatures

This paper proposes a flexibility-based method for the analysis of steel frame structures with semi-rigid joints subjected to fire loading. The semi-analytical non-discretisation formulation is able to capture material and geometric non-linearities. The modelling of the cross-sections as comprising of elastic and inelastic domains allows for the spread of yielding to be modelled, while the geometric non-linearity included in the method allows for catenary action to develop in the heated compartment within the frame. The accuracy of the technique is verified against an independent analysis using ABAQUS as well as by analysing a rigid steel frame with 104 members.