Wind tunnel testing - Dubai

Buro Happold

07/11/2012 Written by: Mark Lavery No comments

The news that Dubai Municipality will soon mandate the use of wind tunnel testing for tall buildings and other dynamically sensitive structures is a very positive development and puts Dubai in line with internationally accepted best practice. The timing of the news coincides with the upcoming release of the Council on Tall Buildings and Urban Habitat (CTBUH) guide: Wind Tunnel Testing of High-Rise Buildings, providing current best practice on wind tunnel testing, which will undoubtedly provide a wealth of useful information for the authors of the new Dubai guidelines.

Over the last ten years, wind tunnel testing has become increasingly accepted by clients as an integral part of the development of tall buildings, but the mandatory use of such testing is nevertheless welcomed, particularly considering that standard design codes of practice do not cover the effect of wind on buildings above certain heights. It will be important however to ensure that the criteria for mandatory testing are clear, well understood and result in the provision of real benefit to clients and their projects, rather than just becoming burdensome to designers. When wind is disturbed by tall buildings, the effect on adjacent buildings is often highly unpredictable and can have the result of greatly magnifying loadings on buildings; the recently announced proposal highlights this as a key factor in triggering the mandatory requirements, and is again positive. It will be particularly interesting to see how the requirement for wind tunnel testing of other dynamically sensitive structures is set out.

Greater awareness of the issues and implications of wind interaction on and around tall buildings will hopefully also encourage a more integrated design approach that could lead to optimisation of building design, helping to reduce cost, and increase environmental comfort of pedestrian areas at street level; a significant issue in areas densely populated with tall buildings.

The selection of appropriate wind speeds for design is perhaps the most important aspect to be addressed by any wind guidelines. Wind speeds should be based on appropriate levels of risk for the building under consideration and should be derived from statistical analyses of historical data and an evaluation of changing atmospheric considerations. It will be important to gain a consensus from the larger design and wind engineering community to draw on the vast body of knowledge built up over the last decade and more. The recent hurricane that struck the west coast of North America should act as a stark reminder of the importance of evaluating risk properly but it should be ensured that any decisions are made on a basis of evidence rather than from a knee-jerk reaction.