International Science Index


Behavioral Study of Reinforced Concrete Beams Designed for Shear Using Compressive Force Path and ACI Code Models

Abstract:Compressive Force Path (CFP) concept is a proposed shear design method to explain shear behavior in reinforced concrete (RC) beams. This concept identifies 04 behaviors based on the shear span to beam depth (a/d) ratio and provides detailed shear design and transverse reinforcement detailing procedure for each behavior. Therefore, author of this paper intended to use this concept as a practical tool for the designing of RC beams particularly for Type II (2 ≤ a/d < 5) and Type III (1 < a/d < 2) behaviors to validate the concept. Total 08 beams of 100×200×1800 mm size beams were cast; out of which, 04 beams were designed according to ACI Code approach while, rest were designed and detailed using CFP concept strategy. The beam sizes in this study are identical, and all parameters are constant except shear span ‘a’. The two-point loading test results of RC beams showed that the shear resistance of concrete (Vc) is better estimated by the CFP concept with a good prediction of cracks pattern, load carrying capacity and actual behavior of the beams in shear as compare to the beams designed according to ACI Code approach. However, most of the beams, particularly a/d ratio less than 4.44 were observed to be deficient in serviceability and failed in shear in spite of attaining theoretical predicted loads.
[1] ACI 318M-08, “Building code requirements for structural concrete (ACI 318M-08) and commentary,” American Concrete Institute, USA, 2008.
[2] M. D. Brown, O. Bayrak, and J. O. Jirsa, “Design for shear based on loading conditions,” ACI Structural Journal, 103(4), 2006, pp. 541–550.
[3] M. P. Collins, E. C. Bentz and E. G. Sherwood, “Where is shear reinforcement required? Review of research results and design procedure,” ACI Structural Journal, 105 (5), 2008, pp. 590–600.
[4] M. D. Kotsovos, “Compressive force path concept: a suitable basis for reinforced concrete ultimate limit state design,” ACI Structural Journal, 85(1), 1988, pp. 68–75.G. N. J. Kani, “The riddle of shear failure and its solution,” ACI Journal Proceeding, 61(4), 1964, pp. 441–467.
[5] M. D. Kotsovos and M. N. Pavlovic, “Ultimate limit-state design of concrete structures: a new approach,” Thomas Telford, London, 1999.
[6] G. N. J. Kani, “The riddle of shear failure and its solution,” ACI Journal Proceeding, 61(4), 1964, pp. 441-467.
[7] S. F. A. Rafeeqi and T. Ayub, “Behaviour of reinforced concrete beams detailed for shear in compliance with compressive force path method,” NED University Journal of Research, 10(1), 2013, pp. 13–30.