The Dynamic Characteristic And Cable Tensions Optimization Study Of (41+158+96)m Leaning Single Tower Cable-stayed Bridge Of Spatial Cable

Because of excellent performance, beautiful appearance and other advantages, Cable-stayed Bridge has become one of bridge models with most advantages. However, many problems come out with the growth of long span, especially self-vibration characteristic of structure, vehicle collision impact and other dynamic problems. Thus, dynamic characteristic analysis becomes one key research point. Taking the project of Sanwei Road cable-stayed bridge, this thesis establishes 3D integrated model with Midas Civil FEM software, analyzes the impact of stiffness of cable support tower, initial cable tensile force and assistant pier of Sanwei Road cable-stayed bridge on the self-vibration characteristic, discusses the influence factors.With the highly redundant structure, cable-stayed bridge has obviously different features from other bridge models. Its line shape and internal force are realized by adjusting the cable tensile forces. And with the growth of long span, the impact of cable tensile forces becomes more obvious. Therefore, cable tensile force becomes the essential part of design. Generally, the design should firstly determine the cable tensile forces of the completed status of bridge, then determine the cable tensile forces in the construction stage with Formal-Backward method or Forward Iteration Method, and finally reach the goal of the completed status of bridge by controlling construction process. Then, how to determine the reasonable completed status of bridge has become the primary issue to be dissolved by the designer, and that whether the completed status of bridge of this anchorself-type leaning single tower cable-stayed bridge has reasonable cable tensile forces could directly impact the reliability and applicability of the structure.This thesis firstly summarizes and compares various methods to determine reasonable cable tensile forces of cable-stayed bridge to demonstrate the focus and the limitation of various methods. Using Midas Civil FEM software, this thesis establishes whole bridge model, then utilizes unknown load coefficient method in Midas Civil, and controls bending moment of main grinder, internal force of main tower, displacement of tower top to obtain initial forces, considering line shape of main grinder and assistant pillar reaction. Later, This thesis conducts further adjustments to make the structure reach the completed status of bridge by considering the change trending of cable tensile forces. This thesis utilizes the forward-calculation function of considering Not cooperate close together in Midas/civil to analyze cable tensile force in the construction stage, and finally get the reasonable cable tensile forces in the construction stage.