Gable End Bracing

[rcast044]

Hello everyone,

I am currently trying to figure out what is adequate for gable end bracing. Currently I am running 2 x 4 at about 5'-4" O.C. along the length of the gable and attaching them to the bottom (tie-beam) of each truss, extending approximately 8'-0" over 4 trusses. I do not have any bracing on the rafters of the truss. Looking for any recommendations on common practice and is this adequate enough. Thanks for the help!

 

[BAretired]

Check your bracing for wind load on the end wall.

BA

 

[oldestguy]

Your roof sheeting is a great system for transferring horizontal gable load to side walls.

 

[jayrod12]

Only if your gable end walls are framed full height. If they are platform framed, then you need to block between the trusses/ceiling joists in the first couple of spaces, and brace it up to the roof sheathing as well.

 

[DaveAtkins]

I do not think what you propose is adequate. The wind load is transferred to four truss bottom chords, but then where does the wind load go?

I recommend using diagonal kickers (2 X 4's might work) from the wall top plate up to the top chord of a truss.

DaveAtkins

 

[dhengr]

Rcast044:
The entire truss system has to be braced so that it just doesn’t roll over like a bunch of dominos, even during its erection and the construction phase. DaveAtkins’ diag. kickers can act as part of this, and to get the gable end wall loads up into the roof system too. Many gable end walls are framing with a hinge at the normal double top pl. and this has to be designed for. Finally, the roof diaphragm (sheathing) has to be blocked and properly fastened to the side walls to make the whole system work. Be careful in arranging your bracing (what you might think is bracing) so that you don’t just cause 3,4,5 truss members (diags. or bot. chords) to all buckle in the same shape and direction. This is not a very efficient bracing reaction system. Most of the truss suppliers, these days, have a fairly elaborate, all inclusive, but with no responsibility on their part, 3-4pg. bracing instruction pamphlet with their erection and shop drwg. package. Get a couple of these, from different suppliers and really study them for their full intent and meaning.

 

[rcast044]

My apologies, the truss is attached to both sides of the gable roof with a simpson strap on the exterior bearing wall top plates. The 2x4's on located in the middle of the truss. Similar to the link below, letter B.

https://hugheslumber.net/blog/35021/building-for-high-wind-resistance

 

[jayrod12]

That is quite likely adequate for bracing/supporting the top of the wall, but how does it get from the 2x4 extending across 4 trusses to the side/interior shearwalls?

 

[BAretired]

How is the gable-end truss connected to the double top plate? Toe nails? Is there a gable-end truss in your project? You didn't say so in the OP.

How is the wind force transmitted to the roof diaphragm? No cross bracing is shown. Whether the force is from direct pressure or suction pressure, it has to be delivered to something other than four trusses.


BA

 

[rcast044]

Sorry for not being more detailed. The gable truss is connected to the exterior walls with a Simpson connector, similar to letter D in the link I provided. The 2x4 bracing is attached very similar to detail B in the link. The spacing of those connections was the question of concern. No structural engineer has given me a good answer other than judgment so was just wondering.

 

[BAretired]

A good answer is to calculate the wind force q.h.s/2 where q is wind pressure, h is height and s is spacing. Check that your connection can handle the wind force and that the top plate can span distance 's'. But the reaction from all those bracing members has to go somewhere and that seems to be missing from your design.

BA