STRUCTURAL SEISMIC DAMPER

The energy-dissipating characteristics of U-shaped mild steel strips, called U elements, are investigated by subjecting them to a rolling-bending motion (like that of a bulldozer's tracks). Cycles of such motion are applied to the U elements, obtaining information whereby viscous effects as well as fatique life are determined. Temperature rise during cyclic deformation of the U elements is recorded. A force-displacement model of the U elements is worked out to facilitate analysis of structures to be equipped with these elements. A prototype of a structural seismic damper consisting of a multiplicity of U elements is constructed and tested, and illustrations are presented regarding possible installations of such dampers in structures. A qualitative model of plastic-hinge formation in the U elements is proposed to show the difference between perfectly plastic behavior and real behavior.