Optimization on Stay Cable's Initial Tension Force for Extradosed Cable-Stayed Bridge

Initial tension force of stay cables have large influence on mechanical performance for extradosed cable-stayed bridges (ECSB) at state of completed bridge. The paper defines relationship between structural members' internal force and initial tension force of stay cables based on influence matrix method. Setting the minimum potential energy of whole structure as objective function, the optimal model of quadratic linear programming for initial tension force of stay cables is presented. Embedded the optimal model in general finite element program, optimal soft for initial tension force of ECSB stay cables is programmed and named CBOP. Using the optimal program to a two spans ECSB, the maximum positive and negative moment of girder are decreased 14% and 49% respectively while total initial tension force only increased 8%, meanwhile the girder's moment distribution is more homogeneous along girder. The optimal method and program is useful and effective to determine and adjust of initial tension force of stay cables for ECSB.