Study On Effect Of Vertical Flexural Tension Cracking On Flexural-capacity Of T-beams And Reinforced

In bridge engineering, it has an urgent need to inspect and strengthen many of these bridges with a fast, effective and reliable method. In this paper, the assessment methods of bridge carrying capacity which make use of vertical flexural tension cracks are presented. For the inspection fail to meet requirements of the carrying capacity of bridge need to be reinforced by externally bonded carbon fiber reinforced polymer (CFRP) sheet technique.Combining with the research program'Huangling-Lizhang river inspection and strengthen project of the railway bridge, the key techniques of application of CFRP composite to strengthen reinforced concrete bridges are studied. The major contents are mainly summarized as follow:1. Vertical flexural tension cracks in reinforced concrete T-beams are the one of the main factors of flexural-capacity decline of beams for in-service bridges. The complete flexural-course of the reinforced concrete T-beams is divided into four stages, that is, before cracking stage, cracking stage and elastic-plastic stage, limit stage of compression zone of reinforced concrete. The complete flexural-course of the reinforced concrete T-beams were analyzed by application of the theory of elasticity. On this basis, the equation of compression zone height of concrete in the four stages was presented. Numerical solution of compression zone height of concrete was solved. The reinforced concrete T-beams cracked in work is divided into three stages that cracking stage and elastic-plastic stage, limit stage of compression zone of reinforced concrete. The relationship with the crack height and compression zone height of concrete in the three stages were presented. Crack height was calculated by numerical solutions of compression zone height of concrete.2. Based on analysis of the complete flexural-course of the reinforced concrete T-beams, the relationship with the compression zone height and ultimate flexural-capacity of concrete after crack was presented. The relationship of ultimate flexural-capacity and crack height was established to assessment of bridge capacity.3. Through force analysis of the reinforced concrete T-beam in phase of the normal, taking into account the structure of the second-loading. Based on determining the ultimate flexural-capacity of CFRP strengthened beams, the relationship of the ultimate flexural-capacity and CFRP layers of CFRP strengthened beams was established.4. Apply the results of this paper to'Huangling-Lizhang river inspection and strengthen project of the railway bridge'. After reinforced by ANSYS simulation and do Dynamic Load Test of strengthen bridge, verify the feasibility and reliability of research results in this paper.