Study On Mechanical Properties Of Ramp B Overpass Of Landscape Avenue

The development of modern bridge construction in China has made rapid progress,the efficiency and construction environment of on-site construction have been paid more and more consideration by various branches.Because of the long construction time of traditional construction measures in the construction of urban Bridges,the traffic will be affected to a certain extent,and the site environment will be affected to a greater extent.Steel-mixed composite girder bridge structure is adopted in the overpass between Binhe West Road and Landscape Avenue in Linfen City,which can save a lot of mold supporting process and template,immensely reduce the duration,and well fix the problem of urban traffic jam caused by bridge construction,showing a broad development prospect in urban Bridges.The material properties of steel and concrete can be given full play by steel-concrete composite girder bridge,the overall stress is reasonable,strong applicability,beautiful appearance,and has been gradually used in the construction of urban Bridges.However,in urban application,the design rationality of steel-concrete composite continuous beam and the cracking of the bridge deck in the negative bending regions are gradually became one of the emphasis of the industry.On the basis of summarizing the research status of steel-composite continuous beam at home and abroad,and the related factors affecting the composite girder are studied through practical engineering analysis,as well as the influence of different construction methods on the reasonable stress state in the negative bending moment area of composite continuous girder bridge.The main research contents of this paper are as follows:(1)In this thesis,the Diszinger method and the age-adjusted effective modulus method which can creep analyze steel-composite continuous girder Bridges is introduced.Then,the age-adjusted effective modulus method and the combined force method are used,the calculation formula of the internal force redistribution of steel-concrete composite continuous girder section considering the creep effect is derived.Finally,the theoretical calculation results are compared with the software results through an example to verify the reliability of the calculation results and provide reference for designers.(2)Midas Civil finite element software is used to emulate the full bridge.The stress distribution in each phase is calculated by analyzing the construction process.The results suggest that the stress of the steel beam in the composite beam does not exceed the requirements of the code,but the concrete part in the negative bending moment area appears a large tensile stress,resulting in the concrete will be subjected to a large tensile stress and crack.The mechanical characteristics of the composite structure under the most unfavorable load are calculated by the force analysis of the composite girder in the operational phase.The section stress,bending bearing capacity,shear bearing capacity and the maximum crack width of the bridge deck in the negative bending regions all accord with the requirements of the specification by calculation.(3)Several key design factors affecting the mechanical properties of steel-concrete composite continuous beam,such as the thickness of steel box girder floor,the height of web and the thickness of concrete slab,are analyzed by single factor variable,and the influence of each factor on the mechanical properties of the structure is summarized in detail.Meanwhile,the impressions of creep on the deflection and stress of the framework is contrasted and analyzed,and the influence of relative humidity on creep effect is obtained by changing the relative humidity.(4)The recent approaches to cut down the crack width of the bridge deck in the negative bending regions of steel-concrete composite continuous girder bridge are outlined,and diverse finite element models are established respectively to emulate the construction process according to the theoretical basis of the weight method,the method of adjusting the pouring sequence of concrete slab and the method of fulcrum jacking.The influence range of the three methods on the structure is compared through model calculation,united with actual engineering,propose the corresponding improved measures and proposals,the direction for the optimal construction method of composite continuous girder is rendered.