Problem is these days that we are being forced into a situation where riggers are not allowed to make informed decisions any more
It is however, a little weird when the building guy asks you to land the grid so the roof can "rest" over a few dark days......
Sounds like working in Russia where we had to re-do the PA, because the venue engineer told us there was more snow on the roof than they expected and they had to reduce the production load to keep the total roof loading within tolerances.
We offered to go up on the roof with spades and boiling water but they wouldn't let us.
The "old barn" in St. Louis was a totally wooden roof and they were hanging shows in there up until the mid 90's. I was told that they used to hang a rope at center ice that just touched the floor, by the time the show was up a foot or two would be on the ground. Never confirmed that, just what I was told.
Boy, that brings back memories! Back in 1982, we played an old "forum" style theater/club called "The Playpen." (long gone) The roof had been built out of the hull of an old ship so no one knew how to rate it! After all, it was designed to be upside down and floating in the water. Anyhow, since sound and lights were both flown, the rope trick was used to measure sag. With about 2000 pounds flown, it didn't budge! Years later, after being long closed, it burned down. I remember driving past it, and there sat the roof frame on top of the rubble! Didn't even look that distorted.
Boy, that brings back memories! Back in 1982, we played an old "forum" style theater/club called "The Playpen." (long gone) The roof had been built out of the hull of an old ship so no one knew how to rate it! After all, it was designed to be upside down and floating in the water. Anyhow, since sound and lights were both flown, the rope trick was used to measure sag. With about 2000 pounds flown, it didn't budge! Years later, after being long closed, it burned down. I remember driving past it, and there sat the roof frame on top of the rubble! Didn't even look that distorted.
Everyone is saying its ok. Here's another factor:
The venue isn't a theater, etc., it's an old truck barn which now being used for social events,, etc. it is unlikely that any engineer tested the beams. Granted, we didn't hang more than 200# on a point, but just because it SEEMS ok doesn't mean it is.
I did lighting on a show a few years back where we were hanging a FOH truss with a few lights. We'd been assured by the client there were big beams available to rig from (note the truss weight with lights was only about 200lbs). We showed up and found massive wooden beams that had been cut through in various places when the loft was added. Myself and the other lighting tech were a little concerned about rigging from these (due to them being cut in places, not being wood). Audio engineer overhears part of the conversations and walks up and tells us its okay to use for a couple thousand pounds. We're kinda like thanks, but I think we need to see an engineering report or something on this at least saying that an engineer signed off on the beams being cut in the first place. Audio guy then introduces himself fully as a licensed structural engineer with a local firm who does audio on the side for fun. Yup we hung the show. He turned out to be a cool guy that we asked about a few other situations as well.It would not be that hard to get the beams analyzed. Old is probably good unless there is rot or rust. Around here the barns built with old growth lumber and iron bolts are WAY over built and you can do whatever you want in them. It always amazes me how over built things use to be before modern structural analysis took hold.
It would not be that hard to get the beams analyzed. Old is probably good unless there is rot or rust. Around here the barns built with old growth lumber and iron bolts are WAY over built and you can do whatever you want in them. It always amazes me how over built things use to be before modern structural analysis took hold.
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