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Indoor Tension Structure- Cable/Fabric

Indoor Tension Structure- Cable/Fabric

Indoor Tension Structure- Cable/Fabric

(OP)
I am in the process of designing a large indoor tension structure (horizontal cables and fabric) to serve as a temporary visual barrier obstructing the view of the floor of an indoor atrium space where construction work will be performed. The purpose of the visual barrier is to block/ obscure the view of the tenants above whose windows overlook the atrium.(the atrium is open to the roof above ~10 floors) The visual barrier will be located at the elevation of the floor above where the work will be performed and it will be supported along its perimeter (post installed anchors to concrete floor slab edges). The size of the atrium and visual barrier is approximately 100'x100'=10,000SF. For discussion purposes the cables and fabric will form square grids (two-way system) and span the ~100ft width of the atrium.

Question: Without test data relative to the interior pressures within the atrium (above and below the fabric visual barrier) do I default to a 5psf(positive and negative) vertical live load on the horizontal fabric? - (5psf born from IBC-1607.13 for interior partitions) This loading creates very large reactions at the cable ends which does not seem intuitive considering the purpose of the structure. Just looking for someone else's two cents...

I am interested in loading information/ standards relative to indoor fabric structures/ canopies. Perhaps info on loading from differential internal pressures/ temperatures in large open buildings. Thanks in advance to all replies.

RE: Indoor Tension Structure- Cable/Fabric

Ahyeaut:
For the cost of the wire rope, fittings and attachments, and loadings, there may not be much advantage in a two way system in this particular application. The two way system will reduce the total deflection of the system, and reduce the attachment forces but double the attachments. There are companies that specialize in these tension structures, and they have the knowhow and all the equipment and various hardware needed. And, I would assume you can rent or lease something which would work and not leave you with several thousand feet of used cable and hardware in eight months. I’d worry more about falling objects if the windows above can be opened, or if there is a hallway around the atrium at each upper level. RE: the 5#/sf pressure, I’d do this in a square grid pattern of cables at 5' or 10' o.c.; have the fabric shop apply grommets near the corners of the 11' squares of fabric; set every other fabric square 6" high or low, and let er breath.

RE: Indoor Tension Structure- Cable/Fabric

(OP)
Appreciate the feedback. There's plenty of other design criteria/ parameters not included in the post that were imposed by others and forced our hand into such a system (two-way cable/fabric). My concern is specifically indoor loading due to air pressure differential; more specifically large indoor spaces. No open windows or walkways above to worry about; (i.e. no concern of catching a falling object).

RE: Indoor Tension Structure- Cable/Fabric

We default to the 5 psf interior partition loading if we have nothing else. If you have large opening doors into the space, you may want to use a larger factor for your loads. Loads will be large! Especially if you don't allow enough 'sag' in the catenary. But the difference in going up a shackle or wire rope size is small. When doing blackout curtains of that size, often you hang them and make them in smaller lengths and overlap them to help lose some of the load as air will pass in between. Hope that helps.

ZCP
www.phoenix-engineer.com

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