achanner Posted September 24, 2012 Share Posted September 24, 2012 Hi All, (Apologies if this is a dumb question, but I dont think ive ever once seen a way to solve this problem!) A local hall I have been working with is looking to dead hang some scaff bars over their stage - In the centre of the stage there is an ibeam running up/down stage which a rigger should be able to use to provide the relevant centre support with beam clamps etc. However at each end, there are only wooden beams (which I assume are only providing lateral support to the structure and so couldnt advise their use for rigging). Just beyond these wooden beams howerver, at each side of the stage at trim height there is a double skin brick wall which I think could be used to take the weight assuming there was some way to dead fix a scaff bar perpendicular to a wall? Before I advise them to get someone in to take a look, I need to think about what is possible - I dont recall ever seeing a rated method of attaching a scaff bar perpendicular to a brick wall? Have I missed something? Anthony Link to comment Share on other sites More sharing options...
Ynot Posted September 24, 2012 Share Posted September 24, 2012 How about something like the Doughty Stand off Brackets... Link to comment Share on other sites More sharing options...
achanner Posted September 24, 2012 Author Share Posted September 24, 2012 How about something like the Doughty Stand off Brackets... Hiya mate, I thought about that, but they would put the bar parallel to the wall as opposed to perpendicular? Unless I'm being dumb? (Always a possibility!) Anthony Link to comment Share on other sites More sharing options...
Ynot Posted September 24, 2012 Share Posted September 24, 2012 Ah - sorry - misunderstood you.However, you can use the brackets to mount an upright barrel, then use the de-rig/boom arms for your perpendicular options - and have an adjustable height option to boot. Link to comment Share on other sites More sharing options...
achanner Posted September 24, 2012 Author Share Posted September 24, 2012 Ah - sorry - misunderstood you.However, you can use the brackets to mount an upright barrel, then use the de-rig/boom arms for your perpendicular options - and have an adjustable height option to boot. Sorry mate - unfortunately doesnt work, let me explain a bit better, I probably didnt make the problem clear... Essentially what they need are standard lighting bars dead hung from the roof of the stage, but instead of being ceiling mounted at the ends, are wall mounted instead so that the force bears down on the wall (there is no beam which will support the bar at the ends, only the centre). I wondered if there was some kind of method of rigging a horizonal bar mounted to the walls each end, with a centre point at the middle I Beam. Anthony Link to comment Share on other sites More sharing options...
Brian Posted September 24, 2012 Share Posted September 24, 2012 One of these (doughty 34000) with a half-coupler bolted on top? Link to comment Share on other sites More sharing options...
brainwave-generator Posted September 24, 2012 Share Posted September 24, 2012 Ah - sorry - misunderstood you.However, you can use the brackets to mount an upright barrel, then use the de-rig/boom arms for your perpendicular options - and have an adjustable height option to boot. Sorry mate - unfortunately doesnt work, let me explain a bit better, I probably didnt make the problem clear... Essentially what they need are standard lighting bars dead hung from the roof of the stage, but instead of being ceiling mounted at the ends, are wall mounted instead so that the force bears down on the wall (there is no beam which will support the bar at the ends, only the centre). I wondered if there was some kind of method of rigging a horizonal bar mounted to the walls each end, with a centre point at the middle I Beam. Anthony You can hang off the middle I-Beam using Gravloks. They're not very expensive. http://www.scaffolding-direct.co.uk/scaffolding-fitting-forged-girder-coupler-gravlok-12-.aspx Link to comment Share on other sites More sharing options...
brainwave-generator Posted September 24, 2012 Share Posted September 24, 2012 Depending on how high the roof is, they may however be better off getting some wind up stands instead. The benefit of wind up stands is that: - Work at height is not required when the things on the bars need maintaining - you just lower the bar, take stuff off, fix it, put it back on, lift the bar again.- There's no (or at least less) hiring in of specialist people to install the kit, sign it off, inspect the building, etc that may be associated with installing fixed bars. Just because the middle of the room features an I-Beam, it is not safe to assume that the I-Beam is able to support any more weight than is already on it. As such, any good rigger would want to see evidence from a structural engineer that the beam was safe to hang loads from. The same goes for the walls. Just because something looks sturdy, nobody worth their salt is going to put their name against it until they've seen hard evidence that it's safe to use for the suspension of equipment above people's heads! The hall are probably thinking that it can't be that expensive to buy a load of scaff tube and clamps and stuff and hang it up. By the time you've factored in costs of a structural engineer, installation contractor(s), access equipment... and the kit itself, the cost will probably be far greater than what the place originally had in mind. If the roof is not drastically high up, and you don't need that many bars, I really wouldn't be surprised to see that some decent wind up stands would come in cheaper than installed bars. Link to comment Share on other sites More sharing options...
