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StructuralEng
StructuralEng, Consultant
Category: Structural Engineering
Satisfied Customers: 7073
Experience:  Structural Engineer
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I am looking to eliminate one of the thre lally columns from

Customer Question

good evening
JA: Hi. What seems to be the problem?
Customer: I am looking to eliminate one of the thre lally columns from the basement. I do not know too much about load calculation
JA: OK. Tell me a bit more about what's going on so we can help you best.
Customer: what do you need to know?
JA: Is there anything else important you think the Structural Engineer should know?
Customer: if you ask me, I'll answer. What do you need to know? it is one single storey house, with a basement
Submitted: 6 months ago.
Category: Structural Engineering
Expert:  StructuralEng replied 6 months ago.
Hello
Expert:  StructuralEng replied 6 months ago.
Is there a Wall above the beam to support the attic or do you have roof trusses? What is the joist length on each side of the beam? Does it support any ceramic tile? And what is the current make up of the beam?
Customer: replied 6 months ago.
I can send you sketches
Customer: replied 6 months ago.
the phone call will it be an additional $34?
Expert:  StructuralEng replied 6 months ago.
Correct
Expert:  StructuralEng replied 6 months ago.
Sketches will help
Customer: replied 6 months ago.
I will send sketches
Customer: replied 6 months ago.
the file doesn't go. do you know why?
Expert:  StructuralEng replied 6 months ago.
You have to attach it with the paperclip icon
Customer: replied 6 months ago.
ok. I guess that you got it. My questions are:
1. can I get away without installing a new lally column (as I show in green in my sketch) (by other hand I do not know for sure if the remaining lally columns have correct footers 2'x2'x2')
2. how to reinforce the existing main beam (flitch plate seems too complicate)
Expert:  StructuralEng replied 6 months ago.
I'm going to need some time to look over these sketches and make sense of them. I will get back to you tomorrow morning
Customer: replied 6 months ago.
I thought that my sketches are pretty self-explanatory. is it something there what you do not understand? just ask me.
Expert:  StructuralEng replied 6 months ago.
I don't see any existing being shown. I see weld plates shown as if you want a custom steel section designed. There's no directions or section cuts for the sections you show so it's not clear what direction they're cut. And in the one section to lolly columns are a couple feet apart. Which looks like you want to offset the beam from where it currently is.
Customer: replied 6 months ago.
there are three existing lally columns (the grey ones). I do not know for sure how to do this, for this reason I am asking you.
the house is a single storey house (20' x 30'), with a main beam 30' long, supported by three existing lally columns. I will prefer to cut nothing. I was thinking to add the new column just 28" apart .... only because I do not know if the existing one has a correct footer (2'x2'x2'). if it is not need to add a new column ... than ... it is much better. how should I reinforce the existing main beam so the new span of 15' it will be safe?
Expert:  StructuralEng replied 6 months ago.
I can't begin to tell you how to reinforce it if I don't know what it is
Customer: replied 6 months ago.
I do not remember exactly how to calculate the load, plus I do not know exactly which is the approximate weight of the existing house (I am not a contractor or a structural engineer)
When you say that you do not know what it is .... what do you mean?
Expert:  StructuralEng replied 6 months ago.
Is it a double 2 x 8 a triple 2 x 12? What is the beam made of
Expert:  StructuralEng replied 6 months ago.
Is this place over the supports? Is it spliced randomly along the length?
Customer: replied 6 months ago.
here it is another sketch (detail)
Expert:  StructuralEng replied 6 months ago.
How are the pieces of lumber spliced and where
Customer: replied 6 months ago.
I guess it is a standard main beam, as I shown in detail
Expert:  StructuralEng replied 6 months ago.
There's no such thing as a standard main beach. Summer spliced over the columns. The summer is placed over every other column. Summers placed randomly along the length.
Expert:  StructuralEng replied 6 months ago.
Some are
Customer: replied 6 months ago.
looks like this
Expert:  StructuralEng replied 6 months ago.
You will need. 1.25" X 7.5" steel plate on each side of the existing beam bolted together to span the 15'. And that is with a minimal deflection ratio appropriate for only non brittle floor finishes
Customer: replied 6 months ago.
do i need a new column or not?
the reinforcement it should be as the picture attached, right?
Expert:  StructuralEng replied 6 months ago.
If you provide the plate that I listed on each side then you don't need another post. That detail looks schematically accurate, but the bolt pattern will need to be designed.
Customer: replied 6 months ago.
1.25" x 7.5" looks like a lot. this is a very small house. I shall see what the town engineer says. Thank you.
Expert:  StructuralEng replied 6 months ago.
Then why bother asking? Honestly. That's what you need to spend 15 feet supporting one floor and an attic limiting the depth to seven a half inches.
Expert:  StructuralEng replied 6 months ago.
To span 15'

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