Abstract: One of the main failure modes of steel structure is fatigue failure, which is often accompanied by sudden fracture of steel. At present, there are little research on fatigue properties of Q690D high strength steel. In order to obtain the fatigue characteristic curve of Q690D high-strength steel, the high-cycle fatigue test of Q690D high-strength steel was carried out in this study. The S-N (stress-life) fatigue curve of Q690D high-strength steel was fitted based on the test results and compared with the existing fatigue test curves of standard fatigue formula and other strength grades of steel. The test results show that the fatigue performance of Q690D high strength steel is much better than that of ordinary steel, and is larger than the calculated values of the American steel structure specification (ANSI/AISC 360-10) and the European steel structure specification (BS EN 1993-1-9). It indicates that the fatigue performance of Q690D high strength steel is superior, and the calculated values of the specification are conservative. The fatigue curve of steel is highly correlated with its yield strength and has strong discreteness.

Key words: steel structures, high strength steel, high-cycle fatigue, fatigue test, fatigue strength