| Reinforced concrete structure has good durability,integrity,plasticity and the advantages of saving steel.It is an excellent form of building structure.It was widely used in China's industrial and civil buildings.If the reinforced concrete structure is damaged,only need to be reinforced for continue use,which play a huge economic benefits roles.As CFRP not only has the inherent characteristics of carbon materials,but also combines the soft processability of textile fibers.It has construction convenience,simple operation.It is the good ideal to strengthen the reinforced concrete columns.CFRP reinforcement technology has been widely used in the field of building structure reconstruction and reinforcement in our country.However,in recent years,building fires often occur,and various fires have brought immeasurable losses to people's lives and property.Because,the components be reinforced by the CFRP have poor fire resistance,which gives CFRP reinforcing structure's safety bring a hidden danger.The concrete will burst in high temperature,the material strength and mechanical properties of the reinforced concrete structure will change greatly,and the bearing capacity will be lost.Therefore,it is imminently to study the fire prevention technology of the CFRP reinforced structure to ensure the bearing capacity of the structural components in fire.The main work of this paper is as follows:Firstly,structural damage of concrete columns was routinely repaired,in order to make the repaired reinforced concrete columns have good fire resistance,the paper studied the thermal and thermodynamic properties of various materials,especially investigation and research the high temperature performance of CFRP materials,trying to solve the fireproof problem of CFRP strengthening components from the material high temperature performance.On the basis of studying the structural features of CFRP strengthening components,puting forward a fire protection method to protect CFRP by virtue of steel structure fire protection method.A thick fire retardant coating was used to protect the two tier carbon fiber reinforced concrete columns.The fire experiment was conducted in the test center of Shenyang Jianzhu University.During the experiment the data was collected by thermocouples,and the temperature of the CFRP surface was obtained.The results of fire resistance experiment show that concrete columns reinforced with carbon fiber was protected by 40 mm thick fire retardant coating exceeds 2.5h in the fire,and the remarkable effect on the addition of thin steel pipe outside the fire retardant coating can prevent the fire retardant coating cracking and falling at high temperature.The experiment result was analyzed for evaluating the fire protection effect of the fire retardant coating and the stress characteristics of the test components.It is proved that the fire protection reinforcement method is effective and feasible.Secondly,in order to better prove the reinforcement fire prevention method is effective and provide a reliable theoretical basis.In this paper,the finite element software ANSYS was used to simulate the experiment,a lot of domestic and international models were summarized,and the best enough model was selected to simulate the temperature field.The temperature field distribution of the specimen in high temperature condition was obtained.And compared with the test results,the reliability of the modeling method is verified,providing a reliable theoretical basis for the future.Based on the results of temperature field analysis and considering the nonlinear effect of material,a temperature-structure coupling analysis model was established.The stress characteristics and ultimate bearing capacity of the model in fire conditions were obtained.By comparing with the experimental results,reliability of modeling methods.Finally,the ultimate bearing capacity of composite reinforced concrete columns in fire and the effective and feasible modeling method of ANSYS simulation modeling are obtained. |
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