고강도 콘크리트를 사용한 플랫 플레이트 구조의 기둥-슬래브 접합부 강성에 관한 연구

초록

In this study, the four column-slab connections in flat plate system using high strength concrete exceeding 60MPa, modeled after a typical reinforced concrete flat plate building, were tested under combined gravity and lateral loadings. The variables selected for this study were the slab reinforcement ratio and the level of slab gravity load. The test results were compared with the stiffness predictions of elastic finite element analysis, the ACI equivalent frame method and the AIJ method.The followings were found: 1) The stiffness of column-slab connection under gravity loading reduced as the slab gravity load increased. At the level of service gravity load, the gravity stiffness was about 70 percent of initial stiffness. 2) The lateral stiffness of column-slab connection decreased with increasing the lateral deflection and was dependent on the level of slab gravity load and slab reinforcement percentage. 3) The initial lateral stiffness was about 50 percent of elastic finite element analysis in lateral drift ratio of 0.0625 percent. This was attributed to the accelerated slab cracking around the connection as a result of the increased gravity load moments. 4) The lateral stiffness varied from 24 to 37 percent of elastic finite element analysis and from 17 to 26 percent of ACI equivalent frame method in lateral drift ratio of 0.2 percent. This result gave agreement with other researcher's test result of column-slab connection in flat plate system using normal strength concrete.

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