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walkereng
walkereng, Consultant
Category: Structural Engineering
Satisfied Customers: 2596
Experience:  Over 30 years of Structural Engineering experience.
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We have to put a pole building up and the print is calling

Customer Question

We have to put a pole building up and the print is calling for 3 1/2" x 16 1/2" x 32 ft. Glulam power beams. Our problem is that we cannot get them quick enough. If I substitute a double LVL will it be as strong or stronger than the glulam?
Submitted: 1 year ago.
Category: Structural Engineering
Expert:  walkereng replied 1 year ago.
Do you have a copy of the building plans you could share with me?
Customer: replied 1 year ago.
I attached a Pdf of the building plan. The plan has change from what is show the area in questions is from the outside column to the first interior column span.
Expert:  walkereng replied 1 year ago.
Just an FYI, you should be able to replace the larger single beam with a double member.
Let me take a look at your drawing
Customer: replied 1 year ago.
We would like to switch from the glu-lam specified out to a 16" deep double member LVL
Expert:  walkereng replied 1 year ago.
I do not see your 3 1/2" x 16 1/2" x 32 ft. Glulam power beams called out on the attached drawing. Can you explain where they will be placed?
Customer: replied 1 year ago.
correct the building has changed from the print. What is actually going on in the building now is that there is a center truss that spans from the first column in from each sidewall over the center. from that first column in to the out sidewall columns is where the original builder still used the 3 1/2" power beam. We are having an issue getting the 3 1/2" power beams for that outter span and want to change to a LVL what size would we need for that span?
Expert:  walkereng replied 1 year ago.
Before we get started I’d like to point out that a Professional Engineer’s standard of care typically includes a site visit to assess field conditions and get an overall understanding of the structure. This can obviously not be accomplished through the internet. The information provided here is meant for planning purposes only (general sizing and budgeting) and is based on the information provided by you. All loading cases considered are for vertical loads only, no lateral analysis has been completed. The information should be verified by a professional engineer who can visit the site to ensure that potentially important information has not been overlooked or omitted.
I have several questions:
1. So this structure will be in Marshall, MI?
2. OK, so in your top left cross section, this member will be your roof beams that span from your exterior column lines out to the exterior walls on each side?
3. Are these beams still spaced at 12' o.c.? Are you still using a metal roof with purlins?
4. So your horizontal span for this beam is approx. 26' with a 3' overhang/eave?
Customer: replied 1 year ago.
Yes to all of the above.
Expert:  walkereng replied 1 year ago.
For a simple single span for your outer bay roof beams, I am coming up with something much larger that you currently have called out.
From the Building Code snow load table, you are located right near the line between 25 psf and 30 psf, so I used 30 psf. Do you know if you are in the 25 psf snow load region?
Expert:  walkereng replied 1 year ago.
Also, I am using a 10 psf Dead Load, yours may be slightly lower.
Expert:  walkereng replied 1 year ago.
Do you know if I can used lower values in my beam calculations?
i.e. 25 psf snow load and maybe 7 psf for dead load
Customer: replied 1 year ago.
Yes you can use the 25# ***** snow load and we typically use 5# ***** load
Expert:  walkereng replied 1 year ago.
I can give you another engineered wood option for your 26’ span roof beams that are spaced at 12’ o.c. and have a 3’ overhang: Double 3-1/2” x 16” Versa-Lam 1.7 2650 DF This is a Boise Cascade product and you can go to the following link to find distributors in your area. http://www.bc.com/locations/#!/building-materials-distribution You will need to have a local engineer detail your connections, size your support columns and determine foundation requirements.
Expert:  walkereng replied 1 year ago.
If you feel you have received a satisfactory answer to your question, click the Rating button that is appropriate. Experts are credited for each appropriately Rated answer they provide. If you have additional questions, please let me know. Thanks
Expert:  walkereng replied 1 year ago.
Let me know if you have any more questions
Customer: replied 1 year ago.
Original question was can we replace this Glulam with a double LVL and it would appear that you are still talking a Glulam which does not help us with the answer.
Expert:  walkereng replied 1 year ago.
The Versa Lams I specified above are LVL's not Glulam Beams.
Based on the Boise Cascade software I use, I could not come up with the original size that was specified on your plans "3 1/2" x 16 1/2" Glulam". For a single beam you would need something more in the range of a 5-1/2"x16" King Beam or a 5-1/4"x18" Versa Lam.
Based on a Live Load of 25 psf and a Dead Load of 10 psf, with a 26' span and a 3' cantilever at one end, and a beam spacing of 12' o.c., you would need the Double 3-1/2” x 16” Versa-Lam 1.7 2650 DF if you wanted to use two beams instead of one.
Expert:  walkereng replied 1 year ago.
Let me know if you have any more questions.
Expert:  walkereng replied 1 year ago.
If you feel you have received a satisfactory answer to your question, click the Rating button that is appropriate. Experts are credited for each appropriately Rated answer they provide. If you have additional questions, please let me know. Thanks

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