Basic Characteristics and Fatigue Properties of Lead Damper for Seismic Isolation System

Abstract eng:
In order to protect people, buildings and other important facilities from damage caused by earthquakes, seismic isolation systems have been developed. In Japan, many buildings are protected using seismic isolation with supplemental damping, including U-shaped lead dampers. Lead is used as the energy dissipation component of these dampers, because pure lead has the characteristics of low yield stress and very high ductility with minimal strain hardening. The hysteretic behavior of this damper is elasto-plastic, and this allows it to provide high levels of damping performance. However, the formation of fatigue cracks on the surface of the lead caused by small oscillations due to wind or traffic vibration, affects the damping properties of the damper. Although it is known that the fatigue properties of lead can be improved by a vaseline-coating or a greasecoating on the specimen surface, the effect of the coating is not well understood qualitatively and quantitatively. To clarify this effect, we carried out two types of tests: (1) very small deformation cyclic tests under similar actual conditions using a full-size, U-shaped lead damper, and (2) rotating-bending fatigue tests on pure lead round bars. Based on the results of these tests, a grease-coating is identified as an effective method of fatigue life enhancement.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket