Determining the Appropriate Contribution of Each System to Lateral Load in a Dual Frame with Linked Columns to Achieve a Two‑Level Performance and Repairability

Abstract

Recently developed structural systems with rapid and low-cost repairability, such as dual moment frame–linked column frame (LCF) systems, make it possible to replace damaged components quickly after an earthquake and restore the structure to service in a short time. In these systems, the lateral load-resisting mechanism is provided by a combination of a moment frame and linked columns. To fully utilize the repairability feature of such dual systems, the moment frame should remain essentially elastic after the linked columns have yielded, maintaining lateral resistance and ductile behavior. In this study, fuse-type links were assigned only to selected members, allowing them to yield under seismic actions. The contributions of the linked columns and the moment frame to the total base shear were investigated through nonlinear analyses. Based on the results, the minimum and maximum proportions of lateral load that each subsystem should resist were determined to achieve the desired two-level performance. The findings indicate that, in order to ensure ductile and repairable behavior, the moment frame alone should be capable of resisting at least 40% of the total base shear, while the contribution of the linked column system should be limited to approximately 60% to control large inelastic deformations.