Investigation of Grouted Dowel Connections for Precast Wall Construction

The grouted dowel connection has been simple, cost-effective, and widely used in precast concrete structural systems. The grouted bar length in this connection is currently designed similarly to a regular steel bar in reinforced concrete. This underestimates the connection's bond strength, thus resulting in excessive connection length. The effect of the duct's presence in this connection is examined in the present study and was found to be crucial in generating a considerable confinement effect and relatively larger bond stress than accounted for in current design codes. Full-scale pullout tests were performed, and their results were compared with relevant data in the open literature to develop a more accurate design equation for predicting the required dowel development length. The equation was found to produce results three times smaller than that determined by the ACI 318-14 code while being desirably 10% more conservative than equations proposed in previous research. Keywords: bond strength; connection; development length; duct; precast concrete.