As I mentioned in yesterday’s post there will be some things in this post that could be considered theatre magic spoilers. So if you like your magic unexplained it might be best to stop reading now. However, if you’re the kid at the magic show who was bugging the magician to show you how he did it, read on.
Of the two mainstage theatres at ACT, the Allen Arena theatre is my favorite, and my favorite place in the theatre is the walking grid. The building that houses ACT theatre used to be The Eagles Aerie No. 1 and the room that the Arena theatre is in was the grand ballroom. The history of the room is most apparent when you climb the stairs to the mezzanine level. There the architectural details on the walls and ceiling are less obscured by the grid and the sound baffles which turn what would otherwise be a large echoing space into an intimate theatrical setting.
Since the building is an historic landmark the minimum amount of alteration was done to the original structure when it was converted into a modern arena-style theatre, and any pieces of decorative molding that were removed were put away in storage in case the building is ever restored to its original state. This means that the entire grid framework is suspended from the ceiling by four points in order to preserve the elaborate ceiling decorations. This four point system is flexible and strong. During the Nisqually earthquake in 2001 the entire grid swung from its anchor points, like a clapper in a bell, just as it was designed to and took no structural damage. I’m a little disappointed I wasn’t there to see it, but perhaps it’s just as well.
You can see one of the anchor points in the middle right of this picture attached to the diagonal supports. The other vertical posts in this photo are three of the four towers that I helped build for this show so that we could fly a group of lights in from the grid. They don’t actually touch the ceiling at all. I’ll write a bit more about that shortly. The Arena theatre by virtue of its nature as a 360º space is not a candidate for a traditional fly system. This does not obviate the desire of designers to fly things in from above and as a result calls for creative solutions.
The walking grid is a big square deck made of subway grating that sits at about 35 feet above zero level and approximately 12 feet above the lighting grid. Everything that flies in to the stage during a show in the Arena is hung from the walking grid. None of the mechanics that run the flies are permanent parts of the structure. This means that everything up in the grid has to either be hoisted on a rope through a fairly narrow window between the grid structure and the sound baffles at the south end of the stage or it gets carried by hand up the ships ladder.
The first time I walked out on the floor of the grid and looked down to stage level I was almost overcome by vertigo, but it quickly transformed to a giddy excitement and from then on I was hooked. I jump at any chance I have to work in the Arena walking grid and I consider myself lucky that I have the opportunity to since I am the junior carpenter on the crew and everything I know about stage rigging I learned from my patient and knowledgeable coworkers. Rigging is a skill that requires, among other things, patience and sticky fingers and when you’re working through the subway grating that makes up the floor it also helps to have small hands and wrists.
When I’m up in the grid I am all too aware that if anything slips from my grasp it will plummet to the stage floor below and possibly hurt someone. It’s important to move with purpose in the grid, not only to keep from dropping things, but also because more often than not the floor of the grid is strung with cables and other trip hazards. For instance in The Trip to Bountiful there are four set pieces that fly in from the grid; a ticket sign, a glass globe lamp, a window and stars. All of them are run by air-powered cable cylinders which are hooked into the building-wide compressed air system, and all of them have wire rope cables that run through sheaves bolted to the floor of the grid.
The valves are fired by a DMX relay box controlled by the light board. We use air rams to run our automated fly systems because they are almost entirely silent. Any noise in the system is either caused by friction in the cables or air being exhausted from the ram. Since our theatre is so intimate a lot of time and effort is spent making the systems run as silently as possible.
The stars are the most ambitious of the four flies in this show, the structure that moves the stars up and down is a truss that is almost the entire footprint of the walking grid.
The truss pieces were built in sections and then hoisted by rope and pulley up to the grid where they were assembled. Each corner has a wire rope pick point. The wire rope runs from the points up the four vertical towers through sheaves at the top of each tower and back down to a sheave at the bottom that routs the cable over to the air ram which runs the whole truss up and down. Each corner of the truss tracks on the sides of the tower using a pair of fixed rubber caster wheels.
With something this large there is often an expectation that when we first install it there will be a certain amount of tweaking and troubleshooting that has to happen before it runs smoothly. So when we ran the star lift for the first time and it worked perfectly it was almost as magical a moment as we hope it will be for the audience when the stars appear on stage.