THEORETICAL ANALYSIS FOR STATIC AND DYNAMIC CHARACTERISTICS OF MULTI-SIMPLE-SPAN BRIDGE WITH CONTINUOUS DECK

Because a multi-simple-span bridge introduces many expansion joints that negatively affect the riding comfort and structural maintenance, a continuous deck is becoming an alternative to the expansion joints to improve the performance of this kind of bridge. However, the method for the mechanical analysis of this partially continuous bridge structure is deficient, and the application and optimization are impeded. In this paper, a model for a simple-supported beam with boundary rotational springs is presented to analyze the mechanical properties of a multi-simple-span bridge with a continuous deck, in which the spring stiffness is obtained from the tensional, bending and shearing analyses of link slabs and adjacent bridge girders. Based on this model, the static and dynamic performances of a unconventional bridge structure are analyzed using the method similar to that applied on a conventional simple-supported girder bridge, and the equations of static displacement, internal force, natural frequency and vibration mode are obtained. The numerical analysis of a practical bridge suggests that the stiffness of a rotational spring from a theoretical equation agrees well with that from 3D finite element analysis. The static deflection, strain and natural frequency from the model considering the boundary rotational spring are closed to the test results of a bridge, and better than those obtained from the model of a simple-supported beam. Thusly, the new method can be applied in the mechanical analysis of a multi-simple-span bridge with a continuous deck.