Structural Design of High-Rise Steel Structure Installed with Suspension Type Base Isolation System

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Abstract The author has prior research paper published about Suspension Type Base Isolation (STBI); a seismic isolator intended to mitigate earthquake’s devastating impact on structures. Based on the prior research performed, it was found out that the said isolator could significantly reduce the earthquake intensities “felt” by the structure installed with the said isolation system. The prior study found out that if the actual ground shaking, for instance, was around intensity 9, the structure installed with STBI would experience around intensity 5 only. Consequently, the prior study showed that the reduction in earthquake intensity could be related to reduced lateral force or base shear acting on the structures. This present paper is a sequel of the previous one; and it is intended to show how STBI could be integrated in the design of high-rise steel structures. Also, a parallel design of the same structure was performed following the standard procedure for fixed-base structures. The purpose of conducting this study was to compare how the two design methods differ; and the subsequent results in cost-effectiveness between STBI-isolated and the non-isolated or fixed-base structures. Both design schemes followed the same structural codes, material properties, loading conditions, and base shear calculation procedure. At the end of the present study, it was found out that the calculated base shear for STBI-isolated was 0.068W, while for fixed-base, it was 0.137W. This indicated that there is 50% reduction in base shear between the two structural configurations. This reduction in base shear became evident in the reduced sizes of structural members in the STBI-isolated structures. Moreover, the STBI-isolated structure requires no structural walls. On the other hand, the fixed-base structure requires larger structural members; and that structural walls were needed to prevent the said structure from failure. In terms of maximum lateral deflections, fixed-base structure incurred 318.5 mm, whereas STBI-isolated structure incurred 226.0 mm only.