Performance Validation of a Self-Centring Steel Structure Using Robust Data Sets from Shake Table Testing

In recent years there has been a shift in seismic design from moment resisting frames to concentrically braced frames (CBF’s). CBFs resist the actions created in seismic events through energy dissipation in the form of plastic deformations in braces. This paper analyses the performance of a novel self-centring CBF (SC-CBF) which aims to reduce interstorey drift and residual deformations in a frame through the uses of post tensioned (PT) strands running parallel to the beam members anchored to the exterior flange of columns. The system works upon the principle of closing gap openings which open at joints between beams and columns due to acceleration of the structure. As these gap openings form due to drifting of the structure, increased tension forces will act through the PT strands closing the gap openings and returning the structure to its vertical position while energy is dissipated though the plastic hinges formed in the bracing members.