Research purposes:As steel bridges are becoming more heavy - loaded and integrative,many complicated structures that their nominal stress can not be identified and their details can not corresponded with the existing design codes have happened in the steel bridge structure. In practice,the prototypical fatigue tests are usually done to validate these structures. However,the fatigue tests need long time and high cost and it restricts the fast and wide application of the fatigue test to validate the details of these structures. In order to accurately evaluate the fatigue behaviours of these details of the complicated structure,the study was done on the application of the hot spot stress in evaluating the bridge fatigue.
Research conclusions:The analysis of the concentration factors of the hot spot stress of many kinds of joint was made and the shs - N curve of the hot spot stress for checking the steel bridge fatigue was deduced by using the concentration factors of the hot spot stress. The comparison of the fatigue strength of nominal stress of the many kinds of structure details stipulated in BS5400 with the deduced fatigue strength of hot spot stress showed the deduced fatigue strength of hot spot stress was obviously less than the discreteness obtained with the nominal stress method. So the hot spot stress method is available for bridge construction.