I have a project with a hotel ballroom. They want anchor points in the ceiling to anchor overhead light trusses and screens - for events. Instead of erecting towers - they want all overhead rigging. When other events don't need the rigging they want the anchor points on the ceiling to disappear.
Is there a standard connection or fitting or manufacturer that I can look up? Is there a name for this stuff that will help me fine tune my search?
TIA
OHSCrifle said:Is there a name for this stuff...?
Expensive.
Beer Baron said:OHSCrifle said:Is there a name for this stuff...?
Expensive.
That's alright. So is the building around it.
How is the access to the ceiling structure? How big will the lighting truss be? How do you plan to run the power to the lights? To be honest, for insurance reasons you may need to have the attachments designed by a structural engineer.
I made a post about engineering that was unnecessary, so deleted.
It's not standardized, and that is not really the theatrical side. That's the building side.
(I'm a contractor now, but my training and earlier career was in theatrical scenery and lighting)
I would think a relatively simple way would be eye nuts. You could install some grade 8 bolts in a truss/joist/rafter with some extra length popping through. Install eye nut and a hex nut to lock it and bingo. When you're done, spin the eye nut off and it disappears.
More info on the ceiling construction would be a good thing.
When I do stuff at the Hilton convention center in town, they have a drop ceiling. We keep a few tiles with holes in them. Pop out the "good" tiles, rig a chain to the steel joist, drop a wire rope through the holey tile and re-install.
Also, look into griplocks. Not really rated for tons of weight (often a good bit less than the wire rope they go on) but they slip on aircraft and are adjustable. When you're done, just slide them off. I don't have any specific solutions using griplocks, but it might spark something in your brain.
If it's a wood construction (unlikely) ceiling, just don't use a screw thing. No screw eyes. Always drill through and use a forged eye bolt. Screws rely on the small surface area of the threads in the wood not ripping out. Bolts means that the entire beam would have to rip in shreds to fail.
If it's steel, that's a different story. Always try to go in tension instead of shear with your fasteners.
A phone call to the architect is always a good thing. They can research the load rating of the ceiling. More than likely you are perfectly safe unless there is not another floor above. If it's just roof, it's only rated to carry a snow/hurricane load. If it's a second floor, it's probably rated to carry hundreds of people.
In reply to Curtis73 (Forum Supporter) :
OHSCrifle IS an architect.
That's why I deleted my engineering post. He understands all that.
For anyone else reading, this CAN'T be done without the help of an engineer. EVAR.
In reply to Curtis73 (Forum Supporter) :
None of that can be done without engineering.
In reply to OHSCrifle :
Just curious...
What are they gonna do with the equipment, rigging, trusses, lighting instruments, electric cabling, etc when they take this stuff down from the ceiling?
SV reX said:In reply to Curtis73 (Forum Supporter) :
OHSCrifle IS an architect.
That's why I deleted my engineering post. He understands all that.
For anyone else reading, this CAN'T be done without the help of an engineer. EVAR.
Oh yeah. Forgot the architect part.
There was tic tic where a guy said he'd sit in church and look at the large lighting fixtures and wonder who'd they kill if they came off the ceiling.
Just seemed kinda funny - hopefully your stuff is all good!
In reply to Datsun310Guy :
Yup.
If you look closely, every piece of equipment that is hanging over people should have a redundant safety cable. The actual truss should have a 4X safety margin for the weight it carries.
A 20' truss with equipment on it can weigh a couple thousand pounds. That's hanging a car over an audience. If it's hanging on 2 cables, they've each got half the load hanging on a point load. Changes the structural dynamics of a building entirely.
Add to it that every performance will load the rigging differently. It's unlikely it is ever evenly distributed.
My first reaction was "what the berkeley is an eye nut"? But it looks like exactly the missing link. this place is still. amazing.
This is a hotel with a post tensioned concrete slab about 20' up. I managed to get steel embed plates designed in the underside of the slab on a 10'x10' grid but the ceiling will be built down about 3-4'. We will need a steel tube as a down leg (inverted post) and then diagonally / laterally brace each post - likely just use diagonal steel angles across several posts.
The eye nut solution looks golden. I'm thinking a threaded rod welded to each post. Then a removable panel in the ceiling to hide them when not in use.
edit: and a safety cable
edit 2: this is the building
JK!!!!!!!!!
Datsun310Guy said:There was tic tic where a guy said he'd sit in church and look at the large lighting fixtures and wonder who'd they kill if they came off the ceiling.
Just seemed kinda funny - hopefully your stuff is all good!
I admit to doing the same thing everywhere I go. Restaurant with some artistic drop ceiling/sound panel decoration? I judge.
