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Determination of strut efficiency factor for concrete deep beams with and without fibre

  • Sandeep, M.S. ;
  • Nagarajan, Praveen ;
  • Shashikala, A.P. ;
  • Habeeb, Shehin A.
  • Received : 2016.01.10
  • Accepted : 2016.06.28
  • Published : 2016.07.25

Abstract

Based on the variation of strain along the cross section, any region in a structural member can be classified into two regions namely, Bernoulli's region (B-region) and Disturbed region (D-region). Since the variation of strain along the cross section for a B-region is linear, well-developed theories are available for their analysis and design. On the other hand, the design of D-region is carried out based on thumb rules and past experience due to the presence of nonlinear strain distribution. Strut-and-Tie method is a novel approach that can be used for the analysis and design of both B-region as well as D-region with equal importance. The strut efficiency factor (${\beta}_s$) is needed for the design and analysis of concrete members using Strut and Tie method. In this paper, equations for finding ${\beta}_s$ for bottle shaped struts in concrete deep beams (a D-region) with and without steel fibres are developed. The effects of transverse reinforcement on ${\beta}_s$ are also considered. Numerical studies using commercially available finite element software along with limited amount of experimental studies were used to find ${\beta}_s$.

Keywords

strut;efficiency factor;strut-and-tie;STM;fibre reinforced concrete;SFRC;ANSYS;nonlinear analysis of concrete;nonlinear finite element analysis of reinforced concrete

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