Behaviour of concrete deep beams with high strength reinforcement

The Strut-and-Tie Method is a widely accepted design approach for reinforced concrete deep beams. However, there are differences between various design code implementations with respect to reinforcement tie influences on the capacity of adjacent concrete struts. Furthermore, each design code specifies different limits on the maximum permitted design stress for the ties. This study validates the Strut-and-Tie Modeling approach for deep beams incorporating high strength steel reinforcement.;Laboratory tests of ten large-scale deep beams were conducted, where primary test variables included the shear-span-to-depth ratio, longitudinal reinforcement ratio and strength, and presence of web reinforcement. The results showed that member capacity decreased as the shear-span-to-depth ratio increased, and as the longitudinal reinforcement ratio decreased. The inclusion of web reinforcement significantly increased the member strength and ductility. It was possible to design members to efficiently exploit the high strength reinforcing steel when applying Strut-and-Tie modeling techniques according to CSA A23.3-04, ACI 318-05 and Eurocode 2 provisions.