On Sun, 28 Jun 2009 15:25:36 GMT,
wrote:

In a free-standing garage, where one wall is almost entirely absent to make
a door opening, what parts of the structure prevent the door wall from
racking?

I am second-guessing myself about my shed plan. One wall, a gable end wall,
is non-load-bearing but is a shear wall. Its plan has an 8x8 door opening
in a 12' wide by 9' high wall. I don't have the background to determine
whether such a wall will have sufficient shear strength. I'm using
conventional 2x4 framing 16" OC with APA-rated 7/16 OSB sheathing, no
interior sheathing is planned.

The obvious things would be to reduce the door opening, to use heavier
sheathing, and/or sheathe it inside and out. But first I would like to hear
any advice this august group has to offer, and with my thanks.

You don't say whether or not you're in earthquake country....

If not, standard let-in diagonal bracing combined with properly
applied and nailed sheathing should be fine.

If you are in earthquake or high-wind zone, or just want a beefier
design, Simpson makes pre-engineered shear walls designed for the
narrow walls next to garage door openings:

http://www.strongtie.com/products/strongwall/

Googling "shear wall design" will get you lots of info.

HTH,

Paul F.