A Seismically Isolated Building Design Example Using Response History Analysis Method Based on Japanese Code

In October 2022, “ISO 23618:2022 Bases for design of structures - General principles for seismically isolated structures” was published. A Technical Report based on ISO 23618:2022 is prepared to demonstrate how to use the ISO standard. In this paper, a seismically isolated building design example using response history analysis method based on Japanese code is summarized. In Japan, the same design earthquake ground motions and the same procedure of response history analysis method are applied to all structure types such as aseismic, seismically isolated or energy dissipation structure. There are four types of ground motions to be considered in the response history analysis. The maximum response values from the above ground motions are used to design. The design shall be conducted on both Level 1 (damage limit) and Level 2 (safety limit) earthquakes. To check the vertical response of isolators, vertical motions pairing with the horizontal one are usually used. Both the equivalent linearization method and the response history analysis method may be used for a seismically isolated building. However, 80% of the projects adopted the response history analysis method for the performance-based design or economic reasons. For the building model, a multiple-degree-of-freedom lumped mass model or/and a 3D frame model may be used. 70% projects were reported to adopt the lumped mass model due to the physical understanding of the response. Members of the super-structure are assumed as non-linear. Isolators and dampers are modelled appropriately based on test results. A seven-story RC education building will be used to demonstrate the design process in detail.