The Effect Of CFRP Sheets And Prestressing Steel Strand After Reinforcement On Concrete Bridges

With the development of economy,the amount of traffic in our country is increasing and so does the car loading.About 20% of the bridges in China were built before the 1980 s,and this part of the bridge design standard is low.In addition,with the increase of the service life,the bridge structure has been affected by physical and chemical corrosion,external impact and other factors,many bridges can not meet the requirements of the heavy traffic.The cost of new bridge is high and the cycle is long.It is a very economical and effective way to prolong the service life and the bearing capacity of bridge structure by reinforcement.Aiming at many kinds of strengthening methods commonly used in engineering,the influence of CFRP sheets reinforcement method and prestressed steel wire reinforcement method on the mechanical properties of bridge structures is studied.In this paper,a prestressed concrete beam is used as a prototype in the test section of one of the expressway.Six test beams are designed by the scale model.The following main contents are studied:1.Summarized the research and achievements of CFRP sheets reinforcement method and prestressed steel strand reinforcement method,Understand the current research on the two reinforcement methods of the stage.Analyzed what is still need to be further studied.2.Studied the reinforcement theory of CFRP sheets and prestressed steel strand.Comprehensive understood plane assumption,material properties,reinforcement design specifications of reinforcement materials and so on,which laid the foundation for the following theoretical analysis and component fabrication3.The theory of similarity model is studied,and the scale components are made according to the proportion of 1: 5.And the experimental scheme was designed in detail;4.The static and dynamic tests were carried out to study the mechanical properties of the strengthened beams,including the change of the bearing capacity,the deflection of the beam,the change of the concrete,reinforcement and reinforcement materials,the number and development of the crack,the change of fatigue life and so on.The results showed that:1.CFRP sheets reinforcement method and prestressed steel strand reinforcement method can improve the bearing capacity of the beam effectively;2.CFRP sheets reinforcement method can limit the development of concrete cracks by disperse the tensile stress of tension zone concrete.Prestressed steel strand reinforcement method can bind the bending of the beam obviously,as well as reduce the beam deflection effectively;3.The two kinds of strengthening materials have very remarkable effect on improving the anti-fatigue performance of the beam.