Building in Okachimachi

Geometry of architecture that transcends the regulation
The site is located near Okachimachi Station, behind major streets such as Kasuga-dori and Showa-dori. The flat land has a grid-like layout, with small and medium-sized multi-use buildings, apartments, and detached houses standing in a chaotic fashion, creating a typical modern downtown atmosphere. From the perspective of the Building Standards Law and urban planning, most of Taito Ward, except for a few areas, is designated as a commercial district and fire prevention district, and there are virtually no restrictions on building coverage ratios, with designated floor area ratios being high. On the other hand, the floor area ratio is determined by the road width, and the height is limited by the road diagonal line. Since regulations are looser in commercial districts than in other areas, buildings of various uses and scales are mixed together, making the surrounding environment difficult to grasp.
This plan involves combining the site, which was previously a warehouse and a parking lot, into an office building. Despite the severe road diagonal line from the north, it was found that a volume over 40m in height could be built by taking advantage of the sky ratio and setting back 5m from the neighboring land boundaries on the east and west, making it possible to use the floor area ratio. Considering that the minimum road width under the building code is 4m, the 5m separation from the neighboring land is equivalent to laying a road on the east and west sides. From the outside, it looks like it is connected to roads on three sides, and the height of the volume makes it a landmark, and it is built in a way that makes it seem independent from the cluttered surroundings.
The 5m separation from the neighboring land boundary removes the so-called "fire spread line," so this building is free from that constraint. Therefore, the RC frame is exposed, and the entire building is composed of a structure of diagonal columns and beams that penetrate two stories. The beam depth of each floor is 600mm, but the span is shorter on floors where the diagonal columns do not intersect, so the beam width can be kept thin, and by passing the sashes and exterior walls on the outside, the beams are visible on every two stories from the outside. The columns also appear to penetrate two stories, so the contrast between the slender proportions and the solid RC material, as well as the transparency through the large, irregular shaped sashes, create an exterior expression that combines the two. As mentioned earlier, the surrounding buildings are chaotic and diverse in their uses and sizes, but because the size of the site means that most of the buildings have a "fire spread line," their openings are fire prevention facilities and the geometry of each individual exterior is dominated by rectangles. This is a landscape created by a regulation, and in a sense it is uniform. This architecture was constructed from a geometry discovered by overcoming that rule, and I believe it will expand the possibilities of the urban landscape.