Good morning! I am designing a new home. In a couple areas, I have chosen to run a steel beam from a pocket in the wall. What are the acceptable methods, or requirements, for anchoring the beam to the conrete basement wall?
Thanks!
Regards,
Tachi
tachi
Family in Tucson, business in the Far East, and heart in the Colorado mountains!
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Replies
Gravity will work initially. Follow up by stacking a lot of lumber. flooring, roofing etc on it.
You might want to run it by an engineer. I am using a W8 as a floor girder for a project now and the engineer likes gravity too. It's locked in by floor joists hanging on both sides, and the ends are under the bottom plate of the wall above. That's all he needs, apparently.
If you do more than that, be sure to talk to your BI about what is required for field welding. Here I need a certified welder and some paperwork if I do anything like weld on brackets, etc. I've worked before in jurisdictions where a welding inspector was required as the work was being done. That is not cheap.
Actually, that jives with what I was thinking. Fortunately, I have setup a design that does not require any beams to intersect and connect. They are simply 'down-the-center' support for the wood trusses that will sit on top. The whole thing then becomes overkill, as intended. I kind of wondered if it was necessary to actually anchor the beam at the wall. Should the beam rest directly on the concrete? or do you put a block (hunk of 2x) underneath?
Thanks, David.
Regards,
Tachitachi
Family in Tucson, business in the Far East, and heart in the Colorado mountains!
When we sell steel beams we generally supply a "shim pack" with them. It contains 3" of steel plates of various thicknesses to use under the ends of the beams.
One for the gals:
Q: What is that insensitive thing at the base of the pen!s called?
A: The man.
David, looks like the OP has mastered wood trusses on concrete and is moving on to steel beams. Still think he will use a professional and/or nobody's going to get hurt?
DG/Builder
It looks like we'll get plenty of chances to help him get it right. I've seen lots of horrible work done by 'pros' and fine work done by owners. I doubt he'll physically do all of the work himself, so hopefully he'll pick up at least an ace carpenter to spearhead the effort.
Gravity will do the work..The beam should sit on steel bearing plates usually 1/4" thick..you can also get thinner plates to shim the beam if necessary..
I usually have tabs welded perpendicularly onto the web of the beam. Once the framing is done, I will fill the pocket solid with structural grout. The tabs help in locking everything in..
But, as stated in other posts, check with the building inspector and/or an engineer if they require the beam to be welded down..
Sometimes if the beams are big, we specify bearing plates with studs welded onto them (downward) that are cast into the concrete, and have the beams welded onto them..but that's usually in our commercial projects..
Edited 2/14/2006 12:49 pm ET by MJLonigro
Now that's an interesting idea. The side webs that you pre-weld onto the steel will provide some additional anchoring into the pocket when you fill it with construction grout. That makes sense. Thanks!
The intent is to provide a little overkill support to 11-1/4", 24" OC, wood trusses that are spanning an area of approx 23 ft. I had selected an I beam, 8" high, with a 4" flange. Not huge, but with posts at strategic points, and trusses that are almost good enough to handle the span without the beam, nothing should be put even close to their design limits.
Ultimately, the design will be checked by the local architects/engineers before the hole is dug!
Regards,
Tachitachi
Family in Tucson, business in the Far East, and heart in the Colorado mountains!
wood trusses that are spanning an area of approx 23 ft
Hmm, "trusses" only 11 1/4" tall may be hard to come by (boss hog will weigh in if that is inaccurate).
However, TJI will span 23' rather readily (if, perhaps, at 16" OC instead of 24" OC).
This is where having an experienced professional in at the begining can be a great advantage. Or, where polling a pool of experts (even if we are but annonymous "drips under pressure" over the Internet) can be helpful. That gets to how to ask the question.
You could, one supposes, have asked the question in both threads (possibly) better by posing it as "What might be the most elegant/efficient way to create a 23-24' floor span for southern Colorado.
Posing the question that way might have gotten you some sprightly debate on, say, 14" v. 16" TJI (engineered wood I-beams) as various spacings, and cross-bridging versus blocking for best floor rigidity. Note that there might have been some sage advice on using "flush" beams to shorten the spans (if needed). You can get engineered wood beams (gluelams, laminated veneer lumber, etc.) in dimensions to match the floor TJI, and without all of the complications of connecting steel to wood and/or steel to concrete.
