Creating and designing repairable regular steel buildings with seesaw motion to achieve seismic resilience

Abstract

Using seesaw structural system in buildings is a way for creating earthquake-resilient buildings, namely buildings which can be easily and quickly repaired with little cost, even after major earthquakes. To create such a system, all internal columns at the lowest story are removed and instead, a central mega support is used, combined with a grid of orthogonal strong girders as the first floor, and all circumferential columns at the lowest story are equipped with energy dissipaters at their bottoms. In this article, after presenting a simplified dynamical model for seesaw buildings, to create the analytical base for proposing the preliminary design rules for this type of buildings, the proposed rules have been developed and supported by conducting several non-linear time history analyses (NLTHA) cases on a set of regular steel buildings with concentric bracings, having 3, 5, 7 and 9 stories with different number of bays, and various bay sizes. NLTHA results indicate that the immediate occupancy performance level is mostly achieved in the designed seesaw buildings. The efficiency of this system in low-rise buildings is more than mid-rise ones. Although seesaw buildings respond relatively well to both near- and far-field events, they behave less effectively in near-field pulse-like earthquakes.