Title Out-of-Plane Shear Performance Evaluation of New-to-Existing Slab Interface Reinforced with Steel Plate Shear Jackets
Authors 신동진(Shin, Dong-Jin) ; 강수민(Kang Su-Min) ; 김성현(Kim Sung-Hyun) ; 엄태성(Eom, Tae-sung) ; 윤대영(Yune, Dai-young)
DOI https://doi.org/10.5659/JAIK.2025.41.12.279
Page pp.279-288
ISSN 2733-6247
Keywords Horizontal Extension Remodeling; New-to-Existing slabs; Post-Installed rebar; Out-of-Plane Shear; Seismic Retrofit
Abstract In Korea, the demand for horizontal extension remodeling of aging apartment buildings is increasing. To ensure structural integrity and improve constructability at the connection between new and existing slabs, this study proposes a steel plate shear jacket system. This method reduces reliance on post-installed rebars and eliminates the need for surface roughening. Five specimens were tested under five-point vertical loading, with variables including the number of post-installed rebars, jacket shape (Z- or L-type), plate thickness, and fabrication method (bending or welding). Results showed that shear jacket specimens had higher load capacity (up to 1.14 times) and significantly improved ductility compared to the control. The jackets delayed interface slip and shifted failure modes from brittle shear to ductile flexural behavior. Thicker plates and orthogonal rebars enhanced performance. Plastic analysis reflecting positive moment resistance showed good agreement with test results (77?93%), whereas elastic analysis underestimated strength. Although the test setup aimed to induce pure shear, flexural action dominated. Further research is needed to isolate shear behavior and better quantify the strengthening effect. Overall, the proposed detail is effective for enhancing structural performance and constructability in slab extension remodeling.