Typhoon-Induced Nonstationary Buffeting Response of Long-Span Bridges

This paper presents a framework for predicting nonstationary buffeting responses of long-span cable-supported bridges under typhoon loading. First, based on the measurement data of typhoon winds, a non-stationary typhoon wind model is proposed, which includes time-varying mean wind speed, mean wind speed profile, and evolutionary power spectral density (EPSD) function. Typhoon loading is correspondingly described as time-varying mean wind force, nonstationary buffeting forces associated with time-dependent aerodynamic coefficients, and self-excited forces characterized by time-dependent aerodynamic derivatives. The analytical method in the time-frequency domain is then developed to compute time-varying mean responses and EPSD-expressed dynamic responses. The proposed framework is finally applied to compute nonstationary buffeting responses of the Stonecutters cable-stayed bridge in Hong Kong under Typhoon Dujuan. The results display the distinct time-varying properties of mean and standard deviation responses of the bridge under Typhoon Dujuan.