Circular tube-in-tube dampers for seismic resilience of structures

Abstract

A new brace-type slit damper, called ‘Circular Tube-in-Tube Damper (C-TTD), comprises two solid steel cylinders and one circular cross-section tube equipped with slotted holes, is proposed for seismic resilience of structures. In the proposed damper, a system of bolts was used to connect up various components of the damper, allowing inspection and replacement of the damaged components without any requirement for the replacement of the entire damper. Nonlinear finite element analyses using ABAQUS were carried out to verify the experimental results and to investigate the effect of damper geometric properties on the yield load capacity of the C-TTD dampers. The seismic performance characteristics of 4-storey, 8-storey, and 15-storey steel structures equipped with C-TTD dampers were determined by nonlinear time history analyses using three different earthquake excitations. The results indicated that when the structures were equipped with C-TTD dampers, the inter storey drift decreased in the range of 8%–55%, the base shear load decreased in the range of 27%–35%, and the input energy decreased in the range of 70%–80%, depending on the number of storeys and the earthquake type, compared to the counterpart structures without the damper.