W-Beam Splice

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I'm getting ready to use up a bunch of beam shorts (both 12 x 30s and 16 x 26) to put up a crane system, it doesnt have to be all that pretty, but the top of the bottom flange must be ground smooth to allow the rollers to go over them without a bump, I've seen standards for Ship-lap splices, but what about the following (see pdf)first question, is there a standard as to the dimensions A and B(B obviously you need to get above the k value)(A I was thinking about half the height of the beam)second - is there an actual name for this joint like there is for ship-lap? personally I think it's a tongue and groove, but havent found it anywherethird, is this this a "legal" splice? I've seen it in older buildings without a backing bar, I was thinking Flanges with full pen welds & the web with a splice plate welded all the way around on both sidesThanks for your time Attached ImagesTongue and groove.pdf (31.4 KB, 1310 views)
Reply:W beam?  Anyway you cannot grind a structural weld. So that means the trolly could not travel freely.As far as the design of a splice it would require stiffening plates on each side.This is an engineering question.I would go to http://www.eng-tips.com/viewthread.c...19633&page=531Talks about this very problem.Last edited by Donald Branscom; 03-25-2011 at 06:58 PM.AWS certified welding inspectorAWS certified welder
Reply:Here is how I spliced the W-12X87 for by bridge crane. Then I ripped a 12 inch S-shape for the tapered flange for the trolley. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:1. bolted splice plates are only allowable within n feet of joist support (usually directly below) if I attempted to use 3 bolted connections per span (22') there would be a "valley" formed in the center of each span (I have varying lengths 7'-13' that will make up the overall length of the run, spanning 22' centers for the joists)2. attached file is from http://www.eng-tips.com/viewthread.c...=260902&page=7his is a problem of the contractor not doing what his drawing showed & not submitting an rfi, that notwithstanding all he ended up doing was add a plate to the sides of the web3. cant grind a structural weld? please elaborate, do note that I am not talking about grinding all welds flush, simply the top of the bottom flange to allow for the trolley not to bump4. w-beam (wide-flange beam) commonly mistaken and called "I Beam"5. cep if I'm understanding you correctly you have essentially a w-beam laying |-----| with an ST welded to its web for the trolley?I'll hop over to eng tips again and see if they have anything to add.Thanks Attached Images
Reply:No the Structural Engineer who helped me with the crane, suggested I use the W-shape because an S-shape would be too tall for the span and weight I was dealing with. I welded the ripped S-shape to the bottom flange of the W-shape. You could go with an open root splice. Or use the backer plates on the outside of the flange. Not grinding on a structural weld is a new one on me! Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:What type of crane system are you building?  If you don't care about the appearance of the splice, I doubt if your work will pass inspection. I can't imagine a customer who would be willing to pay for a crane that he can't get certified.
Reply:CEP - makes more sense nowPro-Fab - when I say I do not care about the appearance, I do not mean I want an ugly uncertifiable weld, I mean that there is no aesthetic consideration being given to the splice itself so long as the beam strength is developedIt is for a 2-ton underhung crane for our low-bay roof for loading and unloading sheets of steel to our plasma setup & moving machines in our stainless rail-making bay
Reply:Originally Posted by CEPNo the Structural Engineer who helped me with the crane, suggested I use the W-shape because an S-shape would be too tall for the span and weight I was dealing with. I welded the ripped S-shape to the bottom flange of the W-shape. You could go with an open root splice. Or use the backer plates on the outside of the flange. Not grinding on a structural weld is a new one on me!
Reply:Originally Posted by andrewevans1. bolted splice plates are only allowable within n feet of joist support (usually directly below) if I attempted to use 3 bolted connections per span (22') there would be a "valley" formed in the center of each span (I have varying lengths 7'-13' that will make up the overall length of the run, spanning 22' centers for the joists)2. attached file is from http://www.eng-tips.com/viewthread.c...=260902&page=7his is a problem of the contractor not doing what his drawing showed & not submitting an rfi, that notwithstanding all he ended up doing was add a plate to the sides of the web3. cant grind a structural weld? please elaborate, do note that I am not talking about grinding all welds flush, simply the top of the bottom flange to allow for the trolley not to bump4. w-beam (wide-flange beam) commonly mistaken and called "I Beam"5. cep if I'm understanding you correctly you have essentially a w-beam laying |-----| with an ST welded to its web for the trolley?I'll hop over to eng tips again and see if they have anything to add.Thanks
Reply:Originally Posted by Donald BranscomNot grinding on a structural weld is because the raised crown of the weld bead is considered the reinforcement. It is important to the strength of the weld.
