The Model Design And Analysis On Mechanical Behaviors Of Concrete Filled Steel Tube Bridge Tower On Liujiaxia Bridge

The diameter of concrete filled steel tubular bridge tower on Liujiaxia bridge is the biggest in China at present, and concrete filled steel tubular structure is the first time in the suspension bridge tower bridge. In order to understand the mechanical behavior and bond slip behaviors of Liujiaxia bridge concrete filled steel tubular bridge tower. This paper according to the principle of similitude, designs concrete filled steel tubular bridge tower model, and analyse the test model by finite element theory.Through consulting the related theory of concrete filled steel tubular literature at home and abroad, and summarizes the research results of the former. At home and abroad to the experimental study of concrete filled steel tube structure analysis, the paper analyzes the relevant steel tube concrete bridge towers model tests. In the research of concrete filled steel tube is conducted on the basis of summary liujiaxia bridge steel tube concrete bridge towers test model design and the scheme is selected, and use of the universal finite element analysis software ANSYS to establish the test the finite element model of the bridge tower. In steel and concrete setting on contact interface unit, analysis steel tube and concrete under load slippage of the state and force performance.No welding was launched in concrete filled steel tube component test steel pipe stress with change place curve and concrete stress with the change of the position of the steel tube and a response curve concrete bond-slip relationship is the same, slippage at both ends by gradually into the middle, from local extended to the whole. Both ends in local sliding range (shear relay length) in steel tube and the stress of concrete change rules are linear change, binding part of steel tube and concrete stress have stayed the same, steel tube and concrete in the collaborative work condition. Contrast is welding nail and no welding nail oondition launch test, we found that the structure of concrete filled steel tube welding nail can only reduce the steel tube and the sliding distance between concrete, and cannot increase steel tube and the initial bonding between concrete.The original bridge under the action of load condition analysis shows that, since bias, three components to stress changes along the circumference is larger, the structure stress non-uniform, steel pipe to stress have not more than three design strength, working with a working two concrete to stress have not more than three design strength, working three concrete compressive stress between vertical compressive strength design value and compressive strength between standard; Steel tube and concrete in radial did not happen from, both good contacts, interface slip first occurs in the top, and gradually downwards, with the load increasing began sliding lower part, but eventually the scope of the sliding lower happened less, sliding value from bottom to top increase in turn.Of the three design load stress state of structure is compared, and the three conditions of bridge tower structure load the stress of the most unfavorable. The working condition of1.5times three load on model analysis, the analysis results showed that the load from120%to150%in the process, concrete are already more than design compressive strength, steel pipe were not more than design strength, steel tube and concrete in radial began to appear from the trend,150%load steel tube and concrete surface almost all happen to slide, and only a few areas in binding condition.