Effect of Stirrup Anchorage on Shear Strength of Reinforced Concrete Beams

The performance of improperly constructed beams is of particular concern in the repair of concrete structures. Not only is there uncertainty about the actual as-built strength and what measures may improve capacity, but also the presence of improper structural details may lead to litigation concerning what structural repairs are really necessary to restore perceived loss of strength. For the specific case of shear, there is value in knowing a reasonable and safe approximation of the shear capacity of improperly detailed beams. To study the effect of improperly anchored stirrups on the shear strength of reinforced concrete beams, four 13 x 24 in. (330 x 610 mm) reinforced concrete sections were fabricated with varying proper and improper shear reinforcement details and loaded to failure. Current ACI 318 and AASHTO LRFD code provisions were used to compare the resulting failure loads from tests with calculated nominal capacities. The experimental results suggest that reinforcement anchorage, as tested, has no significant effect on the shear capacity of a reinforced concrete section.