Experimental research on seismic behaviors of RC frame strengthened with attached self-centering member

In view of the problems existed in the seismic strengthening and reconstruction project of an existing reinforced concrete frame structure, a method using attached prefabricated self-centering members to strengthen the reinforced concrete frames is proposed. That is, the existing frame beams and columns are strengthened by enlarging section method, and prefabricated beam members are installed side by side along the frame beams. Unbonded prestressed tendons are installed throughout the length of the prefabricated beams and anchored to the outer side of the frame columns. Energy dissipating steel bars are installed between prefabricated beams and frame columns, so that the reinforced frame can obtain certain self-centering ability under the given performance design objective. In order to verify the strengthened effect of this method, three plane frame structure test specimens were designed and constructed, and the quasi-static test was carried out. Among them, one specimen was the non-strengthened comparative specimen, and two specimens were the frame structure specimens strengthened with attached prefabricated self-centering members. The test results show that the method can significantly improve the seismic capacity and ductility of the reinforced concrete frame structure, and the energy dissipation capacity is significantly enhanced. The residual deformation of the strengthened specimen is significantly smaller than that of the non-strengthened specimen within a certain range of inter-story drift ratio, and the self-centering capacity after the earthquake is significantly enhanced. The refined finite element simulation analysis is carried out for the test, and the finite element analysis results are in good agreement with the test results. This method can be combined with the performance-based seismic strengthening design to meet the demand of displacement based performance-based strengthening design.