Analysis on Dynamic Characteristics for a High Strength Light-weight Concrete Continuous Rigid-fFrame Bridge

According to the structure and design characteristic of a prestressed high strength light-weight continuous rigid-frame bridge,a dynamic model for it was established with FEM theory.Natural frequencies and primary mode shapes of it were calculated and analyzed ,dynamical characteristic of the same structure common concrete bridge were compared with it. Conclusions are drawn as follows: 1) Fundamental frequency of the high strength light-weight concrete bridge is 13.4% lower than that of the same structure common concrete one; as a result of depressing of mass and stiffness of the girder with using of light-weight concrete, self-shake frequency of the continuous rigid frame bridge descend on the whole.2) The first mode shape of the light-weight concrete continuous rigid frame bridge is longitudinal excursion, which is the same as the common concrete bridge. It indicates that the longitudinal stiffness of the bridge is smaller than that of other direction due to great influence of the flexible double thin-walled piers.