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Estimating wind forces causing sudden crane rotation under wind gusts

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Overview: The last decade has witnessed several accidents involving cranes falling suddenly in the middle of construction sites under the action of unpredictable extreme wind gusts, as shown in the first images (upper left). Devastating damages could occur, both on physical integrity of workers and pedestrians as well on the
financial aspect of the projects. The same is true for other structures, for example cable cars in ski resorts.

The challenge: The focus of wind and environmental engineers active in urban design is to estimate wind forces that may lead to an accidental rotation of a crane placed in the yard of a buildings construction site under the action of wind gusts. Such studies – based on CFD – become now mandatory for all in-situ urban constructions under EU laws since a couple of years now, and are strictly applied in the UK and France in particular.

TransAT Solution: Classical approaches to the problem rely on the re-construction of the wind energy spectra from steady state RANS simulations. This has shown to be rather limited in most cases, suggesting the use of real unsteady simulations, either using the U-RANS approach or the LES. For high Re numbers, a well-resolved LES requires very large grids and small time steps. One way to avoid these constraints in practical applications (when a full wind rose is required) is to resort to less expensive techniques such as the V-LES technique in TransAT. With V-LES, the wind energy spectra are obtained and are used for the structural analysis of the crane, as shown in the lowest figure.
InfoExpert: Contact our expert

Dr Mathieu Labois
ASCOMP Switzerland
Tel. + 41-44-445-4072
Labois@ascomp.ch