| After the fire,the reinforced concrete structure will be damaged,resulting in a decrease in structural bearing capacity and even collapse,which seriously threatens the safety of life and property of firefighters and people around the accident.Most of the numerical analysis of structural safety performance after fire uses large-scale finite element simulation software such as FDS,ANSYS and ABAQUS.These numerical analysis methods are complex and take a long time to obtain results.In order to quickly give a more accurate quantitative judgment on the structural safety of buildings after fire,it is necessary to propose a rapid evaluation method for damage of reinforced concrete members after fire.In this paper,the method of rapid simulation analysis of temperature distribution of reinforced concrete members after fire is discussed.The rapid evaluation method of reinforced concrete members after fire is based on CFAST rapid fire simulation software,and the high temperature damage of components under hot and humid environment is studied.Provide a reference for damage assessment of post-reinforced concrete members.The main research contents and conclusions are as follows:(1)Introduction the rapid analysis method of surface temperature distribution of reinforced concrete members after fire,using CFAST fire simulation software to simulate the surface temperature of key components,the temperature peak obtained by CFAST simulation is different from the temperature peak of large field simulation software FDS.4.84%,indicating that the method is reliable,and using the CFAST software modeling process is simpler,faster,and more efficient than FDS.(2)Taking the temperature curve of the concrete surface under the standard fire curve as the boundary condition of the component,the finite difference method is used to establish the difference equation,and the transient temperature distribution of the component section is numerically analyzed by computer programming.Through the comparison with the temperature distribution map of the refractory design technical specification of building concrete structure(DBJ/T15-81-2011),the analysis results arein good agreement,and the reliability of the method is verified.And the numerical analysis method combined with the CFAST simulation can quickly obtain the temperature distribution of the cross section of the member.(3)Detecting the temperature distribution of concrete specimens at high temperatures by embedding temperature sensors along the thickness direction of the concrete specimens,and setting up concrete specimens with different water contents and different water-cement ratios to conduct experiments.The high temperature temperature distribution of concrete in hot and humid environment was studied.The results show that with the increase of water-cement ratio,the temperature coefficient of concrete increases gradually;the higher the water content,the slower the temperature diffusion.(4)Developed a software based on CFAST platform to quickly evaluate the damage of reinforced concrete members after fire,and used the system software to quickly evaluate the damage of reinforced concrete wall of a fire building.The evaluation results include the material properties of the wall.Damage and depth of damage to the wall.It shows that this evaluation system reduces the problem of long analysis period and complicated operation of large-scale finite element simulation software to a certain extent. |
