Experimental Uncertainty Quantification of Flutter Derivatives for a PK Section Girder and Its Application on Probabilistic Flutter Analysis

Aerodynamic flutter instability could lead to the catastrophic collapse of flexible long-span bridges and needs to be prevented. This study investigated the variability of eight experimentally measured flutter derivatives (FDs) for a commonly used a Pasco–Kennewick (PK) section girder using a free vibration technique in a wind tunnel, which provided some new insights into the identification of FDs and supplemented the reliability analysis for buffeting and flutter performance. The aerodynamic uncertainties in terms of the dispersion of flutter coefficients were studied and two implications behind the extraction of FDs were discussed. The statistical and probabilistic behaviors of FDs at different reduced wind speeds were examined before generating sufficient independent random samples using the Monte Carlo (MC) approach. The intercorrelations between experimental FDs quantified by correlation coefficients were also examined and were employed to randomly sample the correlated FDs. The probabilistic flutter solutions in terms of critical wind speed propagated from the FDs uncertainties were studied utilizing step-by-step analysis, which resulted in several multimodal probability distributions of flutter onset. In addition, the role played by each FD on the variation of critical wind speed was discussed.