Fabric Bessonneau hangars had snow poles which are lowered between October and March to support the roof at part span. They didn't save our one at Odiham last winter though (fortunately empty at the time), as for some daft reason they were not attached to the nodes (joining points of structural members) but part way between them. The principle is sound though.
Some sort of snow pole to support the middle on these low roofed, wide span hangars has got to be the answer, Making the unsupported structure sufficiently strong for four feet of snow could be prohibitively expensive . It could be a fixed piece which hangs down from the roof to 'top of door' height, then a removable piece to fill the gap once the toys are in place. A few things they would need to take into account:
- Snow poles would have to be light enough to be man handled into position and removed, whilst having enough compressive strength to do their job.
- The floor beneath the base of the snow pole would have to be strong enough to take the point load imposed
- Aircraft would need to be positioned to allow room to install the snow poles without risk of damage. Its no good waiting until snow is forecast as the manpower may not be available to move aircraft around to make room.
Compare the structure of what is presumably the hangar that collapsed, with that of a Canadian hangar:
