Research On Cable Force Of Reasonable Construction State Of Extradosed Cable-stayed Bridge

Extradosed cable-stayed bridge is a bridge between continuous girder bridge and cable-stayed bridge, which is the cable bearing combination system of three basic components by cable, tower and beam. It has a variety of forms, good appearance, large spanning capacity and the advantages of short tower, rigid beam, concentrated cable. Extradosed cable-stayed bridge is also a kind of bridge with more construction difficulty and complex technology.lt is very important to determine a reasonable construction state to the structure safety and beautiful line shape of main girder during construction period.The cables can be adjusted,so to choose a reasonable cable force is the core problem in construction period of extradosed cable-stayed bridgeBased on the project of Changshan extradosed cable-stayed bridge as the background, build a Midas/Civil finite element model for the analysis of the stay cable. First calculate the bending moment feasible region of the main girder, verify the rationality of completion cable force, and the cable force is designed to bridge for resonable bridge completion stage, this group of cable force values determine the reasonable bridge completion state; Then take the reasonable bridge completion state as the target, determine the cable force value of extradosed cable-stayed bridge in the process of construction. Combined with the characteristics of construction and in the case of ensuring the reasonable safe process of the construction, propose unknown load factors method and use forward analysis to solve the cable force in the process of construction, and keep extradosed cable-stayed bridge construction in safe state; Finally use Pressure test method and frequency method for the test of construction cable force and completion cable force, test whether the construction cable force and completion cable force values meet the design requirements.This paper provides a reference for related extradosed cable-stayed bridge solution of cable force, it has practical research significance.