Design and Experimental Assessment of a Prestressed Lead Damper with Straight Shaft for Seismic Protection of Structures

This study introduces a new energy dissipation device with a high damping capacity for the seismic protection of buildings. The device exploits the friction losses between a movable shaft and a lead core to dissipate the seismic energy and takes advantage of the prestressing of the lead material to control the friction force. Numerical analyses are introduced to evaluate the influence of prestressing on the axial force of the device. Cyclic tests performed on a prototype demonstrate the high damping capability, with an equivalent damping ratio ξeff of approximately 55%, a robust and stable response over repeated cycles and a low sensitivity of the mechanical properties to the frequency, suggesting that the proposed device may be a potentially effective solution for providing supplementary energy dissipation to structures in seismic areas. Moreover, the device is able to endure multiple cycles of motion at the basic design earthquake displacement, ensuring maintenance-free operation even in presence of repeated ground shakes.