Abstract：Long span cable-stayed bridge is a kind of flexible structure which is sensitive to wind effects, especiallyduring construction stages. Variation rule of wind-resistant behaviors during two types of construction process,containing single-cantilever and double-cantilever construction stages, are studied via numerical methods. The resultsshow that the lateralandtorsionalfundamental frequency decrease with the increase of the single-cantilever length,while the vertical item presents a rising tendency until thecantilevelengthreaches250m. With the increase of thedouble-cantilever length, all the three fundamental frequencies decrease, among which the lateral item decrease mostdistinctly. Moreover, it is found that the vertical buffeting response increase linearly within the single-cantilever length of300m. The same variation rule appears for the lateral item until the single-cantilever length reaches 200m, out of whichthe lateral buffeting response increases distinctly. For the double-cantilever construction states, the limitation ofcantilever length for linear variation of buffeting response is about 200m. The buffeting responses of single-cantileverconstruction states are generally dominated by the first vibration mode of the girder and significantly influenced by thesecond mode. For the double- cantilever construction states, however, the symmetric mode dominates the buffetingresponse.
2013, Vol. 32 
