Shear response of reinforced concrete deep beams with and without web opening

Reinforced concrete deep beam (RCDB) analysis is frequently complex, and the presence of openings alters the behavior and may result in early cracking even at service load. It is thus critical to provide a method for reducing the effect of the disturbance offered by this opening to improve the performance of the beam. An experimental investigation has been conducted to examine the response of RCDB with and without web opening subjected to increasing three-point monotonic loading, a modified STM approach recommended by ACI 318R-19 was used to detail the shear reinforcement around the web opening after investigating the weakness of beam without shear reinforcement. Eight RCDBs with dimensions of 2000 x 200 x 600 mm loaded at shear span-to-depth ratio of 1.04 were considered. Three of the beams have solid sections, while the rest have a web opening in the center and a web opening close to the shear supports. The shear reinforcement increased beam capacity and ductility by more than 70% and 300%, respectively, over beams without shear reinforcement. Applicability of a three-dimensional FEM was also investigated under multi-fixed crack approach by considering stiffening/softening of RC elements. The damage response of the test beams agreed with the analysis, with shear damage being the dominant failure. However, concrete softening factor needs improvement for RCDB having sudden change in geometry.