Non-Linear Behavior of Multi-Story Walls using Unbonded Post-Tensioned Concrete Coupling Beams

Abstract

This paper presents an analytical investigation of the behavior of concrete shear walls coupled together using unbonded post-tensioned precast concrete coupling beams under monotonic and reversed-cyclic lateral loading. At the beam-to-wall interface, steel top and seat angles are utilized to yield and dissipate energy during an earthquake. As the structure is laterally displaced, the non-linear deformations occur primarily as a result of the opening of gaps at the beam-to-wall interfaces. This system offers many advantages over monolithic cast-in-place beams such as reduced reinforcement detailing, the ability to undergo large nonlinear rotations without a significant amount of damage, and self-centering capabilities. A parametric investigation is presented to establish the effects that different structural design parameters have on the lateral strength and deformation capacities and demand. Additionally, the stiffness, strength, and ductility characteristics along with the energy dissipation and self-centering capabilities of the system under reversed cyclic loading are investigated.