Design Comparison by Node Width Variation of Strut-Tie-Model

스트럿-타이 모델의 절점 폭 변화에 따른 설계 비교

  • Uy, Lymei (Dept. of Civil, Environmental & Architectural Engineering, Korea University) ;
  • Son, Byung-Jik (Dept. of Civil and Environmental Engineering, Konyang University)
  • Received : 2014.02.24
  • Accepted : 2014.10.10
  • Published : 2014.10.31


In the Strut-Tie-Model(STM), the width of a node is important in both analysis and design. Its effects on the force distribution at truss analogy system. In addition, it effects the verification of all struts and nodes, which need to be checked to satisfy the code of design. Code here refers to the ACI-318 code. Four methods were used to define the width of node: 1) effective depth is assumed to equal to 0.9 of the overall depth of beam, 2) moment equilibrium 3) assumption of the width of node at the bottom equal to 380mm, and 4) the new proposed method by this study. 106 selected samples of a parametric study obtained from the four methods were analyzed. Because total steel requirement from these four methods are similar, the easiest would be a good choice for a time saving calculation.


ACI;deep beam;node width;STM


  1. ACI Committee 318, 1999, "Building Code Requirements for Structural Concrete (ACI 318M-99) and Commentary (318RM-99)", American Concrete Institute, Farmington Hills, pp.163-164, 1999
  2. ACI Committee 318, 2011, "Building Code Requirements for Structural Concrete (ACI 318M-11) and Commentary (318RM-11)", American Concrete Institute, Farmington Hills, pp. 387-401, 2011
  3. James K. Wight and James G. MacGregor, "Reinforced Concrete Mechanics and Design", Pearson, Six Edition, pp. 879-971, 2012.
  4. James K. Wight and Gustavo J. Parra-Montesinos, "Strut-and-Tie Model for Deep Beam Design", Concrete International
  5. Karl-Heinz Reineck and Lawrence C. Novak, "Further Examples for the Design of Structural Concrete with Strut-and-Tie Models", 2011
  6. Schlaich, J. Schafer, K. and Jennewein, M., "Toward a Consistent Design of Structural Concrete," PCI Journal, V.32, No. 3, 1987. DOI:
  7. Uy Lymei and Byung-Jik Son, "Design Comparison of Strut Tie Model and ACI Traditional by Clear Span-to-Depth Ratio", Journal of the Korea Academia-Industrial Cooperation Society, Vol. 15, No. 4, pp. 2406-2413, 2014 DOI: