|Project||Motomachi and Chojuen Apartments|
|Address||along Otagawa river north of city center|
|Building Type||Slab, gallery-access, skip stop|
|Number of Dwellings||1800|
|Section Type||single-loaded, skip-stop|
|concrete, steel & plastic|
|Construction Type||steel frame|
|Ancillary Services||primary schools, comm. etc. shopping center, pool|
This community of high-rise apartment slabs adjacent to the center of Hiroshima is important as perhaps the densest example of multifamily housing in Japan. Built on land along the Otagawa river on the site of a former military camp the area was used as a large overcrowded refugee camp for homeless citizens after the destruction caused by the atomic bomb in 1945. The two groups of buildings, Motomachi and Chojuen, have come to symbolize the final stage in the rebuilding of Hiroshima. The public-owned land along the river was planned as a park but, since it was impossible to relocate the 4000 households of illegal quarters who had settled here, it was decided in 1956, to build medium density housing. By 1967, about 900 families had been housed but this was still not enough and the Prefecture and the city government developed a new plan for high-rise apartments to be built in a park-like setting along the river. Spatially, this was seen as an extension of Hiroshima Peace Memorial Park, which had been built at the epicenter of the atomic blast.
Several different housing agencies worked together to develop two separate groups of buildings and supporting facilities. Chojuen, to the north, is built on a long narrow strip of land along the river and is 12-14 stories in height. Motomachi, built on a rectangular site, is a group of zigzag buildings around a central open space. Motomachi ranges in height from 8 floors on the east opposite the old Hiroshima Castle, to 20 floors on the north and west. Both groups employ similar skip-stop gallery-access slabs that are organized in connected "L" forms resulting in the continuous stepping form. Stairs and elevators are located at the intersections of the "L" blocks where there is a higher exterior "lobby" space. The typical dwellings are 2 and 3 room flats. Stairs connect the gallery to the larger upper dwellings. All apartments have balconies. Elaborate terraced roof gardens are used at Motomachi with public meeting rooms occurring at building intersections. All buildings are built on a system of "pilotis". A combination of steel frame, precast and cast-in place concrete is used in a unique structural system where the steel frame, which occurs at every other floor with a cast slab is designed to resist lateral loads while the intermediate floors are built using a precast system. About 70% of the planned 3200 dwellings have been built providing housing for a population of about 10,000. The community includes a 1000 student primary school, a 160-pupil kindergarten, nursery schools, shopping, commercial space, a hospital and centers for youth and the elderly.
Japan Architect, Aug,. 1973, pp.17-40.
Bauen + Wohnen, Mar., 1975, pp. 109-112.