| The creep of concrete filled steel tubes is more complicated than that of plain concrete, because the core concrete of concrete filled steel tube structure is in the airtight environment of the steel tube, the influence by external environment is relatively slight, meanwhile, the stress of the concrete is decreasing and the stress of the steel tube is enlarging due to the redistribution of section stress by creep. The analyses of shrink and creep of concrete filled steel tubes arch bridge mainly involve two questions: one is the calculation mode of shrink and creep, the other is the analysis method.This thesis has made the contrast test of shrink and creep for plain concrete and concrete filled steel tubes on the basis of long term in-door test, obtains the principles of shrink-creep of concrete filled steel tube, simulates the test data, analyses and contrasts the coefficient of shrink and creep, thus offers reference for the calculation mode of creep, furthermore by introducing reasonable assuming at the same time, develops the calculation formula of equivalent elastic modulus at the same time, develops the calculation formula of equivalent elastic modulus, adopts common structure analyses procedure Ansys to calculate the redistribution of section stress in the steel tube and concrete during operation. The main research contents are as follows:1. This thesis observes the shrink and creep curve of plain concrete and concrete filled steel tubes.2. This thesis analyses the curve, then obtains the principles of shrink and creep of concrete filled steel tubes, estimates the creep of concrete filled steel tubes by the test data of plain concrete creep.3. This thesis analyses and contrasts the coefficient of creep of concrete filled steel tubes, develops the calculation formulas of equivalent elastic modulus, adopts common structure analyses procedure Ansys to calculate the redistribution of section stress in the concrete filled Steel tubes arch bridge.
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