Study On Mechanical Properties Of Reinforced Concrete Column Strengthened By HPFL After Fire

Fire bring a lot of convenience to human life while cause disasters, seriously threaten human life and property safety. a large number of reconstruction work needs to be carried out after building fire; how best to reduce the cost of reconstruction increasingly become a problem of concern. High performance ferrocement laminate(HPFL) plays a more and more important role in the field of reinforce concrete structure because of its a variety of advantages,such as better ductility,better refractory high temperature resistant performance and simple construction、low cost.This paper analyzes and discusses the mechanical properties of RC column reinforced by HPFL after fire based on the existing research results at home and abroad.The main research contents of this paper are as follows:(1)Summarize the existing research results of thermal parameters and material properties of steel and concrete after fire(high temperature) at home and abroad,including strength, elastic modulus, stress-strain relations,etc, and put forward a simplified model used in theory calculation in this paper.(2)Under the premise of without considering the changes of the temperature field along the direction of column height, the temperature field of two-dimensional(2D) of RC column section was simulated by ANSYS, and presents the section temperature field distribution with different section sizes under different time by fire.Three-dimensional(3D) model of RC column reinforced by HPFL after fire was established by ANSYS, and the material characteristics and modeling process were introduced in detail, and the bearing capacity of RC column normal section was analyzed by finite element method.(3)Based on the strength equivalent section method, the theoretical calculation formula of the residual bearing capacity of the normal section of RC column after fire(high temperature) is presented.the failure mode of RC column reinforced by HPFL after fire was analyzed, and the theoretical calculation formula of the bearing capacity of normal section of RC column reinforced by HPFL after fire under secondary load state was put forward, and the calculated results were compared with the experimental results. The results show that the error range between the theoretical value and the experimental results is less than 16%.(4)Use ANSYS to establish the finite element numerical model of RC columnreinforced by HPFL after fire, simulate the pseudo-static test, and verify the finite element model rationality by comparing with existing experimental results.Comparison results show that: the seismic performance indicators of RC column strengthened by HPFL after the fire, such as strength, ductility and hysteretic energy dissipation, are improved in different degrees.