COMPARISON OF FULL-SCALE MEASUREMENT AND COMPUTATION OF WIND EFFECTS ON A CABLE-STAYED BRIDGE

This paper compares full-scale measurements of wind-induced accelerati on of the Saint-Nazaire cable-stayed bridge with quasi-steady aerodyna mic approach. The full scale turbulence was measured on the deck (thre e components on four masts), as well as the structural damping of vert ical modes and natural frequencies. Other dynamic characteristics of t he bridge were obtained by usual modal analysis and steady aerodynamic coefficients by section model tests. Comparisons have shown a satisfa ctory level of accuracy of the quasi-steady theory in predicting aerod ynamic damping. This theory, assuming aerodynamic admittance equal to unity, is conservative, as a rule, but it is not in the particular cas e of the vertical mode of the Saint-Nazaire bridge.