×
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

Drag loads on corrugated metal roofing and siding

Drag loads on corrugated metal roofing and siding

Drag loads on corrugated metal roofing and siding

(OP)
Is there a way know how much load should be applied to parallel-to-wind surfaces of a building system when the cladding is corrugated metal? My question specifically relates to wind acting parallel with the ridge of a building. The load has to be more than the wind pressure acting on the cross-sectional width of the building I believe, but not sure how to consider that. Does anybody know how something like that can be figured? Is it some "surface roughness" characteristics that can or should be considered? Is there a ratio of cross-sectional endwall area to length of building that could be utilized?

And then................what if the sidewalls of the building are open? How does wing load hitting the webs and chords of trusses impact the overall lateral loading on a building? To sum up the surface area of every truss in the building and apply load over that area seems overkill as no doubt there would be lots of turbulence created as wind would rush through the trusses. Not sure how to think about that either.

Any thoughts would be appreciated.

RE: Drag loads on corrugated metal roofing and siding

I've never heard of an increase for corrugated roof surfaces. I personally wouldn't sweat that too much. As for the open end walls. I would consider something reasonable. I think the last one that I did, I just assumed it was "closed" for the design. That also gave the owner flexibility should they want to close the thing in one day.

With that said, I don't know of a code-prescribed way to calculate the added effect you could have from wind coming in at an upward angle and hitting more than one roof beam. I think letter of the law you could just do projected area. But I wouldn't do that. I'd look at the loads and use judgment based on what the calculated load is for one projected surface, and then the whole surface assuming it was closed off. Based on those numbers, I'd start to see where I was at and make an assumption at that point.

One other thing is you could contact your local PEMB engineer. THey do open buildings all the time and might have insight into their industry standards.

RE: Drag loads on corrugated metal roofing and siding

I've participated in a similar discussion here in the past. Apparently, Australia has a provision for wind drag on parallel surfaces which makes a ton of sense to me. In the past I've pretended that parallel to wind surfaces were pitched at 15 degrees in order work out poor man's version of a drag load.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Drag loads on corrugated metal roofing and siding

MBMA has commissioned research on the issue of wind load on frames of a building with roof panels only. The attached provisions from the MBMA Design Manual show the equations. An attempt was made to get this included into the ASCE7-16 standard but did not succeed. I think the basic issue was lack of time from presentation until ballot closure and it will be taken up again for the next edition. While ASCE7 currently has provisions for open building winds on roof surfaces there is nothing in ASCE for the lateral forces. Unless you have a very long building, the assumption of fully sheeted endwalls as an option is generally pretty reasonable.

RE: Drag loads on corrugated metal roofing and siding

@KootK,
Thanks for the lead on how the Australian code handles wind frictional forces. bigsmile
Dave

Thaidavid

RE: Drag loads on corrugated metal roofing and siding

KootK: Correct, Australia has all things that are good.

OP - I'll scan the relevant page from our portal frame bible in the morning for your reference.

RE: Drag loads on corrugated metal roofing and siding

See below. However in the worked solution in the textbook, the frictional drag forces make up just over 7% of the total lateral force at the ridgeline... therefore I wouldn't worry too much, unless you have a really long building or massively ribbed cladding.







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


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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