Development of Models for Predicting Strut Efficiency Factors for Conventional and Steel Fibre Reinforced Concrete Deep Beams

Abstract:

Commonly used analysis and design methods are applicable only to Bernoulli’s region or B-region where strain distribution is linear. Due to the peculiarity of the geometry for certain structural members like deep beams, corbels, etc, their entire strain distribution is nonlinear. Hence, they will act as discontinuous regions or D-regions where strain distribution is nonlinear. The designers are forced to depend on empirical relations and their past experience for designing such elements. Since, deep beams form an important structural element in bridges and high-rise buildings as pier caps and transfer girders, their design deserves much more importance. Strut-and-Tie method (STM) is a unified approach that can be used for both regions. The main parameter that influence the accuracy of results produced by STM is the strength reduction factor (β_s). In this paper, new relations are developed for predicting strength reduction factor for concrete struts with and without steel fibres. The effect of steel fibres content and percentage of vertical and horizontal reinforcement were considered for developing this relation.

• Periodical: Materials Science Forum (Volume 969)
• Pages: 187-192
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.969.187
• Online since: August 2019
• Authors: M.S. Sandeep*, Praveen Nagarajan, A.P. Shashikala
• Keywords: Deep Beams, Steel Fibre Reinforced Concrete, Strut Efficiency Factor, Strut-and-Tie Method

References

[1] S.J. Foster, A.R. Malik, Evaluation of efficiency factor models used in strut-and-tie modeling of nonflexural members, Journal of Structural Engineering. 128.5 (2002) 569-77.

DOI: 10.1061/(asce)0733-9445(2002)128:5(569)

[2] C.G. Quintero-Febres, G. Parra-Montesinos, J.K. Wight, Strength of struts in deep concrete members designed using strut-and-tie method. ACI Structural Journal. 103.4 (2006) 577.

DOI: 10.14359/16434

[3] M.D. Brown, C.L. Sankovich, O. Bayrak, J.O. Jirsa, Behavior and efficiency of bottle-shaped struts. ACI Materials Journal. 103.3 (2006) 348.

[4] D.K. Sahoo, B. Singh, P. Bhargava, An appraisal of the ACI strut efficiency factors. Magazine of Concrete Research. 61.6 (2009) 445-56.

DOI: 10.1680/macr.2008.00112

[5] D.K. Sahoo, B. Singh, P. Bhargava, Strut efficiency factors for structural concrete made from coarse recycled concrete aggregates. Journal of Structural Engineering. 37.1 (2010) 49-54.

[6] D. Dupont, L. Vandewalle, Shear capacity of concrete beams containing longitudinal reinforcement and steel fibers. Special Publication. 216 (2003) 79-94.

DOI: 10.14359/12893

[7] M.S. Sandeep, P. Nagarajan, A.P Shashikala, S.A Habeeb, Determination of strut efficiency factor for concrete deep beams with and without fibre. Advances in Computational Design. 1.3 (2016) 253-64.

DOI: 10.12989/acd.2016.1.3.253