Study On The Sensitivity Of Long-term Deflection And Sunshine Effect On Long-span Continuous Rigid Frame Bridge On Highway

With the advantages of strong bearing capacity, good seismic capacity, quick construction and beautiful and simple bridge body, the long-span continuous rigid frame bridge on highway has been rapidly developed. But it has been found that the long-term deflection of the main girder will bring inconvenience to the normal operation of the bridge and even may cause danger to driving safety. Thus, this thesis carries out a detailed analysis on the main factors that influence long-term deflection, i.e. long-term creep effect and sunshine effect. The main researches include:With Tsang Ka Bridge which spans160meters as the engineering background, an elaborate finite element model is built by MIDAS/CIVIL. On this basis, the thesis analyses the deformation in its construction process and operation stage of the whole bridge, and studies the influences that made by the annual average relative humidity, age of concrete, the whole and local stiffness loss of main girder, and the longitudinal prestress loss on long-term creep effect. The result shows that the annual average relative humidity and the longitudinal prestress loss make a greater effect on long-term creep effect than others.The distribution of temperature field of long-span continuous rigid frame bridge on highway box girder and the calculation and analysis method of3D temperature effect have been introduced briefly in this thesis. The author builds an entity model of Tsang Ka Bridge by using block element on ANSYS, and does a research on the distribution of temperature field and3D temperature effect of box girder in summer and winter, with the overall consideration of the factors such as solar radiation, convective heat exchange, radiation heat transfer, changing progress of daily temperature and so forth. The result indicates that the vertical temperature gradient of main girder regulated in the existing code is a little smaller and the transverse temperature has been ignored, which results in a smaller tensile stress extreme value of the longitudinal and transverse normal stress of main girder when calculating according to the code.