Nonlinear aerodynamic stability of the maximum cantilever state of long- span continuous steel box bridge in the construction process was analyzed. Aerodynamic stability analyses based on wind load nonlinearity and geometry nonlinearity were proposed. A cross-sea bridge was taken as the subject, and the effects of static wind force and buffeting force were calculated and the maximum RMS of displacement response in the longest cantilever state was determined. The nonlinear aerodynamic stability analysis of the maximum cantilever state was carried out taking static wind force and buffeting force as the external load and the displacement under the dead load as initial defect. The results show that with the increase of wind speed, the horizontal and vertical displacement of the cantilever end and mid-span of the steel box girder both had a nonlinear increasing trend; the displacement response changed with the positive and negative transformation of wind attack angle, so the influence of wind load should not be ignored. Due to high stiffness of the steel box girder, the buckling critical state did not appear within the wind speed of 120 m·s^-1, but the horizontal and vertical displacement of the cantilever end were relatively large. Three measures for wind resistance were proposed to ensure safety of the personnel and smooth closure process.

bridge engineering  /  high wind speed region  /  aerodynamic stability  /  buffeting force