Fire load for performance fire design of car park steel structure

Abstract

Three advanced fire models for structural design are defined in Eurocode: one-zone model, two-zone model and model based on Computational Fluid Dynamics (CFD). This paper describes the effects on structures exposed to fire, based on the CFD model. The advanced computational fluid dynamics model was used to define the thermal action and temperature of the structural steel elements on the analysed case study object, open multi-storey car park Obilićev Venac in Belgrade. The support structure of the car park is a typical composite floor structure with steel columns. Distance between the columns and the floor beams corresponds to the dimension of one parking slot. The maximum temperature values of steel structural elements that occur during a fire are investigated. Based on the results of the tests available in the literature, CFD fire load models were created. Two different fire loads are used in numerical simulations. The first one is the fire load model based on combustible materials, which simulate the typical modern small car weighing up to one tonne. In the second case, the fire loads model was described with the Heat Release Rate (HRR) curve. Two of the referenced HRR curves defined by the French CTICM and Netherlands TNO Institute are used in CFD models. The discussion in this paper is limited to fire cases with one burning car. The parametric study considered the dimensions and positions of the burner element in the model. The effects of the natural ventilation in the open car park during the fire were also investigated. The presented results are from the Research project “Advanced structures design – fire safety guideline for V4” funded by the Višegrad fund. A joint effort of colleagues from Hungary, Czech Republic, Slovakia, Poland and Serbia, produced the project report, which described five different case studies.