Strain rate effect on development length of steel reinforcement

Accidental or premeditated explosions have detrimental effects on infrastructure in the vicinity of the centre of explosion and pose major threats to human life. Thus, a lot of research is currently underway to study the effects of explosions on infrastructure systems with an ultimate goal of minimizing infrastructure damage and saving lives. Since reinforced concrete is the most common building material used in blast resistant infrastructure design and construction, understanding the effect of blast loads on reinforced concrete components is vital. The design philosophy of critical infrastructure systems is energy dissipation through reinforcement yielding (ductility). Thus it is essential to preclude non-ductile failure modes such as shear and bond failures in infrastructure systems. This paper presents an experimental program to investigate the strain rate effects on steel reinforcement-concrete bond. Reinforced concrete beams were tested under static and shock tube testing to investigate the high strain rate effect on development length. The bond stress was determined to increase with an increased strain rate and that the development length calculated in accordance with CSA A23.3 is adequate to resist the dynamic yield strength of steel reinforcement. The dynamic increase factor for bond stress was determined to be 1.71.