Using an active turbulence grid in wind tunnel testing of bridges: An experimental study

Abstract

The goal of the PhD project was to study how turbulence may affect the aerodynamic properties of long-span suspension bridges. To study turbulence effects, a new active turbulence grid was used to generate turbulence in a wind tunnel, and it was shown that testing in turbulent flow produced results different from testing in laminar flow. Various models for representing aerodynamic loading were assessed using different system identification procedures and coherence models. The observed changes in aerodynamic properties were investigated by experiments, Monte Carlo simulations, and the development of closed-form analytical expressions for uncertainty estimation. The developed analytical expressions yielded specific advice for decreasing uncertainty when conducting tests in turbulent flow. Overall, the work contributes toward the scientific goal of producing models able to predict more, assume less, and fit with other models. This, in turn, makes us able to increase safety and decrease costs related to long-span suspension bridges.