Innovative dissipative devices with tensegrity architecture and super elastic behaviour for the seismic protection of structures

The present paper deals with the design and the mechanical modeling of a seismic bracing system with tensegrity architecture, which operates as a lightweight mechanical amplifier for longitudinal displacements, efficiently limiting the inter-story drifts while dissipating energy. The proposed brace is based on a D-bar tensegrity structure with rhomboidal shape comprising Shape-Memory Alloy (SMA) tendons. The SMA tendons can develop austeniticmartensitic (solid to solid) phase transformations, which enable them to amplify the signals into wide super elastic hysteresis, while subjected to mechanical cycles, comprising strains up to ≈6-7%, with no residual deformations. The underlying concept of the proposed device is the use of SMA wire sections as the dissipating component, and some preliminary results have been presented in previous studies. Enhanced energy dissipation and re-centering capability of the current SMA-D-bar (SMAD) braces are illustrated by the seismic analysis of a benchmark structure. The efficiency of the designed bracing to minimize the seismic damage of the served structure paves the way for the development of advanced seismic energy dissipation systems incorporating tensegrity concepts and superelasticity.