2003 Fiscal Year Final Research Report Summary
Diagnosis System of Fatigue Damage and Development of Retrofitting Technologies for Existing Steel Highway Bridges
| Project/Area Number |
13355020
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
構造工学・地震工学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
MIKI Chitoshi Tokyo Institute of Technology, Civil Engineering, Professor, 大学院・理工学研究科, 教授 (20016645)
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| Co-Investigator(Kenkyū-buntansha) |
FUJINO Yozo University of Tokyo, Civil Engineering, Professor, 工学系研究科, 教授 (20111560)
YAMADA Kentaro Nagoya University, Civil Engineering, Professor, 大学院・工学研究科, 教授 (50109310)
ICHIKAWA Atsushi Tokyo Institute of Technology, Civil Engineering, Professor, 大学院・理工学研究科, 教授
YAMADA Hitoshi Yokohama National University, Civil Engineering, Professor, 大学院・環境情報工学院, 教授 (00143735)
KITADA Toshiyuki Osaka City University, Civil Engineering, Professor, 工学部, 教授 (30029334)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Highway Bridge / Fatigue Damage / Repair and Retrofit |
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| Research Abstract |
The summary of this research project is as follows.
(1)Database of fatigue and repair cases was built on the Internet. In the database, fatigue damage cases in steel bridges were. listed and organized by the causes. Furthermore, the repairing and retrofitting methods applied to the damaged structures were shown with the effectiveness of the methods.
(2)For the new retrofitting methods for fatigue damage of out-plane gusset joints, bolted stop holes, grinding, additional welding by low temperature transformation weld materials were proposed and the effectiveness of them was evaluated quantitatively by fatigue tests with large scale girder specimens.
(3)For the development of fatigue damage prediction methods, the causes of fatigue damage were investigated in details by Finite Element Analysis and field stress measurements. As a result, it was clarified that there are unexpected causes such as three dimensional behaviors due to complicated structures and vibration characteristics.
(4)The monitoring systems of bridges were developed to grasp the present conditions of the bridges. In the monitoring system, the measured data by the sensors set on the bridges were transferred to the remote monitoring center on real-time through fiber-optic networks. In this monitoring system, the Weigh-in-Motion (WIM) algorism was built in to obtain vehicle weights. By the WIM, illegally overweight trucks that can cause fatigue damage were detected.
(5)For the repairs by welding, the risk of lamellar tearing must be examined from the viewpoint of material properties. In this study, it was shown that to apply welding repairing methods, the Sulfur inclusion of the steels must be less than 0.01%. Furthermore, the proper procedure to judge the applicability of welding repairing methods was proposed.
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