Experimental Research On Fire Resisitence Performance For R. C. Beams With Damages Caused By Service Loads

The occurrence probability of the fire is extremely high, which is at the first position among various disasters. What’s more, the huge property damage and casualties caused by fire was a fearsome sight. So Fire protection as a branch of building disaster prevention has attached more and more attention in recent years with the development and perplex of tall buildings.It is quite a wide-spread concern that how the mechanic performances of the structure change after the building fire. When building structures exposed to fire, high temperature will result in continual changes of the temperature distribution in the structure, deflection and inner forces of the structure. The effects of fire on building are rather complicated, such as relevant issues are still unsolved so far. The law of temperature field and bearing capacity about section after fire were selected as the main research object in this paper. The concrete contents is as follows:1) The status about experimental study and theoretical analysis of domestic and foreign materials and components of R.C frame structures under fire were comprehensively reviewed. Institute of achievements and shortcomings were comprehensively analyzed.2) The experiments of seven reinforced concrete beams under fire are accomplished. The deformation characteristic and damage form of members are investigated through the tests. The influences for its fire-resistance behaviors of damages exposed to fire are researched and discussed.3) Concrete compression strength and yield strength could be attained according to the temperature distribution of cross-section. The formula of capacity and damages were obtained by analyzing the section of beam limited stress-stain properties.