Design of coupled wall structures as evolving structural systems

Abstract

Coupled wall (CW) structures are outstanding lateral load resisting systems that not only reduce the deformation demands on the building, but also distribute inelastic deformation both vertically and in plan, between the coupling beams and the wall piers. When subjected to large seismic loads, coupling beams may deteriorate relatively quickly exhibiting both strength and stiffness degradation. This results in a rapid evolution in the performance of the CW system from behaving as a coupled wall system to behaving as a system of linked wall piers (LWP). This evolution of behavior is the focus of this work which considers a prototype 12-storey reinforced concrete coupled core wall (CCW) building. Five prototype variations, having the same wall pier pairs but degrading degrees of coupling were designed to study the effects of decayed coupling action. Elastic analyses using the equivalent lateral force (ELF) procedure and the continuous medium method (CMM) were used to establish initial proportions for the CCW prototype, and to determine the design forces and moments. Nonlinear static and dynamic analyses were conducted to investigate the CCW structural behavior, adequacy of the design, and the effect of the evolution of the structural form from a CCW system to a collection of LWPs. As expected, the structures having weaker coupling beams exhibited yield at lower lateral loads. The accompanying reduction in coupling stiffness, however, mitigated this effect although the wall pier demand clearly rose with reduced coupling. In every case, however, the walls embodied sufficient overstrength to permit the overall structure to perform well. An additional aspect of this work is that the wall piers in the CCW were significantly different in terms of their dynamic and geometric properties: the moments of inertia of the two wall piers of the CCW differed by almost an order of magnitude. The different wall pier capacities affected performance and require bi-directional pushover analyses but did not result in a significant reduction in capacity as may be initially intuited.

Optimized design procedure for coupling panels in steel plate shear walls

“…In a perfectly coupled system, axial forces are induced in the adjacent piers and the resultant moment of the piers axial forces resists against the overturning moment. However, in linked piers, each pier works individually and significant reaction forces are induced in the columns(Eljadei and Harries, ). Thus, the actual force of the VBEs found in coupled frames is somewhere between the axial force of fully coupled piers and completely separate piers.…”

“…The main goal of introducing coupled piers is to reduce the inelastic peak and residual deformations among building components. Furthermore, the coupled walls can distribute the inelastic deformation, both vertically and horizontally, between the coupling members and the wall piers (Eljadei and Harries, ). They can also be useful in respect to architectural limits when mandatory passage ways or openings need to be put into the walls (Sabelli, ).…”

A Performance-Based Design Method for Coupled Wall Structures

“…It has also been employed as a key parameter in the design of coupled wall systems [Eljadei and Harries, 2014;Hung and Lu, 2015]. For example, in order to facilitate the preferred seismic performance, it is suggested that the suitable design values of CR be between 30% and 45% for short coupled walls and between 45% and 60% for tall ones [Hung and Lu, 2015].…”

“…The CR is widely recognized as a critical factor affecting the seismic performance of a coupled wall system [Eljadei and Harries, 2014;El-Tawil et al, 2010;Chaallal et al, 1996;Hassan and El-Tawil, 2004;Harries et al, 2004]. It has also been employed as a key parameter in the design of coupled wall systems [Eljadei and Harries, 2014;Hung and Lu, 2015].…”

Experimental comparative study of coupled shear wall systems with steel and reinforced concrete link beams

“…Coupled shear walls with SLBs usually called hybrid‐coupled shear walls. Rational design recommendations on hybrid‐coupled shear wall structures were presented in various literatures . More specifically, SLBs were suggested to be designed with smaller yield drift to dissipate energy and sacrifice themselves to protect the whole structure from severe seismic damage or even collapse…”