Seismic assessment of linked-column frame structural system considering soil-structure effects

Abstract The Linked Column Frame (LCF) structural system is comprised of moment-resisting frames as the primary gravity load-carrying system and a combination of closely-spaced dual columns interconnected with link beams acting together with the moment-resisting frames as the lateral load resisting system. In this system, the link beams are designed to provide ductility and deform plastically. As the damages are concentrated to the links thus, the LCF rapidly returns to occupancy design performance while retaining architectural privileges of the non-braced steel frames. In this study, 3, 6, and 9-story frames equipped with LCF and resting on soil type II and IV are subjected to seven near and far-field earthquake records. These structures are designed based on the plan of SAC buildings using SAP2000, and then, nonlinear time-history analyses were carried. The results indicate that maximum roof drift of the structures on stiff soil (type II) has been insignificantly affected under both near and far-field earthquakes. In soft soils (type IV), drifts values increase by 6.85%, subject to both far and near-field earthquakes. Moreover, in contrast to the stiff soil, roof acceleration has decreased more when the structure is on soft soil, nearly 6.12%. The result of maximum inter-story drift ratios of the structures founded on soil type II illustrates that under an average of near-field earthquakes, drift ratios of 3 and 6-story structures have increased by 3.2%. On the other hand, the 9-story structure has encountered a decrease of 5.17%. Under an average of near-field earthquakes in soil type IV, a drift ratio of 3 and 6 and 9-story structures has grown to 5.11 and 11.2%, respectively, compared to the fixed-base models. In far-field earthquakes, drift values of 3 and 6-story LCF were reduced by 6.2%, and the 9-story structure has experienced an increase of 8.79%.