Pilot Study On The Fatigue Properties Of Steel - Concrete Composite Beam

In the past several decadal years, the applications of composite beams on high-rise buildings , industrial buildings, and bridge in overseas and in China are more and more prevail, especially on fly-over bridges in cities. And researchers are more interested in the fatigue of composite beams. At present, the researches of composite beams in China are mostly concentrating on their static behaviors, and quite a few refer to fatigue. So there isn't a code about the fatigue of composite beams to comply. By comparison, the overseas researches are perfect in this field and they have special codes which regulate the fatigue of composite beams in detail. However, their primary contents focus on the assessment and the calculation of the fatigue life of composite beams and neglect the fatigue rigidity and fatigue distortion of composite beams. It has not been found the related literatures discussing the two aspects by now, thus it doesn't exist a code involving these. Because of such reasons, the purpose of this thesis is mostly to investigate the fatigue behavior of composite steel-concrete beams and discuss their resistant mechanism under repeated load, then bring forward calculation method of fatigue distortion for the design of composite beams and research the fatigue life of composite beams ulteriorly.Ten beam specimens are tested by two symmetrical point load at mid span. Except for these members, and six push specimens are tested. Test project, test process, and test phenomena are described in detail. Combined with tests, available test results are compared. On the basis of these studying, the analyze is done on the effect to resistance of composite beams caused by the fatigue loading times and the shearing stress of stud caused by fatigue load, Rigidity formulae are presented for composite beams under fatigue load, and the reasonable fatigue life formula is recommended. These research results can be applied as the reference for fatigue design of composite beams in China.At last, some suggestions and advices are proposed on the fatigue of composite beams, and it will be helpful to the coming researchers.