Study on the prearranged angle of girders in construction state for a thousand-meter scale cable-stayed bridge

As the optimization theory and method to the calculation of cantilever construction of girders is introduced.The example bridge is a long-span cable-stayed bridge of a 1088 m central span length under construction in China.The first order optimization method is used to determine the rational construction cable forces and the prearranged angle of girders.The girder elevation errors and the bending strain energy of the girders and the cable tower is the objective function.By making the objective function least,the tension forces of cables as well as the prearranged angle of girders in construction state are obtained.Using spatial nonlinear FEM,the actual cantilever construction process of steel box-shaped girders is simulated,and the prearranged angles of girders during construction are obtained.