The paper presents the analysis of deformations and stresses in a large aspect ratio sandwich panel subject to fire or another source of elevated temperature. The panel, assumed to bend into a cylindrical surface, is simply supported at the edges. The edges are also prevented from in-plane displacements providing an elastic restraint as the panel stretches due to bending. The solution is obtained in a closed form when the deformations are small and when geometrically nonlinear effects are incorporated into the analysis. The solution is open to modification with arbitrary temperature and property distributions through the thickness of the panel, enabling a designer to incorporate the results from a multitude of heat transfer scenarios so long as the structural problem can be treated as quasi-static.