A general design method for buildings with energy dissipation devices

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National Information Centre of Earthquake Engineering
A general design procedure for elastic buildings equipped with linear and non-linear energy dissipating devices is presented herein. The procedure begins with an estimation of the total amount of equivalent damping and stiffness required to achieve a predefined building performance. The method defines the modal significance of some key design performance indicators, and then focuses on the control of the modal properties by solving a singular two-parameter eigenvalue problem. Although simple, the definition of a new measure of modal significance in the classical and non-classical damping case, is also critical for faster convergence of the method. The incorporation of non-classical damping in the design algorithm appears to be critical, and expands its applicability significantly. The design output provides a target frequency shift and damping ratio for the complete structure, obtained from the so called iso-performance design curves (IPCs), which cover the whole design space spanned by these two design variables representing the supplemental stiffness and damping of the devices. Once the linear equivalent properties of the dampers are obtained, the equivalent stiffness and damping of the devices are transformed into parameters that characterize the inelastic force-deformation constitutive models of the physical dampers. The design procedure does not require any a-priori definition of a specific damper type. The design procedure was validated using 8 conventional buildings that were severely damaged during the February 27, 2010 Chile earthquake, and a rather complex free-plan building with two towers of a rhomboid-shape plan. Estimation errors between response reduction factors using linear versus inelastic modeling of the EDDs were usually less than 10% for the 9 buildings considered. The design procedure proposed is better described as a conceptual and practical framework for the design of buildings with passive EDDs. Its step-by-step nature can take advantage of future research in any of the current research topics described herein and could be easily adapted to new knowledge in the field.
Modal significance, Energy dissipation devices, Non-classical damping, Iso-performance curves, Optimal damping distribution