Collaborative working mechanism and theoretical model of latticed CFST column with energy dissipation steel-shear-links

This paper aims to investigate the collaborative working mechanism of the concrete-filled steel tube (CFST) column and steel-shear-links for the composite energy dissipation pier by applying a spring-fiber beam hybrid numerical modeling method, and clarify the influences of different dimensions and design parameters on the seismic performance of the composite pier. The numerical results indicated that the increasing number of steel-shear-links could significantly improve the bearing capacity and lateral stiffness of the composite pier and limit the bending capacity of the tension-bending column base, while it had little effect on the bending capacity of the compression-bending column base and the shear force of the shear link under the specific pier top displacement. The factors including the height and length of the shear link had little effect on the lateral load resistance of the pier. Although the pier height had no obvious effect on the bending capacity of the column base, the lower pier height was beneficial for increasing the bearing capacity and stiffness of the pier. Axial compressive load had no significant effect on the total bending capacity of the two column bases and the shear force of the shear link, but the influence of the second-order effect of axial compressive load would limit the overall lateral resistance of the pier. In addition, a theoretical model was proposed to reflect the force mechanism of the composite energy dissipation pier at different loading stages, and the simplified load-displacement theoretical model was proved to accurately predict the behaviors of the composite pier under the earthquake.