Journal of Korean Society of Steel Construction (한국강구조학회 논문집)

Korean Society of Steel Construction (한국강구조학회)
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Constitutive Relation of Concrete to Predict P-M Interaction Strength of Rectangular CFT Short Columns

콘크리트충전 각형강관단주의 P-M 조합강도 예측을 위한 콘크리트 구성방정식

  • Lee, Cheol Ho (Dept. of Architecture and Architectural Engineering, Seoul National University) ;
  • Kang, Ki Yong (Department of design #2, C.S Structure Engineering Inc.) ;
  • Kim, Sung Yong (Dept. of Architecture and Architectural Engineering, Seoul National University)
  • Received : 2013.10.21
  • Accepted : 2014.10.14
  • Published : 2015.02.27
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Abstract

The plastic stress distribution method and the strain compatibility method are the two representative methods to calculate the P-M interaction strength of RCFT (rectangular concrete filled tube) columns. The plastic stress distribution method is approximate while the stress compatibility method should approach the exact solution if accurate constitutive relations of the materials involved are used. Recent study by the authors pointed out that, because of lack of accurate constitutive model for the concrete confined by the rectangular steel tube, no strain compatibility method according to the current structural provisions provides a satisfactory prediction of the P-M interaction strength of RCFT columns under various material combinations. An empirical constitutive model which can capture the stress-strain characteristics of the confined concrete of RCFT columns is proposed based on analyzing extensive exisitng test database. The key idea was to define the concrete crushing strain as a function of steel-to-concrete strength ratio and width-to-thickness ratio of steel tube. It was shown that the proposed model leads to more accurate and more consistent prediction of the P-M interaction strength of RCFT columns under general design conditions.

소성응력분포법과 변형률적합법은 콘크리트충전 각형강관(RCFT, rectangular concrete filled tube) 기둥의 P-M조합강도 산정을 위한 대표적인 두 방법으로, 일반적으로 소성응력분포법은 근사적인 강도치를 제공하는 반면 변형률적합법은 단면에 사용되는 각 물성치의 구성방정식이 정확하다는 전제 하에서 정해에 가까운 해를 제공한다. 최근 변형률적합법에 따른 RCFT기둥의 P-M조합강도 산정에 관한 필자의 연구에 따르면, 현재 연구된 외부 강관으로 구속된 콘크리트 구성방정식이 부정확하기 때문에, 변형률적합법을 통해 산정된 다양한 물성치를 가지는 콘크리트와 강재의 조합으로 이루어진 단면의 P-M조합 강도가 부정확하게 산정되는 것으로 나타났다. 이에 따라 본 연구에서는 기존에 수행된 실험결과를 분석하여 콘크리트충전 각형 강관기둥의 P-M 조합강도 예측을 위한 변형률적합법에 활용될 수 있는 충전콘크리트의 구성방정식을 제시하고 그 타당성을 입증하였다. 본 연구에서 추구하는 모형은 실무적용을 위한 우회적이고 현상학적 모형으로, 외부 강재와 내부 콘크리트 간 상대강도비와 강재의 판폭두께비의 P-M조합강도에 대한 영향을 압괴변형률의 크기에 반영하여 단면내의 힘의 재분배 정도를 조절함으로써 실험결과와 합치하는 결과를 얻어내는 모형이다. 이를 위해 현 규준에서 제시하고 있는 압괴변형률 0.003의 일괄적 제한의 한계를 지적하였으며, 상대강도비와 판폭두께비의 P-M조합강도에 대한 영향을 압괴변형률의 크기에 반영하여 단면내의 힘의 재분배 정도를 조절함으로써 실험결과와 합치하는 결과를 얻어내는 모형을 제시하였다.