Whether the discussion might have veered into "competent to design and/or build" can only be speculated upon.Occupational hazard of my occupation not being around (sorry Bubba)
Point taken. Thank you. Of course, I would rather do without the center beam, if possible, but I grew up with a Father that used 3 screws, in places that 2 nails would have sufficed! So, I tend to the overkill. I was working from span charts from a company called Trim Joist. http://www.trimjoist.com/spans.html Looked I could squeeze by, depending upon how I calculate the loads. This particular area of the house is master bedroom, MBath, utility room etc. And the flooring anticipated is probably Warmboard, or something similar.
On the other hand, if I go to the larger trim joist at 14" (J-14), I could easily drop the beam, it would seem. I certainly have the head room, so maybe that makes a lot more sense. Have to do a little studying.....!
The discussion here has been great.
Thanks.
Tachitachi
Family in Tucson, business in the Far East, and heart in the Colorado mountains!
The discussion here has been great.
That's why we do it <g> . . .
On the other hand, if I go to the larger trim joist at 14" (J-14), I could easily drop the beam, it would seem. I certainly have the head room, so maybe that makes a lot more sense. Have to do a little studying.....!
Quite, as an open-ended question, a steel beam "halving" the span of wood floor trusses becomes an interesting theoretical question. When you add some specifics, it changes the "scope" a bit.
Now, the only other consideration to make, in choosing a floor system is the mechanicals. TJI's allow for some transverse mechanicals--that "some" can be a bear. Particularly when you are ciphering basement head room. This is where going to the next larger size TJI, or to going to an actual wood floor truss, can be to your advantage (especially if you anticipate any air ducting run under the floor).
There are few things as annoying as finding that a DWV line has to run at exactly the wrong diameter in exactly the wrong spot in the TJI (and the slope is exactly too close to one edge or the other of the TJI). Some of that is "just the breaks" in residential construction. Some of that is smack-self-in-forehead, I could'a run that line the "other" way . . .(which can also be life in construction <sigh>).
Occupational hazard of my occupation not being around (sorry Bubba)
Edited 2/16/2006 10:54 am by CapnMac
There's a whole bunch of variables--many of which are simply defined by your AHJ (Authority Having Jusrisdiction). So, if you have seismic concerns, or mandaeted by Building Department concerns, or the like, they can tell you.
Now, gravity is a fine thing. However, much of the fire fighting community prefers that beams in pockets have a chamfered back cut, so that may be a local requirement for you.
Some jusrisdictions will want a metal beam to be welded to a bearing plate in the bottom of the pocket (or engineering drawings saying it's not needed). That bearing plate might then need tying to the reinforecment in the wall (or not). Your AHJ will be better placed to tell you.
Sounds like a neat idea, to have the one run of steel to bear the trusses above, though.
Thanks for the input. My intention is to build in the So. Colorado area. So, I suspect that is not considered a seismic issue, however, I have sent a message to the local Pueblo County planning commision to see what their requriements might be. I intended to anchor the steel at the other end, of course, but assumed the pocket itself, with all of the trusses bearing on it, would be sufficient at that end. One respondent indicated that stell shims are sent with beams.
To assuage the 'fears' of several who have responded, before I submit final plans to the county, I will have them thoroughly checked by a licensed architect/engineer in the area. I am not foolish enough to believe that I will not miss something important in the process of completing the design.
Regards,Tachitachi
Family in Tucson, business in the Far East, and heart in the Colorado mountains!
Bridges ride on rollers or some other means of support due to expansion and contraction due to temperature. You dont want to firmly set both ends of your beam.
That makes a lot of sense. Probably should anchor the end that is not channeled into a pocket.
Tachitachi
Family in Tucson, business in the Far East, and heart in the Colorado mountains!
Tachi: Our very rural GA county didn't have anyone really qualified to say what to do, so I asked the engineer that designed my floor trusses that bore on the WF. He said to bury a couple bolts in the poured concrete & have the beam's flanges punched for them, Didn't need shims because I was so anal about the measurements when forming the pocket that the beam came out right on elevation. I had engineer stamps on beam design & trusses, so inspector was happy.
Don
The Glass Masterworks
"If it scratches, I etch it!"
Tachi, we set the steel directly on concrete here in MI. If the depth of the pocket is right, we use STEEL shims to raise the beam. Do not use wood under the beam because the concentrated load will crush the wood into paper, eventually.
We don't anchor them in any way, but to get a final inspection, the beam pockets must be filled with mortar. I suppose this prevents the beam from tipping.
We don't have any firecut requirements here.
blue
Thank you. Would you anchor differently if you use a laminated wood beam, instead? Another suggested as much. It also occurred to me that on a long run with intermediate column supports, I may have to break the beam up into shorter lengths. Anchoring a laminated wood beam might be a lot easier at the top of columns.
Tachitachi
Family in Tucson, business in the Far East, and heart in the Colorado mountains!