Survey on the Fatigue Damages of Highway Bridges in Metropolitan Districts and Study on their Protective Measures

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A series of survey on actual cases of fatigue damages in highway bridges and research of how to protect then from fatigue damages was executed in this study during the last three years, from 1987 until 1989, because these problems have become one of the most important ones for the maintenance of the current expressways in metropolitan districts.In the first year 1987, a number of available reports and literatures on the actual fatigue damages of highway bridges were collected and these examples were categorized and arranged according to their structural details. At the same time, discussion was made on the analytical method to be adopted in order to clarify the causes of these fatigue damages.In the following years, 1988, an analytical method, based on finite strip method and finite element method, to evaluate the stress concentration in the structural details of highway bridges was developed and it was proved that this method was effective for evaluating the actual stress concentratio … More n at the structural details. In addition, a method to simulate the stress induced by the actual traffic flow upon the highway bridges was developed based on statistical approach. Furthermore, as a case study, a method for protecting the sole plate near the bearing shoes of highway bridges against fatigue damage, which has been often and frequently observed and whose cases should rapidly be found from the standpoint of fatigue, was researched.In the final year 1989, the remaining problem, i.e., the study on the protection of the fatigue damages in highway bridges was carried out. For this purposes, the standard for the structural details by some Japanese Highway Administrations were collected and the most desirable types in terms of fatigue were discussed. Moreover, a survey through questionare on the best structural detail of highway bridges to protect against the fatigue damages was performed among steel bridge designers and fabricators, and these results were summarized in a report so as to serve as a valuable reference for future studies. Less