METHOD OF REASONABLE FINISHED STATE OF CONCRETE INCLINED PYLON CABLE-STAYED BRIDGE WITH BACKSTAYS

A new type of bridge is the concrete inclined pylon cable-stayed bridge with backstays, which is different from the conventional cable-stayed bridge in structure and mechanical behavior. Main span of this bridge balances through both inclined pylon and the stowage of side span, therefore, bending moment of inclined pylon, displacement, and key sections' stresses are important for determination of reasonable finished state, besides, the top of pier must have support reaction. There are lots of methods to determine reasonable finished state. However, it is difficult to determine the optimal cable tension using just one method, besides, different methods must be adopted for different type of bridges. As a result, it is feasible to combine minimum bending energy with influence matrix method. The basic approach is: the initial cable tension can be determined though minimum bending energy method, then the cable tension is adjusted though influence matrix, whose constraint conditions are stresses of key sections and support reaction from the top of pier, at last, the optimal cable tension of the finished state is determined. This method is not only simple but also very clear. and it achieves a good effect in determining the reasonable finished state of this type of bridge.