| The characteristics of the flexible suspension bridge make it more suitable for areas with relatively low economic level,relatively small traffic volume,and relatively low load levels.Therefore,the use of flexible suspension bridges in southwest mountainous areas in China is very extensive.As a kind of suspension bridge,the flexible suspension bridge takes the cable structure as its main load-bearing component.Suspension bridge cable structure uses steel,and steel is prone to fatigue.Compared to rigid suspension bridges,flexible suspension bridges are subject to more pronounced fatigue problems because of their tendency to deform after being stressed.The components with fatigue problems will bring great potential safety hazards to the suspension bridges.It is necessary to estimate the fatigue life of the cable structures of suspension bridges so as to ensure that they will not cause fatigue damage and cause loss of life and property during the service period.Based on the existing researches,this paper takes Yunlong Bridge Bridge(1-138 m flexible suspension bridge)as the engineering background,and analyzes the fatigue life of hangers and main cable of the flexible suspension bridge.The main tasks include:(1)Summarizing and collating large amounts of data,summarizing important factors affecting fatigue life and fatigue strength,and analyzing methods for determining fatigue life.(2)Introduceing the method of determining the domestic fatigue load spectrum of highways.According to the survey of traffic volume in the area where the project is located and other related researches,the fatigue load spectrum used in the fatigue life analysis of the project is determined.(3)Using finite element software to model the full bridge of the engineering example.Loading the fatigue load spectrum of the vehicle to analyze the time history of the fatigue load,and determine the fatigue location of the boom and main cable of the Chestnut Bridge and obtain the dangerous part.Stress response.(4)Nominal stress method and Miner theory are used to estimate the fatigue life of hangers and main cable based on the influence parameters,and the calculation results are briefly analyzed.The calculation results show that the fatigue danger of the boom is in the area linked with the main cable,and the longest boom near the bridge tower has the shortest life;the fatigue danger of the main cable occurs in the anchorage area and the top of the bridge tower;flexible suspension bridge boom The fatigue life of the main cable is shorter than that of a rigid suspension bridge.In the daily monitoring,maintenance and overhaul,attention should be paid to the danger of fatigue. |
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