×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Folded plate plywood roof diaphragms

Folded plate plywood roof diaphragms

Folded plate plywood roof diaphragms

(OP)
Does anyone have any methods or literature regarding allowable shear values in gabled (sloped) roof diaphragms (folded plate)? I am trying to figure out how to analyze a roof diaphragm that has an 8:12 pitch. I know that I can't get the allowable diaphragm loads normally given in the tables because there would be bending as well as shear on the plywood panels.

RE: Folded plate plywood roof diaphragms

I would try the American Plywood Association (AWP) or the Forest Products Lab, in Madison, WI.  They are the two that develop the load tables we all use, they would surely have some answers for you.

RE: Folded plate plywood roof diaphragms

For steep roofs, I analyze a frame consisting of a rafter pair and a stud, under the influence of the horizontal force. The reactions are four: horizontal and vertical at the bottom of the stud, and longitudinal in each rafter. The equations are four: H, V, & M =0 at the bottom of the stud and M=0 at the stud-rafter joint. M is also 0 at the ridge, but this is redundant. The longitudinal reaction multiplied by the length of roof tributary to a gable wall is the unit shear in the roof sheathing, so I compare this with UBC tables for horizontal unblocked diaphragms (or blocked, if necessary). This force is then applied to the gable rafter, which must be tied down.

RE: Folded plate plywood roof diaphragms

The American Forest and Paper Association; "Wood Frame Construction Manual", 1995 SBC High Wind Edition Table 2.5A, 2.5B, and 2.5C list the allowable unit laterial loads for in-plane shear in gabled roofs.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources