Calculation Of Box Girder’s Distortion With Ordinary Differential Equations Method

In recent years, with the progress of society and promotion of science andtechnology, the large span bridges are constantly constructing. Box section has beenwidely used in large span bridge construction due to good whole space structureperformance. If there are less transverse diaphragm in the bridge with large cantilever,wide flange and thin-walled box girder, the distortion effect of which is very obviousand distortion stress can’t be neglected.Based on the ordinary differential equations established based on the plate grinderframe method, a new method using ordinary differential equations was put forward.According to the difference of boundary conditions, the member bar was divided intoseveral elements., then create distortion ordinary differential equations, By settingboundary conditions of the member bar, deformation compatibility among elements andthe control differential equations of the influence line, the analytical solution ofinfluence lines of distortion angle and bimoment were obtained through solvingordinary differential equations via Maple. Through loading on the influence line, thedistortion angle and bimoment on the appointed section can be calculated, and thedistortion stress can be acquired.According to the different boundary conditions of structure, the distortioncalculation of simply supported beam, restrained beam, one end hinged and the otherrestrained beam and continuous beam are separately discussed. On the distortion forceeffect of structure, the setting boundary conditions and solving progress are elaborated.The calculation method and programming of distortion envelope diagram to simplysupported beam are also discussed. In the last, a realistic bridge is exampled to clarifythe whole progress of the distortion effect calculation with ordinary differentialequations method.The ordinary differential equations method not only provide a new idea for solvingthe problems of distortion effect, but also make the calculation of box girder’s distortion more accurate and convenient. At the same time, it made an important step for theapplication of ordinary differential equations method in bridge.