Bearing Capacity Research For Concrete Component With Damage Under Post-Earthquake Fire

China is one of the largest number of earthquake, losses caused by the post-earthquake fire is very huge.Under the combined effect of the earthquake and fire,The performance under high temperature of earthquake damaged concrete structures will become more and more complicated and unpredictable.At present,whether at home or abroad,the research on fire resistance performance of the structure and component after the earthquake is still less.So it is necessary to do the research about the bearing capacity under high temperature of the seismic damage of concrete structures and to provide a solid theoretical basis for the fire resistance performance of the structure after the earthquake.By referring to the existing concrete components and structures in seismic data.In this paper,cracking and spalling was the main form of damage to concrete structures.According to the components in different way by the fire which in the actual project,the depth of the spalling and the width of the crack in the seismic damage of concrete component as the geometric parameters,by using the ABAQUS finite element software to set up the finite element calculation model of seismic damage of concrete components which in the post-earthquake fire and to do the analysis of the temperature field which under high temperature.On the basis of it,to do the research about the bearing capacity under high temperature of the concrete components which was in the case of seismic damage.Get the calculation formula of the bearing capacity reduction coefficient.The principal conclusions of this analysis are as follows:(1) The influence of crack to the temperature field distribution of the concrete components which was in the case of seismic damage was relative with the heat transfer performance of the cracking section. As the different heat transfer performance of the cracking section. There is a large distinguish between the temperature field of cross section and the axial temperature field in the concrete components damaged by earthquake.(2)In the concrete beam which was spalling and damaged caused by earthquake.The distribution of the temperature field depends on the relative position between the exfoliational and the fire department.When the bottom of beam was spalling,the high temperature area is near the bottom of beam.When the top of beam was spalling, the temperature field distribution of the beam had no change.In the concrete column which was spalling and damaged caused by earthquake, with the increase of the spalling width, the changed of the temperature field distribution near the exfoliational department was more obvious.(3)In the concrete beam which was damaged caused by earthquake,with the increase of the relative crack depth,the reduction in the amount of the compressive bearing capacity is growing quickly,but the reduction in the rate of the compressive bearing capacity is growing slowly.And the reduction in the amount and rate of the flexural capacity of the earthquake-damaged concrete column is greater with the growing of the crack depth.If the crack surface will be adiabatic,the bearing capacity of the seismic damage concrete components is greater than the bearing capacity of the seismic damage concrete components which the crack surface will be non-adiabatic in the concrete components.(4)In the concrete beam which was spalling and damaged caused by earthquake,the reduction in the amount and rate of the flexural capacity when the spalling in the bottom of beam is greater than the spalling in the top of beam.In the concrete column which was spalling and damaged caused by earthquake,with the increase of the spalling width, the reduction in the amount and rate of the compressive bearing capacity is becoming smaller.And the reduction in the amount and rate of the compressive bearing capacity in the different position of the column is not same.(5)At the same time,there is a relationship between the reduction factor of bearingcapacity under high temperature of the concrete components damaged by earthquake and the damage size by the earthquake.It can put forward a quantitative relationship among the degradation of bearing capacity under high temperature of the concrete components damaged by earthquake, the damage size by the earthquake and the fire duration.