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Using wind tunnel coefficients in FEA - time, height, inflation scaling and ASCE wind loading

Using wind tunnel coefficients in FEA - time, height, inflation scaling and ASCE wind loading

Using wind tunnel coefficients in FEA - time, height, inflation scaling and ASCE wind loading

(OP)
I am currently involved in modeling a large inflated structure. The structure wind coefficients were obtained from wind tunnel testing. In reviewing the wind tunnel testing report, the author explains that a ASCE wind requirement of say 160 mph 3 sec gust at 10 meters needs to be adjusted because the wind tunnel test was scaled over a hourly time scale and referenced from top of the model. They continue to explain that the 160 ASCE needs to be converted from 3 sec gust to hourly mean (using a durst factor, 160/1.53 = 105 mph mean hourly at 10 meters) and then since the top of the real world structure is 100 ft above ground, the wind speed for this location needs to be determined as 105*(30/10)^0.15 = 124 mph at top of real world structure, mean hourly time scale.

The report then states that the design wind pressure should be 0.00256*124 mph*124 mph = 39 psf.

The particular case that I have is that the real world structure is an inflated structure. Traditionally, inflation structures have an internal pressure that equals the impact pressure 0.00256*V*V.

Does that mean that since the wind tunnel testing coefficients are based on mean hourly wind speed, the inflation pressure should also be based on that wind speed ????

In other words, if ASCE calls out 160 mph, traditionally the inflation pressure would be 65.5 psf using traditional wind coefficients. But using the most recent wind coefficients as described above as mean hourly and from the top of the model, should the inflation pressure be based in the 39 psf ??

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