Flutter reliability analysis for stiffening girders of long-span suspension bridges during construction

Deterministic flutter analysis for stiffening girders of long-span suspension bridges during construction cannot meet the needs, and probability analysis is necessary. Using wind tunnel test and reliability analysis, the flutter reliabilities of the stiffening girders of a long-span suspension bridge during construction were computed, and the effects of some factors on the flutter reliability were investigated. Results show that the probability method is better than the deterministic method, and the flutter stability is the worst at the construction early stages of the suspension bridge. There exists a nonlinear relationship between the failure probability of flutter during construction and the design wind speeds, and larger design wind speed corresponds to larger failure probability. The coefficients of variation have no effect on the failure probability. Increases in land surface roughness and angle of attack results in larger failure probability. It is dangerous if the turbulent characteristics of wind are ignored for the initial construction stage, while it is conservative if the turbulent characteristics of wind are ignored for the later construction stages. The flutter reliability of non-symmetric construction for stiffening girders is better than that of symmetric construction. It is more effective to increase the eccentric masses than to augment the eccentric distances for reducing the failure probability. The vertical cross suspenders can increase the flutter reliability only during later stages of construction for symmetric construction of stiffening girders, while reducing the flutter reliability during intermediate stages.