Application of Isolation to High-Rise Buildings: A Japanese Design Case Study through a U.S. Design Code Lens

Base isolation of high-rise buildings has been growing in popularity in Japan, yet it is uncommon in most of the world. While tall buildings already have long periods and thus lower input accelerations, the addition of isolation can decrease inter-story drifts and greatly decrease floor acceleration, protecting building content. By protecting building content, high-rises can be kept fully operational and occupiable after earthquakes. The Japanese design code has clearly outlined procedures for designing isolated high-rises, facilitating the implementation of isolation; however, other design codes—and specifically the U.S. code—make the adoption of isolation difficult for these buildings. Using a design representative of typical isolated high-rises in Japan, it is shown that while isolation is feasible under U.S. design levels, requirements are much more stringent, and some changes from the Japanese design would be required to make the design acceptable under the U.S. code.