Why not weld the whole thing?

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I noticed these supports when I was in a produce warehouse the other day....They welded the sides and the bottom but not the topThe racks carry a lot of weightAnd they will actually sway if the forklift operator is sloppy. Whatta you think?Miller 211Hypertherm PM 451961 Lincoln Idealarc 250HTP 221  True Wisdom only comes from Pain.
Reply:old rule... ya never weld across the face of a column... horizontally...  same rule applies to horizontal beams a good application of that would be semi trailers where you see a fish plate so that there are no vertical welds across the horizontal beam.  it causes a stress point. im sure some engineering type on here can explain a better I just know from years in the trade its a bad practice! and we avoid doing it!
Reply:Interesting...So its welded correctly then... Sort of,Cuz they welded the bottoms and left the tops open?Miller 211Hypertherm PM 451961 Lincoln Idealarc 250HTP 221  True Wisdom only comes from Pain.
Reply:^^^^ @rambin   realy?don't listen to him. that's absurd. there should be weld there. they were being lazy and thinking "oh thatll hold, that's all you need is a vertical weld."I was a ironworker and welder at one time. we built 5-6 story buildings. almost all columns have a weld going horizontally across the face (moment welds) in the flat position with a backing bar. and anything ive ever welded offshore structurally has been seal welded! due to rust and corrosion you must weld all the way around. this is definitely a case of oh that's enough weld mentality.Bad welding practice there.Last edited by AndrewDavenport89; 03-27-2015 at 09:58 AM.
Reply:They welded parallel with the upright to prevent distortion or pulling of the upright so it does not draw in toward the horizontal piece. They could have at least tacked it in the crotch top and bottom. It could be welded solid provided you know what you are doing to minimize and pulling.
Reply:A weld on top would interfere with the shelving.
Reply:Originally Posted by tapwelderA weld on top would interfere with the shelving.
Reply:I suspect some engineer said, "Good enough" and specked it that way.Stronger is not always better, especially if there's a chance of it weakening the overall structure (as in the case of some stress risers, or warpage introduced by overwelding).The overall structure will only be as strong as the weakest link, and this weld joint is probably not the weakest link.
Reply:Wood shelving, not metal framing.  The weld would possibly be offset by the weld. If one wanted to notch age set shelving against wall then the weld would have to compensated for.  Kinda, sucks o loose a couple of inches because the weld is in the way.  If I were going to skimp, then I would have left the bottom unwelded or where ever was less visible.Last edited by tapwelder; 03-27-2015 at 10:27 AM.
Reply:Looks like 'erector set' type construction. I imagine top vs bottom is relative. I'll bet someone determined that welded on three sides is plenty for the application. 25% less welding on a production scale is a bunch of savings."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:You guys are all wrong! This is a classic case of drainage! Water in, water out. The welder screwed up by making the one weld on the bottom. 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:I'm going to guess they didn't weld the "bottom" and the rack is installed upside-down from how it was made.1) It's for water drainage (ok maybe, but why not fully weld them to keep water out)2) The engineer spec'd 25% less weld and saved some money (probably true, and they expected nobody to notice the gap when installed on the underside)3) The welder was too damn lazy to welder overhead or flip the part over.Haha,  In either case, it's probably strong enough for the job.  Have any of them broken yet?  Have they broken when speedy-joe banged them with the forklift?Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:I'm no engineer, but if I were fabing these racks. I'd just make the two vertical welds, and down hill at that. 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:I would have welded it out, personal preference though. I have always seal welded everything I do unless it is a spot where it takes hell and high waters to reach then ill leave it be to the elements. structurally, yes it will hold. but for peace of mind....I lay the metal to it. at the very least weld the two sides and the top!!
Reply:Originally Posted by CEPI'm no engineer, but if I were fabing these racks. I'd just make the two vertical welds, and down hill at that.
Reply:Originally Posted by PipelinerWith what your 110v horrible fright mig and .023 er70-6 wire?
Reply:Alright I'll play. I'm going to guess they're installed upside down as well. I'm also noticing in the picture that it looks like the top half uses a larger tubing and just slides over the bottom half, and the cross member is what is used as the "stop", in which case a weld would cause interference. Instead of setting up production to skip only the top welds on one cross member, they figured it would be easier, and just as structurally sound if they all didn't have that joint welded. Everything about this setup makes me think it's upside down. Why put the larger section on top of the smaller section? The top in the picture is taller, and uses larger tubing. Flip the whole thing around and the base is heavier and the open seam is on the underside. Though technically speaking, the bottom seam is more visible than the top seam as you can see the bottom of 3 cross members, but only the top of one from standing on the ground!John 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker
Reply:I think I've been to that warehouse  Needed more welds....Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:That mess above happens too often ^^^Those cross bars are to prevent the column from buckling, under the shelf at 90 degrees is another fixing the column. That's enough weld for what it's doing.The problem with shelving is they don't account for racking, and X bracing gets in the way. So live loads are a no-no, period. A lift truck driver setting something heavy on them and shoving it back will likely wish they hadn't if it racks to failure. Weld it all you want but if a knucklehead dings it like above, it's dropping...Matt
Reply:Originally Posted by CEPWell sure, as long as I got penetration like this weld.
Reply:Originally Posted by Pipeliner Patience grasshopper.
