| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1997: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1995: ¥4,100,000 (Direct Cost: ¥4,100,000)
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| Research Abstract |
Recently, it has been often reported that fatigue failure occurred in many steel highway and railway bridges. From this background, now it becomes much important to estimate the way to predict of life of bridge and to make an efficient plan of maintenance work. In this study, aiming to establish the way of life prediction and life-expansion of steel bridges, the following studies were carried out considering fatigue.
1) In order to predict life of existing bridges, it is very important to know location, type, and reason of fatigue crack in Existing bridge. First, in this study, to establish the data-base, fatigue failure occurred in steel highway and railway bridge in Japan and U. S. A were rearranged
2) Next, in order to discuss the mechanism of occurrence of fatigue failure, stress measurement and FEM analysis were carried out. Here, scallop detail and cross-connection detail were studied in testing laboratory and also actual bridges considering secondary stress and deformation mode.
3) Finally, aiming life-expansion of steel bridges, some fatigue improvement methods were studied with using small welded joint specimens (such as out-of-plane gusset welded joint, in-plane gusset welded joint and cruciform welded joint) and girder specimen including some welded joints (such as web gusset, flange gusset and vertical stiffener). As fatigue strength improvement method, under-matching weld electrode and post-welding processing at welded toe such as TIG-dressing, burr-grinding and hammer peening were dealt with in this study.
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