|
|
hai...i have to make a structural fram which is 15 m long. but in the market 12 m full lenght is only available. so i want to weld 2 beam it together to make it 15 m.what is the better section for weld these i beams together...one of our engineer give me an option to use an extra plate at the joint... but because of excess weld metal height, it is not possible..the top and bottom side should be flat..
Reply:You can go with open root. Or use backing bars. Place the bars inside the flanges, and cut openings in the web. Here are different ways I've done it. Attached ImagesDont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:CEPs design is right, and you can do rathole(s) for added strength
Reply:What is a rathole?"Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:Also you would want to check with the engineer on were the supports will be as to were you would want to join the I beams. Just adding 3 m might not be the best way to do it. Joining them in the middle might work out better for the job at hand. The blue prints and engineer can tell you what you need to know.www.georgesplasmacuttershop.comPlasma Cutter and Welder Sales and Repairs--Ebay storeTec.Mo. Dealer Consumables for the PT and IPT torch's
Reply:Originally Posted by Stick-manWhat is a rathole?
Reply:Here's a beam splice with "ratholes".
Reply:Originally Posted by Stick-manWhat is a rathole?
Reply:Originally Posted by Stick-manWhat is a rathole?
Reply:Ill take #3!!!!!!!!!!!!..now lets talk rat tail...................LOLOf all the things I lost I miss my mind the most...I know just enough about everything to be dangerous......You cant cure stupid..only kill it...
Reply:This is the D1.8 "seismic rat hole" test (which I'll probably be taking at some point here in the near future). It's more about attaching a beam to the side of a column but the detail it shows concerning the "rat hole" is similar to what you would use when butt splicing two pieces of beam together.This is the actual test assembly. Basically it's testing your ability at making repeated sound starts and stops in the middle of a full pen weld.Last edited by HT2-4956; 03-28-2015 at 10:25 AM.
Reply:i use rathole as slang for access hole. they can be used for better access for welding the flange like the author wants and the way CEP described. heres a video, fast forward to 3:45 for a view of some ratholes.
Reply:Originally Posted by HT2-4956Here's a beam splice with "ratholes".
Reply:Originally Posted by snoeproeLooks like C channel to me?
Reply:Originally Posted by 123weldi use rathole as slang for access hole. they can be used for better access for welding the flange like the author wants and the way CEP described. heres a video, fast forward to 3:45 for a view of some ratholes.
Reply:I never watched that video till I saw your statement but have to agree. Half the video is looking at a black screen then no clean up after gouging but he has a grinder. Welds don't look that good and not sure why it even needed a rathole. If a beam can be rolled over, there's no need for a rathole. Put a single bevel on the outside beams, weld the inside first and then grind and/or gouge the beveled side into the weld done from the inside. I spliced beams like this many times, sometimes had to pass x-ray.
Reply:A rathole has nothing to do w/ whether the beam can be flipped over or not. Stickman asked what a rathole was, so i told him to go to 3:45 seconds. If he asked to see quality video, i'd told him to go watch tv. if he would of asked about code quality welds, now I'd know to refer him to you two guys
Reply:Originally Posted by HT2-4956It's an I-beam. You're just looking at one side of it. Look thru the rat hole at the bottom and you can see how the backing continues on to the flange on the other side of the web.
Reply:I've splice welded many I beams. In all cases, I simply beveled the flanges, welded the bevel, back grind the other sides of the flanges and welded again. The web gets the same treatment. Vertical up pass on one side, back grind the other side with the die grinder and another vertical up pass. I've always used 7018.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Originally Posted by snoeproeMaybe it's just my tablet but to me it almost looked like the lower flange was tapered like a c channel.
Reply:Originally Posted by Sharon NeedlesI believe technically an I-beam has a tapered flange, the continuous thickness flange beams are actually wide flange H-beams.
Reply:Originally Posted by Welder DaveI never watched that video till I saw your statement but have to agree. Half the video is looking at a black screen then no clean up after gouging but he has a grinder. Welds don't look that good and not sure why it even needed a rathole. If a beam can be rolled over, there's no need for a rathole. Put a single bevel on the outside beams, weld the inside first and then grind and/or gouge the beveled side into the weld done from the inside. I spliced beams like this many times, sometimes had to pass x-ray.
Reply:Originally Posted by Sharon NeedlesI believe technically an I-beam has a tapered flange, the continuous thickness flange beams are actually wide flange H-beams.
Reply:Originally Posted by HT2-4956I think I have to disagree with that. If you don't have a rat hole how are you going to get complete penetration at the center of the flange where it crosses over the web?
Reply:the rathole dont get filled. thats why its important to think about the radius on it before you cut it. i like mine more like a fat valantines heart.Originally Posted by HT2-4956I think I have to disagree with that. If you don't have a rat hole how are you going to get complete penetration at the center of the flange where it crosses over the web?
