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StructuralEng
StructuralEng, Consultant
Category: Structural Engineering
Satisfied Customers: 7320
Experience:  Structural Engineer
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Approximately 36ft. wide basement with cider block

Customer Question

approximately 36ft. wide basement with cider block foundation walls. 7 inch X 3.75 inch I Beam spans from wall to wall with 3 steel support posts set in concrete floor and bolted to I beam at 9 foot intervals. I want to remove one of the posts (one that is 9 feet from wall) and replace it with two new steel supports. On next to wall and one and one 13.5 feet from the wall. Result would be an open span of about 13.5 feet total of 4 posts. Can I do this ?
ken
Submitted: 1 year ago.
Category: Structural Engineering
Expert:  StructuralEng replied 1 year ago.

Hello

Expert:  StructuralEng replied 1 year ago.

You can certainly do this, but we will need to take a two step approach.

First, I will analyze the beam to see if the span can increase by 50% without a problem. I will let you know that answer. Then we can go to step 2, if needed.

Expert:  StructuralEng replied 1 year ago.

What exactly is the beam supporting?

Customer: replied 1 year ago.
A one story, 1150 sf house.
Expert:  StructuralEng replied 1 year ago.

Do you have roof trusses or rafters and joists?

Expert:  StructuralEng replied 1 year ago.

What is the joist length on each side of this beam?

Is the beam spliced over any of the supports?

Will it support any ceramic tile?

Customer: replied 1 year ago.
Approx 11.5/12 feet on each side of beam. Small bathroom has ceramic tile floor. Attic consists of rafters and joists ( I think) please assume heaviest, if that is why you asked. No splices. I beam is one continuous single piece.
Expert:  StructuralEng replied 1 year ago.

Can you measure the exact depth, width, and flange thickness of the beam?

Customer: replied 1 year ago.
I Beam is 7 inches high, 3.75 wide and is a typical steel beam
Expert:  StructuralEng replied 1 year ago.

Can you measure the thickness of the top or bottom of the I?

Expert:  StructuralEng replied 1 year ago.

I am going to assume it's a S7x15.3 ASTM A36

Customer: replied 1 year ago.
1/4 to 3/8 inches thick
Expert:  StructuralEng replied 1 year ago.

10'-6" is the maximum allowable span for that beam with that loading.

Customer: replied 1 year ago.
Thanks, ***** ***** allow me to remove the problem post and add one 18 inches away, thus opening up or clearing the area I want to free up. Are you also saying tathat adding the two post I mentioned will not allow for the open span of about 13.5 feet ?
Expert:  StructuralEng replied 1 year ago.

Correct. The maximum span between any two posts is 10.5'. I can determine what reinforcement you need to get the 13.5' span as a premium service, if you want.

Customer: replied 1 year ago.
Am good to go now with your info. If I need further info, will contact you. Thanks, ken
Expert:  StructuralEng replied 1 year ago.

No problem. I'm happy to help. Good luck with your project.