×
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

Cantilevered Decks and Balconies

Cantilevered Decks and Balconies

Cantilevered Decks and Balconies

(OP)
When you compare Table 2 from the DCA6 to a similar Table (R502.3.3(2))in the 2012 IRC for cantilever spans for floor joists supporting exterior balconies there is a huge discrepancy.

For a 2x10 floor joist @ 24" o/c spacing I can construct a cantilevered balcony per the IRC with cantilever span of 43" and a backspan with a 2:1 ratio.

Using the same 2x10 deck joist @ 24" o/c spacing I can only create a cantilever of 2'-9" and the backspan must be a 4:1 ratio per the AWC DCA6 document.

Why is the AWC DCA6 so conservative? I must be missing something here. I've attached a quick calculation for this scenario and with a 220 lbs point load I'm well below capacity of the joist in bending or any other parameters.

A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com

RE: Cantilevered Decks and Balconies

The IRC is much less restrictive than the IBC. Perhaps AWC too...

Mike McCann, PE, SE (WA)


RE: Cantilevered Decks and Balconies

I don't see the attachment. Any chance it's SYP? If so, could it be the reduced values that came out in 2012?

Also, could it be the incising factor based on the AWC assuming treated wood?

You using same Cd factors? Tables may be assuming different values. I don't have AWC DCA6, just brainstorming.

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