After The Earthquake Damaged Reinforced Concrete Frame Column Fire Resistance

Beams and columns are the most important components in reinforced concrete frame structure that is widely used in the field of architecture. In severe cases, damaged columns result in the whole structure collapses. While there are a lot of researches on seismic resistance and fire resistance of reinforced concrete columns, researches on fire resistance of reinforced concrete columns damaged at different levels, such as those with cracks after earthquake, with partially crushed concrete or with protective layers falling off. This paper focuses on reinforced concrete frames whose protective layers fall off, analyzing factors influencing their fire resistance under 233 conditions. The research is as follows:(1) Through actual data on damaged frame columns after earthquake and related experiments, the location, features, form and damage process of frame columns which are damaged in earthquake are defined. It is basis of reasonable size of broken column model.(2) This dissertation analyzes how the temperature distribution is influent by Form by the fire, cover thickness, broken parts and damage length, using the software of ANSYS.(3) Analysis on the fire resistance of columns by established finite element model of reinforced concrete columns. Verify the accuracy of simulation results by compare the simulation results and test results of the German Hass. It is the basis of study of fire resistance of columns.(4) This dissertation analyzes that how the fire resistance of columns is influent by axial load ratio, slenderness ratio, eccentricity, damage length. Fire endurance of axial-compression columns decreases with the increase of axial-pressure ratio and slenderness ratio. Fire endurance of eccentric compression columns which are bent decreases with the increase of axial-pressure ratio, slenderness and eccentricity ratio. Fire endurance of eccentric compression columns which are damaged due to destabilization increases with the increase of axial-pressure ratio, slenderness and eccentricity ratio. The fire resistance reduction coefficient of columns decreases with the increase of damage length. Reduction coefficient, however, decreases very slowly.