Journal of Korean Society of Steel Construction (한국강구조학회 논문집)

Korean Society of Steel Construction (한국강구조학회)
권호 표지

Evaluation of Internal Bracing Member Forces due to Distortional Behaviors of Tub Section Steel Box Girders

U형 강박스 거더의 뒤틀림 거동에 의한 내부 수직브레이싱 부재력 평가

  • 김경식 (청주대학교 토목환경공학과)
  • Received : 2010.09.19
  • Accepted : 2011.03.29
  • Published : 2011.04.27
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, the distortional behaviors of tub-section steel girders subjected to torsional loading were analyzed, and predictor equations were developed for estimating the member forces induced in the internal bracing system installed in the steel tub girders. Torsional loadings originated either by eccentric vertical loading or girder curvature were decomposed into the pure torsional force component that does not affect the distortional box deformation, and into the distortional force component that directly induces box distortion. The axial member forces induced in the internal cross frames were formulated as a function of the magnitude of torsional loading through the analytical investigation of the interactions between the distortional force component and internal cross frames. To verify the proposed equations, three-dimensional finite element analysis (3D FEA) was conducted for the straight simple-span girder and the three-span continuous girder samples. Very good agreement was found between the member forces from the FEA and the proposed equations.

본 연구에서는 비틀림 하중을 받는 U형 강박스 거더의 뒤틀림 거동을 해석적으로 분석하여 거더 내부에 설치되는 수직브레이싱의 각 부재에 발생하는 부재력을 산정하는 수식이 개발되었다. 편심하중 또는 거더의 곡률에 의해 발생하는 비틀림하중을 박스단면내 상대적인 변형과는 무관한 순수 비틀림 성분력과 박스 단면내 뒤틀림을 유발하는 뒤틀림 성분력으로 분해하여 뒤틀림 성분력과 이에 저항하는 내부 수직브레이싱의 상호작용 효과를 분석함으로써 각 부재에 발생하는 부재력을 비틀림하중의 함수로 도출하였다. 제안식의 타당성을 검증하기 위하여 편심하중을 받는 단경간 직선거더 및 전경간 일정한 곡률을 가지는 3경간 거더 예제를 선정하여 3차원 유한요소 모델링을 수행하고 해석을 통해 얻은 내부 수직브레이싱의 각 부재력을 제안식으로 산정된 값과 비교 분석하였다. 해석 및 제안식으로 결정된 각각의 부재력은 높은 수준으로 일치함을 보였다.

Keywords

References

  1. 심낙훈, 박영석 (2006) 실물모형 시험체를 이용한 U형 강박스 거더의 상부 수평브레이싱에 관한 실험적 연구: 비틂강성, 한국강구조학회 논문집, 한국강구조학회, 제22권, 제4호, pp.447-455.
  2. 심낙훈, 오귀환, 박영석 (2004) 축소모형 시험체를 이용한 U형 강박스거더의 실험적 연구-II:비틂 거동, 대한토목학회논문집, 대한토목학회, 제24권, 제4A호,pp.837-843.
  3. 이광일 (2010) U형 강박스거더의 W형 상부수평브레이싱 부재력 산정에 관한 실험적 연구, 박사학위논문, 명지대학교.
  4. AASHTO (2003) Guide specifications for horizontally curved steel girder highway bridges. American Association of State Highway and Transfortation Officials, Washington, D.C.
  5. AASHTO (2004) AASHTO LRFD bridge design specifications, American Association of State Highway and Transportation Official, Washington, D.C.
  6. ABAQUS Inc.(2005) ABAQUS Analysis user's manual, Pawtucket, RI.
  7. AISC (1986) Highway Structures Design Handbook. American Institute of Steel Construction, Chicago, IL.
  8. AISC (2001) Manual of Steel Construction. American Institute of Steel Construction, Chicago, IL.
  9. Bradberry,T.E., Cotham,J.C.,and Medlock,R.D. (2005) Elastomeric Bearings for Steel Trapezoidal Box Girder Bridges, TRB 2005 Annual Meeting, paper number 05-2526, pp.1-25.
  10. Dabrowski, R. (1968) Curved thin-walled girders:Theory and analysis. Cement and Concrete Association, U.K.
  11. Fan,Z.and Helwig,T.A.(1999) Behavior of steel box girders with top flange bracing. Journal of Structural Engineering, ASCE, Vol. 125, No. 8, pp.829-837. https://doi.org/10.1061/(ASCE)0733-9445(1999)125:8(829)
  12. Fan,Z.and Helwig,T.A.(2002) Distortional loads and brace forces in steel box girders. Journal of Structural Engineering, ASCE, Vol. 128, No. 6, pp.710-718. https://doi.org/10.1061/(ASCE)0733-9445(2002)128:6(710)
  13. Heins,C.P.(1978) Box girder bridge design-State of the art. Engineering Journal, American Institute of Steel Construction, Vol.15, No.4, pp.126-142.
  14. Heins,C.P. and Hall,D.H. (1981) Designer's guide to steel box girder bridges. Bethlehem Steel Corporation, Bethlehem, PA.
  15. Heins,C.P.and Oleinik,J.C. (1976) Curved box beam bridge analysis. Computers and Structures, Vol.6, No.2,pp.65-73. https://doi.org/10.1016/0045-7949(76)90054-7
  16. Kim, K. (2004) Research on horizontally curved box girders, Ph.D. dissertation, Auburn University, Auburn, AL.
  17. Kim,K. and Yoo,C.H. (2006a) Brace forces in steel box girders with single diagonal lateral bracing systems. Journal of Structural Engineering, ASCE, Vol.132, No.8, pp.1212-1222. https://doi.org/10.1061/(ASCE)0733-9445(2006)132:8(1212)
  18. Kim,K. and Yoo,C.H. (2006b) Interaction of top lateral and internal bracing systems in tub girders. Journal of Structural Engineering, ASCE, Vol.132, No.10, pp.1611-1620. https://doi.org/10.1061/(ASCE)0733-9445(2006)132:10(1611)
  19. Kollbrunner, C.F. and Basler, K. (1969) Torsion in structures, Springer-Verlag, New York, NY.
  20. Nakai, H. and Yoo, C.H. (1988) Analysis and design of curved steel bridges. McGraw-Hill Book Company, New York, NY.
  21. Richardson,G. and Associates(1963) Analysis and design of horizontally curved steel bridge girders. United States Steel, Structural Report No. ADUCO 91063.
  22. Tung,D.H.H. and Fountain,R.S. (1970) Approximate torsional analysis of curved box girders by the M/R method. AISC Engineering Journal, Vol.7, No.3, pp.65-74.
  23. United States Steel Corporation (1978) Steel/concrete composite box-girder bridges: A construction manual, Pittsburgh, PA.
  24. Wright, R.N., Abdel-Samad, S.R., and Robinson, A.R. (1968) BEF analogy for analysis of box girder. Journal of the Structural Division, ASCE, Vol.94, No.7, pp.1719-1743