Experimental comparisons of repairable precast concrete shear walls with a monolithic cast-in-place wall

摘要

Previous research has shown that nonemulative (jointed) precast walls with unbonded posttensioning can achieve superior seismic performance (e.g., self-centering) compared to conventional monolithic cast-in-place reinforced concrete walls. However, the progression of significant damage and failure in nonemulative precast walls is through the yielding of ductile steel reinforcing bars (referred to as energy dissipating bars) followed by the crushing of concrete at the wall toes, greatly limiting the ability to repair these walls after a major earthquake. In this paper, a nonemulative precast wall system with replaceable, external buckling restrained plates (BRPs) for energy dissipation, and steel jackets for confinement of the concrete at the wall base is investigated through reversed-cyclic lateral loading tests. Four precast wall specimens with varying cross-sectional area of the BRPs and number of horizontal joints were tested and compared against a monolithic cast-in-place reinforced concrete wall. The precast walls exhibited no significant unrepairable tensile or compressive damage with increasing lateral strength up to 4% drift, showing advantages over the cast-in-place wall and non-jacketed precast walls in previous research. With out-of-plane buckling restrained, the BRPs yielded in tension and compression, providing the precast walls with desirable energy dissipation. To highlight the reparability of the precast wall system, one of the specimens was repaired after being subjected to a complete cyclic loading history up to 4% drift. The repair was done by replacing the damaged BRPs, after which the wall was re-tested. The repaired wall restored most of its original energy dissipation, lateral stiffness, and strength, with limited cumulative damage in the wall. In general, the proposed precast wall system with buckling restrained plates is desirable for seismic regions, offering excellent reparability and seismic resilience.