Research Of Calculation And Analysis Of PC Box Girder Structure With Long Span

PC box-girder structure, with its various advantages, has been widely applied in bridge engineering. The aim of this research project is to deal with the existing problems in the calculation and analysis of the PC box-girder structure with long-span. On the basis of an engineering practice of non-navigable channel superstructure of Hangzhou Bay Bridge, in-depth research has been carried out on the following aspects.To develop a simplified calculation method for the global analysis of the PC box-girder structure, the units of web plate and wing plate were constructed, and the high order axial displacement function was introduced. As a result, based on the plate beam theory it put forward the method of global analysis which takes account of warping, shear log, distortion and the variation of the plate thickness. The accuracy and efficiency of this method has been validated by comparing with the results of the solid element.In the accurate calculation research of the PC box-girder structure, the finite element software has been used as a platform to create expedite model of the entity in three-dimension, and the equivalent nodal force method has been introduced to analyze the entity of PC box structure in the space. It is observed that this method is direct, detailed and precise, when simulating the real engineering projects.The purpose of the calculation and experimental research of anchorage zone under the effect of large-tonnage PC anchors is to validate the blueprint of the non-navigable channel superstructure of Hangzhou Bay Bridge. To calculate, validate and analyze the anchorage strength and crack resistance of the PC box-girder under the effect of large-tonnage PC anchors, several different normative calculation methods have been compared, three-dimensional finite element method has been used to simulate the entity under the effect the anchor devices and the results from the stress testing on spot has been analyzed.In the temperature and stress field calculation methodology research of the PC box-girder, based on the finite element principle and the consideration of geography and temperature, a method is developed to calculate the stress field under different temperatures by using thermal instantaneousanalysis and thermal-structural coupling analysis techniques. Depend on the calculation, the characteristics of the temperature effect on the PC box structured bridge was summarized. By comparing the results with the public bridge temperature normative calculation, on one hand the deficiencies of the normative calculation method has been shown, on the other hand the statistics evaluation method of maintaining and building the PC box has been put forward. The accuracy of this method was proved by comparing with the experimental results. In addition, various normal ways in controlling the temperature of the PC box were evaluated with the example of construction blueprint of global pre-molding of PC box of Hangzhou Bay Bridge. Finally it discussed the changes of temperature, stress in the early stage, so that some suggestions were given about the anti-crack measures in the early stage.In the ultimate bearing capacity calculation research of PC box-girder structure, the non-bilinearity finite fabric sect element method and the displacement increment methods with full freedom were set up. The precision efficiency of different increment methods were compared by calculatbg examples. The bearing capacity experiment of the original girder model was also carried out to investigate the features of its limit state and to validate its applicability and accuracy. Take example by Hangzhou Bay bridge, the bearing capacity of the PC box-girder structure in the process of construction was calculated and the redistribution law of the internal force in the structure which develops plasticity was investigated.The conclusion and research results in this thesis can be taken as reference to the calculation design and construction of the PC box-girder structures.