Development of the System for Foreseeing and Assessing Fatigue Damages in Steel Bridges

钢桥疲劳损伤预测和评估系统的开发

基本信息

批准号：
63302041
负责人：
TAJIMA Jiro
金额：
$ 6.27万
依托单位：
Saitama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

It is essential to pay attention to fatigue problems of steel highway and railroad bridges, because a number of bridges have experienced fatigue crackings. There are many factors to affect the fatigue of bridge, so it is difficult to accurately estimate the location and the time of the cracking. Following considerations, therefore, are effective in using the existing bridges safely : (1) to comprehend the cause and feature of past cracking experiences, (2) to inspect the pertinent locations at a adequate period of time by using an appropriate inspection system, (3) and to cope with the cracking with the use of a suitable retrofitting method.This report describes the basic concepts of the system for inspecting the steel bridge components and for predicting the location and the tim of fatigue cracking. This system will be of great assistance in the safe use of existing steel bridges. The summaries of the report are as follows.A large number of data for fatigue crackings in steel bridges … More in Japan are collected, arranged and analyzed. Furthermore, the papers in relation to the crackings are examined, and then we indicate the cause and repair method of the crackings.We investigate the applicability of non-destructive testings ( visual examination, magnetic particle examination, eddy current examination, liquid penetrant examination and ultrasonic examination ) to detect and measure fatigue cracks in steel bridges through experiments on fillet welded joint specimens with surface fatigue cracks. We also examine the practicability of electrical potential method and AE (acoustic emission) method, which are suitable to continuous on-line inspection, for quantitative measurement of crack in steel plates and fillet welded joint specimens.A method is presented for predicting the life of steel bridge components under variable amplitude stresses in highway and railroad bridges.Case studies on some actual bridges are performed, with emphasis on inspecting system, assessment of fatigue damage and retrofit for the damage.The features of inspection manuals of various administration facilities for bridges are indicated. Less

钢质公路和铁路桥梁的疲劳问题必须引起重视，因为许多桥梁都出现过疲劳裂纹，影响桥梁疲劳的因素有很多，因此很难准确估计疲劳裂纹的位置和时间。因此，以下考虑对于安全使用现有桥梁是有效的：（1）了解过去发生裂缝的原因和特征，（2）通过适当的检查在适当的时间内检查相关位置。系统，（3）并应对该报告描述了用于检查钢桥构件以及预测疲劳裂纹的位置和时间的系统的基本概念，该系统将对安全使用有很大帮助。报告摘要如下。收集、整理和分析了日本钢桥疲劳裂纹的大量资料，并对与裂纹相关的论文进行了审查。我们指出通过角焊缝试验，探讨无损检测（目视检查、磁粉探伤、涡流探伤、液体渗透探伤、超声波探伤）在钢桥疲劳裂纹检测和测量中的适用性。我们还检验了适用于连续在线检测的电位法和AE（声发射）法对钢板裂纹进行定量测量的实用性。提出了一种预测公路和铁路桥梁变幅应力下钢桥构件寿命的方法。对一些实际桥梁进行了案例研究，重点是检查系统、疲劳损伤评估和改造各种桥梁管理设施检查手册的特点较少。