Research On Mechanical Performance And Failure Analysis Of The Tied-arch Bridge Under Different Cable Forms

As the core transmission member of the Tied-arch Bridges,the cable bears the task of transferring the permanent load and live load of the bridge to the arch ribs during the construction of the bridge or during the normal operation of the bridge.The layout form of cable directly affects the internal force distribution of the tied arch under the action of dead load and live load.In addition,this paper also studies the excitation response of structure under external force.Based on the relevant research results,this article discusses in depth the effects of different arrangement of cable on the internal force distribution of Tied-arch Bridges under dynamic load,static load and response spectrum loads.It also innovatively explored the excitation response of the net-shaped cable Tied-arch Bridges to the internal force of the structure after the cable sudden broking,so as to promote the application of the inclined cable system in the construction of Tied-arch Bridges of China.This article mainly completed the following work:First,through the investigation of a large number of papers at home and abroad,we understand the origin,development,structural classification,material characteristics,structural characteristics,stress characteristics,construction characteristics ect,of Tied-arch Bridges.There is a large proportion in the construction of Tied-arch Bridges,but most of Tied-arch Bridges are in the form of vertical-shaped cable.Therefore,it is necessary to study the internal force response of the Tied-arch Bridges under different load conditions.Through the simplification of the built bridge model,the finite element method is used to analyze the mechanical behavior of the Tied-arch Bridges in the live load and static load under different cable arrangements,and force transmission law.The thesis also compares the differences in the internal force of the arch rib,the internal force of the beam and the internal force of the cable.In the end,we analyzed the reasons.Firstly,we separately explored the free vibration characteristics of the Tied-arch Bridges in different cable forms.Then we selected the appropriate response spectrum and the suitable loading direction,according to the division of the seismic fortification area of the bridge and the location of the bridge,to explore the different internal force response of bridge under different cable forms.Finally,we compared the structural response of different cable forms,during earthquake and analyzed the influence of the cable forms on the structural system under seismic action.Taking the net-cable bridge as the research object,the live-and-death function and transient dynamics analysis module in ANASYS were used to simulate the sudden fracture of the cable due to cable corrosion,and the dynamic response of the Tied-arch Bridges due to the impact force released by the sudden breakage of cable of different lengths was explored.