Axial Compression Analysis Of Burned CFST Reinforced Concrete Short Columns Strengthened With CFRP

The composite component of CFST is the combination of steel and concrete.Two materials work together to improve the overall performance of composite components.Therefore,CFST composite structure has the following characteristics: high bearing capacity,ductility,good seismic performance and better fire resistance than pure steel components,so it is widely used in the construction industry.As a cheap and effective material,carbon fiber cloth can be used for material repair.(1)firstly,the finite element simulation software ABAQUS is introduced to simulate,and the related parameters needed to set up the simulation software are studied.The results show that the diameter of steel tube has little effect on the temperature field of inner core concrete.It can be seen that the temperature distribution is circular from outside to inside,and it is evenly affected by fire.With the increase of fire time,the temperature difference between inside and outside decreases gradually and the temperature inside the core concrete tends to be stable.Because of the special form of the composite component,the temperature lag phenomenon of the component also shows that its fire resistance is good.(2)select the thermal parameters of steel and concrete and the mechanical performance parameters of carbon fiber cloth,and limit the boundary conditions and loading methods according to the requirements,use ABAQUS software to build the static field model of composite members,and analyze the factors affecting the temperature field.When the steel ratio is only considered,the increase has an impact on the component,which is about 12%;and for the influence of the bearing capacity of the test piece,the fire time is also the main factor affecting the bearing capacity.(3)in the parameter analysis,the residual bearing capacity of the component decreases with the increase of temperature.The diameter and section of the steel tube increase the residual bearing capacity,while the type of steel,the internal concrete and the external concrete change their relevant parameters,which does not increase the residual bearing capacity of the test piece much.For the members with one layer of transverse carbon fiber cloth,the residual bearing capacity is increased by about 11%.