Footings, Columns,Beams, and Floor slabs

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Re: Footings, Columns,Beams, and Floor slabs

Postby MGV12 » Fri Aug 24, 2012 9:10 am

sirineou wrote:They might want to eliminate the two columns upstairs,as they are really not supporting anything other than that portion of the roof.


If your 'bump' is cantilevered you certainly don't want to be doing that ... bridge the beam across the gap and tuck the bump under the existing eaves; as previously discussed.

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Re: Footings, Columns,Beams, and Floor slabs

Postby Roger Ramjet » Fri Aug 24, 2012 10:01 am

sirineou,
As you increase the weight the ground floor columns carry, so you must increase the size of the "foot" over the piles, to spread the load. At the same time you must increase the strength of the columns by either adding a larger column or, increasing the size of the rebar used and the amount used. All this extra weight transmits to the piles, so I would be looking at increasing the number of piles under those two columns so the weight is better spread and then making a larger "foot" by linking the piles to the footings to take the added weight.
I tried to make this point before. It's not about the design, it's about the engineering involved. Cantilevers are all well and good, but you must compensate and the drawing doesn't do that.
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Re: Footings, Columns,Beams, and Floor slabs

Postby BKKBILL » Fri Aug 24, 2012 3:30 pm

sirineou wrote:I Think I need the columns downstairs to support the staircase landing,

Just lower the second floor ring beam to suport the landing as it isn't required where it is now.

Since you are not using piles that won't be a problem.
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Re: Footings, Columns,Beams, and Floor slabs

Postby sirineou » Fri Aug 24, 2012 6:05 pm

Thank you all for your responses, your contributions are very helpful and highly appreciated. :)
by MGV12 » Thu Aug 23, 2012 9:10 pm
If your 'bump' is cantilevered you certainly don't want to be doing that ... bridge the beam across the gap and tuck the bump under the existing eaves; as previously discussed.

there will be a false floor on that ring beam, and they will be laying concrete planks on that ring beam, If i bridged the gap, they will not be able to place concrete planks over the bump out section. (they seem to be very concerned with security, and break ins from the roof)
by Roger Ramjet » Thu Aug 23, 2012 10:01 pm
sirineou,
As you increase the weight the ground floor columns carry, so you must increase the size of the "foot" over the piles, to spread the load.

I don't believe they will be using piles, as they are rarely used in the area do to the dense ground composition.What you are saying is correct,but this bump out is so small (1m X 3,5 M ) and the weigh of it I believe would be negligible to the overall structure. Next week we are starting a new build in Manhattan, I will run it by the engineers and see what they say. If we think it might present a problem, then it would be a simple matter to place small footings under it, and carry at least some of the weight.
by BKKBILL » Fri Aug 24, 2012 3:30 am
Just lower the second floor ring beam to suport the landing as it isn't required where it is now.
Since you are not using piles that won't be a problem.

I wonder if that would be adequate for transferring the horizontal loads of the ring beam across the gap of the bump out?
there are two beams near that area, the beam in the center of the building, and the beam under the upstairs hallway 2.5m away, (tying the house together horizontally)
combined with the lowered beam that should provide adequate horizontal strength. But then I will have a 4 m high wall unsuported, they will have to place a lintel half way up, especial since there will be a window there(probably a lintel under the window and one over the window all the way across.
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Re: Footings, Columns,Beams, and Floor slabs

Postby sirineou » Fri Aug 24, 2012 8:56 pm

BKKBILL wrote:
sirineou wrote:I Think I need the columns downstairs to support the staircase landing,

Just lower the second floor ring beam to suport the landing as it isn't required where it is now.

Since you are not using piles that won't be a problem.

I thought about that some more, and did some work on Sketchup, and it will not work because i need some place to rest the floor concrete.(
As I had it drawn you were correct, but when I looked it again it help me realize that i was missing a beam, (see red beam) the second floor slab ends ther and also the wall for the upstairs bathroom,so on that respect your suggestion helped a lot.
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That's why I love sketch up it allows me to virtually build this house and make all the mistakes on paper.
I appresiate all suggestions keep them coming :)

Ps: the bump out also simplified the plumbing , now most of the bathroom plumbing is under the cantilever, and in the open.
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Re: Footings, Columns,Beams, and Floor slabs

Postby BKKBILL » Fri Aug 24, 2012 9:45 pm

Glad to be of some assistance.

Sketchup certainly does help, spent many hours with that program.

It let my wife visualize our build and when time to build showing our building team 3D drawings saved the day many times.
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