Nonlinear thermoelastic analysis of composite steel–concrete arches including partial interaction and elevated temperature loading

Composite structural elements containing two materials joined by means of an elastic shear connection find widespread use in both traditional and innovative structural engineering applications. The most common of these are steel–concrete members, joined by headed mechanical stud shear connectors. Despite their popularity and ubiquity, a thorough understanding of the behaviour of composite elements has yet to be fully developed, especially in an environment when they are subjected to elevated temperatures. This paper presents a somewhat generic model for the nonlinear elastic behaviour of composite arches subjected to sustained loading at elevated temperatures. The effect of partial interaction between the steel and concrete components in the tangential direction, as well as the variation of internal axial compressive forces along the member, is taken into account. Based on the governing differential equation obtained from the longitudinal equilibrium of an element of the concrete component, exact solutions for the displacement field are presented. The generic technique that is developed is shown to agree with solutions obtained from ABAQUS, and has a potential for inclusion in prescriptive design recommendations. The scope of the formulation is illustrated by presenting a parametric study of a steel–concrete composite arch at elevated temperatures, which indicates the variation of the displacements, axial force and internal bending moment with respect to both the thermal profile and the degree of partial interaction between the concrete slab and steel component.