This paper presents the measured behavior from the testing of a 0.4-scale "hybrid" precast concrete wall specimen under reversedcyclic lateral loading and provides an assessment of the seismic design and analysis of the wall by using the experimental results. The hybrid precast wall system investigated in the paper utilizes a combination of mild (i.e., Grade 400) steel and high-strength unbonded posttensioning (PT) steel for lateral resistance across horizontal joints. A seismic design procedure that conforms to ACI 318 and ACI ITG-5.2 was used for the design of the test specimen based on ACI ITG-5.1. The behavior of the specimen was measured with conventional data acquisition techniques and also full-field digital image correlation of the base panel and the critical joint between the base panel and the foundation, providing unprecedented information on the wall performance. The paper compares these measurements with the design and analytical predictions, focusing specifically on the applied lateral load and displacement, energy dissipation, behavior of the steel reinforcement, and behavior along the horizontal joints. The test specimen was not able to reach the expected ultimate drift level owing to a combination of poor unconfined concrete strength and poor placement of the confinement reinforcement at the toes. However, the performance of the wall up to the failure point was consistent with the predicted behavior based on both the design procedure and the analytical models.

This paper discusses the lateral load behavior of two, 0.40-scale, hybrid, precast concrete shear wall test specimens and the behavior of a third precast specimen designed to emulate monolithic cast-in-place RC shear walls. The walls had identical overall geometry and were constructed by placing rectangular precast panels across horizontal joints. The hybrid walls used mild steel bars [Grade 400 (U.S. Grade 60)] and high-strength unbonded posttensioning (PT) strands for lateral resistance, whereas the emulative wall used only mild steel bars. The mild steel bars crossing the base joint were designed to yield and provide energy dissipation, with the PT steel in the hybrid walls reducing the residual displacements of the structure. The mild steel bars at the base of the emulative wall and one of the hybrid walls used Type II mechanical splices, while the other hybrid wall used continuous bars grouted into the foundation. Because of the lack of PT steel, the emulative wall developed a large residual uplift at the base joint, resulting in excessive horizontal slip and strength degradation. The behavior of the hybrid wall with Type II splices was also limited, which occurred because of the pullout of the mild steel bars. In contrast, the hybrid wall with continuous mild steel bars showed superior restoring, energy dissipation, and ductile behavior over larger lateral displacements. The results show the potential for the use of precast walls in seismic regions, while also revealing important detailing considerations.

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