Keywords

References

  1. ACI (2008) Building Code Requirements for Structural Concrete (ACI 318-08) and Commentary, American Concrete Institute, USA.
  2. AISC (2010) Specification for Structural Steel Buildings, American Institute of Steel Construction, USA.
  3. EC4 (2005) Design of composite steel and concrete structures, European Committee for standardization, UK.
  4. 대한건축학회(2009) 건축구조설계기준 및 해설(KBC 2009), 기문당. AIK (2009) Korea building code and commentary - structural, Architectural Institute of Korea (in Korean).
  5. 이철호, 강기용, 김성용, 구철회 (2013) 각형 콘크리트충전 강관기둥 부재의 구조설계기준 비교연구, 한국강구조학회논문집, 한국강구조학회, 제 24권, 제 4호, pp.443-450. Lee, C.H., Kang, K.Y., Kim, S.Y., and Koo, C.H. (2013) Review of Structural Design Provisions of Concrete Filled Tubular Columns, Journal of Korean Society of Steel Construction, KSSC, Vol.24, No.4, pp.443-450 (in Korean).
  6. EC2 (2004) Design of Concrete Structures, European Committee for standardization, UK.
  7. 최영환, 배규웅(2005) 미국 강구조학회의 설계법에 기반한 콘크리트 충전강관 보-기둥의 새로운 내력평가 방법, 대한건축학회논문집구조계, 대한건축학회, 제21권, 제11호, pp.69-76. Choi, Y.H. and Bae, K.W. (2005) New Method to Estimate the Strength of Concrete Filled Tube Beam-Columns Based on AISC/LRFD, Journal of the Architectural Institute of Korea Structure and Construction, Vol.21, No.11, pp.69-76 (in Korean).
  8. Furlong, R.W. (1967) Strength of Tteel-Encased Concrete Beam Columns, Journal of the Structural division, ASCE, Vol.93, No.ST5, pp.113-124.
  9. Gourley, B.C., Tort, C., and Hajjar, J.F. (2001) A Synopsis of Studies of the Monotonic and Cyclic Behavior of Concrete-Filled Steel Tube Beam-Columns, Structural Engineering Report No.ST-01-4, U. of Minnesota.
  10. Schneider, S.P. (1998) Axially Loaded Concrete-Filled Steel Tubes, Journal of the Structural Division, ASCE, Vol.124, No.10, pp.1125-1138. https://doi.org/10.1061/(ASCE)0733-9445(1998)124:10(1125)
  11. Liu, D. (2004) Behaviour of High Strength Rectangular Concrete-Filled Steel Hollow Section Columns Under Eccentric Loading, Thin-Walled Structures, Vol.42, No.12, pp. 1631-1644. https://doi.org/10.1016/j.tws.2004.06.002
  12. Liu, D., Gho, W., and Yuan, J. (2003) Ultimate Capacity of High-Strength Rectangular Concrete-Filled Steel Hollow Section Stub Columns, Journal of Constructional Steel Research, ELSEVIER, Vol.59, No.12, pp.1499-1515. https://doi.org/10.1016/S0143-974X(03)00106-8
  13. Liu, D. and Gho, W. (2005) Axial Load Behaviour of High Strength Rectangular Concrete Filled Steel Tubular Stub Columns, Thin-Walled Structures, Vol.43, No.8, pp.1131-1142. https://doi.org/10.1016/j.tws.2005.03.007
  14. Varma, A.H., Ricles, J.M., Sause, R., and Lu, L.W. (2002) Experimental Behavior of High Stength Square Concrete- Filled steel tube Beam-Columns, Journal of Structural Engineering, ASCE, Vol.128, No.3, pp. 309-318. https://doi.org/10.1061/(ASCE)0733-9445(2002)128:3(309)
  15. Hognestad, E. (1951) A Study of Combined Bending and Axial Load in Reinforced Concrete Members, University of Illinois.
  16. Fujimoto, T., Mukai, A., Nishiyama, I., and Sakino, K. (2004) Behavior of Eccentrically Loaded Concrete-Filled Steel Tubular Columns, Journal of Structural Engineering, ASCE, Vol.130, No.2, pp.203-212. https://doi.org/10.1061/(ASCE)0733-9445(2004)130:2(203)
  17. Mander, J.B., Priestley, M., and Park, R. (1988) Theoretical Stress Strain model for concrete, Journal of Structural Engineering, ASCE, Vol.114, No.8, pp.1804-1826. https://doi.org/10.1061/(ASCE)0733-9445(1988)114:8(1804)
  18. Sakino, K. and Sun, Y. (1994) Stress-Strain Curve of Concrete Confined by Rectilinear Hoop, the Architectural Institute of Japan, No.461, pp.95-104.
  19. Tomii, M. and Sakino, K. (1979) Elasto-Plastic Behavior of Concrete Filled Square Steel Tubular Beam-Coumns, Transactions of the Architectural Institute of Japan, No.280, pp.111-120.
  20. Uy, B. (2001) Strength of Short Concrete Filled High Strength Steel Box Columns, Journal of Constructional Steel Research, ELSEVIER, Vol.57, No.2, pp. 113-134. https://doi.org/10.1016/S0143-974X(00)00014-6
  21. 서성연, 정진안(2002) 고강도콘크리트충전 각형강관장주의 내력에 관한 실험적 연구, 한국강구조학회논문집, 한국강구조학회, 제14권, 제4호, pp.471-479. Seo, S.Y. and Chung, J.A. (2002) An Experimental Study on Strength of Slender Square Tube Columns Filled with High Strength Concrete, Journal of Korean Society of Steel Structures, KSSC, Vol.14, No.4, pp.471-479 (in Korean).
  22. 서성연, Tsuda, K., and Nakamura, A. (2002) 2축휨을 받는 고강도콘크리트충전 각형강관기둥의 내력에 관한 연구, 한국강구조학회논문집, 한국강구조학회, 제14권, 제5호, pp.567-576. Seo, S.Y., Tsuda, K., and Nakamura, A. (2002) A Study on Strength of Steel Square Tubular Columns Filled with High Strength Concrete Under Biaxial Eccentric Load, Journal of Korean Society of Steel Structures, KSSC, Vol.14, No.5, pp.567-576 (in Korean).
  23. Kim, C., Park, H., Chung, K., and Choi, I. (2014) Eccentric Axial Load Capacity of High-Strength Steel-Concrete Composite Columns of Various Sectional Shapes, Journal of Structural Engineering, ASCE, Vol.140, No.4, 04013091. https://doi.org/10.1061/(ASCE)ST.1943-541X.0000879

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