The Flexural Behavior Of Simply Supported Beam Bridge Considered Size Effect And Strengthened With Near-Surface-Mounted FRP Laminate

The carbon fiber CFRP, the abbreviation of Carbon Fiber Reinforced Polymer, is onekind of new material emerging in the developed country to reinforce concrete structure,and is called “the structure reinforcement nova” because of its outstanding mechanicalproperties in the project domain. The carbon fiber material not only has the significantcharacteristics of high strength, light quality and anti-corrosive, but has the superioritiesof convenient construction, fire proof performance and well roller compactionperformance and so on, therefore, it is widely applied in reinforcement domain ofreinforced concrete structure. At present, the reinforcement methods ofNear-Surface-Mounted carbon fiber mainly focus on the flexural reinforcementexperiment aspects of simply supported beam, and the reinforcement experimentsconsidering size effect factor are relatively few. Unifying reinforcement situations ofactual project, basing on the original model of Central South University literaturecovering test beams, using classical similarity theory and manufacturing the scaledmodel of reinforced concrete beams, this article carries on the flexural reinforcementexperiments of scaled model beam strengthened with Near-Surface-Mounted CFRP.Finally the experimental results of scaled model beams are compared with that of theprototype structure. The main research contexts are as follows:(1) Three reinforced concrete scaled model beams are manufactured in thisexperiment and the geometrical similarity factor is1/2.One of which is secondary load,the other two are not initial load when in reinforcement. The following items areobserved and measured in this work: the deflection and failure mode, the shape andgrowth of cracks, the cracking load, the yielding load and ultimate load of model beams.The comparative analysis of testing data of model beams and prototype beams arecarried on separately, and on account of test results, probe into the issue of size effect.(2) This article, on the foundation of testing results, proposes the theoreticalcalculation formulas of bearing capacity of simply supported beam strengthened withNear-Surface-Mounted CFRP, and conducted the comparison of theoretical calculationresult and the testing result. It has been confirmed that the theoretical calculation formulas are rational and accurate.(3) Based on large-scale general finite element analysis software, the nonlinear finiteelement analysis of model beams strengthened with Near-Surface-Mounted CFRP isimplemented properly. At the same time, the article carries out the analyticalcomparison of the finite element results and the testing results. The uniformity of thefinite element results and the testing results illustrates the computational modelproposed is suitable and feasible.(4) According to test and theoretical analysis, the flexural design of reinforcedconcrete beams strengthened with CFRP is carried out, and for actual reinforcementproviding reference information, a design formula of flexural reinforcement and aformula of maximum amount of reinforcement are proposed.