Thursday, March 4, 2010

Hangar Problems

The maintenance person at KVKX has had a look at N631S's hangar and the news is not so good. In my earlier post on the problems with the hangar doors I pointed out that the structure is about 50 years old, and that it seemed the snow load from our recent storms had deflected the hangar roof causing the sliding doors to hang up on the apron.

The hangar, I'm told, has a cable-stayed roof. Here's a schematic depiction of how such a structure works:

The support cables for the roof span rise from concrete anchors that are buried in the ground, pass over the tops of the upright posts and descend at an angle to their attachment points on the roof beam.

The maintenance person says he believes that due to the snow load (since melted), either (1) the cables have been stretched, or (2) the concrete anchors have lifted from their original locations. In either case the result is a "permanent" deflection of the roof beam from which the doors are suspended.

There are turnbuckles in the cable runs, intended to adjust the tensions and compensate for any elongation of the cables that might occur over time. But after half a century it's likely that the turnbuckles won't be too keen on turning.

The upshot of all this is that the maintenance folk are figuring out how they can fix all this, and tomorrow night when (if weather) N631S and I get back home we'll probably be parking under the stars.

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