Analysis Method Of Alarming For Long-span Suspension Bridges Based On Redundancy

As an important part of national transportation system,bridge structure bears the important task of national economic development,and plays a significant role in high-speed steady growth of the country's and development.To make sure bridges give full playing to the roll,bridge structure should keep the normal operation.However,growing traffic and overload cars regulation is lax moment threatening the health of bridge structure,once the bridge damage accumulating rapidly in a short time,the sudden disaster will be inevitable,and bringing serious damage to the development of the socialist harmonious society,caused a major threat to people's property security.Therefore,bridge structure damage alarming,has become one of the important link of major bridge structure health monitoring.This thesis is based on redundancy theory and finite element analysis,the early warning analysis of long span suspension bridges is proposed,provided a theoretical basis for the operation of large suspension bridge damage early-warning.In this thesis,main work is as follows:1.In order to realize fast accurately obtained suspension bridge into the bridge linear,putted forward in combination with the cable shape analytic method and finite element analysis and the calculation method of taking a long-span suspension bridge under construction as the research object,using the MATLAB program compiled iterative calculation,and contrast calculated results to MIDAS CIVIL and find form program based on ANSYS.2.The importance coefficient based on the sling suspension bridge redundancy analysis method is putted forward,using suspension bridge cable strain energy of the whole structure,determine the importance coefficient of sling,for all kinds of the most unfavorable damaged conditions of redundancy for quantitative calculation of suspension bridges,at the same time analyzed damage of the structure of the stress increment.The analysis results show that the closer the redundancy of long-span suspension bridge across the sling failure effect,the greater the thought when redundancy is less than 0.201,the stress variation in the bridge is huge,and the trend of the overall collapse,no longer fit to continue to bear the load.3.With suspension bridge steel-mix combined beam system as the research object,established a multi-scale finite element model of suspension bridges,the importance coefficient is larger near the line of main girder segment of the local beam refined modeling,determine the action of stiffening stress under the car sling failure,analyzes the failure of suspension bridge steel sling-mixed combining beam local stress.Results show that the fracture of the sling stiffening girder and the security of local area instead of improving,and the adjacent line near the beam section in great tension stress,the bridge panel has reached the limit tensile stress of concrete,concrete bridge panel in collapse.