TABATA, Sadatoshi

The objective of this study is to investigate the existing pattern of open space and composition of greenery space to raise the quality of residential environment in high-density residential districts. The high-density residential districts examined in the study are classified in three categories by the height of building; high density residential districts of low, middle and high-rise buildings. This study attempts to analyze the existing pattern of open space by the area of residential lots and open space, the building-to-land ratio, the floor-site ratio, the density of dwelling units and greenery space ratio. The results are as follows: (1) In the low-rise, high-density residential district, the area of a residential lot tends to decrease as the building-to-land ratio and the density of dwelling units increase. As a result, the area of open space will be reduced to the critical point along with the fragmentation of the residential lots under the current regulation to control land development. (2) The low-rise high-density residential district maintains three times as much open space as the middle-rise and high-rise districts. (3) In general, the composition of greenery space closely relates to the usage pattern of open space, Therefore, there is a possibility to maintain the quality of greenery space by reorganizing the boundary area between residential lots to create common space.