Efficient Approach for Reliability Assessments on Aeroinstability of Long-Span Bridges

Abstract

Probabilistic evaluation on aeroinstability of long-span bridges is a practical requirement because the aeroinstability behaviors of a bridge are seriously affected by structural uncertainties and wind fluctuations. In this paper, a practical framework is proposed to perform reliability analyses on flutter and aerostatic instability of a long-span bridge, in which uncertainties from structural properties and the wind environment are considered. Modified limit state functions for aeroinstability reliability analyses are first established. Then the critical wind speeds in the functions are evaluated by empirical formulas. The structural dynamic characteristics involved in the empirical formulas are expressed by structural random variables with approximate functions based on the idea of response surface method, and a Monte Carlo simulation is further conducted to obtain the statistical properties of the critical wind speeds. Finally, the failure probability of aeroinstability is obtained by the conventional reliability analytical method. The present approach is applied to the reliability analysis of a long-span cable-stayed bridge, indicating the effectiveness of this approach.