Cyclic behavior of shear-type hysteretic dampers with different cross-sectional shapes

Abstract

Metallic shear-type dampers are widely used as seismic-energy-absorbing devices because they are easy to produce, install, and maintain. This study investigated a metallic shear-type damper constructed with a circular hollow section; an H-shaped section damper, which is commonly used as a metallic shear damper, was included in the study for comparison. A structural equation for calculating the strength and initial stiffness is provided based on the plastic collapse mechanism of the two types of dampers. For both types, a cyclic loading test was conducted to investigate their mechanical characteristics as hysteretic dampers. Damper specimens with each of the two cross-sectional shapes were fabricated using low-yield-point steel and were designed to have nearly the same full plastic shear strength, initial stiffness, and weight. The experimental results confirm that both types of damper exhibit stable spindle-shaped hysteresis characteristics and have sufficient plastic deformation capacity and energy absorption capacity. Consequently, under identical loading conditions, the two types of damper have nearly the same strength increase ratio and deformation capacity. The local plastic strain was evaluated using a finite element analysis of monotonic loading; the results verify the validity of the proposed plastic collapse mechanism of the circular hollow section damper and H-shaped shear panel damper. The sharing of energy dissipation among the damper components was also analyzed.