Wind Effects on Bridges

When bridges are dynamically sensitive it is essential to determine the effect of wind. WINDTECH performs a range of studies including early stage studies to estimate effects, wind tunnel testing of bridge sections and full aeroelastic testing.

Preliminary calculations can be performed on any number of different bridge section designs to inform early stage design, with estimates provided for bridge motion (acceleration), moments and forces.

Wind tunnel testing can then be conducted as required to confirm assumptions and provide accurate determination of dynamic stability. Recommendations will be made for improvements to design to improve bridge performance.

For bridges with unusual designs in particularly exposed areas, aeroelastic testing can also be undertaken to ensure absolute confidence.

Case Study

Windtech Consultants completed a wind tunnel study for a pedestrian bridge in Riyadh, Saudi Arabia. Testing was carried out using both a dynamic and a static section test rig. It is sufficient for this type of bridge to perform a test on a typical section model, incorporating the relative stiffness in both torsion and lift in the dynamic test rig.

Windtech modelled all the aerodynamic properties of the bridge section down to the effect of the porous fence on the sides. Additionally, the dynamic properties were correctly modelled based on the latest dynamic properties. The dynamic test rig showed that there are no aerodynamic instabilities for wind speeds up to the equivalent of a once in 10,000 year event.

Wind loads on the main suspended cable, and hangars and towers were included in the final load cases. The pedestrian excitation response of the bridge was also analysed.