Stage Rigging 101
Apr 3, 2010 12:00 PM, Lawrence Graham
Editor's note: This story was originally published in October 2002, but it has shown up so much on our "Popular Stories" list, and the information is so evergreen, that we decided to revive it. Got more stage rigging tips? Facebook or LinkedIn us.
Stage rigging and its impact on structural design always present interesting challenges for structural engineers. Going back as far as Leonardo da Vinci and the Court Masques of 15
Originally, stage rigging was installed and operated by sailors. Men who knew their ropes at sea and were used to working under hazardous conditions high in the air were an ideal choice for employment in theaters. For the most part, modern steel sheaves and wire cables have replaced wooden pulleys (called blocks) and sisal rope. Sandbags are passé, and steel counterweights, similar to those used in traction elevator systems, counterbalance heavy loads. In some instances, theater rigging is motorized, and other systems are computer operated. In spite of those modernizations, the basic principles that underlie the operation of stage-rigging systems have not changed. Operating those systems can still be hazardous.
USING STAGE RIGGING
Stage rigging has two basic uses — to support the stage-lighting system and to support and shift stage scenery. The stage-lighting system consists of a large number of individually dimmed outlets to which various kinds of performance-lighting fixtures can be connected. Large portions of the distribution system for this circuitry are integrated into the stage rigging.
Performance lighting is an art that paints the stage with colored light, so many kinds of portable fixtures are used to achieve particular effects. Multiple specialized fixtures weighing as much as 35 pounds each (or more for some robotic fixtures) are temporarily clamped to the pipe battens in the rigging system. Even modest productions could use 300 or more specialty fixtures, and 60 percent of those could be hung over the stage. The rigging raises and lowers the distribution strips, the multiconductor cables that feed power to them, and the fixtures themselves.
Stage curtains, painted backdrops, and heavier framed scenic pieces are examples of the kinds of scenery raised and lowered by the rigging. Stage scenery tells the audience where the action is taking place. When stage scenery is combined with stage lighting, the overall stage picture establishes the locale, mood, time of day, and weather.
Obviously, if the locale of the play changes, so does the scenery. Sometimes a play has no scene changes, so the action may be confined to just one locale. More often, however, the locale and scenery change frequently. That can involve moving several tons of scenery vertically, in a matter of a few seconds, in absolute silence and total darkness, while performers and stagehands move across the stage below it.
At first that may seem unnecessarily hazardous. But live performances, much like televisions shows and films, have a rhythm and pace that must not be interrupted if they are going to engage and entertain an audience. Of course, the scene shifts are rehearsed, just as the rest of the production is. Nevertheless, split-second timing is essential to avoid injury to personnel and damage to the expensive scenery.
The various kinds of loads imposed on the building structure by these kinds of stage operations cannot be predicted during the design phase. Yet the structure must support them, and the rigging must operate safely and reliably every time it is called upon to move. To understand how this can be achieved, one must first look at how a typical stage is put together.
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