Effect of Damper Sub-System Stiffness on the Response of a Single Degree of Freedom System Equipped with a Viscous Damper

Elastic flexibility of a viscous damper sub-system can alter the phasing of damper and structural forces. This paper investigates how damper sub-system flexibility affects overall seismic response, using linear and nonlinear dampers. A suite of analyses with damped single degree-of-freedom systems show that a damper with significant flexibility can experience median peak displacements 40% higher than those of the same damper with rigid supports, depending on the added damping, damper sub-system stiffness, and period. To limit the impact of phasing effects, the damper sub-system stiffness should be 5-10 times the stiffness of the main lateral load resisting system.