Research On The Visual Of Box Girder’s Calculation Method

Box section have been widely used in the Modern Bridges,because of it’s goodstructural behavior.But the stress distribute along cross-section is not uniform underthe symmetrical load.It’s called shear lag effect in the enclosed box girder that willlead to stress focus and structural instability or destruction.Under the eccentricload,box girder will turn around and distortion which will cause turn stress anddistortion stress.All of those are adverse to box girder design.It’s not convenient to use these methods which appeared during the recent dozensyears,so we don’t consider those when we make a bridge design.Accordingly,thisdissertation use VB to conduct the visual design of box girder’s shear lag effect anddistortion.By it,we can get the stress which we need from inputting some basicparameters.The dissertation research the shear lag effect and distortion of box girder whichsection is single-box single-cell of rectangle and trapezoid and single-boxdouble-cell.For constant section box girder’s shear lag effect,I select the result ofvariational method to programming and for variable cross-section use differencemethod to create a liner equation which is solved by VB program.For distortion I useelastic foundation beam analogue method (BEF analogue method) to solve equalsection and stiffness method to solve variable cross-section.Then we can get thedistorting stress by loading a lication on the influence line of angle of distortion andbimoment which have got.The dissertation is made up of six chapters,the chapter one is simply introducethe characteristic of box girder section and VB program and the significance of thedissertation. The chapter two is do the visual design of shear lag of constant sectionbox girder, the chapter three is use the elastic foundation beam analogue method todo the design of box girder’s distortion,the chapter four is about variablecross-section box girder’s shear lag which is solved by difference method,the chapterfive is about the distortion of variable cross-section box girder which is settled bycombine stiffness method and elastic foundation beam analogue methodThere are some simple examples in the dissertation,from comparing its result byvisual program with Midas to check the reliability of visual program then make sure the result can be straight forwardly used in the bridge design.