Fatigue Life Analysis Of Suspension System Of Large Span Flexible Suspension Bridge In Mountainous Area

Bridges in the form of cable structures are increasingly used in the construction of modern bridges.Especially when mountainous areas need to cross canyons,rivers and rivers,suspension bridges are considered more bridge types.In the southwestern region where the economy is relatively backward and the traffic volume is small,the application of flexible suspension bridges is more extensive.Due to the harsh mountain environment,the fatigue life of bridge types is also becoming more and more obvious.The boom is an important force-transmitting member in the structure of the suspension bridge.Most of the finished booms are made of steel and are prone to fatigue safety problems.The fatigue of the boom has great hidden dangers to the safe operation of the suspension bridge.The disaster brought by it is difficult to estimate,bringing huge economic losses and personal injury to the country and the people.This requires fatigue life prediction of the flexible suspension bridge boom to ensure the safe operation of the bridge.Based on the existing research,this paper analyzes the fatigue life of the long-span flexible suspension bridge boom with the Xiaohekou Bridge in the Makoushan Reservoir Area of ??Jinping County as the background:(1)The development history and structural characteristics of the flexible suspension bridge and the stress characteristics and advantages of the flexible suspension bridge are introduced.Lists various bridge accidents caused by the destruction of the boom structure at home and abroad.The main cause of the accident is the corrosion of the steel.(2)Introduce the basic concept of fatigue load spectrum and the development status of fatigue load spectrum at home and abroad,as well as the value method and fatigue design method of fatigue load spectrum of highway bridges at home and abroad.(3)Corrosion of the boom is the main cause of the suspension bridge accident.The corrosion principle of the suspension bridge suspension rod and various influencing factors of the suspension rod corrosion are introduced.The corrosion rate of the suspension rod and the post-corrosion suspension rod are introduced throughtheory.The intensity changes.Corresponding daily protection and maintenance measures are proposed for the problem of boom corrosion.(4)According to the Xiaohekou Bridge in the Makoushan Reservoir Area of ?? Jinping County,the finite element software was used to establish the full bridge model.After the fatigue load of the whole bridge is loaded,the dynamic response of the boom under fatigue load is obtained.Considering the influence of wind load,the dynamic response of the boom is obtained by loading the wind load on the bridge.The fatigue life of the suspension bridge suspension rod is estimated by using the fatigue analysis curve in the current specification combined with the commonly used fatigue cumulative damage theory.(5)The calculation of different working conditions was carried out when the fatigue life analysis of the suspension bridge boom was carried out.The fatigue life of the boom was analyzed by loading with two different fatigue vehicle loads.The service life of the boom under corrosion was investigated under two different fatigue vehicle loads.The boom was subjected to wind load and corrosion.The fatigue life under the joint action is predicted.