| Since the prestressed hollow beam has so many advantages ,such as strong span ability, easy to construe and can be volume-produced etc, it has been widely applied to bridge construction especially high grade highroad. But because of design, construction and lots of other reasons, local crack frequently exists during the hollow beam's pre-tension procedure and courses large economic losses. So it has great practical value to study the pre-tension performance of the prestressed hollow beam. At the same time, It also has important practical value that to find out what form of the hollow beam cross-section can bring best economy, due to the multitudinous application of the hollow beam. Therefor:First, the distribution of the stress when bearing local pressure for general structure is summarized by using Fea method in this paper. The universal law about the distribution of transversal stress in anchorage zone is obtained. Pesent standard local concrete strength theory and methods are presented. Meanwhile, the parts of anchorage zone for varied codes are computed and compared.Second, to know the stress and deformation of the hollow beam during the pre-tension procedure, a pre-tension performance experiment of an existing 16m hollow beam is taken.Then, a fine fea model of the test plate beam is set up in order to further know the stress-strain distribution of the hollow beam during pre-tension procedure. The result is compared with experiment outcome.In the end, the anchorage zone of hollow beam is topological optimization analysed by using Fea program. According to the result, the caculated model is modified and recomputed so to improve the condition of the stress concentration in the anchorage zone. At the same time, which cross-section form and dimension of prestressed hollow beam can bring better economic preformance is studied by writing computer program, and the optimum cross-section under the project condition in this paper is obtained.
|
PDF Full Text Request