Seismic Precast Concrete Shear Walls with Short-Grouted Ductile Reinforcing Bar Connections

This article presents results from the experimental testing of three precast concrete shear wall specimens that used nonproprietary, short-grouted corrugated steel straight duct connections for ductile energy-dissipating rein¬forcing bars crossing horizontal joints. In this type of connection, the energy-dissipation bars are terminated inside the connectors, and the bar forces are transferred into the precast concrete components through the design of vertical, transverse, and longitudinal tie reinforcing bars around the connectors. The performance of the specimens was evaluated against the seismic acceptance criteria for special precast concrete shear walls in the American Concrete Institute’s Acceptance Criteria for Special Unbonded Post-Tensioned Precast Structural Walls Based on Validation Testing and Commentary (ACI 550.6-19). All three specimens outperformed a previously tested precast concrete wall with Type II grouted mechanical reinforcing bar splices in terms of drift capacity and energy dissipation. However, only one wall (specimen 3) satisfied the maximum lateral strength loss limit (20%) at the validation-level drift specified by ACI 550.6-19. Important connector design and detailing recommendations are made based on the performance differences among the specimens. These details include the bonded and intentionally unbonded lengths of the energy-dissipation bars inside the connectors, as well as design of the vertical, transverse, and longitudinal tie reinforcement around the connectors. The results demon¬strate that nonproprietary short-grouted connectors using materials readily available in the construction industry can achieve ductile behavior of special precast concrete shear walls for use in high-seismic regions.