屋上綠化 植栽基盤構成에 따른 積載荷重에 관한 硏究
(The) Study on the Live Load according to Composition of the Planting Base of Green Roof
옥상녹화 식재기반구성 적재하중 건축공학;
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City development of 20th century pursuing modernization and efficiency decrease nature and green zone in urban area and increase concrete structure. In result nowadays, urban area has been formed by artificial structures. At present, ground area is already full and possible space to make green zone is limited. So plan to make green zone on the roof, wall or interior of the structure is considered and among of these making a green zone on the roof of the structure is established by regulations of a local government and advised positively as a plan to improve city environment. If we apply the plan to make a green space on the roof for structure, we can hope various effects like energy saving by insulation effect of planting base and to improve durability of structure by mitigating outer deteriorative facts of structure such as acid rain. But, making a green space on the roof is restricted because of supplement creation of planting base for planting and considering structure for load of planting base. Also, composition means of planting base and study for load increasement as species of wood is few so when we apply plan to make a green space on the roof it is very hard to consider effect for load increasement. Hence, in this study to examine live load according to composition of planting base and species of wood, we compute each load after dividing planting base into waterproof layer, drainage layer and soil layer and classifying wood as a herbaceous plant, a small shrub, a large shrub to consider changing for composition of planting base and species of wood. On the basis of that we consider live load according to composition means of planting base of green space on the roof and species of wood. The result that we consider live load for a green space on the roof according to waterproof means of roof slab, planting base and species of wood is showed below. (1) As concerning construction and live load, sheet waterproof is superior (2) When we compute load of the green space on the roof we have to consider load of state of humidity of each materials. (3) When materials of drainage layer are changed crushed gravel into artificial lightweight grave or ferrite, live load of planting base is decreased about 22% and 25% in order. (4) When ingredients of soil are changed normal sand into volcanic sand, live load of base is decrease about 28%. Especially, when it is changed into ferrite, 54% of live load is decrease. (5) Live load of the green space according to waterproof means, planting base and species of wood exceed the standard of roof live load of office, school and house in all item. Hence, more accurate structure examine for the new structure has to be done than old structure. (6) If we consider proof garden during designing new structure, I think we can apply various means of green space on the roof. As a result of examining live load by the prooftops green area, we found there are structural problems case by case. By the way, if we consider prooftops green area of old structure and use various lightweight materials it is possible to make rooftops green in existing structures.