The Influence Of Flexural And Shear Properties By Concrete Encasement For Box Girder Bridge With Corrugated Steel Web

Box girder bridge with corrugated steel web as a kind of new bridge structure form has obvious advantages, can effectively improve the mechanical performance of box girder bridge with corrugated steel web. It is mainly composed of concrete roof, concrete floor,corrugated steel web and prestressed cables. In the past structure design, only considered the shear of corrugated steel web, but in the actual construction of long-span box girder bridge with corrugated steel web, always arrangement concrete encasement near zero block of the pier top to facilitate the corrugated steel web under the force. So the concrete encasement will affect the force performance of corrugated steel web. In order to clear the influence law,making the investigations of the box girder bridge with corrugated steel web more perfect,it is necessary to research the laws of the performance impact influenced by the bending and shearing resistance of the structure.Access to and summarize a large number of domestic and foreign research data, this paper introduces the corrugated steel web’s development history and research status at home and abroad, expound the box girder bridge with corrugated steel web’s bending and shearing calculation analysis theory. The thesis on the basis of a box girder bridge with corrugated steel web, established different thickness and length of concrete encasement finite element model. Through comparing analysis by finite element analysis software, deply researched the distribution of strain along the beam, the shear lag effect, deflection, the shear ratio of concrete encasement resisted and ultimate load of elastic bucking. The results show that:Concrete encasement can make the cross section strain decrease of the concrete roof and floor and make the cross section strain increase of the corrugated steel web; Concrete encasement have great influence for the bending behavior on the top of the pier but have little impact on the midspan’deflection; Decorate concrete encasement can reduce shear lag effect;When the thickness of the concrete encasement more than 40 cm, the cross section shearing force is mainly composed by concrete encasement; The length of concrete encasement is not as long as possible; Concrete encasement can limit the lateral deformation of corrugated steel web and significantly reduced the corrugated steel web’s shear stress before bucking; Whenthe thickness of concrete encasement more than 80 cm, the bucking limit load gradually stabilized.