Tom Posted October 28, 2009 Share Posted October 28, 2009 Our building has lots of half exposed I beams in the foyers - running under balconies and walk ways etc.You can sort of see what I mean here, both half way up and at the top of the vertical beams: http://www.bdonline.co.uk/Pictures/web/l/I/b/Concrete_Hamp03.jpg For a temporary event we want to hang some truss from these beams to allow for a few extra bits of lighting kit.Does anybody know of an off the shelf Girder Clamp or similar designed to be used when only half the I Beam can be accessed, effectively only giving you a C section to work with?I'm assuming that Lindapters, which is what we'd usually use, should really be used in pairs across the beam. Or am I wrong? Any thoughts appreciated. T Link to comment Share on other sites More sharing options...
trussmonkey Posted October 29, 2009 Share Posted October 29, 2009 Speak to Arian Skelton at Excel in London I know they use a clamp along the lines your thinking of. He might be able to help you more. TM Link to comment Share on other sites More sharing options...
dsharp7th Posted October 29, 2009 Share Posted October 29, 2009 Doughty Engineering : Girder Clamps http://www.doughty-engineering.co.uk/shop/67/index.htm Link to comment Share on other sites More sharing options...
Brian Posted October 29, 2009 Share Posted October 29, 2009 Doughty Engineering : Girder Clamps Errr, and how do you use those in the OP's situation? Link to comment Share on other sites More sharing options...
dsharp7th Posted October 29, 2009 Share Posted October 29, 2009 effectively only giving you a C section to work with? apologies, missed that bit. Lindapters seem to be suitable for single use: http://www.lindapter.com/images/products/additional/main/176.jpg http://www.lindapter.com/Products/Support_Fixings/16/Type_FL Link to comment Share on other sites More sharing options...
trussmonkey Posted October 29, 2009 Share Posted October 29, 2009 http://www.ropemarine.com/Superclamps%20114-116.pdf have a look at the adjustable superclamp AC1-4 . TM A concurrent post has been automatically merged from this point on. lindapters dont give you a very high SWL at all. A concurrent post has been automatically merged from this point on. 300kg SWL for lindapters Link to comment Share on other sites More sharing options...
adamharman Posted October 29, 2009 Share Posted October 29, 2009 Don't think those superclamps would work in this situation, as they're designed to clamp against the back of an angle section and in this case that's not possible. Given the price of lindapters, I don't think the SWL is too much of an issue - just use more of them. And at max 300kg per point, I'd be thinking of checking how many of them the beam will take..... Gut feeling doesn't like clamping onto the edge of the flange like that, but if there's enough of them and it's properly safetied? Link to comment Share on other sites More sharing options...
GRisdale Posted October 29, 2009 Share Posted October 29, 2009 EDIT: Don't bother reading this - Adam already said it... http://www.ropemarine.com/Superclamps%20114-116.pdf have a look at the adjustable superclamp AC1-4 .It's interesting to know that these exist... But it looks like they might not be the answer here. They still need to be able to access the back "corner" of the C or L section involved in order to be secured, which (it looks to me anyway) can't be accessed in this case (these being I beams up against a wall, presenting a C section - but not really being a C section). lindapters dont give you a very high SWL at all... 300kg SWL for lindaptersI suppose it depends on what needs hanging, but I suspect it's more a case of a few generics than a roof full of movers. In any case, at the cost of lindapters, you could use quite a few if you needed to... Even so, there's something about using "one sided" fittings like this that doesn't feel right to me. Those vertical I beams may also be an option if you don't need to hang much... Gareth. Link to comment Share on other sites More sharing options...
Tom Posted October 29, 2009 Author Share Posted October 29, 2009 Thanks people - seems a I may have discounted Lindapters too quickly - though I must say that doesn't look amazingly safe (finger tight plus an extra 90 degree turn they say!!) And I'll try and contact Excel as well. Lovely. T Link to comment Share on other sites More sharing options...
trussmonkey Posted October 29, 2009 Share Posted October 29, 2009 if your thinking of adding more lindapters to spread the load out it then bear in mind as the load spread isnt as easy as splitting the load by tthe number of points. I.e 600 kgs UDL over 3 points isnt 200kgs per point. the centre point will take 60% of the load. over more points than that the load share is again differently split. TM Link to comment Share on other sites More sharing options...
