Analysis On Mechanical Properties And Optimization Of Steel-concrete Composite Deck System Based On Measured Traffic Flow

The steel-concrete composite deck system has plenty of advantages such as light,transportation,easy to install,good stress condition and so on,It's widely used in the construction of long-span bridges in China.With the increase of the overall traffic flow and the difference of the regional distribution of the traffic flow,Just obey the standard is hard to calculate the vehicle live load effect in the design of bridge structure.Otherwise,With the increase of span of long-span bridge,The influence of bridge's structure form and construction size is more and more obvious.So it's important to choose the appropriate bridge's structure form and construction size.Based on the steel-concrete composite deck system of the long-span bridge,Collecting the information of vehicle load by WIM system.Calculate the equivalent vehicle load and the live load effect.Then compared the load effect caused by the actual measurement vehicle load and the standard live load.Considering the influence on the stress of itself caused by the structural parameters of steel-concrete composite deck system and how to choose the optimal value of the structural parameters,Based on the workbench,Using Workbench as the computing platform,Combining the theory of orthogonal experimental design and response surface methodology,Finished the sensitivity analysis and optimization design of the steel-concrete composite deck system and the conclusion will provide reference for the same type of bridge design in the future,The specific work are as follows:(1)Based on 3 months' WIM data from June to August 2016 of the bridge,Calculated the equal axle load caused by the actual measurement vehicle load refer to the standard's probability design method.Comparing the static load effect caused by the actual measurement equal live load and the standard live load on the section model of steel-concrete composite deck system,The results show that the load effect caused by the actual measurement vehicle load is much bigger than which caused by the standard live load,If the design is based on the standard live load,The service life of the most important vehicle lane will much lower than the design value under the cycle action of actual measurement live load.(2)Take the steel-concrete composite deck system as the research object,using orthogonal design method,The main calculation is the effect of stress on Steel-concrete composite section caused by the thickness of concrete slab,concrete elastic modulus,the height of steel beam and the Steel truss,The sensitivity order of steel-concrete composite deck system to the above parameters is determined;(3)Based on the conclusion of the parameter sensitivity analysis,Combined with the response surface optimization theory,Using the large-scale general finite element software Workbench to optimize the cross section of steel-concrete composite deck system,After optimization,the mass M of the steel-concrete composite deck system is reduced by about 8.86%,and the simulation results are consistent with the predicted values calculated by the response surface method.On the premise of ensuring the safe use performance of bridge structure during service period,Reducing the size of the composite section,Cutting down the engineering cost,providing the concept of bridge structure design model for the high level designer.