Innovative pier comprised of CFST-columns and steel-shear-links: Conception, design principle, experimental investigation

An innovative fabricated energy dissipation pier comprised of concrete filled steel tubular (CFST) columns and steel shear links was proposed and its mechanical performance was experimentally investigated. Firstly, based on basic mechanical behavior analysis of such pier, the design principles of its components, including the CFST column, energy dissipation shear links and joints, were suggested. Furthermore, two test specimens with different shear link configurations were designed and experimentally investigated. The bearing and deformation capacity of the specimens were obtained, and experimental phenomenon and failure mode were analyzed. In addition, load-displacement curve, strain distribution characteristics, bearing capacity, ductility and energy dissipation capacity of the specimens were also comparatively analyzed and discussed. The results showed that the suggested design principles could achieve reasonable failure mode. During the loading process, the energy dissipation shear links firstly occurred shear yielding, and the stiffness of piers decreased correspondingly due to yielding of links. Then, with continuous increase of the lateral loading displacement at top of the pier, the shear displacement of energy dissipation links gradually increased, and the piers exhibited significant secondary stiffness due to plastic over strength of shear links. In addition, the feet of columns gradually yielded due to the moment in column feet and tension or compression in columns induced by the shearing force in the links. Finally, the piers failed in column feet due to cyclic tension-flexure and compression-flexure at large lateral drift ratio. Before column feet failure occurred, the pier exhibited stable bearing capacity and excellent energy dissipation capacity.