Reply:Originally Posted by AndrewDavenport89I would have welded it out, personal preference though. I have always seal welded everything I do unless it is a spot where it takes hell and high waters to reach then ill leave it be to the elements. structurally, yes it will hold. but for peace of mind....I lay the metal to it. at the very least weld the two sides and the top!!
Reply:Originally Posted by rambinold rule... ya never weld across the face of a column... horizontally...  same rule applies to horizontal beams a good application of that would be semi trailers where you see a fish plate so that there are no vertical welds across the horizontal beam.  it causes a stress point. im sure some engineering type on here can explain a better I just know from years in the trade its a bad practice! and we avoid doing it!
Reply:Is it jusy the center crossbar or is it all of them? If just the one it's probably OK, there's nothing riding on it.
Reply:Originally Posted by AndrewDavenport89I would have welded it out, personal preference though. I have always seal welded everything I do unless it is a spot where it takes hell and high waters to reach then ill leave it be to the elements. structurally, yes it will hold. but for peace of mind....I lay the metal to it. at the very least weld the two sides and the top!!These are engineered shelving racks. The strength is in the vertical welds and that's how the engineer had it set up to weld. It's strong enough for the weight capacity they are designed to hold.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Time is money. The beads in the image are far better than average.
Reply:Again, that's a storage rack, not a frame for an automobile or aircraft or bicycle.  Heck, it's not even a table...Welding all around won't make it any less wobbly and indeed could create enough stress at the joint to create fatigue cracks after a short while.  Large structures are designed to bend before they break, sometimes they bend an alarming amount but that's why engineers go to school for calculating all those variables.  Believe it or not but there's significant research and data that goes into something as simple as a commercial storage rack.  Many welding plans will call for 'missing' welds, skip welds or certain techniques that may make one wonder why.  If those plans have an engineers stamp on them and one improves on them at an amateur level, then any problems down the line falls fully on them.  If the plans were followed, then there's little liability to the fabricator.There's many instances of some Danny-do-gooder altering a plan by 'beefing up' a structure he found insufficient only to discover structural failure because the stresses involved were never calculated.  Sometimes more weight in the form of tube thickness or extra welds only insures that the structure can barely hold its own weight, resulting in failure when loads are encountered.
Reply:I'm no expert by any means, and my welds are pretty ugly compared to most on this forum (hobbyist), but awhile back, I was looking into fabricating a new subframe for the bankhoe on my tractor (old Kubota).  That led me to researching frame welding (trucks/auto).  From everything I have seen/read, when welding is possible (many times it's not advised or even legal), it's always stated that there should be no weld perpendicular to the direction of the frame.  You can weld either parallel, or slightly diagonal (ie fish plates as mentioned earlier), but NEVER perpendicular, as there is a danger that the frame will bend/crease/crack at the weldment in the event of the collision or from weight stress.Perhaps that is the underlying reason?  The stress is vertical, so it kind of makes sense that it was not welded across the horizontal plane.
Reply:honestly looking into it that much is just a waste of time. don't think about the dynamics lol just weld it out and on to the next project
Reply:Depending on the strength of the cross-bar, that might not be the best way to weld it.  The veritical piece sees mostly compression load.  The cross piece sees a vertical load which will tend to stretch the top of the cross bar at the weld area and compress the bottom.  Which means, in my opinion, that the ends of the weld are the most likely areas for the weld to fail.   And give there is already a crack (or rather unwelded area) on top, it has a good place for the failure to begin.Which means, I highly suspect that the whole thing is over designed - steel too thick, and weld beads long enough etc. to handle any anticipated static load.Also, the weld beads are down the middle of the tube, the weakest point against compression.Probably would have been better to square it up - save the expense of notching every beam and put that money to welding a bead across the top.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Weld that thing anywhere but longitudinally in the web, and you'd spend a month straightening out that entire rack system.Somebody had their act together when they designed it.  Notice that the columns are at an angle to allow for the maximum amount of weld where the corners are.  A square butt joint would require welds along the shoulder of the tubing, and pull that thing like a pretzel.  You cannot apply heat to one side of a member without applying heat to the other side to balance it, so you weld to the web."Any day above ground is a good day"http://www.farmersamm.com/
Reply:My best guess is that the uprights started out to be oriented "diamond" not for purposes of a stronger connection, but rather as part of the system's overall design, and then it stuck to keep things backward compatible.One advantage is that because diamond creates a "funnell" of sorts it reduces the likelihood of a skid or its load hanging up as it's pushed through the rack system. Also, the diamond orientation of uprights makes for a "V-saddle" that is easy to secure horizontal cross-beams to - without punching, etc. Maybe in an earlier iteration of the system, horizontal beams used simple stock angle at their ends to straddle the column tube?To boot, diamond orientation allows for a simple secure connection of horizontal beams, while also allowing for economy in system expansion through sharing of columns with "Siamese" beam connections.  As to the absence of weld, my best guess is that experience showed that more weld was not necessary -or- created a too-rigid connection, which was crack-prone in the "dynamics" of rack use.Again, this all my best guess.Last edited by denrep; 03-30-2015 at 11:52 AM.
Reply:Originally Posted by con_fuse9The cross piece sees a vertical load which will tend to stretch the top of the cross bar at the weld area and compress the bottom.
Reply:i agree... the cost adds up, the welders shop rate, the mig wire, electricity... it all adds up! fatigue maybe...
Reply:Originally Posted by KelvinSure you don't have that backwards?