Nonlinear design and sizing of semi-active resetable dampers for seismic performance

Semi-active resetable devices can be used in a wide range of structures to reduce damage due to seismic loading. The specific benefits of these devices in reducing displacement, base shear, or both have been illustrated using linear and experimentally validated nonlinear device models, as well as in a range of large to full scale experiments. However, designing the specific device dimensions to obtain a specific device force-displacement capacity and response is difficult and no set design approach exists. More importantly, there is no design approach for specifying device dimensions to both meet a desired force-displacement capacity and linear or near linear device hysteresis loop shape. s research a design procedure is developed and presented by example that allows an device dimensions to be sized so that its response approximates the desired ideal linear responses and the desired force or stiffness (force-displacement) capacity. This method is validated by systematically by comparing device designs with equivalent ideal linear models to assess how well they meet design goals, using an experimentally validated nonlinear model. Methods are presented for the most common device control laws in terms of the basic device dimensions. Errors were generally less than 10%. The overall approach is seen to deliver the device dimensions for a highly linear device response that meets design specifications, and is the first generalised design approach presented for these semi-active resetable devices or any similar semi-active device.