Reply:Originally Posted by CEPVery true! But there always seems to be exceptions.
Reply:I saw a drawing of a spice on a 7 inch beam but o the drawing it said that a splice had to be with in 24 inches of a post .I have never seen a trolly supported on a beam with a splice.Might want to double check. It makes me nervous.AWS certified welding inspectorAWS certified welder
Reply:not sure if you were looking at the right picture or not Donald, the attached pic here is what I'm proposing Attached Images
Reply:Ok, generally welds are not ground down, but in this case it is necessary for the intended use and only enough weld need be ground flat to allow the trolley to pass.  I would add a small plate on the bottom of the beam across the bottom joint welded only on the sides parallel to the beam flanges to reinforce this if it is a concern.  Do not weld across the bottom flange.  I have had success just butt welding beam sections together especially for lightly loaded or oversize beams, but the shiplap and finger joints shown would certainly be stronger.I have also seen many crawl beams made with a piece of channel welded to the top flange with the channel flanges pointing down particularly on S beams to reinforce against lateral deflection.If you do feel the need to add splice plates over the web joints, avoid welding across the webs and just weld the sides of the plate parallel to the flanges.As to the legality of the splice you will need to hire an engineer for that one."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:I have never seen a trolly supported on a beam with a splice.Might want to double check. It makes me nervous.
Reply:Originally Posted by WeldingMachineI had a guy that wanted me to weld a class II hitch to the bottom of his civic the other day.
Reply:Originally Posted by Donald BranscomI have never seen a trolly supported on a beam with a splice.
Reply:The other comment that I would make is that this may depend somewhat on how stressed the beam is.  If the beam is 10 times as strong as it needs to be, the weld can be 50% of the strength of the base metal and you will still be OK.   If the beam is more or less the minimum size (including safety factor), the weld becomes a bigger concern.Another odd consideration is by welding half of an I beam to an H beam, you are making a more complex structure, and could conceivably increase the stress at the high stress point, even over the H beam!   (It would require some real calculation to figure out if that was true in this case.)But I would not feel comfortable with a beam with a joint near the middle of the span.  Another poster suggested that any joint should be within 24 inches of a post, which is a lower stress point, so that makes sense to me.   I would not do a splice personally, and I would not sign such a drawing.  You are just being cheap, in my view.I agree completely that the weld should not be ground down, as that is part of the strength.  Maybe you could grind one side and not the other.My two cents, wearing my engineer hat.  I will say that I am not 100% sure exactly what the original poster intends to do, not having seen drawing of the entire design.RichardLast edited by raferguson; 03-26-2011 at 12:06 PM.Sculptures in copper and other metalshttp://www.fergusonsculpture.comSyncrowave 200 Millermatic 211Readywelder spoolgunHypertherm 600 plasma cutterThermal Arc GMS300 Victor OA torchHomemade Blacksmith propane forge
Reply:My bridge crane was designed for 1-ton. The span beam, (W-12x87) is good for 20-tons point loaded in the center, (splice). Not a bad safety factor, don't cha think?Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Originally Posted by andrewevansnot sure if you were looking at the right picture or not Donald, the attached pic here is what I'm proposing
Reply:I think the part the scares me the most is "a BUNCH of beam shorts.." How many do you plan on putting together, and whats the finished span going to be?Making one splice is one thing, putting a bunch of drops together as a substitute for one beam that's going to be holding sheets of steel over my head is not something I would even consider.Have we all gone mad?
Reply:Originally Posted by sn0border88Making one splice is one thing, putting a bunch of drops together as a substitute for one beam that's going to be holding sheets of steel over my head is not something I would even consider.
Reply:we have spliced i beams together in the boilers to move heavy loads think 45 tones ....straight cut open root welds ground flush with reinforcement fish plates put on the top and bolth sides of the beams that was designed by the engineers.After the arc has died the weld remains
Reply:Your beams are not an issue at all, definitely over-kill - a good thing.I agree totally with boilermaker237 as far as method of splicing. The finger joint that you describe will take more time, and would require the reiforcing plates to be longer, but there is nothing wrong with it. A dovetailed prep is much the same, and I have used that as well. As long as you burn in penetration welds and maintain your alignment, your planned design will definetly be adequate.