Light Framed Walls w/ Flat Strap Bracing
Light Framed Walls w/ Flat Strap Bracing
(OP)
I am designing some three-story, light framed (wood) apartment buildings. The contractor wants to use flat strap bracing as opposed to sheathing on "shear walls".
I was provided an old set of drawings indicating Kant Sag flat strap "wrapped around" the bottom and top plates. I contacted USP (who bought Kant Sag), and they informed me that the flat strap bracing system is really only for erection stability and that there are no systems out there for shear walls. Furthermore, there are no strap systems that include bending or wrapping strap around the plates.
My quick hand calcs show needing ~3500# strap force - but terminating the strap w/ ~50 nails on ~10 studs at each end of each shear wall is not practical. Anybody have any knowledge of this system or any manufacturers providing these products?
I was provided an old set of drawings indicating Kant Sag flat strap "wrapped around" the bottom and top plates. I contacted USP (who bought Kant Sag), and they informed me that the flat strap bracing system is really only for erection stability and that there are no systems out there for shear walls. Furthermore, there are no strap systems that include bending or wrapping strap around the plates.
My quick hand calcs show needing ~3500# strap force - but terminating the strap w/ ~50 nails on ~10 studs at each end of each shear wall is not practical. Anybody have any knowledge of this system or any manufacturers providing these products?






RE: Light Framed Walls w/ Flat Strap Bracing
DaveAtkins
RE: Light Framed Walls w/ Flat Strap Bracing
I agree with Dave.
Mike McCann
McCann Engineering
RE: Light Framed Walls w/ Flat Strap Bracing
RE: Light Framed Walls w/ Flat Strap Bracing
RE: Light Framed Walls w/ Flat Strap Bracing
I just wanted to see if this was a common, known and tested system that I had just not yet encountered. You can never stop learning...
RE: Light Framed Walls w/ Flat Strap Bracing
Wind there can get just as strong, but seismic is not really an issue there.
RE: Light Framed Walls w/ Flat Strap Bracing
Like I said, I already got the contractor to surrender to sheathing. However, I would like to know more about those systems if you have any info. Do you know the manufacturer's name for any of those systems? Or do they use common flat strap and have some "trick" for the end connections?
Thanks
RE: Light Framed Walls w/ Flat Strap Bracing
msquared...
It's been a while since I did light-gage framing, but I often used straps with steel studs. Are you suggesting it is "out of date" for light-gauge or wood (or both)? Just curious about your experience(s).
Thanks
RE: Light Framed Walls w/ Flat Strap Bracing
The light gage systems I have seen recently do not use straps, but an ICBO rated system of either plywood or gypsum wallboard screwed to the metal studs. I guess I should say that as far as I have recently seen professionally, the practice is obsolete.
Mike McCann
McCann Engineering
RE: Light Framed Walls w/ Flat Strap Bracing
The contractor 'fished' metal strap (16 or 18 ga, I don't recall) and it was pop rivetted for splices and final attachment at the columns... First time I used straps and pop rivets and the building is still standing. If straps work for serious commercial stuff, they should be able to be used for houses. I had a difficult time getting load capacities for the pop rivets.
Dik
RE: Light Framed Walls w/ Flat Strap Bracing
RE: Light Framed Walls w/ Flat Strap Bracing
I worked in the west for many years and have never used or heard of the straps for conventional wood framing, in the midwest they are used often in residential construction, but only as bracing and the walls are sheathed with either OSB or R-Board.
RE: Light Framed Walls w/ Flat Strap Bracing
Yes, I'm on the west coast, and regarding your statement on the high seismic regions, that could be the reason why I have not seen any in quite a while. Unless it is IRC or IBC prescriptive, any shear wall system has to be a tested, rated system, ICBO or otherwise.
By the way, when the big one hits here, I expect my property value to go up. I'll have waterfront property!
Mike McCann
McCann Engineering