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No.13 (1977/03) >

Title :那覇市内中学校の鉄筋コンクリート造校舎の耐久性調査
Title alternative :An Investigation on the Durability of Rein-forced Concrete School Houses in Naha City
Authors :具志, 幸昌
和仁屋, 晴讙
伊良波, 繁雄
Authors alternative :Gushi, Yukimasa
Waniya, Haruyoshi
Iraha, Shigeo
Issue Date :28-Mar-1977
Abstract :In this paper, the results of site investigations on durability and deterioration of the reinforced concrete school houses of junior high schools in Naha City are described. In general, the school houses are damaged seriously due to corrosion of reinforcing bars embeded in concrete. The rate of school houses damaged in columns and beams to all school buidilngs amounts to 29.4%, and 77.9% is the rate of school houses damaged in slabs. Some fundamental measures to improve above mentioned serious conditions must be taken against corrosion of reinforcing bars embeded in concrete. The followings must be also mentioned: 1. Contractcr's men and inspectors have little knowledge about durability of reinforced concrete. 2. Inspection works in concrete construction must be done more severely, especially, in reinforcing steel bar placing. 3. The average salt content in concrete samples taken from school houses is 0.23% in mortar weights. This figure is the least one in the series of the school house investigativns in Okinawa Prefecture. But this quantity is enough to corrode the steel bars embeded in concrete, and the salt contained in concrete is responsible for the school house damages mentioned above. 4. The above mentioned salt contained in concrete comes from sea sand and mixing water. 5. To promote the durability of school houses in Naha City; 1) The salt contained in concrete must be minimized by use of tap water as mixing water and de-salt-action~washing the sea sand by tap water or rain-fall. 2) Inhibitors against steel rusting are to be used. 3) Good quality concrete (low water cement ratio and low water content) must be used and carefull concrete work must be done. 4) Rain-stopping inverse channels in laves are to be harmful. 5) The number of outside exposed surfaces of school houses must be minimized, such as outside corridors, outside stairs, and laves. 6) The depth of concrete cover on reinforcing bar must be increased.
Type Local :紀要論文
ISSN :0387-429X
Publisher :琉球大学理工学部
URI :http://hdl.handle.net/20.500.12000/26795
Citation :琉球大学理工学部紀要. 工学篇 = Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering no.13 p.25 -85
Appears in Collections:No.13 (1977/03)

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