| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2015: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Outline of Final Research Achievements |
In order to improve fatigue durability of welded parts of steel bridges with complicated geometric 3-dimensional shapes, a technique of local heat treatment with a portable heat source was developed. A series of experiment was carried out on specimens modeled a steel plate deck with U-shaped rib, in which a lot of fatigue damages are reported. A thermal elastic-plastic analysis method was investigated for simulating the heat treatment process.
It was confirmed that the welding residual stress was reduced by 80% through the heat treatment. Furthermore, a method for saving heat energy during the heat treatment was proposed. It was shown that the fatigue durability was improved by the heat treatment under the condition of relatively low applied stress level.
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