Experimental Research Of Reinforced Concrete Member After Fire

When the mechanical property of concrete members is considered, temperature is usually the unique factor considered; the undergoing time is commonly ignored. Four concrete slabs after different fire conditions were test to study the residual bearing capacity in this paper, and the finite element analysis software "ANSYS" is also applied to simulate the process. The study carried out in this paper includes thefollowing aspects:1) Four two-span continuous concrete slabs (5200* 1200* 120mm) were test to study the residual bearing capacity. One was tested at ambient temperature for comparison and three slabs was exposed to ISO 834 fire for 50, 70, 100 minutes respectively. In the period of heating, the values of temperature distribution (by thermocouples), deflection, counterforce of supports were recorded.2) After the slabs cooling, loads were applied to the slabs in steps. In the period of loading, the values of flexibility, strains of materials and the utmost bearing capacities were recorded. The different influencing factors' effects to the slabs' capacity are analyzed.3) Element models were established by "Ansys" to simulate the loading process of 4 slabs above, in which the material properties were assigned "layer by layer" according to the extra damage. The border and loading conditions of finite element model were all in line with the extra slab. After computing, the models were proved to be reliable to predict the flexibility, material's strain and bearing capacity of slab after fire.