複合環境促進装置による構造物の劣化機構の解明と耐久性設計法の確立

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In this research project, researches on the mechanism of deterioration and durabily of steel and concrete structures were carried out for 3 years term. The main research was environmental accelerate tests for the structural members. Fatigue tests were carried out about deteriorations of the highway bridge slabs and shoes. Also, the load-carrying capacity of corroded steel members were investigated analytically. The main themes and their research results are as follows: (1)Environmental tests on Corrosion of Welded Steel Structures: From a survey about corrosion of actual structures, it is clear that welded parts are apt to corrode earlier than plane parts. So, many environmental accelerative tests were carried out to prove the trends using welded models. In a comparison with the exposure test results, the mechanism and acceleration rate were clarified. (2)Bucking Strength of Corroded Steel Members: By making a non-linear computer program by finite element method, residual load-carrying … More capacity of corroded steel members were investigated and an evaluation formula was derived. (3)Corrosion of Reinforcements in Concrete Members:Corrosion of reinforcements in concrete was investigated by changing the parameters of specimens. Also, varidity of concrete coat ings were approved through the same environmental tests. (4)Corrosion Mechanism of Stay- Cables in the Cable-Styed Brides: Corrosion of the cement grouted cables was reproduced experimentally and thermal repetiton of the cables was pointed out to be the main cause. (5)Corrosion of Tendon in Prestressed Concrete Structures: The corrosion were verified to occur due to same reason of the cement grouted cables. (6)Corrosion of Reinforcements in Highway Bridge Slabs and Fatigue Life of the Deteriorated Slabs: An potential corrosion test were carried out to investigate a relation between spalling of concrete cover and corrosion of reinforcements. Then, fatigue life and reparing of the deteriorated slabs were discussed. (7)Deterioration of Bridge Shoes:One of the main phenomena on shoes is the deterioration of concrete under the shoes. The main cause was proved as fatigue failure under water environment through the fatigue tests. Less