How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask StructuralEng Your Own Question

StructuralEng
StructuralEng, Consultant
Category: Structural Engineering
Satisfied Customers: 6689
Experience:  Structural Engineer
59685895
Type Your Structural Engineering Question Here...
StructuralEng is online now
A new question is answered every 9 seconds

I want to replace a triple 2x8 by 32' beam supporting a

Customer Question

I want to replace a triple 2x8 by 32' beam supporting a patio pergola that has 3x8 joists with a 16foot span. There is a solid corrugated polycarbonate roof so there can/will be a snow load. There are currently 4 columns but is it possible to reduce that to 3 or even 2 columns
Submitted: 1 year ago.
Category: Structural Engineering
Expert:  StructuralEng replied 1 year ago.
Hello: I can help. I'm away from my computer right now. Can I get back to you this evening?
Customer: replied 1 year ago.
Sure
Expert:  StructuralEng replied 1 year ago.

Thank you for your patience.

Expert:  StructuralEng replied 1 year ago.

You can reduce this to three or two columns. Going to 3 columns will require a big glulam beam. Going to only two columns will require VERY large glulam beam or a steel beam. Which do you prefer?

Expert:  StructuralEng replied 1 year ago.

What is the city and state so I can look at snow loading?

Customer: replied 1 year ago.
I live on Long Island, NY
3 columns could be workable.
What about replacing the triple 2x8 with a triple 2x10 bonded with construction adhesive and through bolted. or building a new triple 2x8 with fitch plates sandwiched between the layers and through bolted (this would be easiest because the columns would not have to be shortened.)
the 3x8 joists are on 24" centers with 2x4s perpendicular on top to which the polycarbonate corrugated roofing is secured.
Customer: replied 1 year ago.
the 2x4s are on 16" centers
Expert:  StructuralEng replied 1 year ago.
A triple 2x10 won't even be close. I'll size it now.
Expert:  StructuralEng replied 1 year ago.
You can plan for one of the following beams with 16’ span. All are pressure treated glulam 24F-V4 and will limit deflection to about ½” under a full design load.
3.125” x 13.5” or 5.125” x 12” or 6.75” x 10.5”
Expert:  StructuralEng replied 1 year ago.
Hello. Do you have any other questions for me on this topic? If you could rate my answer, I would appreciate it

Related Structural Engineering Questions