Installs Speaker Rigging Coordination With Structure

[museav]

I just had an experience that while not the first of its kind, made me think it might be good to share.

The situation involves the audio system for a theater in a county performing arts center that I had designed as part of the facility design. For more than a year I have been asking when we would see the the speaker rigging Shop Drawings required by the Specifications, meanwhile the facility construction has been proceeding.

I finally received the related drawing from the Contractor and it reflected a significantly different approach than what I had shown in my design Drawings. I knew there had been some coordination issues regarding conflicts with ductwork for which the Architect had been involved so before responding I contacted the Architect to see if the deviation was a result of his input. He also forwarded the information on to the Structural Engineer for the building. The response back was that not only was what was shown not in response to the Architect's input, but the structure they showed using to support speaker arrays was not designed for and would not support their load.

The specific aspects that stood out on this for me were:

1. I had a drawing from the Contractor showing rigging that not only deviated from the design intent but that was not feasible.
2. That drawing was actually stamped and signed by a licensed Structural Engineer who apparently reviewed only the rigging itself and not the structure to which it was attached.
3. Because they waited so long to submit the information, the construction progress is such that they may have to tear out much of the work already done in order to rig the speakers safely, much less as intended.

This is a great example of why it is so important when flying anything to consider not only the rigging, but also its attachment to structure and the structure itself. In this case the 'rigging' probably would have been fine but because it was being attached to structure not designed for that purpose, apparently may have resulted in failure of the supporting structure.

 

[VCTMike]

I just had an experience that while not the first of its kind, made me think it might be good to share.

The situation involves the audio system for a theater in a county performing arts center that I had designed as part of the facility design. For more than a year I have been asking when we would see the the speaker rigging Shop Drawings required by the Specifications, meanwhile the facility construction has been proceeding.

I finally received the related drawing from the Contractor and it reflected a significantly different approach than what I had shown in my design Drawings. I knew there had been some coordination issues regarding conflicts with ductwork for which the Architect had been involved so before responding I contacted the Architect to see if the deviation was a result of his input. He also forwarded the information on to the Structural Engineer for the building. The response back was that not only was what was shown not in response to the Architect's input, but the structure they showed using to support speaker arrays was not designed for and would not support their load.


The specific aspects that stood out on this for me were:

1. I had a drawing from the Contractor showing rigging that not only deviated from the design intent but that was not feasible.
2. That drawing was actually stamped and signed by a licensed Structural Engineer who apparently reviewed only the rigging itself and not the structure to which it was attached.
3. Because they waited so long to submit the information, the construction progress is such that they may have to tear out much of the work already done in order to rig the speakers safely, much less as intended.

This is a great example of why it is so important when flying anything to consider not only the rigging, but also its attachment to structure and the structure itself. In this case the 'rigging' probably would have been fine but because it was being attached to structure not designed for that purpose, apparently may have resulted in failure of the supporting structure.

The General Contractor on the job did not review it? The architect did not review it? Sounds like a break down in the chain of communication. Who gets to sign off on that job?

 

[museav]

The General Contractor on the job did not review it? The architect did not review it? Sounds like a break down in the chain of communication. Who gets to sign off on that job?

The General Contractor did approve it but I can probably count on one hand the number of times I've had an E.C. or G.C. actually review what a sub submitted and not just rubber stamp it. And I am working for the Architect so they forward anything AV related on to me for review.

It's also a great example of how not to approach a theatre construction project. The G.C. does not have much experience with performing arts venues but they are also the Construction Manager and have a relationship with the Owner, so they pretty much dictate everything. Before the work was bid I offered to provide them a list of several AV Contractors that I thought were qualified for the work and was told they "didn't need me trying to get work for my buddies". Despite recommending they not do so, they bid the AV as a sub under the Electrical Contractor and many of the Electrical Contractors bidding apparently waited until a day or two before the bids were due to start looking for AV bids, I literally had an AV Contractor call me the day of the bid saying that he had just been contacted that morning asking them to have a bid that afternoon. Apparently the G.C. thought that AV Contractors went out and put together bids for every project they could find and then just waited for someone to call them and ask for their number. So we ended up with whatever AV Contractor that the low bid Electrical Contractor decided to use and had no say in it.

