Visco-Re-Centring Energy Dissipating System for Seismic Protection of Framed Buildings

摘要

Energy Dissipating Bracing (EDB) system using both Shape Memory Alloy (SMA) and viscous damper (VD) devices has been considered in order to control seismic vibrations on buildings. The basic mechanical properties of the SMA+VD were used in order to recentre the gravity-load resisting system to its initial configuration at the end of the seismic event and to increase the energy release during the seismic motion. A performance based design procedure for the evaluation of the mechanical characteristics of both SMA and VD devices, starting from an equivalent Hysteretically Damped (HD) EDB designed for the same inter-storey target drift, was proposed. In order to verify the effectiveness of the design method and the performances of the system a parametric study was developed considering numerical nonlinear time history analysis and an extensive program of dynamic experimental tests, has been carried out at the Structural Laboratory of the University of Basilicata considering a 1:1.5 scaled three-dimensional steel frame within the JetPacs project (Joint Experimental Testing on Passive and semi-Active Control Systems). In this paper the main results obtained by numerical nonlinear time history analysis (NTHA) are compared with experimental ones.