Etude par simulation numérique du comportement des portiques métalliques en situation d'incendie

Pitched roof Steel frame structures are widely used as industrial buildings for practical reasons of exploitation, durability and cost efficiency. However, steel although is a ductile material, it remains vulnerable to excessive temperatures. The recent accidents which occurred in the industrial buildings of Sonatrach (Algeria), in an urban area in Algiers or in an industrial zone in Skikda, remind us of the real danger and the potential risk of fire. The recent European norms define active and passive requirements for the design of industrial buildings under fire. The objective of this work is to investigate the behaviour of portal steel frames in fire situation. A numerical analysis using FEM software ANSYS is performed using geometric and material non-linear finite strength with a variation in temperature until ultimate collapse. Several load ratio and fire scenarios are considered in order to evaluate the critical temperature and the variation of the displacements with increasing temperature. The results of the numerical modelling are compared with simplified methods of EC3-1.2.