Experimental Beyond Design and Residual Performances of Viscoelastic Dampers

Experimental Beyond Design and Residual Performances of Viscoelastic Dampers

Most analytical and experimental research relevant to viscoelastic (VE) dampers installed in structures has been aimed at their design (or pre-damage) performance. In reality, under shaking conditions caused by earthquakes, the shear deformation of VE dampers may exceed or even be much larger than their nominal design range, thus leading to damage to the VE material. Under such circumstances, the structural design may no longer be conservative when the viscoelastically damped structure is a retrofit design or not a supplemental damping design. In this study, the beyond design and residual performances of full-scale VE damper specimens that have suffered damage are experimentally tested. The results indicate that VE dampers can remain relatively undamaged and maintain their design performance characteristics after being subjected to severe shear strains, that they become weaker at higher strains, but that their mechanical properties tend to approach constant values under both extreme and residual conditions. For engineering purposes, a suitable and conservative empirical post-damage model is derived by applying deduced reduction factors to the Kelvin-Voigt model. The new model produces accurate predictions of post damage behavior of dampers.