Upgrading the seismic performance of underground structures by introducing lead-filled steel tube dampers

Abstract

Central-column failure can cause large underground structures to collapse during strong earthquakes. The use of lead-filled steel-tube dampers (LFSTDs) in the seismic design of such structures is proposed to mitigate or prevent such an eventuality. Three-dimensional nonlinear dynamic analyses of the Daikai subway station with and without LFSTDs under the action of the Hyogoken–Nambu earthquake has been performed, considering soil-structure interaction. The feasibility of the proposed method was verified from four aspects—force, deformation, damage, and energy dissipation. The effects of variability in seismic inputs, strength ratio, and arrangement mode of dampers on the structural dynamic response characteristics have been discussed. Results reveal that the application of LFSTDs to large underground structures remarkably reduces the force, deformation, and damage associated with the central column under seismic loading. Additionally, a strength ratio of 0.4 is recommended when using LFSTDs, whereas in cases without LFTSTDs, the strength of the central column must be appropriately enhanced.