General Category > DB Cooper
The Cooper Vortex Podcast
snowmman:
interesting that air density has a wind load effect that's measurable, even for the variation in tall buildings.
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Accurate determination of wind load is of great importance for the wind-resistant design of building structures. Despite the fact that air density varies systematically with altitude, and somewhat less so with barometric pressure, air temperature, and latitude, there is a lack of studies on the dependence of wind load on air density especially for highrise buildings. This article presents a special study on this topic. The dependence of air density on latitude, season and altitude is investigated first, based on meteorological records at several national stations in China. The height-dependence of air density in the inner region of a tropical cyclone (TC) is highlighted, since there is a fast development of highrise buildings in TC-prone areas and TC wind load dominates the design wind loads for such slender wind-sensitive structures. A data-driven model for the height-dependence of TC air density is established. It is shown that the measured TC air density is reduced by 8%–10% compared with the values recommended in the wind load codes. The dependence of wind load and wind-induced structural response on air density for a supertall building is then analyzed through a combined usage of the proposed TC air density model and wind tunnel testing. Results suggest that the wind load and wind-induced response of the building obtained by considering the height-dependence of air density can be decreased by as much as ~12% compared with those without considering such effects. Thus, more economic wind-resistant designs for highrise buildings may be achieved by taking into account the height-dependence of air density.
Shutter:
Mean roof height is always used to determine wind loads..different parts of a building react different. corners are "end zone" conditions where winds can double causing anchor spacing to increase. a window in the center of a building could have attachment spacing of 6" on center. the same window on a corner will call for 3" inch on center.
Most things are over engineered. impact windows will fail with the glass blowing out vs the whole window.
snowmman:
You are not allowed to view links.
Register or LoginMean roof height is always used to determine wind loads..different parts of a building react different. corners are "end zone" conditions where winds can double causing anchor spacing to increase. a window in the center of a building could have attachment spacing of 6" on center. the same window on a corner will call for 3" inch on center.
Most things are over engineered. impact windows will fail with the glass blowing out vs the whole window.
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agree with all that
Yet:
People want to argue that a single sled test, is sufficient for determining what happened when Cooper jumped or didn't jump.
The sled test represented something close to what happened with Cooper. But to say there's enough data to say it was the exact same thing? Nope.
Variation exists. Saying you know the extent of variation is silly without tests that cover the variations.
I suggested variation when the plane is turning. Sure you can laugh at that, but it seems like a thing to me.
Shutter:
It's always open to debate. they did have the guy who reported what happened during the hijacking on the plane recreating what happened. he appears to have agreed they recreated the same issues heard and felt that evening. putting them together seems to be the hurdle nobody has gotten over to date.
Might not be a factor of data vs eyewitness account?
snowmman:
You are not allowed to view links.
Register or LoginIt's always open to debate. they did have the guy who reported what happened during the hijacking on the plane recreating what happened. he appears to have agreed they recreated the same issues heard and felt that evening. putting them together seems to be the hurdle nobody has gotten over to date.
Might not be a factor of data vs eyewitness account?
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Good point.
Yet, people will claim they "know" based on I don't know what.
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