Seismic Design and Performance of Composite Coupling Beam-to-SpeedCore Wall Connections

Abstract

Coupled composite plate shear walls—concrete filled (CC-PSW/CFs) are an effective seismic lateral-force-resisting system for the design and construction of mid- to high-rise buildings around the world. The coupled system consists of two or more composite plate shear walls—concrete filled (C-PSW/CFs) connected to each other using composite coupling beams located at the story heights. The CC-PSW/CF system can provide higher overturning moment capacity, lateral stiffness, and ductility than uncoupled walls. Concrete-filled steel box sections are typically used for the composite coupling beams, which are designed to be flexure critical members. When the CC-PSW/CF system is subjected to lateral seismic forces, plastic hinge formation and inelastic deformations (energy dissipation) occur near the ends of most of coupling beams along the structure’s height, followed by flexural hinging of the C-PSW/CFs, typically at the base. This paper presents the details and design of four composite coupling beam-to-C-PSW/CF connection configurations. Six connection specimens representing the four connection configurations, with beam clear span-to-section depth, Lb/d, ratios of 3.5 and 5.1, were designed and tested. The lateral force-displacement and moment-rotation responses of the specimens are summarized. All six composite coupling beam-to-C-PSW/CF wall connection specimens (1) developed and exceeded the plastic flexural capacities, Mp, of the coupling beams calculated using the plastic stress distribution method and (2) developed chord rotation capacities greater than 0.03 radian before their flexural strength degraded to 80% of the plastic moment capacity, Mp.