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StructuralEng
StructuralEng, Consultant
Category: Structural Engineering
Satisfied Customers: 7318
Experience:  Structural Engineer
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What size steel beam do I need to clear span 30 feet? Do I

Customer Question

What size steel beam do I need to clear span 30 feet? Do I need a box beam or I-beam?
Submitted: 1 year ago.
Category: Structural Engineering
Expert:  StructuralEng replied 1 year ago.

Hello. How are you doing? I'll be happy to assist you

Customer: replied 1 year ago.
What size steel beam do I need to clear span 30 feet? Do I need a box beam or I-beam
. I am using 4 inch steel post for a deck that is 30 X 50 feet.
Expert:  StructuralEng replied 1 year ago.

Is it supporting 50' long joists?

Customer: replied 1 year ago.
No The joists are 30 feet long. The beam will be 50 feet across 4 posts.
Expert:  StructuralEng replied 1 year ago.

Do you want the joists sized or the beam? You used beam with the 30' span, so I assumed the joists were spanning the 50'

Customer: replied 1 year ago.
I guess I should have ask what size joists to span 30 ft clear span
Expert:  StructuralEng replied 1 year ago.

what kind of decking will you use and what spacing do you desire? Is this a residential deck?

Customer: replied 1 year ago.
Composite decking on a commercial deck
Spacing will be 16 inches
Expert:  StructuralEng replied 1 year ago.

I will assume you can attach the composite decking to the steel beams.

Expert:  StructuralEng replied 1 year ago.

Assuming a residential deck, W8x18 ASTM A992 Gr. 50 at 16" on center. Attaching the deck boards to boards to every beam is very important to the proper performance of the beams.

Customer: replied 1 year ago.
I will strip it first
Customer: replied 1 year ago.
This is a commercial deck.
I plan to strip it before putting the composite deck down
Expert:  StructuralEng replied 1 year ago.

What setting will the deck be used in?

Customer: replied 1 year ago.
It is a recreation building and kids and adults will be sitting on the deck eating
Expert:  StructuralEng replied 1 year ago.

That will make the beam larger

Expert:  StructuralEng replied 1 year ago.

W8x28 ASTM A992 Gr. 50 at 16" on center.

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.