기존 중·저층 R/C 건물의 CFT 외부접합형 합성보강공법의 내진성능평가

Abstract

In this study, in order to enhance the connection performance between the existing reinforced concrete (R/C) frame and the strengthening member, we proposed a novel concept of CFT External Composite Methodology (CECM) for seismic retrofit of existing domestic medium-to-low-rise R/C buildings. The CECM method, proposed in this study, can conduct the seismic retrofitting construction while residents can live inside building. The CECM rehabilitation system is a type of strength-enhancing reinforcement systems, to easily increase the ultimate horizontal shear capacity of R/C structures without seismic details in Korea, which show shear collapse mechanism. Two test specimens of full-size two-story R/C frame were fabricated based on an existing domestic R/C building without seismic details, and then retrofitted by using the proposed CECM seismic system; therefore, one control test specimen and one test specimen reinforced with the CECM system were used. Pseudo-dynamic testing was conducted to evaluate seismic strengthening effects, and the seismic response characteristics of the proposed system, in terms of the maximum shear force, response story drift, and seismic damage degree compared with the control specimen (R/C bare frame). Experiment results indicated that the proposed ECCM reinforcement system, externally installed to the existing R/C frame, effectively enhanced the horizontal shear force, resulting in reduced story drift of R/C buildings under the maximum design earthquake level designated in KDS 41.