Behavioral Study of RC Beams Designed for Shear Using CFP and ACI Code Models

¹ Department of Civil Engineering, NED University of Engineering and Technology, Karachi 75270, Pakistan
² Department of Urban and Infrastructure Engineering, NED University of Engineering and Technology, Karachi 75270, Pakistan

^* Corresponding author: tehmina@neduet.edu.pk

Abstract

Compressive Force Path concept is a proposed shear design method to explain shear behavior in reinforced concrete 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 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 compared 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.