Hysteretic dampers for earthquake‐resistant structures

Abstract The earthquake resistance of many structures can be increased by the inclusion of special components which act as hysteretic dampers. During moderately severe earthquakes these dampers act as stiff members which reduce structural deformations, while during very severe earthquakes the dampers act as energy absorbers which limit the quasi‐resonant build‐up of structural deformations and forces. The hysteretic dampers are not required to withstand the main structural loads, and may therefore be optimized for their required stiffness and energy‐absorbing features. On the other hand, the main structural components no longer require large energy‐absorbing capacities and they may therefore be optimized for their required stiffnesses and load‐bearing features. For many structures this separation of component functions should lead to increased reliability at a lower initial cost. Under earthquake attack structural damage should be reduced. Non‐structural damage should be lower during moderately severe earthquakes, and for certain types of structure it should also be lower for very severe earthquakes. Various ways in which hysteretic dampers may be utilized in structures are discussed briefly. The development of several types of high‐capacity, low‐cost hysteretic damper, suitable for use in structures, is described. The dampers utilize solid steel beams deformed plastically in various combinations of torsional, flexural and shear deformations.