전단슬립 효과를 고려한 합성보의 유효강성

Effective Stiffness of Composite Beams Considering Shear Slip Effects

  • 투고 : 2004.07.12
  • 심사 : 2004.08.23
  • 발행 : 2004.10.27

초록

본 연구는 부분 전단연결을 가지는 강-콘크리트 합성보의 처짐에 미치는 전단슬립의 영향을 조사하는 것이다. 현재 각국의 설계규준에서는 합성보의 처짐 계산시 전단연결재의 강도와 관련되어 있지만, 본 연구에서는 하중조건에 상관없는 전단연결재의 강성에 기반을 둔 정확한 해를 유도하였다. 우선, 평형조건, 곡률의 적합조건에 기반을 둔 3가지 하중조건에서의 합성보의 등가강성을 유도하고, 이로부터 하중조건에 상관없이 슬립의 영향을 적용할 수 있는 간편한 제안식을 유도하였다. 이러한 제안식의 타당성을 검증하기 위해서 현재 AISC에서 사용하고 있는 합성보의 유효강성 및 Nie가 제안한 식과 비교하였다. 일반적으로 사용되는 보의 경우, 전단슬립의 영향은 스팬이 짧을 경우, AISC에 비해서 최대 18%까지의 강성의 감소를 나타냄을 알 수 있었다. 완전합성보의 경우, AISC의 제안 값이 본 연구의 결과 보다 크게 나타났는데, 이는 안전측이 되지 못함을 알 수 있었으며, 불완전 합성보의 경우, AISC 제안식이 본 연구보다 강성을 과소 평가하는 결과를 나타내었다.

This study investigated the effects of a shear slip on the deflection of steel-concretecomposite beams with partial shear interaction. Under the guidance of various current design codes, this deflection was related to the strength of shear connectors in the composite beams. In this paper, a shear connector stiffness based on exact solutions, regardless of loading conditions, was developed. The equivalent rigidity of composite beams that considered three different loading types was first derived, based on equilibrium and curvature compatibility, from which a general formula accounting for slips was developed. To validate this approach, the predicted maximum deflection under the proposed method was compared against currently used equations to calculate beam effective stiffness (AISC)Nie's equations, which have recently been proposed. For typical beams that were used in practice, shear slips might result in stiffness reduction of up to 18% for short-span beams. For full composite sections, the effective section modulus with the AISC specifications was larger than that of the present study, which meant that the specifications were not conservative. For partial composite sections, the AISC predictions were more conservative than those in the present study.

키워드

참고문헌

  1. Proc. Soc. Exp. Stress Anal. v.9 no.1 Tests and analysis of composite beams with incomplete interaction Newmark, N.M.;Siess, C.P.;Viest, I.M.
  2. The Struct. Engr., London, U.K. v.53 no.8 Partial interaction design of composite beams Johnson, R.P.;May, I.M.
  3. Design of composite steel concrete structures Yam, L.C.P.
  4. J. Constructional Steel Res. v.15 The deformation of composite beams with discrete flexible connection Wright, H.D.
  5. Struct. Eng. v.47 no.9 Partial shear connection in composite beams Jhonson, R.P.;Molenstra, I.N.
  6. J. Struct. Eng. v.119 no.4 Composite beam-columns with interlayer slip-exact analysis Girhammar, U.A.;Gopu, V.K.A.
  7. Load and resistance factor design specification for structural steel buildings AISC American Institute for Steel Construction(AISC)
  8. Design of composite steel and concrete structures. Part 1 : General rules and rules for buildings Eurocode 4
  9. Composite structures of steel and concrete Johnson, R.P.
  10. J. Struct. Eng. v.124 no.10 Deflection of steel-concrete composite beams with partial shear interaction Wang, Y.C.
  11. J. Struct. Eng. v.129 no.1 Shear Connection Nonlinearity and Deflections of Steel-Concrete Composite Beams: A Simplied Method Faella, C.;Martinell, E.;Nigro, E.
  12. J. Struct. Eng. v.129 no.4 Steel-Concrete Beams Considering Shear Slip Effects Nie, J.G.;Cai, C.S.