Hysteretic Dampers for Wood Frame Shear Walls

Available hysteretic dampers can offer large and stable energy dissipation, but are not suitable for wood frame shear wall construction. A new type of hysteretic damper, called a kinematically expanding hysteretic damper (KE-HD), can dissipate significant energy through controlled tension-only yielding of the device. The damper employs a special anchorage that permits the yielding-element to slide on compression cycles without buckling and then load in tension at any arbitrary displacement amplitude. This feature has the apparent effect of expanding the kinematic surface of the element. The device has been installed in a wood frame shear wall and results shown significant improvement in response with no pinching, stiffness, or strength degradation. Eventual failure of the yielding elements occurs through fracture of the gross section at large elongations. Time-history analysis of single-degree-of-freedom structures with KE-HDs indicates the dampers can provide significant response reduction.