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Over the period 1986 to 1991, seven different passive energy dissipation systems were studied in experimental research programs at the Earthquake Engineering Research Center of the University of California at Berkeley. This paper presents an overview of these studies, describing the different types of devices, the results of the shake table experiments, and associated analytical work. Four of the systems studied are friction systems, and of these, three (Sumitomo, Pall, and Friction-Slip) are based on Coulomb friction. The fourth is the FluorDaniel Energy Dissipating Restraint, which is a device capable of providing selfcentering friction resistance that is proportional to displacement. The three other systems all have different energy dissipation mechanisms: ADAS elements, which utilize the yielding of mild-steel X-plates; viscoelastic shear dampers using a 3M acrylic copolymer as the dissipative element; and Nickel-Titanium alloy shapememory devices that take advantage of reversible, stress-induced phase changes in the alloy to dissipate energy. The effectiveness of the various systems is evaluated by comparing the response of the test structures without and with the energy dissipators. In some cases, where devices were studied using the same test structure, they are compared directly. All of the systems investigated exhibited characteristics beneficial to improved structural response to earthquake loading.

This paper describes the mechanical operation and presents parametric studies for the Energy Dissipating Restraint (EDR). The EDR is a strongly self-centering passive friction-based seismic energy dissipator with a wide range of hysteretic behaviors. In the behaviors of most interest in seismic design, the slip load is proportional to displacement. Typically the EDR would be installed in a building as part of the bracing system which resists seismically induced lateral forces.

Passive energy dissipation devices have the potential to increase the seismic resistance of a structure by increasing its capability to dissipate energy and by reducing the seismic demand on the structure. They offer particular promise for seismic retrofitting as well as extensive applications in new construction. This paper describes and compares earthquake simulator tests of four new types of passive energy dissipators that were performed at the Earthquake Engineering Research Center of the University of California at Berkeley. The four types of energy dissipator are a Coulomb friction damper; a self-centering friction device in which the slip load is proportional to the slip displacement; a viscoelastic shear damper; and a shape memory alloy. Two different model structures were used in the experimental studies, and the energy dissipators were incorporated as part of the bracing systems of the structures.

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