Torsional balance of plan-asymmetric structures with frictional dampers: analytical results

Abstract

SUMMARYThis investigation deals with the torsional balance of the earthquake response and design of elastic asymmetric structures with frictional dampers. Plan asymmetry leads to an uneven lateral deformation demand among structural members and to unbalanced designs with larger capacities in some resisting planes. Frictional dampers are capable of controlling lateral-torsional coupling by placing the so-called empirical center of balance (ECB) of the structure at equal distance from all edges of the building. This rule is developed for single-story systems with linear and inelastic behavior. However, recently obtained theoretical and experimental results demonstrate that this rule carries over to multistory structures. Results show that the peak displacement demand at the building edges and that of resisting planes equidistant from the geometric center may be similar if the damper is optimally placed. It is also shown that torsional ampliÿcation of the edge displacements of arbitrary asymmetric structures relative to the displacement of the symmetric counterparts are approximately bound by a factor of 2. Furthermore, frictional dampers are equally e ective in controlling lateral-torsional coupling of torsionally exible as well as sti structures.

Evaluation of the Reduction of Seismic Response of Adjacent Structures Using Viscous Damper Joint

“…This means that the damping forces had no effect on seismic forces leading to increased structural deformation. Addition of a damper fluid class structure reduces horizontal acceleration and lateral deformation of up to 50% and sometimes more [5].…”

“…Thus, when the piston of the damper fluid pressure increases, it is able to generate larger dampening forces. Therefore, a significant amount of energy cannot dissipate from the earthquake [5].…”

A review of research on seismic behaviour of irregular building structures since 2002

“…De la Llera et al (2005) considered frictional dampers more effective than other type of devices for passive control in asymmetric systems, as they enable dissociating stiffness and strength. They proposed an optimizing procedure, within the framework of the torsional balance concepts.…”

Torsional Balance of Two-Way Asymmetric Plans With Optimal Distribution of Viscous Dampers

“…Even though, this is not meant to zero rotation of asymmetric structure, but due to the existence of equal expected maximum displacement of two edges of structure, it shows the optimized mode of performance of resistant elements [6].…”