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Diagnosis System of Fatigue Damage and Development of Retrofitting Technologies for Existing Steel Highway Bridges

既有公路钢桥疲劳损伤诊断系统及改造技术进展

基本信息

批准号：
13355020
负责人：
MIKI Chitoshi
金额：
$ 30.78万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

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.

本研究项目的概要如下：(1)建立了Internet上的疲劳与修复案例数据库。数据库中存在钢桥疲劳损伤案例。按原因列出并组织。 (2)针对平面外角板节点疲劳损伤提出了螺栓止动孔、磨削、低温相变焊材补焊等新的修复方法，并通过大尺寸梁试件疲劳试验定量评价了其有效性。(3)对于随着疲劳损伤预测方法的发展，通过有限元分析和现场应力测量详细研究了疲劳损伤的原因。结果表明，由于复杂的结构和振动特性，存在三维行为等意外原因。(4)开发桥梁监测系统，掌握桥梁现状。在监控系统中，桥梁上设置的传感器测量的数据通过光纤网络实时传输到远程监控中心。在该监控系统中，内置了动态称重（WIM）算法来获取车辆重量。通过WIM，发现了可能造成疲劳损伤的非法超重卡车。(5)对于焊接修复，必须从材料性能的角度审查层状撕裂的风险。这项研究表明，要应用焊接修复方法，钢中的硫夹杂物必须低于0.01%。此外，还提出了判断焊接修复方法适用性的正确程序。