TomHoward Posted September 24, 2012 Share Posted September 24, 2012 Someone would have to advise on the rating when used horizontally but Alvin clamps A10 and A12 would fit (although it'd be a squeeze getting it in..) http://alvinkeyclamps.com/images/Clamps/Alvin_Key_Clamp_A10.gif http://alvinkeyclamps.com/images/Clamps/Alvin_Key_Clamp_A12.gif Link to comment Share on other sites More sharing options...
J Pearce Posted September 24, 2012 Share Posted September 24, 2012 The clamps above are used in the above scenario in the installation at work (5 SWR pickups to the roof, ends supported with those clamps).That's no guarantee of their suitability of course, but its passed a PUWER inspection by a respected rigging company. Link to comment Share on other sites More sharing options...
Brian Posted September 24, 2012 Share Posted September 24, 2012 Someone would have to advise on the rating when used horizontally but Alvin clamps A10 and A12 would fit (although it'd be a squeeze getting it in..) http://alvinkeyclamps.com/images/Clamps/Alvin_Key_Clamp_A10.gif http://alvinkeyclamps.com/images/Clamps/Alvin_Key_Clamp_A12.gifMy concern using these to support a horizontal tube, running between two walls, is what happens when the tube is loaded and bends? The tendency would be for the tube to try and pull itself out of the clamps. Link to comment Share on other sites More sharing options...
Tom Posted September 24, 2012 Share Posted September 24, 2012 I don't think they are particularly suited to the task. I can se how they could be used in your situation Jon where essentially the SWR is doing the work and the fixings at the ends provide more stability than support. The big issue is spreading the load over a wide enough area of the brick wall - which I suspect these won't - and how you fix to the wall. I think you're better off with something like these from Doughty but sized to take a single tube. The important bit is the big back plate which can be bolted to the wall and spread the load.But you're going to have to get a structural bod in to asses both the wall and the beam I'd have thought and give you an idea of what rating you can achieve. So, yes there will be a rated method of fixing to the wall but it may be that you'll have to get it fabricated specifically for the job. T Link to comment Share on other sites More sharing options...
paulears Posted September 24, 2012 Share Posted September 24, 2012 The engineering company I use simply welded a large L bracket up, with a decent sized wall plate, and 75mm top plate that had bolt through clamps for the tube, and 10mm bolt holes for rawlbolt style fixings to the wall. Probably over the top, but it wasn't that expensive. If the OP has just the middle steel beam pickup, it could be better to use ladder truss to minimise bending on the span to the wall fixings. Link to comment Share on other sites More sharing options...
achanner Posted September 24, 2012 Author Share Posted September 24, 2012 Cheers Everyone, Plenty of food for thought - I had thought about the Key/Alvin baseplates, but Im fairly sure these are only rated for handrails etc, and not for rigging. Just wanted to see if anyone had been in a similar situation before I offered advice.... the next step for them of course will be a structural engineer rather than a technician! Anthony Link to comment Share on other sites More sharing options...
brainwave-generator Posted September 24, 2012 Share Posted September 24, 2012 The clamps above are used in the above scenario in the installation at work (5 SWR pickups to the roof, ends supported with those clamps).That's no guarantee of their suitability of course, but its passed a PUWER inspection by a respected rigging company. Difference there is that with 5 SWR pickups, the majority of the load was likely suspended from those points. The clamps were likely just preventing the bar from moving around. Because SWR is not rigid, not securing the ends would permit movement of the bar which would look a bit rubbish in terms of the lights wobbling around. So if you want a bar that stays still you do need some form of rigid connection to the structure, even if it is not a load-bearing connection. Link to comment Share on other sites More sharing options...
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