jojo12
New Member
Posts:60
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| 06 Jan 2011 04:27 PM |
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in my house design I need to place a steel beam into my exterior walls. The beam will come out of the one icf wall at 90 degrees to the wall but at the other side of the basement the beam will meet the icf wall at 45 degrees. my question is whether or not there is any special things that I need to do or consider when constructing my beam pocket on the 45 degree wall, or is it a no-no to put a beam into the wall at 45 degrees.
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Alton
Veteran Member
Posts:2164
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| 06 Jan 2011 04:31 PM |
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One thing to keep in mind regardless of the angle is that the beam must have adequate bearing on the wall. Angles can be somewhat difficult to work with at times. |
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Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period .
334 826-3979 |
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jojo12
New Member
Posts:60
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| 06 Jan 2011 09:29 PM |
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does anyone know how much must be bearing on the concrete |
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TexasICF
Advanced Member
Posts:622
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| 06 Jan 2011 10:02 PM |
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Jojo,
1st you should consult an engineer. 2nd you should consult and engineer. 3rd if no engineers are available use horizontally set embeds with nelson studs so that your steel beam will bear on the plate and can be welded accordingly. Most commerical work I've seen is 4" minimum bearing. I would let the beam extend entirely across your availble bearing surface and torch off the part that would otherwise compromise your thermal envelope. It will obviously be a 45 degree cut as well. Regards.
P.S. I can probably find a picture or two of this if necessary. |
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galore
New Member
Posts:40
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| 10 Jan 2011 07:53 PM |
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Like TexasICF says, structural steel members should be welded to steel embeds which are installed before the concrete is poured. In my case the structural engineer specified 4"x8"x3/8" plates with two 2.5" studs in 5"x8" pockets so that the steel joists rest on 4" of steel plate. This was for very small 12K1 steel joists.
I also have several I beams with the biggest one a W18x55, 20 ft long. The engineer specified much bigger embeds, this time vertical with the I beam bolted to a WT4x9 welded to the vertical plate. I requested if it was possible to do pockets instead but he didn't want to specify a pocket for the larger I beams. I did notice that in commercial construction, beams are typically not in pockets but installed like the engineer specified for my house. |
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jojo12
New Member
Posts:60
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| 10 Jan 2011 09:44 PM |
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so if I am understanding you correctly the engineer for the larger beams wants a wt 4X9 beam placed vertically in the icf wall down to the footings on which the main support beam is either bolted or welded, in essence all the concrete is doing is giving the vertical beam support for movement side to side? |
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galore
New Member
Posts:40
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| 11 Jan 2011 12:00 AM |
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No, the beam is bolted to a WT (which looks like a tee) which is welded to a studded steel plate (a concrete embed) which is embedded into the concrete (placed before the pour). It's a three component system: plate, tee, beam
See attached picture.
Personally, I don't know why the structural engineer chose this method for the main beams but he didn't want to use a pocket except for the light steel joists.
I would consult with a professional structural engineer. I'm not an expert and just show what the engineer designed for my house...  |
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TexasICF
Advanced Member
Posts:622
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jojo12
New Member
Posts:60
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| 11 Jan 2011 08:54 PM |
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okay I understand, thankyou. I am not an engineer and for that reason I do not understand why this is a stronger method than bearing on the concrete. I can see this being stronger in the horizontal axis beacause it is up against concrete whereas in a beam pocket it would only likely have foam and siding to push against??
I know virtually all the basements around here are simply beam pockets, however, I dont personally know of any 45 degree conections so I cant say for that.
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dmaceld
Veteran Member
Posts:1465
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| 12 Jan 2011 01:19 AM |
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Posted By jojo12 on 06 Jan 2011 09:29 PM
does anyone know how much must be bearing on the concrete
That depends entirely on how large the beam is and how much load is on the beam. The only way to know is do all of the calculations. A seat-of-the-pants approach could be used but more than likely whoever does it would probably say to use a beam twice as big as necessary "just to be safe." And steel ain't cheap. You need someone who knows your situation to run the numbers for you. |
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| Even a retired engineer can build a house successfully w/ GBT help! |
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TexasICF
Advanced Member
Posts:622
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| 12 Jan 2011 09:39 AM |
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Posted By jojo12 on 11 Jan 2011 08:54 PM
okay I understand, thankyou. I am not an engineer and for that reason I do not understand why this is a stronger method than bearing on the concrete. I can see this being stronger in the horizontal axis beacause it is up against concrete whereas in a beam pocket it would only likely have foam and siding to push against??
I know virtually all the basements around here are simply beam pockets, however, I dont personally know of any 45 degree conections so I cant say for that.
dmaceld is correct. However, (jojo) I wanted to clarify something above as I might have led you down the wrong path. You're assumption is correct. The method I've attached as a photo is not as strong as a beam pocket. A beam pocket approach is usually significantly stronger because there's less moment at the connection. That said, beam pockets are often used for large primary beams in commerical work - sometimes the wall goes on up with concrete poured around and in the pocket as well. An 8" concrete wall would be stronger than a 6" concrete wall as well but you need to keep in mind what you are building. At some point 10x stronger is okay and 15x stronger is not necessary. Regards. |
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TexasICF
Advanced Member
Posts:622
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| 12 Jan 2011 09:43 AM |
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Further clarification, a beam pocket does not usually have "a beam in the wall" -- this is rarely seen. You can take the detail provided by galore and rotate the embed plate 90 degrees and weld your beam to the plate. Typically, the engineer will add some additional vertical steel (rebar) under the plate. Run it by an engineer. Regards. |
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