lxkev Posted January 20, 2006 Share Posted January 20, 2006 I started work at a venue about 6 months ago, I become concerned when rigging I notice the whole grid was moving. I’ve contacted the local council to come check it but its taken forever. Today I took down a ceiling tile and ouch. The grid which holds about 40-50 fixtures, upto 8 moving lights, and 6 speakers cabs is suspend by the following; Half couplers from the grid into long bolts, these bolts then connect to a 5mm thick 90 degree bracket. Both the bracket and bolt have bent a little. This Bracket is then connecting to wooden joists by bolts drilled through. I then looked at the joist, they are connected to I beams, but from what I could see they have been simply forced in between the eye. The grid has been up for 6 years, but im very concerned. What are your views? Link to comment Share on other sites More sharing options...
TommyToad Posted January 20, 2006 Share Posted January 20, 2006 Reinforce it now! Had a similar problem 2 weeks ago, did a inspection at the grid and saw it had moved. Bought wire and locks and did a new suspension, better then the old one. Had a engineer come down the day before to tell me how to do it best. Link to comment Share on other sites More sharing options...
ianl Posted January 20, 2006 Share Posted January 20, 2006 you don't say how many points the grid is suported on, you don't say how much movement and whether it is side to side or up and down or strange twistings you don't say how long the long bolts are or what diameter, if they were say 500mm long and m8 or m10 then I would expect the grid to have a fair bit of side to sidemovement but would be very concerned if the grid moved up or down you don't say how big the grid is , what it is made of (truss, aliscaf, steel scaff, etc) and the distance between supports you don't say how big the joists are but my main concern from what you have said so far would be the use of wood because you can't give a bit of wood a SWL in an ideal world your grid would have a tag (or paperwork) telling you the max load and max UDL. obviously there are a lot of grids out there that don't but if I was responsible for it I would want to either find some existing paperwork or get a rigging company to come and advise you and access it you mention contacting the council, is it a council venue?, do you just work there for some one else or are you in charge? Link to comment Share on other sites More sharing options...
Brian Posted January 20, 2006 Share Posted January 20, 2006 ... What are your views?Get in a structural engineer, only they are qualified to offer an opinion. Link to comment Share on other sites More sharing options...
flypig Posted January 20, 2006 Share Posted January 20, 2006 ... What are your views?Get in a structural engineer, only they are qualified to offer an opinion. I agree with Brian. You need to get a structural engineer and a professional rigging company (preferably to meet at the same time) to assess the problem. You should also inform your superiors / employers / managers in writing as soon as possible to cover yourself. If the bolts and 5mm metal brackets are bent, it means that they have been overloaded and placed under considerable stress. Wood is definitely NOT a good rigging point in any permanent install. If you have any concerns about the safety of a structure you should not use it until declared 'safe' by a competent authority, remember Justin Timberlake? Link to comment Share on other sites More sharing options...
bruce Posted January 20, 2006 Share Posted January 20, 2006 Agree with all of the above - only an expert can advise. However, you mentioned "contacting the council" and that "it had taken forever". Obviously I don't know the details, but I'm guessing it's a local authority venue, and you've contacted the council tech services people. To cover yourself, you may also want to contact the safety office at the council. This should be completely separate from the tech services/estates people. It will usually guarantee a very quick response. However, it may not be the response you are looking for. Safety people will err on the side of caution, potentially "condemning" an installation. Moreover, they will NOT advise on what needs to be done to bring the installation up to standard. But my experience is that their involvement - or even the suggestion that they might get involved - can cause other departments, which are "far too busy to get involved for several months", to suddenly realise that they can come and have a look this afternoon.... That's my experience of the public sector - your mileage may vary. Bruce. Link to comment Share on other sites More sharing options...
lxkev Posted January 21, 2006 Author Share Posted January 21, 2006 Thanks for all your posts. Its part of a performing arts college, yes I am in charge. The grid is about 15/20 meters square, not all the bars on the grid have supports, there is about 20 points - 4/5 meters apart and yes 10mm. 60mm bolts, it shakes left to right by a lot, made out of aliscaf. My main concern is the wooden joists and 90 degree bracket. I rang the company who installed it and there response was we have no paper work on it. Is the company liable for installing a unsafe grid? Link to comment Share on other sites More sharing options...
Brian Posted January 21, 2006 Share Posted January 21, 2006 I rang the company who installed it and there response was we have no paper work on it. Is the company liable for installing a unsafe grid?It's still not clear if it's unsafe, that we'll have to leave to the experts. As to the second part, the responsibility should lie with whever designed the grid; it could be they were simply working to architects drawings. Don't worry about 10mm bolts, they are suprisingly strong. The timber - without much more info it's impossible to say. Just to work out how 'strong' a bolted connection is you need to know - stress grade of timber, width of joist, depth of joist, length of joist, size of hole, position of hole from timber edge, how many holes, position of hole from end of timber, size of contact area of bolt head, size of contact area of nut head, orientation of hole wrt timber axis.........you can see why it's one for a structural engineer. Link to comment Share on other sites More sharing options...
