Struts and Ties Realization in Reinforced Concrete Ring Deep Beams

This study aims to shed light on the inclined direct stress paths of curved struts in deep ring beams by converting them into real members. Five specimens were tested with three loading and three supporting points. Three specimens were conventional rings and two were in the form of a frame that took its cross-sectional dimensions from the strut-and-tie model (STM) in ACI 318-19. The effect of reinforcing struts was studied by reinforcing the rings with both proposed and conventional reinforcements, and the frames with the proposed reinforcement only. The findings show that the proposed reinforcement reduced weight and cost by approximately 18% and 13%, respectively, and provided openings for services by approximately 24%. Additionally, strut curvature was found to reduce load capacity by 3 to 6%, meaning that the STM is safe and can be used efficiently in this type of deep curved member.