Seismic response of linked column steel braced frame with mechanical springs

Abstract

Linked column frame (LCF) is a new resilient structure. However, previous studies have shown that both the plastic rotation and plastic hinge distribution of link beams in LCF system are unsatisfactory, which significantly affect the seismic performance. To expand the plastic deformation and optimize the plastic hinge distribution, an uplifted column foot with springs is introduced. A 1:3 scale pseudo-static test and numerical analysis were conducted to evaluate the hysteresis performance of LCF system with springs, specifically the frame lateral deformation, the shear deformation of link beams and yielding mechanism. Moreover, the virtual work principle was applied to analyze the lateral bearing capacity theoretically. The result shows that when the frame was subjected to lateral forces, axial deformation was observed in the springs, thus releasing the vertical restraint of columns, eventually the link beams are motivated to develop inelastic deformation and the frame rotated, similar to a rocking structure. Additionally, compared to the numerical simulation and experiment results, the relative errors were analyzed and the theoretical bearing capacity was modified. In conclusion, the proposed foot configuration can significantly improve the energy dissipation capacity of LCF system. The shear deformations of link beams in different storeys are relatively uniform along the frame height.