Theoretical And Experimental Study Of Reinforced Concrete Continuous Beam With CFRP

In recent years, carbon fiber reinforced concrete bridge technology has been widely used in a number of simply supported bridge strengthening works, which has been made fine reinforcing effect. However, carbon fiber reinforced concrete continuous beam bridge technology has not been studied in further. As a result of the mechanical characteristics of reinforced concrete continuous beam are very different from reinforced concrete simply supported beam, the reinforcement of hyperstatic structure, mechanism of the structure, mechanical model are more complicated and not clear. If we use such of reinforcement methods in continuous beam reinforcement, that will be a new attempt.In this paper, all the works is in-depth study. It relies on the project of Ministry of Communications -- <> (2003353322100). A series of research about reinforced carbon fiber reinforced concrete continuous beam structure is carried out, such as theoretical research, experimental study and other effective works. As follows:First, the carbon fiber reinforced concrete continuous beam was researched based on laminated theory, reinforced concrete continuous beam after carbon fiber reinforced is a complex mechanical system, the author used composite structure theory studied it in this paper, and introducted the classical laminated theory, and established the calculation model of reinforced concrete continuous beam structure by carbon fiber reinforced. The model was verified the accuracy by ANSYS. The model shows that the theory has a higher accuracy. This model accurately reveals that the mechanical behavior of carbon fiber reinforcement for the reinforced concrete continuous beam structure and the status of the deformation. We investigated that changing parameters such as strength of concrete, structure changes in the size affect extent to the structure after reinforcement. The model based on the laminated theory was set by non-linear theory. If we use carbon fiber to reinforce the higher statically indeterminate concrete continuous beam structure, it has a great significance. The author prepared the non-linear program, the program can be used in the beam bending calculation and improve the calculation speed. It has a certain practical significance. So far, appling the theory of laminated carbon fiber reinforced concrete continuous beam structure has not been reported in all the carbon fiber reinforced concrete continuous beam theory study. This developed a new theoretical study ideas for the reinforced carbon fiber reinforced concrete continuous beam.Second, the carbon fiber reinforced concrete continuous beam bending properties of the structure was researched. We pasted carbon fiber in the negative moment region reasonably, successful turned a 4m simply supported beam into a 1.8m long two-span continuous beam. Which lacked of reinforced bars in the negative moment region. The structural conversion of the mechanical system of " simply supported to continuous " is effectively.And researched the bending performance, anti-bend capacity analysis of converted structure system by test, investigated affecting extent of reinforcement of the paste pattern and some mechanical properties after reinforcement.Test results show that pasting carbon fiber in the negative moment region can effective improve the mechanical properties of the original structure with weak negative bending moment, improve load-bearing capacity of the structure. The pasting of carbon fiber on the reinforced concrete continuous beam caused re-distribution of the internal bending moment, and improved outstanding. Continuous beam structure of reinforced concrete is the moment of regional paste carbon fiber structure of the internal bending moment of the re-distribution of improved. The cracking load, yield load, ultimate load, stiffness and flexural capacity of structure could be enhanced. In the elastic stage, every indicator of carbon fiber reinforced concrete continuous beam didn't improve great, the level of limit load enhanced larger than yield load. It illustrated that carbon fiber has played a greater role in the latter stage.Subsequently, the author researched temperature reliability of bonding layer on theory and experiment, demonstrated that the interfacial shear specimen can instead of interfacial bending specimen in theory. The interfacial shear specimen can be used to study the temperature shear stress generated by temperature change in the bonding layer. And it is equivalent and reliable on this problem. Based on elasticity theory, the author set up an analytical model of temperature shear stress on the interface between carbon fiber and concrete.1) The author nalysis the interface shear stress and carbon fiber surface temperature strain distribution discipline under different temperature conditions. And determined quantitative effect of bonded interface shear stress when we changed the parameters such as the thickness of bonding layer, the thickness of carbon fiber pasted on the interface about this model. It included difference at different temperatures and the same temperature difference.2) According to theoretical results, an appropriate increase in the thickness of bonding layer can reduce the interface temperature shear stress of the end, and increasing the thickness of carbon fiber will cause the end of the interface temperature shear stress increase. In the project, we should pay attention to the shear stress of bonding layer which generated by the changes of temperature, if necessary, taking appropriate anchor.3) We made repeated high-low temperature cycling test with reinforced interfacial shear specimen, studied fatigue strength of the bonding layer between the carbon fiber and the concrete interface. The test result shows that temperature fatigue property of the bonding layer is fine. Under repeated freeze-thaw cycles, the bond strength of interface changed unsignificantly. The research work for carbon fiber reinforced concrete structure design and safety assessment is important.