Effect of Prestressing Level on a Lead Damper with Straight Shaft: An Experimental Investigation

The prestressed lead damper is an energy-dissipative device with a high damping capacity and is used for seismic response control in the earthquake-resistant design of structures. The device works as a friction damper and utilizes the friction losses between lead and a moving shaft while prestressing on the lead controls the behavior. This study experimentally investigates the effect of prestressing level on the characteristics of a lead damper. After producing the lead damper with a straight shaft, different prestressing levels were applied to the lead, i.e., 0.0%, 0.5%, 1.0%, 1.5%, 2.0%, 3.0% and 4.0%. The dampers were experimentally tested by applying a three-step displacement protocol to the shaft: five cycles of 5.0 mm target displacement with a rate of 0.5 mm/s, five cycles of 10.0 mm target displacement with a rate of 1.0 mm/s, and ten cycles of 20.0 mm target displacement with a rate of 2.0 mm/s. The cyclic tests showed that the lead damper’s characteristics, e.g., damper force, initial stiffness, hysteretic behavior, and damping properties, were considerably affected by the amount of prestressing on lead. Increasing the lead prestressing levels resulted in more stable hysteretic curves. In addition, the damper force and, consequently, the damping properties were significantly improved.