×
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

asce 7-05 drifting and sliding snow

asce 7-05 drifting and sliding snow

asce 7-05 drifting and sliding snow

(OP)
I have a long (40' per side)shallow pitched (4:12) gable roof that drops down (8 ft) to a 30' long flat roof. I am developing a truss loading diagram for the flat roof area. The question is do you combine balanced snow + drifting snow + sliding snow or do you treat balanced + drifting as one case and balanced + sliding as another and take the worse case?

RE: asce 7-05 drifting and sliding snow

I'm surprised no one has answered this question.

I would not consider balanced + drifting + sliding as one total combination.  The last sentence of ASCE 7-07 section 7.9 states "Sliding loads shall be superimposed on the balanced snow load."  It does not mention superimposing the sliding snow on the snow drift.

In this case, I would look at windward drift + balance snow, leeward drift + balance snow and sliding snow + balance snow.  I would also not consider a mineral surfaced roof slippery (if you have one).

This is how I interpret this section you need to do the same.

RE: asce 7-05 drifting and sliding snow

At the wall projection between the flat and gable roofs I would have a triangular load distribution.  For the altitude of the triangle, I  would have the height of that wall and the base of the triangle would be about 1/3rd of the flat roof; for snow density, I would use wet snow value.--My two cents.

RE: asce 7-05 drifting and sliding snow

You should review ASCE - Guide to Snow Loads by Dr. Michael O'Rourke.  He is the chairman of ASCE7 snow load chapter.  Good reference.
  

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