Wind tunnel testing considered for Orwell Bridge wind closure study
PUBLISHED: 19:30 26 January 2019
More details have been unveiled for an innovative aerodynamic study assessing wind closures of the Orwell Bridge – with experimental wind tunnel testing an option for later this year.
In October Highways England confirmed it had commissioned experts at City, University of London to carry out a nine-month aerodynamic study of the bridge, the results of which will inform potential measures such as wind breaks or allowing cars to continue in high winds.
Data published under Freedom of Information laws has now revealed more details of how the study will work.
Mark Knight, business management team leader from Highways England, said: “The study is exploring the risk of cross-wind induced accidents in vehicles crossing the Orwell Bridge.
“Its aim is to assess the critical wind speed beyond which accidents are likely to occur for different types of vehicles crossing the bridge.
“Only cross-winds are being studied because they are critical to driving stability.”
Highways England said the study will consider:
• Influence of the wind and driving speeds
• Influence of vehicle characteristics such as loading and whether there are exposed surfaces
• Vehicle position across the width of the bridge
• Influence of road surface irregularities
• Influence of aerodynamic properties of the flat surface of the bridge
• Influence of driver’s steering response.
Side-slipping, overturning vehicles and changes of direction will also be analysed.
A detailed model of the bridge has been drawn digitally from engineering models of the bridge, including vibration levels.
A series of tests changing wind velocity, irregular road surfaces, aerodynamic irregularities and other variable factors will then be used to obtain a series of possible scenarios.
Mr Knight added: “By gradually increasing the wind and the vehicle speeds, critical wind curves can be obtained for the different cases.
“This will give us useful information about the risk of vehicle accidents and about the efficiency of the existing traffic protocols.
“Depending on the results, we may be able to determine alternative protocols.”
Mr Knight said it involves the most advanced wind-modelling possible, which could be extended to experimental wind tunnel testing.
The study is due to be completed in the summer, and will cost £25,581.