In order to research the eccentric compression performances of hooping technique strengthening member, mechanical behavior testings of 22 specimens were completed to investigate the influence of 7 different factors on the failure pattern and bearing capacity of the member. Test results indicated that the failure mode of hooping strengthening member was similar to that of common reinforced concrete member. The actual test strains of midsection before cracking basically complied with the plane section assumption, which showed that the young-old concrete can work together. By analyzing the relationship curve of test load and strain, it was inferred that the new-old reinforcement and concrete are able to reach its design strength in the calculation of carrying capacity. Based on the basic design principles of RC structure, and combined with the existing strengthening technical specifications, the formula for the bearing capacity of hooping strengthening member considered various influence factors was proposed. Then, the formula was duly simplified in the light of the actual situation of the test. The comparison between the simplified theoretical calculation results and test results verified the correctness and reliability of the proposed formula.