Making it even more fun, every person initially involved on the Architect's side from the Project Architect to the people doing most of the CAD work are no longer there, which has resulted in a lot of little things being dropped or not fully coordinated. Things like acoustical treatments referenced on one Drawing but not on the finish schedule or in the Specifications, changes to ductwork that were approved without considering how it impacted speakers or theatrical lighting and so on. It also resulted in an obsolete version of the Specifications I had prepared being included in the bid package and no one knowing how that happened.

It's turned into one of those projects that I'd consider walking away from except I can't since my name is associated with it

 

[howlingwolf487]

It's turned into one of those projects that I'd consider walking away from except I can't since my name is associated with it

I'm sorry to hear that, Brad. Making a name for oneself is only the beginning...then you have to keep that reputation (and that's not always easy to do). Keep it up!

 

[RickR]

From what I'm reading it sounds like the original issue may be with the Structural design. If its not capable of holding the load then it doesn't really matter how it's hung. It's all down hill from there. The GC would see the stamp on the submittal and not go further. The Architect did the right thing and got their own expert. Then found that the primary design had a flaw.

Who told who to do what may land in court, especially if anything falls down.

Don't run! If you do then you will likely be blamed for everything without the chance to defend yourself. Professional standards say you should at least try to minimize the damage.

 

[museav]

From what I'm reading it sounds like the original issue may be with the Structural design. If its not capable of holding the load then it doesn't really matter how it's hung. It's all down hill from there. The GC would see the stamp on the submittal and not go further. The Architect did the right thing and got their own expert. Then found that the primary design had a flaw.

Who told who to do what may land in court, especially if anything falls down.

Don't run! If you do then you will likely be blamed for everything without the chance to defend yourself. Professional standards say you should at least try to minimize the damage.

This is really getting off the original point, but there may be some misunderstandings.

There is no problem or deficiency with the building's structural design and we have confirmed that the building structure is coordinated with the original concept of flying the speakers from the roof structure above. However, what the AV Contractor proposed to provide and the General Contractor approved for the speaker rigging deviates from that original design concept and instead proposed to support the speakers off framed walls that were not designed for that purpose.

There is no technical reason that the speakers could not be rigged as originally intended. We did what we could to avoid the situation, including noting in writing on multiple occasions that there was associated coordination required, but despite those attempts to avoid just such issues, what seems to have happened is that the speaker rigging installation was not coordinated with the sequencing of other work with the result that work that should have occurred after some elements of the speaker rigging were installed was instead completed before the rigging Submittals were even submitted. To avoid having to work around or tear out existing work, the AV Contractor apparently developed, and the General Contractor approved, a rigging concept that deviates significantly from the original concept and that according to the building Structural Engineer is not compatible with the building structure. The most appropriate response would be for the Owner to simply tell the G.C. and AV Contractor that they should install the speakers as originally intended, but due to the relationships involved that is not going to happen.

The appropriate response by design professionals to this type of situation is greatly shaped by the Kansas City Hyatt disaster where it was the Structural Engineer who 'approved' Shop Drawings including what turned out to be some critical deviations that the steel fabricator had made from the original design concept that was eventually held liable while the steel fabricator and Contractors, the parties who actually deviated from the original design concept and developed the design elements that failed, were assigned virtually no liability. As a result, design professionals now have to be very careful regarding their assuming potential liability by accepting or approving any changes or work by others.

A factor I did not previously note is that the original design concept included the intent to be able to access the speakers for installation and service from a dedicated catwalk. The associated catwalk is already constructed, however the speaker rigging design submitted prohibits accessing the speakers from the catwalk and instead requires accessing the speakers from the stage/pit lift below. When the facility opens and someone realizes they have to rent a lift to access the speakers and they paid for a catwalk with no purpose, they are going to want to know who was responsible and from experience, the Contractors will likely be all too willing to try to place the blame elsewhere.

And that can be the difficulty in such situations, working to resolve the problems without compromising the original intent or assuming increased risk through the work or actions of others. If there comes a point where you are not comfortable with the compromises involved or the risk entailed, then it is sometimes actually the most professional action to distance yourself.