The Research On Temperature Field And Temperature Effect Of Π Girder P.C.Cable-stayed Bridge

There are numerous factors to influence the force received by concrete double-cable-planesπ-type-girder cable-stayed bridge, but the temperature load is one of the most sensitive factors. Temperature effect directly impacts on the safety of the construction process and the reliability of the stage of use. Therefore, the research of temperature gradient and effect ofπ-type-girder cable-stayed bridge has great significance to improving the construction and design.Taking Poyang Lake Bridge in Jiang Xi province as the engineering background, this thesis will study the temperature field of concrete cable-stayed bridgeπtype girder during constructed stage with the amount of temperature test data obtained in the engineering construction by the supervisors. Which provide the reference for establishing related norms of the bridge. In this thesis, the mian tasks finished are as follows:(1)On the basis of the regression analysis of on-site-test temperature data, the variation law ofπ-type-girder under different circumstances is obtained. Comparative analysis of the cable-stayed, the atmosphere, the temperature of beam rib variation of temperature and atmospheric, as well as cable-stayed cable-stayed with the beam and rib analyzed temperature, and atmospheric temperature reached smaller cable-stayed, in the±3℃or less. During the construction phase of cable-stayed beam rib and the average temperature difference more than±5℃.(2)Using finite element program(ANSYS) , simulation calculation analysis is carried out to study the temperature gradient ofπ-type-girder with the boundary conditions of the real bridge. Compared with the on-site-test data, finally a fitting of the vertical temperature gradient is obtained.(3)With the Software of MIDAS, it will be built to the whole bridge three-dimensional finite element model, and then be amended. On the basis of these, this thesis will analyze the temperature effect of Poyang Lake Bridge in order to obtain the construction phase of the temperature effect is much larger than in the completed status of the bridge, system temperature, temperature gradient on the tower structure was less affected, the main beam temperature gradient influence on the structure, demand structure of beam temperature on the most affected.(4)This thesis will make a numerical analysis of the bridge's hydration heat of mass concrete to form a numerical model, and then verify the accuracy of numerical model through a large number of on-site testing hydration heat of the temperature data. With the sensitivity analysis of the factors of impacting hydration heat, it is to draw the general selection principles of construction related parameters of mass concrete . At last, Combining the on-site process of temperature control, Come to the text of the control measures put forward practical good.