The Nonlinear Finite Element Analysis Of BFRP Reinforced Concrete Beams

In recent years,BFRP(Basalt Fiber Reinforced Plastics)bars have developed rapidly in the civil engineering field.It is another inorganic fiber bars which can well solve the reinforcement corrosion problem of the reinforced concrete structure,and beecomes a new type of fiber bars which is environmental and economical at prensent.As BFRP bars are completely linear elastic,there is no yield stage,so that the BFRP reinforced concrete members are insufficient in the part of plasticity and deformation property,which greatly limits the application and promotion of BFRP bars in practical engineering.There are few researches about BFRP bars and BFRP reinforced concrete members now,the theory and the system is not mature,the research results are also not comprehensive enough.In view of the above problems,this paper mainly studies the force performance,deformation performance and influencing factors of BFRP reinforced concrete beams.The author puts forward the method of using steel bars and BFRP bars in concrete beam at the same time,and analyses the influencing factor and deformation performance of the mixed reinforcedconcrete beams.The purpose of this paper is mainly studying the deformation ability that concrete beams can perform when apply BFRP bars with low ductility,and then analys if mixed reinforcement can effectively improve the deformation performance of concrete beams in order to provide a theoretical analysis basis for the development and application of BFRP reinforced concrete member.The study in this paper is used by the finite element simulation,numerical analysis and theoretical calculation.It makes the numerical simulation about the whole process of stress deformation of BFRP reinforced concrete beams and mixed reinforcement concrete beams.The modeling method,unit type,material constitutive relation and solving method are introduced in detail.The analysis mainly considers about the nonlinear material constitutive relation of BFRP bars,steel bars and concrete.In addition,using MATLAB numerical analysis software,the program statement is programmed to calculate the bending moment and the corresponding curvature value of different concrete beams,and then the bending moment curvature diagram is obtained.Through the research of this paper,the main conclusions are as follows:(1)BFRP reinforced concrete beams have a certain deformation ability,but there is no obvious sign of damage before its brittle failure.In addition,compared with reinforced concrete beams,the deformation performance of BFRP reinforced concrete beams is poor,which can not reach the design requirements of the actual engineering,and the concrete strength and reinforcement ratio have great effect on the force performance,but have little effect on deformation properties;(2)The method of using steel bars and BFRP bars in concrete beam at the same time can effectively improve the deformation performance of BFRP reinforced concrete beams,and the concrete beams have obvious signs before failure,which is plastic damage;(3)The area ratio of steel bars and BFRP bars have great effect on the deformation performance of concrete beams,when the area ratio reaches a certain value,in the case of meeting the strength requirements,it can fully play the plastic deformation capacity of concrete beams,so that make the members meet the ductility requirements.