Rigging I - Simply Circus Community

clanmurderUrban and Civil

Nov 15, 2013 (3 years and 11 months ago)

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Simply Circus

14 Pierrepont Rd (617) 527
-
0667

Newton, MA 02462 Info@SimplyCircus.com

www.SimplyCircus.com


Rigging I:

Transferring forces all the
way down to the ground

Presentation by Steven Santos

Key points for this presentation


What forces do we need to be aware of?


Static Load


Shock Load


Swinging Load


Spinning Load


Rated Strength, SWL, MBS, LBS, KN, SLUG, etc


Overview of tracking forces


Week Link Analysis


Risk Assessments for Rigging


Commonly Used Mount Points


Questions!


What forces do we

need to be aware of?

In

the

world

of

aerial

rigging,

we

need

to

be

aware

of

all

of

the

forces

we

could

possibly

put

on

the

rigging
.

This

includes

the

static

load,

and

the

shock

load



We

also

need

to

be

aware

of

the

directions

of

those

forces
.

A

static

load

places

forces

on

the

mount

point

differently

than

does

a

swinging

load,

and

both

are

different

from

a

spinning

load
.

What forces do we need to be aware of?

When it comes to aerial rigging, we are
generally concerned with four classes of force:


Static Load


Shock Load


Swinging Load


Spinning Load


Static Load


A Static Load is a load that does not change.



Examples of static loads include


Lyra


Static Trapeze


Aerial Silks (except drops)

Shock Load


A Shock Load is the resulting load from the
rapid change of movement, such as impacting or
jerking, of a static load. A Shock Load is
generally significantly greater than the static
load.


Examples of Shock loads include


Drops


Swinging Load


A

Swinging

Load

is

a

load

that

is

in

motion

horizontally
.

By

definition,

Swinging

Loads

cause

side

loading

of

the

mount

point
.

In

a

straight

swing,

the

highest

loads

are

at

4
:
30

and

7
:
30



Examples of swinging loads include:


Swinging Trapeze


Flying Trapeze


Some Aerial Silks


Swinging Lyra

Spinning Load


A Spinning Load is a load that is in constant
rotation. By definition, Spinning Loads cause
side loading of the mount point in all directions.



Examples of swinging loads include


Cordless Lisse


Spanish Web


Some Silks Skills

Strength Terms


Rated Strength is the strength the manufacturer has
determined the equipment should take.



SWL

=

Safe

Working

Load
.

SWL

is

one

way

that

manufacturers

rate

strength
.

SWL*safety

factor=MBS



Safety

Factor

is

a

number

that

the

tensile

strength

is

divided

by

in

order

to

determine

the

safe

working

load




MBS = Mean Breaking Strength. MBS is the average
breaking strength the equipment is tested to.

Weights and Forces

One

of

the

difficulties

with

rigging

circus

apparatus

is

that

we

end

up

using

rigging

components

from

many

different

industries,

almost

none

actually

designed

for

how

we

use

them
.

Some

equipment

uses

the

S
.
I
.

system,

where

weight

is

expressed

in

kilograms

(a

mass),

newtons

(a

force)

and

kilonewtons

(a

force

with

mass)
.

Other

use

the

English

system,

where

weight

is

expressed

in

pounds

(a

force

with

mass)
.



When

dealing

with

rigging

components,

it

is

often

helpful

to

convert

everything

to

use

one

numbering

system

or

the

other
.

Overview of Tracking Forces

When

ever

we

set

up

rigging,

we

want

to

start

by

checking

over

the

mount

point,

and

follow

the

forces

all

the

way

down

to

the

ground
.


DO NOT ASSUME ANYTHING



Is the horizontal beam strong enough for what we
want to do?


Are the vertical beams strong enough for what we
want to do?


Is the connection between the vertical and
horizontal beams strong enough for what we want
to do?


How does our mount point deal with horizontal
forces? Is it strong enough for what we want to
do?


If it is not strong enough, how do we make it
strong enough?

Weak Link Analysis (WLA)

WLA

is

the

process

of

systematically

examining

each

and

every

component

of

a

rigging

setup

to

find

the

weakest

link
.



Once

identified,

rigging

is

designed

and

built

with

the

weakest

link

in

mind,

and

with

the

desired

safety

factor
.


Risk Assessments for Rigging

A Risk
Assessment
for Rigging
is done
much like
any other
Risk
Assessment.

Striar JCC Points 1


5 Risk
Assessment / WLA


Silks Risk Assessment / WLA

Likelihood / Severity

0 Extremely Unlikely

1 Unlikely

2 Possible

3 Likely

4 Very Likely

0 Ext. Insignificant

1 Insignificant

2 Minor

3 Moderate

4 Major

Commonly Used Mount Points


Roof Trusses


Snow Load


Freestanding Rigging Frames


Floor Trusses


Excess Capacity


Questions

Silks Rigging

Lyra

(Single Tab, Single Point)

Lyra Rigging

(Two Tabs, Single Point)