Entertainment Rigging for the 21st Century

Compilation of Work on Rigging Practices, Safety, and Related Topics

Bill Sapsis, Bill Sapsis

• Publisher: Routledge
• Year: 2014
• ISBN:
  9781134462728
• Edition: 1
• Topic: Mezzi di comunicazione e arti performative
• Subtopic: Teatro

From the basics of physical forces and mathematical formulas to performer flying and stage automation, Entertainment Rigging for the 21st Century provides you with insider information into rigging systems and the skills you need to safely operate them. Over the past decade, the entertainment industry has witnessed major changes in rigging technology, as manually operated rigging has given way to motorized systems in both permanent and touring productions, and greater attention has been paid to standardizing safety practices. This book leads you through what is currently happening in the industry, why it's happening, and how. Accessible for riggers and non-riggers alike, it contains details on the technology and methodology used to achieve the startling effects found in concerts and stage shows.

With a foreword written by Monona Rossol, this text contains contributions from industry leaders including:

• Rocky Paulson

• 
  
  

• Bill Gorlin

• 
  
  

• Tray Allen

• 
  
  

• Roy Bickel

• 
  
  

• Keith Bohn

• 
  
  

• Karen Butler

• 
  
  

• Stuart Cox

• 
  
  

• Bill Sapsis

• 
  
  

• Dan Culhane

• 
  
  

• Eddie Raymond

• 
  
  

• Chris Higgs

• 
  
  

• Carla Richters

• 
  
  

• Joe McGeough

• 
  
  

• Scott Fisher

• 
  
  

1

Forces and Formulas

ROCKY PAULSON

Introduction

Most riggers choose their profession because they enjoy working at height, the challenges and responsibilities of the job, and having a job that keeps them in shape. When we head down the road to becoming a rigger, most of us never dream that we would need to hone our math skills along with our climbing and knot-tying skills. However, the most important part of a rigger’s job is to make sure that the rigging system, the attachment points, and the support structure as a whole are able to support the forces imposed by the rigging load. In order to know whether or not the rigging system and attachment points (anchorages) can support the loads, the rigger must know the strengths of the support elements and how the rigging load distributes the forces produced by it to these elements. This chapter will give the reader the techniques to do much of the force-estimating required to prevent overloading in the rigging system or anchorages.

Much of the estimating we do requires the use of math formulas. To keep the formulas concise, we abbreviate the forces and distances by creating symbols. The symbol system used in this chapter conforms to a system developed over a few years by several teachers and was first published in 2009. Since all of our formulas use forces and distances, the system uses F to indicate a force and D to indicate a distance. S will be used to indicate span, the distance between support points or anchorages. When there are multiple forces or distances within a formula, which happens in most cases, subscripts are added to the symbol. The subscript will consist of a number or a letter, and in some cases a number followed by a letter. The letters are used to indicate the direction of the force or distance as well as being a designator for the force being analyzed. Table 1.1 below shows many of the symbols and their definitions.

By reviewing the symbols in the table, the reader will become familiar with the meaning of the symbols including the use of the subscripts.

In addition to creating symbols for use in the formulas, it is useful to have symbols to denote the points of analysis in the rigging system. The end points of the span being analyzed or, in the case of bridles, the anchor points of the bridle legs will be labeled A₁, A₂ or A₃ as required. For the point of attachment of the applied force, the symbol P will be used (see Table 1.2).

TABLE 1.1 Common symbols used in formulas

FA	The force applied to the rigging system
F1	The force at the near support or anchorage
F2	The force at the far support or anchorage
D1	The distance from applied force to the near support
D2	The distance from applied force to the far support
S	The distance between supports
FH	The horizontal force
FL	The force in line with an angled leg
FV	The vertical force
DH	The horizontal distance from the anchorage to the applied force
DL	The length of the angled leg
DV	The vertical distance from the anchorage to the applied force
F1H	The horizontal force associated with leg 1 of a bridle
F1L	The force in leg 1 of a bridle
F1V	The vertical force associated with leg 1 of a bridle
D1H	The horizontal distance from the leg 1 anchorage to the bridle point
D1L	The leg length of leg 1 of a bridle
D1V	The vertical distance from the leg 1 anchorage to the bridle point
F2H	The hor...