Study On Operation Safety Of Large-span Self-anchored Suspension Bridge

The large-span self-anchored suspension bridge is a kind of flexible suspensionbridge cable system. Sling is the main force component of the self-anchoredsuspension bridge, its safety and durability are related to the operation safety of thestructure of the bridge. Once damaged, it can seriously affect the safety of bridgestructure. In addition, the impact that because of thickness of the steel box girder ofthe bridge deck pavement, the environmental temperature variation and overloadedvehicles on a long-span self-anchored suspension bridge cannot be ignored. In thispaper, using the Taohuayu Yellow River Bridge three-span suspension bridge as thebackground, a long-span self-anchored suspension bridge’s operation safety isanalyzed. Main work contents and conclusions are as follows:1. Summarized the self-anchored suspension bridge structural system,mechanical characteristics, since the anchor suspension bridge for well into the stateof the bridge research, derrick damage simulation method, the bridge pavement,temperature effect and summarized the progress on research of overloaded vehicles.2. Using the Midas/Civil software to establish the Taohuayu YellowRiver Bridge’s whole bridge model, use of break up the whole into parts, andthen combined into a step by step to determine bridge method to determine the cableforce, calculated the main cable geometric linear and unstressed length of sling, gotthe reasonable finished state of self-anchored suspension bridge.3. On the basis of reasonable finished state, simulation analysis was carried outon the sling fracture by static method. On the basis of existing theory, thinking thatwhen the steel structure to achieve the yield strength or the rest of the derrick ofmaximum tensile stress to material allowable tensile stress, the structure is damaged;choosing a different location and different breakage condition of derrick, analyzedthe effect on the safety of the bridge structure. Through the analysis, concluding thatthe effect on account of single derrick fracturing on structure static performance is limited, it will affect the main structure of the bridge and increase the difficulty ofthe repair of the bridge when there is two or three continuous derricks fracture. Somemeasures should be taken to protect structure’s strengthen, particularly to the shortbooms that near the middle bridge and the adjacent booms that near the fracturederrick.4. On the basis of the state of the bridge in the second chapter of this article, inconstruction stage, by changing the thickness of the pavement and different locationto simulate the surfacing layer inhomogeneous, analyzed the stress and deformationof the structure of the bridge. Deck pavement layer thickness increases with the mainbeam displacement is proportional, it has little impact on sling force change and haslittle impact on bridge’s overall stress and operation safety.5. On the basis of the theory of temperature effect, the overall risetemperature and temperature gradient analysis, analyzed the cable force of thestructure and displacement change and analyzed the integral structure safety. It isconcluded that the overall rise cooling effect on the self-anchored suspension bridgeis little, the influence of the temperature difference between the roof and floor ismore significant, and the effect on the change of steel box girder of because of dailytemperature is low.6. On the basis of the state into a bridge, analyzed the influence of overload onstructure and provided the basis for operation safety of Bridges. With the increase ofoverload coefficient, the maximum vertical displacement of girder and the maincable stress increase. Calculating the main beam safety overload is2.04and the maincable safety overload is1.32. The overloaded vehicles on the operational safety ofthe self-anchored suspension bridge has a great affected.