| The upper part of the structure of prestressed concrete bridge of prestressed steel beam effective stress calculation is a key step in the design of prestressed concrete. Prestressed steel beam is equal to the effective stress of prestressed steel beam tension value minus the loss of prestress. But in the bridge engineering in the prestressed steel beam, the influence factor of stress loss of many, the construction process and use of the process structure of the causes of calculation errors are very complex, and ultimately difficult to obtain more accurate values of the effective prestress. The relevant specification gives the calculation of steel strands shall be several calculation formulas and the stress loss of prestressed design phase, basically the same specification according to calculated the loss of prestress steel bundle and the measured value, but there are still some error. The effective prestressed steel strand of the actual value and calculation value of error between can directly affect the structure of the life and the performance of the two difference is too large, or even lead to the occurrence of safety accidents of bridge. So we need to be more detailed and comprehensive grasp of prestressed steel beam in the actual use of the effective stress situations, as a basis to guide the prestress design, taking this as the use of reference to understand the performance of the bridge, and as a prerequisite to evaluate and test structure.In this study, by means of the finite element theory of a prestressed concrete curved bridge engineering example was analyzed and a series of calculation. First of all, it is concluded that the curved box girder under the action of the self weight stress characteristics, by exploring the state after the curved box beams with the radius of curvature and the change rules of steel beam tension sequence on the structure stress performance analysis of a comprehensive grasp of the box girder and the stress state of prestressed steel beam. Finally,using the traditional calculating effective stress theory and finite element calculation and analysis of effective stress of prestressed steel beam by comparison of the two methods in the engineering examples, two kinds of numerical results of close and similar, further box beam prestressed steel beam in different parts of the stress loss of. The calculated results confirms the correctness of theory of finite element modeling is used in this research, related research on similar box girder provides certain reference value. |