Last year I went to a high school production of Phantom of the Opera which has a huge chandelier that starts on the stage and then flies out over the audience and hangs right in the middle of the auditorium. Fortunately I was sitting on the side. I had the opportunity to look at the rigging after the show and it was kosher, but my initial thought was - oh god, some volunteer dad with a rope said "hold my beer, I can engineer that," but it was totally on the level. I was impressed.
In reply to Datsun310Guy :
In reply to Curtis73 (Forum Supporter) :
I hear you. (I do the same thing). But there is a difference between the church rigging and a restaurant's rigging...
In 99% of the cases, its HIGHLY likely that the restaurant rigging was designed by an architect or engineer, installed by a professional tradesman per plan, and inspected by the municipal building inspector AND a 2nd third party inspector who is a specialist in inspecting welds, etc.
In 99% of the cases it is HIGHLY likely that the church rigging was done by whatever guy was willing to volunteer as long as it didn't delay him getting in line at the Sunday brunch buffet at Shoney's.
Rigging is not my thing, I do lighting and power. That said, do it right and get an engineer involved. I was in Atlantic City's Boardwalk Hall when their supergrid came down, thankfully nobody was injured, but it was sobering to see the forged hooks on the 2 ton Chain hoists pulled straight.
mad_machine said:Rigging is not my thing, I do lighting and power. That said, do it right and get an engineer involved. I was in Atlantic City's Boardwalk Hall when their supergrid came down, thankfully nobody was injured, but it was sobering to see the forged hooks on the 2 ton Chain hoists pulled straight.
Most definitely. Each connection point will have a stated capacity and all the steel and welds designed by an engineer and inspected as SVRex described above.
OHSCrifle said:My first reaction was "what the berkeley is an eye nut"? But it looks like exactly the missing link. this place is still. amazing.
This is a hotel with a post tensioned concrete slab about 20' up. I managed to get steel embed plates designed in the underside of the slab on a 10'x10' grid but the ceiling will be built down about 3-4'. We will need a steel tube as a down leg (inverted post) and then diagonally / laterally brace each post - likely just use diagonal steel angles across several posts.
The eye nut solution looks golden. I'm thinking a threaded rod welded to each post. Then a removable panel in the ceiling to hide them when not in use.
edit: and a safety cable
edit 2: this is the building
That is a cool looking building!! Where is it?
In reply to dyintorace :
In town Atlanta on the Beltline between North Avenue and Ralph McGill Blvd. Close to Ponce City Market and Old 4th Ward Park.
In reply to SV reX :
Indeed. My theater rigging experience is basically taking some training that was sussed out by engineers and repeated in my presence in a classroom. I feel confident that I won't kill anyone for a 3-week run of a show but I'd feel a bit queasy without knowing exactly what I was doing for a permanent installation.
I've also never rigged to concrete so I have no frame of reference. All of mine is on an established grid with a capacity cert on file. Sounds like plating is the key for concrete. As long as OHSC has a good pick point in the concrete, the rating of the eye nut should determine what he can safely hang (up to the load rating of the individual plates and the total weight for the rating of the ceiling).
OHSC... if you have the choice, I would suggest trying to leave the eye nuts in place behind whatever concealment. Just like a head bolt or a harmonic balancer bolt, there are only X number of times you can torque on the threads before it fails. You'll also get a surprising number of riggers in the future who just make it Gutentite which could accelerate failure.
Keep in mind that I'm educated on the topic (25 years ago) but I'm not certified/union/expert. I know enough to not kill people for three weeks.
In reply to Curtis73 (Forum Supporter) :
The embedded steel plates that were cast into the slab above each have "Nelson studs" welded to the back side. Those studs get woven among the slab's regular reinforcing bars prior to placing the concrete.. so I'm 100% good with the attachment to the slab and even the misc steel "posts".
I just need the right contraption on the end for the sound and lights guys to attach to. That's why I was hoping there is some kind of "standard" male/female hardware with a pin -- something like a trailer hitch receiver.
The desire to have everything hidden 95% of the time is the real wildcard. The eye nut is cool because it can anchor to a post above the ceiling and hang down "just enough".
Agreed. Eye nut for the win here.
I have used Ken Forgings at the theater and they are not only available on Amazon, but also US made, great quality, half the price of most others. I'm sure they're not going to quibble over a couple hundred bucks for a project like this, but if you were looking to save money without losing quality (last minute budget change or something), Ken Forge is a good source.
Amazon.com: Ken Forging EN-8 Style A Eye Nuts, 3/4" : Industrial & Scientific
Edit: I picked a random Ken Forging, not sure if those are the rated version or not, just wanted to give you a starting point.
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