Reply:CEPs game plan was just fine for kumar i'm guessing . it was late at night, i was bored and buzzed, and thought i'd throw in rathole. stickman asks a question, then someone else starts knocking my video for things that arent even the subjact matter,( probably because it surpasses his posted picture). Dave and snoproe both have good senses, but think of it this way. you cut a nice radius out of the upper/above part of k section for access. now for practicality, you got access to both sides of the whole flange for backgouging and welding, w/o having to spend the time w/ a set of dental tools to backgouge the k section / radius fillet area. You go about welding both sides of flange all the way through, and for extra credit, you put runoff tabs at ends of flanges like in the video. its general construction, time is saved w/ the access holes, and none or little integrity is lost to the web the rathole, and everbody knows for sure the flange (more importantly) is welded solid. then if the 100 year earthquake comes, you sort of avoided a heat effected zone in the radius, so if a crack wants to start from your rathole, odds by far it would go into the web being its thinner, intead of the flange. the k section probabaly isnt the best place to be welding anyway in a splice, as you know you avoid it w/ stiffeners.Last edited by 123weld; 03-30-2015 at 11:34 PM.
Reply:Ya, you can go with a cope hole, but the failure rate is significant compared to a solid beam.https://www.ideals.illinois.edu/bits...pdf?sequence=2Splices are inherently weaker than a solid member. But, if it's in the design parameter, it's ok."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Terminology, seems to be a major issue here. Some refer to beams as I-beams, H-beams, Wide Flange beams, and then there are S-beams. There are also Junior beams, so pick your poison and if you are in a conversation with an engineer you will be better served if you are on the same page with regards to names and meanings. As to beams that have inner flanges with "tapers" those are S-beams and they are often used for the beams in bridge crane and other lifting applications that use trolleys to support the associated chain/cable hoists. Tapers are self-centering and serve this purpose well.To address "rat holes" a slang term by AWS standards and definitions, pretty sure that "weld access holes" is the accepted term, although, personally, I completely understand that term. As to leaving the access hole intact and even including it in the first place, welding in that region of a beam, particularly one that is in service as a beam as opposed to a column, causes issues with how the beam reacts to loading and transferring stresses in the loading scheme. Beams deal with stresses on the flanges in forms of compression and tension. The depth of the beam adds to the beams stability vertically and the width of the flanges add to the beams stability in the opposite plane. Compression and tension when applied to the juncture where the flange meets the web of a beam can cause failures if there are voids or other discontinuities in this area, by removing this from the equation there is less likelihood of a failure. Proper shaping of the weld access holes will further prevent undue or adverse effects to the completed welding of a joint such as this by providing radial distrubution of loading stresses. For the majority of beam work that is done in many different applications this sort of attention to detail is not such an issue, but for work that has extreme cyclic loading or moving loads as opposed to static loads, joint design and weld details are of great importance. The North Ridge Quakes brought about a huge amount of change in how structures are designed and welded. Weld access applications are a small part of that and apply to many of todays structures and welding challenges. A few more $.02 to throw at this conversation. Best regards, Allanaevald
Reply:I think welding procedures and filler metals have evolved just a little since 1957.
Reply:Hello 123weld, when it comes to opinions everyone has one. Right, Wrong, or Indifferent, there are gonna be plenty of them, hell even a huge number of the engineers that are supposed to have this all figured out can't come to a common consensus. Regardless of how a splice is planned and executed it is rare that every detail of that plan is followed to it's designed completion point. I am saying all of this due in part to my own response as well as many of the ones that have been included here. When backings are included in a "weld access hole" design they need to be removed upon completion and proper grinding and finishing needs to be included in their removal and the completion of the weld joint. Grind marks running accross the direction of all welds is one aspect, where the access hole is located the grind marks should follow or run perpendicular to the circular edge of that "hole" and not accross the edge(really difficult to achieve), there should be no sharp edges, they should all have radius's with grind lines running longways and not across the edge. Where this "matters" is where the application is applied and what it's designed for, if it's designated, there is a reason, you, I, or others might not understand it fully but someone of a higher pay grade is the one getting paid to put their name on it(if this is a professional application). As to the folks who are not being professionally held to follow a specific regimen, hopefully common sense and a reasonable understanding of "cause and effect" will prevail and there will be no critical failures to cause someone's life to be irreversibly changed. My post here is in no way being critical of anyone's opinion, but more to suggest consideration of why things are called out as they are at times, whether we agree or not. Best regards, Allanaevald
Reply:Your typical I or H beam (what ever you want to call it) web is usually no more than 3/16" thick. Achieving full pen across a flange and ensuring it over the 3/16" thick web in the center of the flanges is not difficult. I've spliced many beams in my career as an Iron worker welder and have asked my Forman on more than one occasion to verify my procedure with the structural engineers. They have never said no. It's not my call to approve the procedure, I'm just the welder executing it.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Originally Posted by MinnesotaDaveAttachment 1056261Attachment 1056271Attachment 1056281
Reply:Rat holes are for acess and not filled in as it would create a stress riser and crack. Splices can develop 100 of beam strength when needed. |
|
发表于 2021-8-31 22:40:19