Experimental Research Of Shear Resistance Performance On Loaded Concrete Beam Diagonal Section Reinforced With Prestressed CFRP Sheet

Recently, prestressed CFRP sheet reinforced concrete structure, which was a new reinforcing method of structure, has been widely used in civil engineering fields and has been a hot research at home and abroad because of the advantages of high strength, anti-corrosion and light weight of the CFRP sheet.It is still blank of the study on the reinforcement of the oblique section of the loaded concrete beams with the pre-tensioned CFRP sheet at present.In order to research the shear behavior of the prestressed CFRP sheet reinforced concrete beams under loading,3 groups and 12 beams were made with different stirrup rates and the control stress of tension. And one comparison beam with no reinforcement and 3 prestressed CFRP sheet reinforced concrete beams were contained in each group. A new tension technology of the CFRP sheet with the advantages of simple operation and easy to use for the reinforcement of the oblique section of concrete beams was proposed in order to achieve the tension and paste of the CFRP sheet.We fist completed the pre-loaded of the nine test beams and then finished the reinforcement of the oblique section with prestressed CFRP sheet under loading. The test data were obtained through the single point load experiment of the 12 test beams. The study of the load, deformation, crack distribution and failure modes was carried out. The results show that, the shear capacity of oblique section was effectively improved, the appearance of inclined crack and the development of the crack was greatly limited and the bearing area shear compressive concrete was increased with the existence of prestressed CFRP sheet in the process continued to bear the load after the reinforcement of the oblique section of the loaded concrete beams.Based on measured data, the influence of the prestressed CFRP sheet on the shear capacity and the regular pattern of collaborative force of prestressed CFRP sheet and stirrup were researched. The influence on the shear failure modes of the paste method of CFRP sheet, prestressed level and stirrup rates were analyzed. On the basis, the following conclusions were got:(1) The shear capacity and the degree of participation in the force of the carbon fiber all showed a negative correlation with the rate of stirrup;(2) There is great impact on failure modes of different structural form of CFRP sheet. (3) Crack stiffness was effectively improved but there is no significant influence on the bending stiffness with the existence of prestressed CFRP sheet. (4) The high-strength characteristic of prestressed CFRP sheet was used effectively and the loaded lag was avoided by the reinforcement of the oblique section of the loaded concrete beams with the prestressed CFRP sheet and it was changed to active stress state from the passive stress state of CFRP sheet.