Testing and behavior of a coupled shear wall structure with partially post-tensioned coupling beams

A 40%-scale coupled core wall structure with C-shaped wall piers and novel unbonded post-tensioned (PT) coupling beams was tested under quasi-static reversed-cyclic lateral loads combined with tributary gravity loads. This paper describes the design, analysis, and testing of this specimen, which included the bottom three stories, the tributary floor slabs, and a large portion of the foundation from an eight-story prototype structure. The upper five stories of the prototype structure were simulated analytically to impose forces and moments at the top of the test specimen. In addition to conventional sensors, the specimen was monitored using 14 digital image correlation (DIC) sensors, providing near-full-field response data of the most critical regions. Overall, the structure performed as predicted, validating the design approach. Strength loss at the end of the test was largely caused by the fracture of the vertical reinforcing bars in the wall pier toes at the base. The coupling beams performed well, demonstrating the advantages of the new PT system.