Study On Fire Resistance Of Reinforced Concrete Continuous Beams Under Fire

With the increase of building scale and population density,building fires will pose a significant threat to life and property.Reinforced concrete continuous beam is widely used in concrete structure,and its fire resistance at high temperature is the basic composition of the fire resistance of the whole reinforced concrete structure.In this paper,the finite element method is used to study the fire resistance of reinforced concrete continuous beam under high temperature.The main work is as follows:1)By consulting the literature,theproperties of steel and concrete at high temperature were summarized,and the suitable material parameters were selected according to the research contents in this paper.2)The software Abaqus was used to establish the analysis model of reinforced concrete continuous beams under high temperature of fire,and the temperature field distribution of reinforced concrete continuous beams under high temperature of fire was obtained through heat transfer analysis.The effects of fire time,thickness of the protective layer and beam section size on the temperature field distribution were analyzed.3)The bending moment,reaction force and crack size of reinforced concrete continuous beam support are obtained through analysis.The internal force redistribution characteristics of reinforced concrete continuous beams under high temperature are obtained by analyzing the influence of protective layer thickness,load size and load action point.4)The influence of parameters on the deformation of reinforced concrete beams under fire is analyzed by adjusting the values of parameters.The variation of deformation curve of reinforced concrete beams with time of fire is analyzed,and the influence of various factors on the fire resistance of structures in the process of fire is obtained.5)The program of calculating section stiffness and ultimate bearing capacity considering temperature distribution is compiled by C#.The stiffness and bearing capacity of the section under different temperature distribution are calculated by the program.Based on the relationship between section bearing capacity and fire duration,the empirical formula of fire resistance and fire duration of reinforced concrete continuous beams is concluded.