Shear Strength Prediction of Palm Kernel Shell RC Deep Beams without Shear Reinforcement

Abstract

Reinforced concrete deep beams transfer heavy gravity loads predominantly through shearing action to their supports mainly through arch-action. Design of deep beams therefore does not follow the conventional sectional method. The strut and tie model (STM) approach, which was introduced recently, has proved to be a useful tool for the design of reinforced concrete deep beams. Palm kernel shell concrete (PKSC), a lightweight concrete produced from palm kernel shell, an agricultural waste obtained from palm kernel oil processing, is gaining popularity due to its numerous advantages as a lightweight construction material. Several studies have been carried out on reinforced PKSC slender beams. However, the suitability of PKSC for the design of deep beams is yet to be assessed. This paper studied the behavior of PKSC deep beams without shear reinforcement and assessed the performance of the STM approach on shear strength prediction. Three deep beam samples without shear reinforcement of 150 mm width and 350 mm depth, having shear span-to-effective depth ratios of 1.0, 1.5 and 2.0, were prepared and tested under three-point monotonic loading. Similar beams were tested for NWC for comparison, and the shear strength was evaluated using the STM provisions proposed by three standard codes. The results were compared with the experimental values to validate the design of PKSC deep beams without shear reinforcement using the STM approach. The ACI318 (2008) STM provisions produced the least average margin of safety and covariance and hence, was confirmed to be the most appropriate design approach for the design of reinforced PKSC deep beams without shear reinforcement.