| Because LWAC have light weight-high strength, good earthquake resistant performance, high durability and remarkable economic benefits characteristic, its application on bridge engineering increases day by day. But its mechanics performance study about some problems badly need to be solved, such as the elastic model of LWAC is relatively low; how much is prestressing losses caused by Shrinkage and creep of concrete, local compression intensity in anchor, etc.In this paper prestressed space finite element model of LWAC hollow beam as research object is set up, by means of general software ANSYS, to analyze its mechanical performance, its sensibility and creep effect. According to the chapter order of this thesis, this paper contains such research result as following:1.Describe LWAC advantages and its state on bridge engineering in the world, and analyze FEM characteristic and current situation that finite element analyses about prestressed concrete hollow beam. On the basis of summarizing existing some problems of present LWAC study, main emphasis and goal of this text are put forward.2.Explaining basic theories and directing against the present commonly use finite element software, the general software ANSYS is selected to analyze prestressed LWAC hollow beam.3.Space finite element model of prestressed LWAC hollow beam is set up by choosing ascending secondary parabola as LWAC constitutive relationship, adopting restrained equation to simulate prestressing force and relative slip between concrete and steels. The result of calculation indicates: the section upper and lower stress value error between calculating value and testing value are in 5%, the deflection error is about 1%. Deflection and section stress are in the range of the request of norm and are in linear range along with the increasing load. The result of calculation on rip stress indicates: tip stress is most after drawing of prestrssed steels, the greatest stress of tip is probably 24.0~28MPa.4.The hollow beam that all adopt the lightweight aggregate concrete and the test beam whose tip is adopts 1m specially normal density concrete (SDC) are compared and analyzed. The analysis results indicate: the all LWAC hollow beam can meet the normal demand both in intensity and rigidity, but the greatest stress oftip is greater than the norm design value. So it is necessary to adopt certain SDC of length in tip. Then the beams of relatively 0.8m, 0. 9m, 1.1m and 1.2m SDC lengths in tip are compared and results indicate: the beam of 1.0m lengths SDC is smaller than other length SDC, about 6-10MPa.5.Through the comparison between the LWAC beam which adopt different elastic model and test beam, test beam and normal concrete beam under equal conditions, some problems are studied that the influence of hollow beam mechanical performance of the elastic model varies with density, and the difference between LWAC and normal concrete. The result shows: different density and elastic have a litter effect on tip stress. LWAC rigidity performance is lighter that the normal concrete on the whole. But the tip SDC improves the hollow beam mechanical performance: the greatest tip stress is smaller than the normal concrete beam.6.Through the numerical simulation of the LWAC creep effect, study prestressed LWAC hollow beam result creep effect in some time after drawing and reflection in using some time, and in contrast in normal concrete. The shows: the deflection and prestressing losses of LWAC is greater than that of normal concrete while the upper and lower stress is difference heavy. However while discrepancy of the upper and lower stress is in the small range, the creep effect of LWAC beam is greater than the normal concrete, but the deflection is basically the same. No matter the LWAC beam and the normal concrete beam it is the same the deflection can be reduced when the upper and the lower stress is different not too.The study on LWAC properties is a comprehensive and stronger synthesizing research field, involving more disciplines. And its engineering application prospect is ext...
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