Wood beam Rigging

James (JT)

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Joined
Nov 9, 2017
Location
Grand Rapids, MI
Hi All, Lately my small but growing AV firm has been doing some intro budget galas at some revamped factory event spaces. In almost every case, the client wants some sophisticated short term lighting. These spaces have (12") wood beams and wood 2x12" rafter ceilings. Lately light trees are not getting it done for us. Is there a rigging solution for wood beams that is safe for small loads (3-4 LED pars)? All the clamps I find are for I-beams rather than this. I saw a local AV firm using ratchet straps and I know that is a "no overhead lifting" soution. Bear in mind that the local places will not allow me to drill, or I would place some quiet forged eye bolts... Any suggestions?
 

BillConnerFASTC

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Jan 30, 2010
Location
Clayton NY 13624
Are you saying that drilling a hole for a through bolt in the 2X12's in an industrial building that has been renovated is not allowed? That seems like a silly prohibition but I've never seen a product or solution that I would be comfortable with in that case. So that leaves the beams that I presume the 2x12s sit on, thus possible to wrap around those. Chain or wire rope with some blocks or something to keep it from damaging the beam seems doable, but may be too low. Is span between beams such that you could rest each end of something on top of the beams? A pipe or a truss design for top chord bearing? Or some sort of steel "saddle" that site on top of beams and allows hanging?
 

RonHebbard

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Joined
Jun 12, 2004
Location
Waterdown, ON, CA
Hi All, Lately my small but growing AV firm has been doing some intro budget galas at some revamped factory event spaces. In almost every case, the client wants some sophisticated short term lighting. These spaces have (12") wood beams and wood 2x12" rafter ceilings. Lately light trees are not getting it done for us. Is there a rigging solution for wood beams that is safe for small loads (3-4 LED pars)? All the clamps I find are for I-beams rather than this. I saw a local AV firm using ratchet straps and I know that is a "no overhead lifting" soution. Bear in mind that the local places will not allow me to drill, or I would place some quiet forged eye bolts... Any suggestions?
@James (JT) @BillConnerFASTC Legal or not, what I've personally done in a couple of similar situations is use four hole pipe flanges designed to accept 1/2" threaded schedule 40 pipe with threaded steel reducers externally threaded as 1/2" schedule 40 pipe and internally threaded to accept 1/2" - 13 hex bolts fitted with flat and lock washers to mount the yokes of fixtures such as 500 Watt 6" fresnels and Source Four Mini's; Mini's NOT Juniors. I've pilot drilled the wood with a 7/64th" bit then attached the flanges using four #8 flat or pan head wood screws. Having taken the time to pilot neatly, coupled with being careful not to damage the wood by over-torquing the screws, I've been able to strike everything leaving only tiny holes essentially invisible from floor level. Of course you'll want / need safeties which I've dealt with in two ways; wrapping standard safety cables or chains over and around the beams or adding additional flanges with forged shouldered closed eye bolts as anchor points for my safeties. I'm neither suggesting this is legal nor perfect, I'm only offering it as a method that's worked for me several times in my past.
Toodleoo!
Ron Hebbard.
 
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James (JT)

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Joined
Nov 9, 2017
Location
Grand Rapids, MI
This is the silliness and the conundrum. The easiest way is a 1,000 pound rated eyebolt. I only need to get a four bar up for most events, and I do enough that an eye bolt in the right spot would be awesome, but owners in two venues have had people tell them not to let people drill or it weakens the rafters especially, the 12" beans are uprights, so I thought If I could find something that is like a bar clamp with some teeth, that maybe I could work it out. But span sets over the rafter holders might be my best bet (though harder in some areas depending where the lights need to sit... Thanks for these first replies.
 

Senorfish

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Feb 11, 2014
Location
West Coast
A 1/2" bolt drilled through the center section of the beam is not going to weaken the structure in any measurable way. The fear of weakening the beams comes from different trades that sometimes do butcher beams and joists. Such as HVAC or plumbers who need to run a 4x6" air duct or 3" drain pipe through a beam. That's the type of hole that actually ruins a beam or joist. But look at the electrical code.... passing a standard 3 conductor 12 gauge wire is SUPPOSED to be done by drilling 1/2" holes through the joists at least 2" away from the bottom or top edge. So definitely I would talk these owners into how necessary it is to have safe and secure BOLTED rigging points over head... so that nothing can slip or fall or come unclamped and kill someone. Your rigging MUST pass over and around the beams completely to form a secure connection. The only way to do that is with bolts through the midsection or spanset over the top.
 

egilson1

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Feb 25, 2009
Location
Boston, MA
Show the owner a diagram of any style of an engineered truss, and point out all the empty space inside of it. Then explain the beam is the same. Much of the material is not needed to maintain the strength.

This is of course over simplified, but is the root of the rule of thumb of being 2” from the edge of a wood beam when you drill holes for electrical wire.

Ultimately I would approach this by trying to permanently install appropriate hardware like rated eye bolts, etc. to then hang whatever is needed for the event. Tell the owner it will cost him nothing and make his space more desirable for future events.
 
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Van

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Portland, Or.
If the Rules of the Venue are "No Drilling" then I would respect them, regardless of how many people tell you "that's silly". My vote would be for a span-set sling over the beam supporting some box truss. Might be overkill for the load but it's probably the best way to suck it up to the beam by making an extra wrap around the chord. If not that then the fall-back would be chain around the beam to a piece of scd 40. I'd wedge two side arms, one on each end, on facing forward, one facing back, against the bottom of the beam to cut down on pipe rotation. Throw a carpet scrap or cut up bicycle tire around the beam where the chain is to keep it from gouging the wood. I do not like the idea of using a wire rope sling, or Sunday as the right angles of the wood are bad for wire rope.

