×
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

hole locations wood joists

hole locations wood joists

hole locations wood joists

(OP)
Some building codes show locations for holes in wood
floor joists at different locations. One code showed holes only to be located within middle third of span, others showed only within outer thirds of span and some do not even show locations. Both 2" clear from top and bottom and D/3 for dia. WHICH WOULD BE THE BEST LOCATION
WITHIN ENGINEERING STANDARDS.

RE: hole locations wood joists

The hole should be sized and placed depending on the controlling capacity of the wood member.  It is assumed that the member capacity is controlled by shear in the end thirds and controlled by bending in the middle third.  The joist will tolerate more shear if the hole is a notch at top or bottom, and will tolerate more bending stress if the hole is near the center.

RE: hole locations wood joists

From a structural stand point, it depends what stresses are critical for your case.  Wood is particularly weak in horz. shear, which for a uniform load will be max near the ends (d dist from support).  Longer spans will be critical for flexure, generally toward the center.  Wood is also weaker in tendion than compression so cutouts in the tension zone are a bit worse.  But the thing really to watch is splitting or cutting notches that may produce spliting along the grain.  The  National Desing Spec. (NDS 2001) gives guidelines of how to avoid putting notches in the wrong places (NDS 4.4.3)

Peter von Buelow
Univ. of Mich. - TCAUP

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