1992 Fiscal Year Final Research Report Summary
Displacement Induced Fatigue Damage on Steel Bridges and Its Retrofitting Method
| Project/Area Number |
02555098
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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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 Prof., Tokyo Institute of Tech., 工学部, 教授 (20016645)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Takeshi Assoc., Prof., Hosei University, 工学部, 助教授 (10157860)
TAKENOUCHI Hiroyuki Japan Construction Method and Machinery Research Institute, 研究課長
MASUDA Nobutoshi Prof., Musashi Institute of Technology, 工学部, 教授 (00016700)
TERADA Hiromasa Head, Research Lab., Yokogawa Bridge Co., 所長
MIKAMI Ichizou Prof., Kansai University, 工学部, 教授 (80067636)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Displacement Induced Fatigue / Welded Joint / Local Stress / Cross Connection Detail / Expert System / Steel Bridge |
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| Research Abstract |
1. A new method of analysis model for plate girder bridges is proposed. In the method, analytical model is constructed in the following way. Most degrees of freedom are allocated to the neighborhood of the structural detail where local stresses are estimated and other whole structure is modeled in macro sense spending considerably few memory size. The structure where most degrees of freedom are to be allocated is decided by referring to related studies and considering statics. In order to realize a proposed mode, plate elements must be connected with beam elements.
2. In order to investigate the behavior at the longitudinal and transverse ribs connections of steel deck plates, stress measurements were carried out on two bridges in Tokyo. From the measured stresses, the influence lines of the longitudial and the transverse ribs were calculated by using inverse problem concepts. F.E.M.analysis was carried out to make clear the relationship between various distortion modes and fluctuations
… More
of local stress.
3. For the fatigue assessment based on the local stress, it is important thow to define the stress to assess the fatigue strength. In this study, the measurements and the analysis of the stress distributions near the welded toe are carried out on three different types of specimen. Through these results and he fatigue test data which has been obtained on these specimens, the method to define the local stress to assess the fatigue strength is investigated.
4. Fatigue strength of scallop details in welded structural members were investigated by experiment and FEM analysis. Fatigue strength of this detail based on nominal stress was extremely low because of high stress concentration occurred in the gap of scallop.
5. Fatigue design stress and allowable stress range of load-carrying fillet welded cruciform joints which fail by fatigue cracking from the weld root were investigated. Many existing fatigue test data of the joints are collected and rearranged. Furthermore, fatigue crack propagation analysis is also carried out by using stress intensity factor which is obtained from the finite element stress analysis and the energy method. Less
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