Seano Posted October 29, 2009 Share Posted October 29, 2009 Given the price of lindapters, I don't think the SWL is too much of an issue - just use more of them.If using more of them, it would also be necessary to ensure the load is shared evenly between them - which may not be a trivial task. ... but if there's enough of them and it's properly safetied?No, no and no.For one thing, if its difficult to get a decent primary suspension, its also going to be difficult to get a strong secondary one. For another, something being "properly safetied" gives no justification whatsoever for going with a sub-optimal primary suspension that would otherwise be deemed unacceptable. Better to make sure its properly rigged, and then the 'safeties' may not be necessary. Those vertical I beams may also be an option if you don't need to hang much...I suspect they may be the way to go if he does. Its the type FL (or whatever) flange clamps that I'd be avoiding for anything but the lightest loads, personally. I'd be inclined to look at getting some brackets fabricated, to attach to the verticals with Type AF lindapters or similar and provide a rigging point stood off from the upright beam by a short distance. If you were to come up with a reasonably elegant design, perhaps they could remain in place as a permanent installation, making a similar event a breeze in the future. UK Rigging have someone who is *very* good at that kind of thing btw, no doubt there are also countless other companies who could fabricate something suitable. hth Link to comment Share on other sites More sharing options...
Tom Posted October 29, 2009 Author Share Posted October 29, 2009 The total load we're going to impose on the truss (or bar) is probably only going to be in the 400kg range so not too bad. Annoyingly the Lindapter catalogue gives SWL info as kN and only with a 2:1 safty factor, not the 8:1 I'd usually use, so a bit of maths is required. Thanks Seano for pointing out the alternative Lindapter options. ( I have to say I'm still amazed that any of those are suitable. they just don't look right used like that - but if that's what the company says...) Any structural reason to stand the rigging point off from the beam, rather than just attaching the bar direct to the beam? T Link to comment Share on other sites More sharing options...
Seano Posted October 29, 2009 Share Posted October 29, 2009 Any structural reason to stand the rigging point off from the beam, rather than just attaching the bar direct to the beam? Depends what you mean by 'structural reason'. On one level - nope. You didn't mention a bar in the OP, you said 'truss'. So I was thinking in terms of hanging a truss (eg: on hoists) rather than fixing one directly to the beams. More like a gig than an install, if you see what I mean: points go in, truss built and floated, then lights rigged and cabled at ground level before truss is flown. For that you'd ideally want your points stood far enough off the columns for the side of the truss/hoists to clear. On another level - yep. You can't just bolt through anything and put lindapters on the back - what you do is bolt a flat steel plate to the beam and attach <whatever> to that. Or, rather, you attach <whatever> to the plate first, typically by getting a fabricator to weld together a nice custom thingamabob - and then use the lindapters to secure the plate to the beam/column. The pdf on that page I linked to above specifies the minimum size and thickness of the plate. By the by, I believe Gravlocks can be used on vertical flanges, and I think their load limit in that orientation is about 1/3 what it is perpendicular to the beam. Obviously you'd need to check that out (and if/when you do, please correct me if I'm wrong). Also by the by - someone above mentioned superclamps. There is a variant of superclamp which has a near 100% SWL parallel to the beam (ie: as a hanging point on a vertical column). Its hard to picture a means of hanging a truss on those that wouldn't be slightly smelly though, on account of the 'clearance' thing. Link to comment Share on other sites More sharing options...
Tom Posted October 29, 2009 Author Share Posted October 29, 2009 You didn't mention a bar in the OP, you said 'truss'.Yes, sorry. We're probably talking ladder truss rather than box and it'll be rigged direct to the points (no room for motors etc) and then the lights rigged at height. Not ideal but we really are only talking about a few units and most of the work can probably be done from the balcony once the truss is in place. On another level - yep. You can't just bolt through anything and put lindapters on the backNo - we would be fabricating something, but it would be fairly flush to the girder rather than sticking out. By the by, I believe Gravlocks can be used on vertical flanges, and I think their load limit in that orientation is about 1/3 what it is perpendicular to the beam. Obviously you'd need to check that out (and if/when you do, please correct me if I'm wrong).If I do go down that road instead I'll let you know. Thanks again Link to comment Share on other sites More sharing options...
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