Statistical buffeting response of flexible bridges influenced by errors in aeroelastic loading estimation

This study discusses the development of an algorithm for predicting the “statistical” buffeting response of a long-span bridge using Monte Carlo (MC) and Quasi-Monte Carlo (QMC) methods. The proposed methodology, based on the standard multi-mode approach for bridge buffeting, was used to compute the power spectral density of the buffeting modal forces and to derive the dynamic bridge response in the case that measurement errors in the aeroelastic loading were anticipated. Closed-form solution, derived through standard numerical integration, was used to validate the MC and QMC algorithms. Preliminary simulations were used for validation of the algorithms and the optimal selection of the number of integration points. second part of the study, fragility curves and surfaces of the dynamic response were numerically derived by accounting for experimental errors in the estimation of the aeroelastic loading. A collection of these curves describes the conditional exceedance probability of representative indicators, associated with a specific feature of the dynamic response, at a given mean wind velocity and direction. A set of thresholds, derived from such indicators, was proposed to characterize the structural performance.