Investigation on the aerodynamic instability of a suspension bridge with a hexagonal cross-section

The aerodynamic instability of a suspension bridge with a hexagonal cross-section is investigated systematically based on a two-dimensional model. Measurements of the dynamic responses of a sectional bridge model in the cross-wind and torsional directions were firstly carried out in a wind tunnel. The results were used to guide and confirm the execution of parallel numerical simulations. Accordingly, both the experimental and numerical results are used as bases to examine the flow effect as well as the aeroelastic behavior of the bridge in detail. Results show that the numerical predictions of the structural responses agree well with those from the experiments, indicating that the proposed numerical method is capable of predicting the deck motion with good accuracy. Based on the time-series numerical results, extensive investigations reveal that a hexagonal deck has much better aerodynamic stability performance than a rectangular one. Finally, among the hexagonal decks studied, it is found that one with a 30 degrees side angle leads to the greatest critical flutter speed.