plabebob Posted August 14, 2014 Share Posted August 14, 2014 I'm doing a show where the set consists of 2 L-shaped metal frames which are supposed to be free standing, but I don't trust them to stand up if someone falls in to them. This is a sketch of one of them: The designer is really against having braces or weights on them & one of the venues we are touring to won't let us screw in to the floor or walls. The only other solution I can think of is to run a line to the grid... would a standard studio grid be strong enough to withstand an actor essentially pulling down on it with all their weight? I'm happy to go with that solution but only if it's safe! Any advice welcomed. Link to comment Share on other sites More sharing options...
kerry davies Posted August 14, 2014 Share Posted August 14, 2014 Some are, some aren't you really cannot say. Though my response to the designer would be; "Well if you don't want braces then you stand back there and catch it." You might be able to do something like an Acrow prop system where you brace it floor to ceiling rather than suspend it. You might just "float" it so that anyone falling on it brushed it aside rather than added their weight to it but at the end of the day unless the designer has invented levitation they need to come up with something practical. It has to be a compromise from all parties. Rehearsal and constant vigilance might be your only solution. Link to comment Share on other sites More sharing options...
ImagineerTom Posted August 14, 2014 Share Posted August 14, 2014 A "safety" up to the grid isn't uncommon but you are asking an unknown grid to take an unknown force in an unknown direction for an unknown duration... in a crisis situation. That frame does look relatively self-supporting and stable but there will still be a surprising amount of "wobble" in it just from its own weight, I'd be wanting a damn good explanation from the designer as to why it definitely cannot have a couple of traditional braces on the back (both for self-stability and to stop it from toppling) and if they refuse then be asking for some proper structural calculations and loading data for it so that you know EXACTLY where on the scenery you can attach your bracing to the grid and EXACTLY what sort of lateral forces the scenery could be applying. You'd be amazed how quickly artistic pretentions go out the window when the alternative is doing lots of hard sums. Link to comment Share on other sites More sharing options...
the kid Posted August 14, 2014 Share Posted August 14, 2014 Could you add a 2nd line of metal at the base. Or perhaps depending on how to make it fill the base with some weight, sand or something. IT does not look super toppely. Why no braces I assume at least a bit of it is upstage and can be hidden. Link to comment Share on other sites More sharing options...
plabebob Posted August 14, 2014 Author Share Posted August 14, 2014 Thanks for the replies everyone, you've convinced me that I was right to be dubious, I reeeealy don't want one of the cast pushing a huge metal frame on to the audience. We've decided to brace the 2 pieces together at the top so it's one large square structure. I feel much better about it now! Link to comment Share on other sites More sharing options...
Dave m Posted August 15, 2014 Share Posted August 15, 2014 IT's not clear to me if the frames are literally just 1" square steel tube welded into boxes or have some sort of covering?is it at 90 degrees to each other? Does it hinge? try to topple it. if you have an off cut you can calculate the weight of the whole thing.Depends if the grid is already loaded to it's max. could a this flat plate be fitted to the upstage bottom? All along? Link to comment Share on other sites More sharing options...
iains Posted August 15, 2014 Share Posted August 15, 2014 I am confused, if the knuckle is upstage the only way it is going to fall is upstage especially if you put pin hinges on the inside of the knuckle, unless you really push that set it is stable, if you have two of them as I understand it from your original post make it rigid with a piece of "U" channel across the open gap in the middle, not even a nudge would move it then Link to comment Share on other sites More sharing options...
Jivemaster Posted August 16, 2014 Share Posted August 16, 2014 Has anyone calculated the mass of the metalwork?Has any method of fixing the angle between the two hinged pieces, been found.Has anyone calculated the force required to tilt the frame to it's limit of stability.Has anyone calculated whether the steel can in fact be supported safely by the grid. Without some serious maths and engineering, this isn't a set it's a disaster waiting to happen. Go, get the calculations done by someone with the skill to do them and the insurance to cover their answers. If the frames are to be solid then how are you going to get them to the theatre in a truck, and through the theatre doors?If the frames are transported as parts then how are you going to have the rigidity that they will need to remain rectangular through the tour. Link to comment Share on other sites More sharing options...
abbotsmike Posted August 16, 2014 Share Posted August 16, 2014 Has anyone calculated the mass of the metalwork?Has any method of fixing the angle between the two hinged pieces, been found.Has anyone calculated the force required to tilt the frame to it's limit of stability.Has anyone calculated whether the steel can in fact be supported safely by the grid. Without some serious maths and engineering, this isn't a set it's a disaster waiting to happen. Go, get the calculations done by someone with the skill to do them and the insurance to cover their answers. If the frames are to be solid then how are you going to get them to the theatre in a truck, and through the theatre doors?If the frames are transported as parts then how are you going to have the rigidity that they will need to remain rectangular through the tour. Whilst care is required, I don't think a structural engineer is needed to work out if that structure is liable to fall over. Some basic mass and turning moments calculations are all that is needed, and that's a-level physics at a push. My main concern would actually be making the thing rigid enough as it's been drawn. I suspect that's not the full piece of set, as an empty steel frame seems a bit pointless to me! Link to comment Share on other sites More sharing options...
iains Posted August 22, 2014 Share Posted August 22, 2014 We have been using book flats for years in the theatre, I'm reading comments about structural engineers reports, calculations of turning moments etc., it's simple or are we all too stupid to see it, if the structure goes "flat" then it will fall over it does not take a genius to work that out. Get your director to "direct" the cast to not fall into them, in thirty plus years working in this industry I have yet to see an actor knock a piece of set over unless it's part of the action Link to comment Share on other sites More sharing options...
LampTramp Posted August 22, 2014 Share Posted August 22, 2014 Has anyone calculated the mass of the metalwork?Has any method of fixing the angle between the two hinged pieces, been found.Has anyone calculated the force required to tilt the frame to it's limit of stability.Has anyone calculated whether the steel can in fact be supported safely by the grid. Without some serious maths and engineering, this isn't a set it's a disaster waiting to happen. Go, get the calculations done by someone with the skill to do them and the insurance to cover their answers. If the frames are to be solid then how are you going to get them to the theatre in a truck, and through the theatre doors?If the frames are transported as parts then how are you going to have the rigidity that they will need to remain rectangular through the tour. YOU ARE JOKING??? I's a bloody 'book flat' Link to comment Share on other sites More sharing options...
kerry davies Posted August 23, 2014 Share Posted August 23, 2014 Couple of points, gentlemen.1) It is not a normal "book flat" in that the director refuses to have stage braces or normal fixings. 2) I have seen actors walk into them, and get quite badly hurt, when they have been free-standing as these are. 3) Most importantly, plabebob wrote that they had found a solution on the 14th so we might as well lock this one down??? Link to comment Share on other sites More sharing options...
top-cat Posted August 23, 2014 Share Posted August 23, 2014 2) I have seen actors walk into them, and get quite badly hurt, when they have been free-standing as these are. Maybe you should call Flints and see if you can buy some eyes for your actors... Link to comment Share on other sites More sharing options...
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