Inelastic seismic shear amplification due to higher mode effects in reinforced concrete coupled walls

Recent numerical and experimental studies on reinforced concrete shear walls and coupled walls have shown shear forces greater than expected when the walls are subjected to earthquakes at an intensity level that does not exceed the design values. This amplification of shear forces is attributable to the effects of higher modes after the walls develop a plastic hinge at the base. These effects have been recently recognized in North American design codes for cantilever walls and is currently neglected in the design of ductile coupled walls. As part of the research program described in this article, a parametric study was carried out on coupled wall systems to identify the geometric and physical parameters having the greatest influence on the seismic shear amplification. Using the results of this parametric study, an extensive numerical study was conducted on classes of ductile coupled walls subjected to seismic excitation representative of Western and Eastern Canada. This extensive study led to the establishment of shear amplification prediction equations for use in building codes.

A Review on Seismic Behaviour of Coupled Wall Structures

Increase in population density and shortage of land are the two major problems in all developing countries including India. To mitigate these problems, the designers resort to high rise building. One of the most important criteria for designing a structural system is its resistance to lateral loads. Coupled walls structures is considered to be one of the potential option for resisting lateral loads in high-rise structure and have widely been used around the world in multi-story buildings. Coupled walls, mainly consist of pier walls which are connected by coupling beams at each floor level. These systems are typically located in the service core and sometimes on the perimeter of the buildings. The main benefit of coupled wall over cantilever walls are, a part of the total overturning moment is resisted by coupling action and there is energy dissipation along the height of the structure through the formation of plastic hinges at both ends of the coupling beams. The present work reviews different factors influencing the seismic performance of coupled wall structural system, importance of coupling ratio, different modeling techniques, a comparative study on different coupled wall systems and a brief overview of design methodologies. Considering structural performance, energy absorption capacity and higher shear stiffness to limit lateral deformation, coupled wall structures were considered to be efficient and economical structural system in high-rise building.