| It has been proved an effect method to strengthen the reinforced concrete members with fiber-reinforced polymer in engineering. In the case of strengthening RC structure with CFRPs, lots of tests and researches have been carried, such as to increase flexural capacity by bonding CFRP sheets to the tension face of a concrete flexural member with fibers oriented along the length of members, to increase the shear strength of existing concrete beams and columns by wrapping or partially wrapping members, to increase the axis compression strength and the ductility of members subjected to combined axial and bending forced by wrapping CFRPs completely around certain types of compression elements. To beams and columns crossing at joints, because of the constructing difficulties occurred by the fact that it is unable to strengthen members with CFRPs crossing a concave angle, no test about these members has been carried. Aiming at this problem, this paper has designed a method and used it to strengthen these members in two beam-column-joint specimens. The tests have shown that the ultimate load capacity and the ductility of the specimens strengthened with this method have been enhanced. A simplified formula to calculate the ultimate bending capacity of beams strengthened with CFRPs is given. The results with the formula are compared with the results of the tests. By testifying the shear capacity of joints, the principles of strong shear capacity poor bent capacity, strong columns poor beams, strong joints in the engineering design of RC frames have been discussed in this paper, several proposals for design have been given also. By the comparison of the theoretical result and the test result of the displacement of the end of beams, the factors affecting the rigidity of the joint are analyzed. Lastly, numeric models have been created with finite element analytic soft –ANSYS and the analysis and comparison about the result have been carried out.
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