| Project/Area Number |
62850083
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
土木構造
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
MIKI Chitoshi Tokyo Institute of Technology Associate Professor, 工学部, 助教授 (20016645)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Takeshi Tokyo Institute of Technology Research Associate, 工学部, 助手 (10157860)
MASUDA Nobutoshi Musashi Institute of Technology Associate Professor, 工学部, 助教授 (00016700)
寺田 博昌 横河橋梁製作所(株), 研究所, 所長
MIKAMI Ichizou Kansai University Professor, 工学部, 教授 (80067636)
TERADA Masahiro Yokogawa Bridge Works, LTD Chief of Laboratory
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥5,900,000 (Direct Cost: ¥5,900,000)
Fiscal Year 1989: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1988: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1987: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | Steel Bridge / Fatigue Damage / Fatigue Design Load / Sway Bracing Member / Fatigue Crack / Expert System / Retrofit / 疲労設計荷重 / Tー20荷重 / すみ肉溶接部 / エキスパートシステム / 損傷度 / 局部応力 |
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| Research Abstract |
Bridges are exposed to a natural environment and time-depend fluctuating loads due to motorcars, trains and so on for a long or semipermanent time. Fatigue damage, therefore, is the most frequent and anxious accidents in existing bridges. The objective of this study is to construct the expert system for assessment of fatigue damage in steel bridges and to offer the basic knowledge for the system. Main contents of the study are follows.
Fatigue design load of highway bridges are studied by means of the simulation of variable amplitude sectional forces in bridge components. The differences of fatigue damages due to various parameters ; the shape and length of influence line, the number of girders in a bridge, the number of lanes and lateral load distribution, are discussed.
In order to make clear the cause of fatigue damage at the connection weld between upper flange of main girder and vertical stiffener with a function of connection plate to sway bracing member, the relationship between the local stresses at the weld and the sectional force of sway bracing member is analyzed by using finite element method, and a simple procedure for evaluating the sectional force of sway bracing member is proposed.
Aspect ratios of fatigue cracks in fillet welds are examined by use of many fatigue data. The results of the examination are useful in evaluating the remaining life of fatigue damaged components and selecting the repair method.
A knowledge-based expert system is constructed to refer the past fatigue damages appeared at various parts of steel highway bridges and to assist engineers's judgment. The system consists of three subsystems : presenting the list of parts to be inspected, appraising the grade of fatigue damages, and proposing the method of retrofit.
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