TSM Project 2008 - Deck Platform
Concept
The concept for my project is simple, I would like to have an Up Stage platform which raises and lowers throughout the perfomance.
Ideas
As I am not particularly confident in this subject I decided to do something which was within my limitations. For my project, I looked at using electric winches in order to raise and lower a platform (Made from 3 Lite Deck). I understand that when briefed on the project we were told we had an unlimited budget, however after costing for these winches (£1165.50 each) I decided to use the counterweight flying system, as I believe that this more like the reality of being a Technical Stage Manager. In order to increase my safety factor, I obtained the hardware for the project as if I were making the platform from Steel Deck. In reality I would use Lite Deck.
Required Hardware
3 x Lite Deck
12 x 1T Round Slings
12 x 0.5T Bow Shackles
6 x 10m Single Leg Wire Rope Bridles (7mm/ Thimbles on both ends)
12 x M10 Bolts
12 x M10 Nylon Lock Nuts
The Rigging Process
The Decks shall firstly be bolted together, so the 8ft side is facing downstage and the 4ft sides are bolted together. Their are 6 bolt holes in a 4ft side of steel deck, therefore 12 bolts and 12 nylon lock nuts will be required. I have chosen Nylon Lock Nuts as when in the air the platform will be suspended above peoples heads. The nylon lock ensures that the nuts cannot come loose and therefore are safer than standard M10 Nuts.
Once the decks have been bolted together, the next step would be to wrap a round sling around each corner in a basket formation and link this, with a shackle to one end of the wire rope bridle. I would also do this at the joins in the decks on the Up Stage edge of the platform, as an extra safety precaution.
Once this has been done I would lower the required bars in, in this case Bars 29 and 25, and attach the other end of the bridle in the same way as before, via a round sling in a basket formation and a shackle.
I would then weight the bars and test them. If the bars are weighted correctly then deads would be set for these and flying speeds would be rehearsed with the flymen.
Costings
Lite Deck- £45 per week for 3 decks from Stage Hire Scotland
Round Slings- £4.01 each from Rope Assemblies,
0.5T Bow Shackles- £1.72 each from Rope Assemblies
10m Single Leg Wire Rope Bridles- £13.83 each from Rope Assemblies
M10 x 100 High Tensile Bolts- £7.08 for 50 from Screwfix
M10 Nylon Lock Nuts- £3.98 for 25 from B&Q
Total
£4.01 x 12 = £48.12
£1.72 x 12 = £20.64
£13.83 x 6 = £82.98
£7.08 x 1 = £7.08
£3.98 x 1 = £3.98
Total Cost = £162.80 (Plus £45 per week for Lite Deck)
This cost would be decreased as some of the items required, such as shackles and round slings may be in stock at the academy.
Safety
As this platform is rigged on 2 Bars it will reguire sufficient rehearsal for the 2 Flymen who will operate it.
As noted previously, I plan to make the structure from Lite Deck, but for extra safety have accounted for the structure being made from steel deck. If made from Steel Deck the struture would weigh 210kgs (sufficiently less for Lite Deck), This is spread across 2 bars, each with a safe working load of 400kgs.
Their are 6 Wire rope bridles in the structure, each with a SWL of 500kgs. This is far greather than the safety factor of 8 which should be standard in the theatre industry. Their are 12 round slings in the structure, each holding 1/6th of the overall weight. Each round sling is rated at 2000kgs when used in the basket formation, this has a sufficient safety factor. Also their are 12 0.5t Bow Shackles, which also would hold 1/6th of the weight, therefore having a more than sufficient safety factor, to work safely in British Theatre.
Sources
Rope Assemblies
Hoist UK
B&Q
Stage Hire Scotland