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No.13 (1977/03) >

Title :沖縄本島北部3村の鉄筋コンクリート造校舎の耐久性
Title alternative :An Investigafion Study on Durability and Deterioration of Reinforced Concrete School Houses in Three Northern Villages of Okinawa Island
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 :This paper describes the results of site investigation on durability and deterioration of school houses in three villages of northern part of Okinawa Island. The school houses in this region have been damaged most seriously in this series of investigations in Okinawa Prefecture. The rate of the damaged school houses in columns and girders to all school houses in this region amounts to as much as 37.1%. The rate of the damaged school houses in slabs and laves is 84.6%. The most prominent cause for above high damage rate is salt contained in concrete of school houses. The largest salt content value is observed at an school house in this region. The value is 1.91%. The average salt content value in this region is 0.52%. The salt contained in concrete comes from sea sand, sea gravels and mixing water, as well as directly from sea water. The first step to decrease the rate of damaged school houses is preventing school houses concrete from salt permeation. Houses of 4 schools in this region are directly attacked by sea water sprays, and the houses are most severly damaged. Other than above, the following comment to be mentioned: 1. The two kinds of coarse aggregate are used in construction of school houses in this region, one is natural gravels in older school houses and the other is crushed hard lime stone in newer school houses. 2. Heavily damaged school house concrete contained the natural gravels. 3. The hand-rails of stairs are damaged as seriously as the ones in other regions of Okinawa Prefecfure, and after 1965 the damages in the hand-rails decreased suddenly on account of the change in mode of stairs. 4. The quality of concrete in this region, estimating from the observed values of specific weight and absorption capacity of concrete, is highest one. But this does not means that concretes in this region is durable. 5. The school houses sprayed by sea water must be moved. 6. There are three critical school houses, not to be used and must be removed.
Type Local :紀要論文
ISSN :0387-429X
Publisher :琉球大学理工学部
URI :http://hdl.handle.net/20.500.12000/26994
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.87 -145
Appears in Collections:No.13 (1977/03)

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