eamon Posted January 22, 2006 Share Posted January 22, 2006 Hi One of the first things you should do here is create a paper trail. This will serve as notice to others this is a serious problem and give yourself some back up if you have to fight for change. If you feel the grid is becoming unsafe, I would at the very least put a limit on the weight you can place on it. Down rate the whole structure until it has been sorted. Consequently document the reasons for this with your management. I would echo other posters about getting your council safety/architects dept as soon as possible. A letter to them may make them move a lot quicker. You should also attempt to contact the structural engineers for the project asap. Make sure you have the council on board with you when you do this. You may find them not wanting to know and dragging their heels. Most people hate revisiting jobs and the associated extra costs that they may become liabale for. In regard to the people who installed the grid, the very least they should do is a proper site visit.... Refer to my previous sentence. Also document the use of the grid from the time you have started and with the previous workers there. I am currently fighting my structural engineers in a similiar situation ( I have an RSJ which has deflected by 70mm and twisted by 8mm!!) and one of the accusations layed was that we had to have overloaded the RSJ at some point. I have documented the weight loadings etc to counteract this. An average of 3tonne versus a loading of 10 tonne. If the rigging company are still of no help, consult another professional rigging company and commision them to write a report. With something like that, they will have no choice but to answer and deal with your situation. How long has the grid being in place? best of luck with & hope the above helps eamon Link to comment Share on other sites More sharing options...
lxkev Posted January 22, 2006 Author Share Posted January 22, 2006 Thanks for all your posts. I'm going to contact the council structural engineers first thing tomorrow and reduce the weight on the grid untill something is done. Link to comment Share on other sites More sharing options...
paulears Posted January 22, 2006 Share Posted January 22, 2006 Hang on lxkev. It is a performing arts college? You are an employee? If so, your duty is to inform your line manager (and possibly the union rep) of the problem, and pass the problem on. While I'm sure you've already done this, and no doubt had no sensible reply - you should NOT go outside, especially to the local council. Fair enough, they do have the people who will sort this out, usually rather bluntly. As one other poster mentioned, they may well simply err on the side of caution and close you down until it is put right by real engineers who can work out how safe it actually is. This is pretty well the kiss of death as far as your career there goes. You close the department and maybe students leave, you create bad press that cuts down next years intake, maybe the part time staff get laid off - all of this will be your doing. Now I'm not saying you should do nothing, but putting it in writing would be the best bet, removing the load is also sensible. These things are within your job description and make perfect sense. 'Shopping' the college to outsiders is great, if you don't want to work there any more. Make your case, and then let the powers that be deal with it. You will be in the clear, the responsibility passed on, and...... you still have a job. Just make sure that what is there is bolstered up, and load reduced. Even taking some weight down to the ground with scaff extra supports would be sensible, especially if these things got in the way a bit - that way more staff would start complaining.paul Link to comment Share on other sites More sharing options...
Stutwo Posted January 23, 2006 Share Posted January 23, 2006 Paul makes a good point with regard to line management. I'm in a similar position employment-wise, and have gone through a similar process with regard to SWL of our FOH bars. I was tempted to go straight to professional advice, and even went as far as contacting Lloyds for costs of assessment and testing. I then went to the caretaker and the powers that be, and discussed the matter. They all agreed that my concerns had been noted, and that I had done exactly the correct thing in bringing it to their attention, and now the onus was completely on them to rectify the problem. So now, the problem and responsibility lies elsewhere. I'm confident I'm not overloading the bars having checked the suspension, but should anything happen, it isn't my head on the block. I would recommend at least discussing it with your building manager or management. Link to comment Share on other sites More sharing options...
bruce Posted January 23, 2006 Share Posted January 23, 2006 Agree with most of the above - make sure there is a papertrail and report it through line management. I stand by what I said about the safety people in your organisation. They WILL get some action. But it may not be the action you want... However, I usually find that even a suggestion that they might be involved causes estates and buildings people to get a move on... A specific example - which is perhaps a little :P, but illustrates my point. A few days ago we noticed a strange smell in one of our offices. Some sort of solvent/fumes smell, coming through a vent duct. Very unpleasant - made some people feel very ill. We reported it to the Estates people, several times, and over the next 3 or 4 days various guys in boiler suits dropped past, stuck their heads above the ceiling, and left. But they had no idea what was causing the smell, where it was coming from and whether it was harmful. And didn't seem too concerned. Later that day, I was in a completely unrelated meeting. Our site safety officer was sitting beside me, and in passing I briefly mentioned the problem. They abandoned the meeting we were supposed to be having, and within 10 minutes they were on-site with the heating & vent services manager, and all the duct plans. 20 minutes later they discovered that another arm of the estates dept was doing refurb work elsewhere in the building, and they were running a petrol compressor beside an air intake. That problem had been "being investigated" for several days, but once I involved the safety people, the "big guns" immediately got involved, and the problem was resolved within minutes. Bruce. Link to comment Share on other sites More sharing options...
lxkev Posted January 23, 2006 Author Share Posted January 23, 2006 My prob is, I have passed it onto to my line managers and the H+S persons. It got sent back onto me to contact the city council. And yes one of my concerns is that they say tough the grid unsafe and I end up with no job. But at the end of the day I would rather have no job then risk the lifes of a possible 270 people sitting below this structure. I original wanted to hire in stage elec etc… to test the structure for me, but I got the following response “if the grid fails it may not be covered if a external company does it and the council will do it for freeâ€. You see the problem…. Link to comment Share on other sites More sharing options...
erroneousblack Posted January 24, 2006 Share Posted January 24, 2006 Had similar concerns when I started at my current venue. I sent emails out left, right and centre, now ,you know it's an issue, you have to act. One possible route is to get your insurers on to it, if they send a report then action will have to be taken. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.