Study On Dynamic Characteristics And Wind Resistance Stability Of Pedestrian Cable-stayed Bridge

With the rapid development of social economy and the gradual improvement of people’s aesthetic level,people are more and more inclined to the bridge with beautiful appearance and complex structure.Cable-stayed Bridges with uniform force and strong sense of rhythm will appear more and more in pedestrian Bridges.The static analysis of bridge structures is a key link in the process of bridge design,but for the pedestrian cablestayed bridge,the main girder width compared with highway cable-stayed bridge girder width narrow,so the pedestrian cable-stayed bridge structure stiffness is smaller than highway cable-stayed bridge,the dynamic response problem become more prominent,makes dynamic analysis is just as important,this makes the static analysis was carried out on the pedestrian bridge at the same time,it must be carried out on the pedestrian bridge dynamic analysis.Based on the practical engineering background of the pedestrian cablestayed bridge in dushan town,the static analysis and dynamic analysis of the bridge are carried out in detail,and the relationship between the width of the main beam,the section type of the main beam and the critical flutter wind speed of the single-tower double-cablestayed bridge is discussed.This paper mainly carried out the following aspects of work:(1)Taking the pedestrian cable-stayed bridge in Dushan town as the engineering background,the full bridge model is established by using finite element software.The stress state of each component is obtained by analyzing the initial equilibrium state of the completed bridge,and then the stress state of each component is obtained by analyzing the stress state during its operation stage.The static analysis results show that the strength and stiffness of the bridge meet the design requirements when the main girder of the pedestrian cable-stayed bridge adopts the open section.(2)Although the pedestrian cable-stayed bridge can meet the requirements of static analysis,it may not meet the requirements of dynamic analysis.Therefore,this paper analyzes the natural vibration characteristics of the bridge by using the finite element software,and then focuses on the flutter stability analysis of the bridge combined with the wind resistant design code of the bridge.The results show that the flutter stability of the bridge does not meet the requirements of the code.Then,the factors affecting the flutter stability index are discussed.Two schemes are proposed to improve the flutter stability of the bridge,i.e.increasing the width of the main girder to 11.6m and changing the section type of the main beam(the open section becomes the box section).(3)In order to further study the relationship between the width of the main beam,the section type of the main beam and the critical wind speed of flutter of the single tower and double cable plane pedestrian cable-stayed bridge,the flutter stability of the pedestrian cable-stayed bridge with different main span,girder section type and girder width is analyzed by using the finite element software.It is considered that the flutter critical wind speed will increase with the increase of the girder width,but when the girder width reaches a certain value,the flutter critical wind speed will decrease slightly when the girder width continues to increase.In order to ensure the flutter stability of single tower and double cable plane pedestrian cable-stayed bridge to meet the design requirements,the design reference wind speed,main span span,girder width and girder section type should meet certain relationship,and the relationship curve is drawn,which provides reference for the wind resistance design of single tower and double cable plane pedestrian cable-stayed bridge in the future.