Analysis of the behavior of concrete loadbearing walls exposed to parametric fires M. S. Dimia 1 , Mohamed Guenfoud 2 1 Department of Civil Engineering, UHLB, Batna, Algeria, email Mohamedsalah.dimia@univ-batna.dz 2 Départment de génie civil, Université de Guelma(24000), Algeria, email gue2905m@yahoo.fr ABSTRACT. In the prescriptive approach, the evolution of the gas temperature in the compartment is considered to be continuously increasing. However, performance-based design is now more and more used for assessing the fire resistance of structures. Performance-based design uses a more realistic representation of the fire which comprises not only a heating phase but also a cooling phase. The influence of realistic fire scenarios is a key issue in the evaluation of the fire resistance. Modelling the cooling phase of the fire, although it is not of current practice in design office, is required for assessing the risk of delayed collapse of a structure. This paper presents the results of numerical simulations of the structural behaviour of reinforced concrete walls during and after the cooling phase of fire. The simulations were performed with the finite element program SAFIR. It is found that failure during the cooling phase of a fire is a possible event and, more dangerous, that a failure of the concrete elements is still possible when the fire comes back to room temperature. The main mechanisms that lead to this type of failure are found to be the delayed increase of temperature in the central zones of the element and the additional loss of concrete strength during the cooling phase of the fire. A parametric study is performed considering different fires scenarios, geometric properties of the wall, the load level, the height, the number of floor adjacent to the wall and the boundary conditions. This shows that the most critical situations with respect to delayed failure arise for short fires and the results also show a risk of delayed collapse for simple supported wall. The mechanical properties during heating and cooling phases were examined. KEY WORDS: Concrete wall, parametric fire, residual strength, delayed failure.