Long-Span Shallow Steel Arches Subjected to Fire Loading

Abstract

This paper considers the thermo-elastic behaviour of shallow steel arches of long span, which are deployed in large roofing applications such as airport terminals, during a fire. The analysis of shallow arches requires recourse to geometrically non-linear analysis, which is further complicated by the nature of the thermal loading which may occur under a fire and of the degradation of the material properties of steel during a fire. A general technique based on the principle of virtual work is developed, and the analysis results in a formulation in closed form, which includes the stiffness of a tie between the supports of an arch and the supporting columns. It illustrates that these long span structural arch roofing elements are stressed at a low enough level to, in general, preclude considering inelastic effects during a typical fire, so that the simplifying assumptions of elastic behaviour are valid. Guidance is suggested for preliminary design purposes.