$.02
 
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teqniqal

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Apr 26, 2009
Location
Dallas / Fort Worth, Texas
If it is a wood roof structure I wouldn't hang anything from it unless a registered / certified structural engineer signed-off on it. Steel pinch-plates are inexpensive to have fabricated, and load-rated thru-bolts are relatively inexpensive, too, so the material cost for some permanent hang points is very little compared to the labor costs and insurance claim risk of 'field-engineered' solutions. There are lots of places that are just not designed to have overhead rigging attached to it. Use ground supported rigging, know the capacity (of both the floor under it and the trussing). In Japan many smaller theatres were built with a fly house and no rigging, so every show that comes in builds a ground supported show rig to sit inside the stage house. If the promoters don't like the look of the corner support columns, then get them pay for some engineering to get load-rated hang points spaced-out at a workable interval. Of course, you can drape the columns with some fabric, too, to make it look a little better (or use a dark color to make it 'go away').

I think one of the biggest challenges will be getting people to not over-load the new fixed rigging points. Even if a load limit label is attached directly to it, people look at a chunk of steel and think they can hang a car from it with nary a forethought to the material the steel is connected-to. This would be a good time to permanently install a load cell system so the roof loading points can all be truthfully monitored. It may be that there will be many 500 Lb. pick points in lieu of a few 2,000 Lb. pick points. It is also extremely important to design the anchor points so they can take the lateral loading from bridles. I frequently see giant eye-bolts that don't pivot to align with the direction of loading and then see them side-loaded by the rigging that is attached. You have to clearly define this typical 'not straight down' loading condition to structural engineers because they generally don't understand how show rigging is implemented and assume every load is towards the center of the Earth.

Another thing for the venue owner to understand is that wood beams can crack and become significantly weaker (read-up about the Oregon Shakespeare Festival venue when they found the giant wood roof beams there had major cracks). A rigorous annual roof inspection would be a reasonable expectation if the roof is regularly being loaded with show equipment. Spotting cracked wood members early can truly save lives in that kind of venue.
 

RonHebbard

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Joined
Jun 12, 2004
Location
Waterdown, ON, CA
If it is a wood roof structure I wouldn't hang anything from it unless a registered / certified structural engineer signed-off on it. Steel pinch-plates are inexpensive to have fabricated, and load-rated thru-bolts are relatively inexpensive, too, so the material cost for some permanent hang points is very little compared to the labor costs and insurance claim risk of 'field-engineered' solutions. There are lots of places that are just not designed to have overhead rigging attached to it. Use ground supported rigging, know the capacity (of both the floor under it and the trussing). In Japan many smaller theatres were built with a fly house and no rigging, so every show that comes in builds a ground supported show rig to sit inside the stage house. If the promoters don't like the look of the corner support columns, then get them pay for some engineering to get load-rated hang points spaced-out at a workable interval. Of course, you can drape the columns with some fabric, too, to make it look a little better (or use a dark color to make it 'go away').

I think one of the biggest challenges will be getting people to not over-load the new fixed rigging points. Even if a load limit label is attached directly to it, people look at a chunk of steel and think they can hang a car from it with nary a forethought to the material the steel is connected-to. This would be a good time to permanently install a load cell system so the roof loading points can all be truthfully monitored. It may be that there will be many 500 Lb. pick points in lieu of a few 2,000 Lb. pick points. It is also extremely important to design the anchor points so they can take the lateral loading from bridles. I frequently see giant eye-bolts that don't pivot to align with the direction of loading and then see them side-loaded by the rigging that is attached. You have to clearly define this typical 'not straight down' loading condition to structural engineers because they generally don't understand how show rigging is implemented and assume every load is towards the center of the Earth.

Another thing for the venue owner to understand is that wood beams can crack and become significantly weaker (read-up about the Oregon Shakespeare Festival venue when they found the giant wood roof beams there had major cracks). A rigorous annual roof inspection would be a reasonable expectation if the roof is regularly being loaded with show equipment. Spotting cracked wood members early can truly save lives in that kind of venue.
@teqniqal And then there are ice and snow seasonal loads to be considered, when and where a consideration, along with water and clogged roof drains.
Toodleoo!
Ron Hebbard.
 

James (JT)

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Joined
Nov 9, 2017
Location
Grand Rapids, MI
Thank you everyone! These are all super helpful replies. I am not a certified rigger, but never take peoples lives for granted when overhead equipment is called for. I hate the part of our industry which sometimes calls for us to come up with an out of the box (or "creative") solution from a hardware store. Much prefer an expensive piece of steel with a certification tag freshly applied. Working in small venues, people just don't understand why pros won't run a length of dog chain over a hanging structure and just half ass it. Trying not to kill anyone here!
 

Van

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Location
Portland, Or.
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BillConnerFASTC

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Jan 30, 2010
Location
Clayton NY 13624
@BillConnerFASTC Enlighten the poor old blind Canadian, what are "WFs"? What the phuques? White Folks? Wrinkled Folks? Wiley Folks? Whirly Fans? Prithee do tell. I know about Unistrut and its Canadian brother Cantruss.
Toodleoo!
Ron Hebbard.
Its the common designation for rolled steel beams - Wide Flanges. Just another and very common steel shape like S, M, C, MC, T, HSS (hollow structured sections), and L (angles).