ABSTRACT
The paper presents a study on an out-of-plane mechanical response of a planar steel frame in standard and natural fire. A numerical model for dynamic analysis of spatial beam-like structures subjected to fire conditions is employed to obtain the out-of-plane deformations. The planar frame is analysed with different planar temperature distributions over the steel cross-sections and different types of supports. A bilinear material model for steel with an explicit model of viscous creep and the material model according to EN 1993-1-2 are considered. It is shown that in certain cases the present spatial numerical model detects out-of-plane deformations of the planar frame, which then have a considerable influence on the calculated failure time. Furthermore, a short study on the effect of in- and out-of-plane geometrical imperfections of the planar frame on its spatial mechanical response is presented.
