Sapporo Apartment Building: Structural order in the concrete-encased steel load bearing structure

This innovative structural scheme arose from the careful unfolding of the design with respect to user requirements, the impact of surrounding buildings, coupled with the fact that there was an untouchable small clinic on the site which had to be kept intact and therefore straddled. The above created a series of conditions requiring ten different plans at each of the ten floors. The structural frame consists of twenty enormous columns ran all the way through the building from top to bottom. Each large column includes 4 steel columns, which at the bottom are encased in concrete, visible as solid and massive legs. Higher up, they are pierced; they are so large that they contain arches, and each one splits into its four smaller columns, and these four columns then become the crossings where the circulation and passages of the upper floors meet. The building designed to work in bending as a moment-resisting frame, with supplementary shear walls at the lower floors, allowed the plans to change freely from floor to floor, yet all tied together and resolved structurally, by the continuity of the 13 clusters of the 4 steel columns, which pass through each plan in the same position. The aperiodic grid, with large bays and small bays, created a structure where the materials of beams, columns and walls, coincided with the architectural and social space required for the apartments, passages and rooms.