Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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Effects of Shore Stiffness and Concrete Cracking on Slab Construction Load I: Theory

슬래브의 시공하중에 대한 동바리 강성 및 슬래브 균열의 영향 I: 이론

  • Hwang, Hyeon-Jong (Dept. of Architecture, Seoul National University) ;
  • Park, Hong-Gun (Dept. of Architecture, Seoul National University) ;
  • Hong, Geon-Ho (Dept. of Architectural Engineering, Hoseo University) ;
  • Im, Ju-Hyeuk (Housing Eng. Team, Samsung Engineering and Construction) ;
  • Kim, Jae-Yo (Dept. of Architectural Engineering, Kwangwoon University)
  • Published : 2010.02.28
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Abstract

Long-term floor deflection caused by excessive construction load became a critical issue for the design of concrete slabs, as a flat plate is becoming popular for tall buildings. To estimate the concrete cracking and deflection of an early age slab, the construction load should be accurately evaluated. The magnitude of construction load acting on a slab is affected by various design parameters. Most of existing methods for estimating construction load addressed only the effects of the construction period per story, material properties of early age concrete, and the number of shored floors. In the present study, in addition to these parameter, the effects of shore stiffness and concrete cracking on construction load were numerically studied. Based on the result, a simplified method for estimating construction load was developed. In the proposed method, the calculation of construction load is divided to two steps: 1)Onset of concrete placement at a top slab. 2)Removal of shoring. At each step, the construction load increment is distributed to the floor slabs according to the ratio of slab stiffness to shore stiffness. The proposed method was compared with existing methods. In a companion paper, the proposed method will be verified by the comparison with the measurements of actual construction loads.

고층건물에 플랫 플레이트의 사용이 증가하면서, 과도한 시공 하중의 작용과 그에 따른 슬래브의 장기 처짐은 콘크리트 슬래브 설계에 큰 영향을 미칠 수 있다. 콘크리트의 균열과 조기재령 슬래브의 처짐을 예측하기 위해서는 시공하중을 정확히 산출할 필요가 있다. 이러한 플랫 플레이트의 시공하중은 다양한 설계 요소에 영향을 받음에도 불구하고, 대부분의 기존 시공하중 산정법의 영향 요소는 시공주기와 콘크리트의 재료적 성질, 동바리 지지층수로 국한되어왔다. 이 연구에서는 이러한 영향을 포함하여, 동바리 강성과 콘크리트 균열의 영향을 이론적으로 연구하였다. 연구결과를 바탕으로 시공하중 산정을 위한 간단한 방법을 개발하였다. 제안법에서 시공하중 산정은 최상층 슬래브 타설과하부 동바리 제거 두 단계로 나누어진다. 각 단계에서 시공하중 증가분만큼 동바리와 슬래브의 강성비에 따라 하부 슬래브로 하중이 전달된다. 제안방법은 기존 시공하중 산정법과 비교되었다. 실제 시공하중 계측결과와 제안법의 비교는 연계된 논문에서 기술된다.

Keywords

References

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Cited by

  1. Parametric Study on Long-Term Deflections of Flat Plates Considering Effects of Construction Loads and Cracking vol.16, pp.1, 2012, https://doi.org/10.11112/jksmi.2012.16.1.044
  2. Evaluation of Construction Loads of Slabs and Shores with Removing Shores and Placing Reshores vol.26, pp.3, 2014, https://doi.org/10.4334/JKCI.2014.26.3.385