Geometrical Nonlinear Analysis of Thin-Walled Box Girder with Variable Height

Based on the variation principle of potential energy and considering the shear lag effect of stresses on flanges and the geometrical nonlinearity of vertical deflection of structures,the nonlinear governing differential equation was derived and solved by using the spline least square collocation method for thin-walled box girder with a variable height.The numerical simulation results are in good agreement with those obtained from experiments.The research shows that the distribution of stresses at the inner support is more uneven than that in the middle section of the middle span for a three-span continuous thin-walled box girder with a variable height under uniform distributed loads,and the nonlinear effectiveness becomes more obvious with the increase of load.