Study On Reinforcement Of Reinforced Concrete Beam After Fire(High Temperature)

In many disasters,the frequency of fire is located in the first disaster.Structural fire resistance has become a hot spot in the field of structural disaster prevention and mitigation.Reinforced concrete beams,as an important component of reinforced concrete structures,once destroyed by the fire will endanger the overall structure and human safety.High Performance Ferrocement Laminate(HPFL)is an effective reinforced concrete beam structure reinforcement method.Compared with other traditional reinforcement methods it can make the old and new concrete interface work together effectively.Because of the durability,corrosion resistance and high temperature resistance and other advantages,it is worth promoting to use.Based on the domestic and international research,this paper combines the ABAQUS finite element simulation to deduce the reinforced beam’s shear capacity with HPFL after fire.The main contents of this paper are as follows:(1)Summarized the domestic and foreign scholars’ research on material properties and mechanical properties of reinforced concrete and steel after fire((high temperature).Compared with the research results of different experts and scholars,the material and mechanical properties of reinforced concrete structures after fire suitable for this paper are selected reasonably.(2)Based on the IS0834 standard,the temperature change of the whole process of the temperature riseing and falling is simulated when the reinforced concrete beam on three sides under fire conditions.Regardless of the change of the temperature field along the length direction of the beam,the temperature field distribution of the reinforced concrete beam section in 30 min,60 min,90 min,120 min,150 min and 180 min was obtained by finite element numerical simulation.(3)The ABAQUS finite element simulation of the shear behavior of reinforced concrete beam after fire,strengthened with three-sided and four-sided HPFL method,was carried out,and the load-deflection curve and shear capacity were simulated.(4)Design formula of the reinforced beam’s shear capacity with HPFL after firewas deduced by a truss-arch model.Compared with the simulation of the shear capacity of the reinforced beam and the shear capacity of the beam before fire,the following conclusions are obtained:The theoretical formula is in good agreement with the ABAQUS finite element numerical simulation;The shear capacity of reinforced concrete beams strengthened by HPFL can reach the shear capacity of reinforced concrete beams before fire,and there is a certain degree of increase,which is about 20%.