EXPERIMENTAL STUDY ON SEISMIC PERFORMANCE OF COMPOSITE STRENGTHENING SEISMIC DAMAGED RC FRAME

The composite reinforcement of CFRP and angle steel can effectively improve the bearing capacity and ductility of the structure and give a full play to their respective advantages. The seismic behavior of damaged frames, strengthened by CFRP sheets, by CFRP sheets with angle steel and, by diagonal braces, was studied under low cycle cyclic loading. The results show that: After strengthening with CFRP sheet, the deformation capacity of the joint is not significantly improved, the beam end is seriously damaged, the CFRP sheet at the joint falls off with the concrete, and the bearing capacity does not return to the seismic energy before the earthquake power; The joint and column base are not damaged obviously after the composite reinforcement, which realizes the seismic design principle of strong joint and weak member, and after the diagonal brace reinforcement, the bearing capacity and stiffness of the frame can be improved obviously, but the anchor bolt failure leads to the rapid reduction of the bearing capacity, thusly the anchor bolt bearing surplus should be increased; After the composite reinforcement, the bearing capacity of the test specimen is obviously improved, the hysteresis curve is fuller, the cumulative energy dissipation capacity is stronger, the number of cyclic loading is obviously increased, the bearing capacity reduction coefficient is reduced, the angle steel improves the anti-failure ability of the joint, and the combination of angle steel and brace can obviously improve the anti-failure ability of the joint; Considering the seismic performance, economy and strengthening technology, the composite strengthening technology of CFRP sheet and angle steel can be used to strengthen the damaged frame.