Elastic and inelastic stability of a steel arch subjected to a crown point load under an elevated fire environment

Abstract This paper focuses on the stability of thin-walled circular arches subjected to a radially-directed concentrated load at the crown point under a temperature increase up to 800℃ induced by fire. A solution is obtained analytically to predict the critical buckling load of the elastic arch based on the principle of minimum potential energy and an admissible displacement function. Subsequently, a planar numerical model is introduced to explore the maximum load (critical buckling load) by drawing the normalized load-displacement equilibrium curves. These curves from the numerical results exhibit close trends with the analytical ones for both fixed-fixed and pinned-pinned arches. In addition, steel arches with inelastic material properties and geometric nonlinearities are considered in the numerical model, indicating that inelastic properties reduce prominently the maximum load. Furthermore, all investigations show the heating process induced by the fire reduces the load capacity (maximum load) dramatically for both elastic and inelastic arches. Finally, parametric analyses are performed to examine the effect of central angle and normalized thickness on the maximum load of the arch.