×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

Drifting Snow Load Questions

Drifting Snow Load Questions

Drifting Snow Load Questions

(OP)
Hi everyone,

When you have a chance, could you please take a look at my following questions and attached sketches (2 PDF files), and let me know your thought/ comments.

• Code: ASCE 7-10
• Ground snow load: 50 psf
• Ce = 1.0
• Ct = 1.0
• Is = 1.0
• Cs = 0.75 for 10:12 roof
• Cs = 1.0 for 7:10 roof
• Height difference between upper and lower roofs: 8’
• Rafter system roofs
• Sliding snow is not considered in this discussion/ calc

1. Lower roofs of Building 1, 2, 3 & 5 received same amount of drifting snow load regardless the pitch of upper or lower roofs. Does this make sense?

2. Building 3: Is it ok to use lu = 12’ (distance from ridge to eave) for drifting (leeward) snow load on lower roof (due to high pitch roof; >7:12)

3. Building 4: How one would combine drifting/ unbalanced SL for design of member (say beam/ header) at the common wall?

4. Building 6- Balanced snow load: Is balanced snow load (equal flat roof SL) within valley area ok?

5. Building 6 - Unbalanced snow load: Please comments

We have a copy of “Guide to the Snow Load Provisions of ASCE 7-05” by O’Rourke
Please point me to additional reference if you know.

Thank you,

Hdn32

RE: Drifting Snow Load Questions

1. Yes - the drifting is based on the horizontal width of the roofs either windward or leeward.
2. I'd say no, you can't discount the upper roof on the other side of the ridge per ASCE 7.

Check out Eng-Tips Forum's Policies here:
FAQ731-376: Eng-Tips.com Forum Policies

RE: Drifting Snow Load Questions

(OP)
@JAE:

Thank you for your comments/ answers.

1. I agree with you about how the drifting snow should be calculated per ASCE 7. However, I still have a hard time making sense of it when comparing the calculated drifting snow loads of building with very steep (say 12:12) roof and that with flat roof :)dazed

2. I would agree with you if we use ASCE 7-05, which requires unbalanced snow on leeward side of the gable regardless of roof pitch. in ASCE 7-10, unbalanced snow load is not required for roof with slope > 30.2deg (or 7:12)

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! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close