Research On Bending Properties Of CFRP Strengthened RC Beams Based On The Nonlinear Contact Simulation

Recently, an advanced composite material named Carbon Fiber Reinforced Plastic(CFRP) has emerged as an alternative to traditional strengthening materials. Manyadvantages such as lightweight, non-corrosive, simple construction and high tensilestrength make it widely used in strengthening field.In order to study the behaviors of RC beams strengthened with CFRP, experimentalstudy and theoretical analysis were combined in the process of research. This thesis putforward the results of experimental and analytical studies concerning flexural reinforcedconcrete beams strengthened with externally bonded CFS to the tension face of thebeams.Based on non-linear numeric analysis theory and modeling technology, on theground of suitable numerical model and numerous calculations, some nonlinear finiteelement models on strengthened beams were made with element method, which due toproper material elements (SOLID65and LINK8were used to model the concrete andsteel bar respectively, SHELL41were used to model the CFRP sheets, CONTA174andTARGE170were used to model target face and contact face) and simulation parameters(the elastic modulus and Poisson ration and the relation between stress and strain ofconcrete and steel bar and CFRP sheets were given).ten R.C beams are analyzed incarrying capacity and the load-displacement curves are put out.The results clearly indicated that after being strengthened, the flexural capacity ofbeams can be significantly raised by bonding CFS to the tension face of beams. Thestiffness of the beams increased, especially after the bending of the steel bars, while theductility of beams decreased to some extent.The paper conducted to the comparison between results of experiment and elementsimulation. The results of comparison between experiment and element analysis showthat the results of experiment is similar to those of models. The data differences of bothresults varied below20%. Based on elastic and plastic theory and finite element theory,the paper interprets the reasons why the differences exist. In this paper, the models also perfectly simulate the flexural performance of beamsand give some systemic data about flexural performance of beams strengthened withCFRP sheets for analysis and applications.