Non-linear dynamic modelling and design procedure of FV spring-dampers for base-isolation

摘要

A viable non-linear dynamic design procedure for fluid viscous spring-dampers used in base-isolation systems of building structures\udis presented herein. The procedure consists of a preliminary design phase developed for a single-degree-of-freedom idealisation\udof the structural system, and in a final verification phase. The damping coefficient values ensuring achievement of the basic performance\udlevels hypothesised in the design problem are estimated at the first stage. An explicit relationship interpolating the damping\udcoefficient demand curves traced out as functions of damper loss factor, and dynamic input frequency composition and amplitude,\udis proposed as the basic design equation to this aim. This relationship, derived from previous analytical studies, is further validated\udherein against the results of experimental forced-vibration tests conducted on a steel frame mock-up. A first demonstrative application\udof the procedure is then carried out on a simple building with very stiff superstructure. Doubled calibration of the damping coefficient\udunder normative-generated and pulse-type input ground motions, and evaluation of the influence of the pre-stress load imposed on\udseveral types of fluid viscous devices in the manufacturing process, are included. Selected case studies are discussed in the\udaccompanying paper.