Theatre Design & Technology - Winter 1980 - 14

TENSION FAILURE

COMPRESSION FAILURE

COMPRESSION SURFACE
NEUTRAL ZONE
TENSION SURFACE

Figure 2: In beams, compression affects the top surfaces, while tension
acts on the bottom. Increasing the separation between the top and bottom
surfaces can upgrade the loading capability of the beam.

Core 1 '12"·99(18)

'I."

8
Core 1 !h"·99(18)

7
6

~"

I

/

L/369~max

I

3

I
I
~

/

COMPlETED SANDWICH STRUCTURE

/
/

sign is also manufactured in other materials such as paper,
and serves even as freeway signs.
The material is low cost. The capital outlay for the honeycomb core material is much less than the materials it might replace. Fabrication time becomes insignificant once the
method is mastered. Moreover, the material allows expanded
design flexibility since it renders the possibility of two-faced
structures which can be not only very thin but also very lightweight. Honeycomb allows platforms to have a load-carrying
capacity far in excess of standard framed platforms.
One of the greatest benefits of honeycomb-lamination is
the density of the final platform which yields an acoustic advantage. Whereas conventionally-framed platforms will have a
high reverberation from percussive footsteps, honeycomb
laminations have such a frequency of support to the adjoining
surfaces that there is no opportunity for reverberation to occur. Walking across a honeycomb-laminated platform is like
walking across a rock: the surface is extremely dead.
Using this new material at the University of CaliforniaSanta Cruz for several productions, we have discovered that
the honeycomb paper lamination is the most singularly flexible
structural concept we have yet discovered. Not only will it
make conventional·straight platforms, but with proper facings
it makes extremely long and strong spans with incredible load
characteristics. The platforms 'can also be shaped into cantilevers, curvatures, and even free-fo'rm shapes.
Honeycomb structure achieves its viability because any
beam has a compression surface (top) and a tension surface
(bottom) (Fig. 2). In honeycomb lamination, the full sheeting of
the top acts as the tension surface. Instead of spreading the
load in only two dimensions, as is useful in a beam, the load is
spread in all directions around the load point. As long as the
spacing between the two surfaces is static and the sheeting
remains intact to longitudinal pressures, the structure will not
fail.
The actual stresses in tne core are slight. Considering an 1beam, the webbing of the beam acts to hold the compression
surface and tension surface at static separation. Those surfaces (flanges) are heaviest because that is where the great-

'12" Plywood
(Deflection controls)

/

2

Figure 1

Core 1"·99 (18)

/

0

fllce sheets, core, adhesIve.

I

I

a: 4

0

(Deflection controls)

I

Gypsum faces

UJ

Three elements make up * honeycomb sandwich panel:

'I." Plywood

/

(Facing stress controls)

5

U

core 1"·99 (18)

Plywood

(Core strength controls)

/

~

~

Stress 2.5

(live)

/

8
96

12
144
SPAN

(dead)

20PSF

Total load

/

4
48

deflection

Factor of safety on face and core.

16
192

+ 2PSF

20
240

Feet
Inches

Figure 3: Surfacing materials can determine the strength of the lamination's structural system. Plywood's are well detailed, while masonite is less
predictable. as the documentation is not readily available.

est stresses occur. There is little stress in the webbing and it
can therefore be correspondingly light. Honeycomb maintains
separation between the sheet flanges while its stresses as
webbing are actually slight.
The most important stress to be aware of is loading that
might compress the cells; this force is called shear. The cells
must not crush, but must maintain equidistant separation between the compression tension surfaces of the lamination. In
one show in which this was a problem, stress was minimized
by partially filling the lamination with urethane foam via a froth
pack.
Surface sheeting can be wood, metal, plastic, or any material suitable for scenic application. Plywood is readily available, easily attached, and has strong, long fibers. Figure 3 indicates comparative strengths for plywoods used as surfacing
material. Use equal plywood thicknesses on both top and bottom to prevent voluntary twisting.
Core honeycomb may be purchased with a variety of structural specifications. Cell size is available in different diameters
and depths. The smaller cells, naturally, will involve more cell
walls within any given area of laminated platform, and the result will be a platform that can withstand greater point load or
greater shear. The depth of the cell is also adjustable. The
material is readily available in cell depths up to six inches and
can be ordered with deeper cells, although six-inch thicknesses can also be laminated together. The cells can be made
from different weight Kraft papers and the paper can also be
impregnated. At UC Santa Cruz we used non-impregnated
honeycomb, which is called "nonstructural." Structural-grade
honeycomb is impregnated paper and the cells are considerably stiffer, having a high resin content. The resin content is
specifiable (Fig. 4).
Engineering data needs interpretation to be theatrically
useful. Obviously, thicker sheeting on both surfaces increases
load characteristics, as does the specific choice of materials



Table of Contents for the Digital Edition of Theatre Design & Technology - Winter 1980

Contents
Theatre Design & Technology - Winter 1980 - 1
Theatre Design & Technology - Winter 1980 - 2
Theatre Design & Technology - Winter 1980 - 3
Theatre Design & Technology - Winter 1980 - Contents
Theatre Design & Technology - Winter 1980 - 5
Theatre Design & Technology - Winter 1980 - 6
Theatre Design & Technology - Winter 1980 - 7
Theatre Design & Technology - Winter 1980 - 8
Theatre Design & Technology - Winter 1980 - 9
Theatre Design & Technology - Winter 1980 - 10
Theatre Design & Technology - Winter 1980 - 11
Theatre Design & Technology - Winter 1980 - 12
Theatre Design & Technology - Winter 1980 - 13
Theatre Design & Technology - Winter 1980 - 14
Theatre Design & Technology - Winter 1980 - 15
Theatre Design & Technology - Winter 1980 - 16
Theatre Design & Technology - Winter 1980 - 17
Theatre Design & Technology - Winter 1980 - 18
Theatre Design & Technology - Winter 1980 - 19
Theatre Design & Technology - Winter 1980 - 20
Theatre Design & Technology - Winter 1980 - 21
Theatre Design & Technology - Winter 1980 - 22
Theatre Design & Technology - Winter 1980 - 23
Theatre Design & Technology - Winter 1980 - 24
Theatre Design & Technology - Winter 1980 - 25
Theatre Design & Technology - Winter 1980 - 26
Theatre Design & Technology - Winter 1980 - 27
Theatre Design & Technology - Winter 1980 - 28
Theatre Design & Technology - Winter 1980 - 29
Theatre Design & Technology - Winter 1980 - 30
Theatre Design & Technology - Winter 1980 - 31
Theatre Design & Technology - Winter 1980 - 32
Theatre Design & Technology - Winter 1980 - 33
Theatre Design & Technology - Winter 1980 - 34
Theatre Design & Technology - Winter 1980 - 35
Theatre Design & Technology - Winter 1980 - 36
Theatre Design & Technology - Winter 1980 - 37
Theatre Design & Technology - Winter 1980 - 38
Theatre Design & Technology - Winter 1980 - 39
Theatre Design & Technology - Winter 1980 - 40
Theatre Design & Technology - Winter 1980 - 41
Theatre Design & Technology - Winter 1980 - 42
Theatre Design & Technology - Winter 1980 - 43
Theatre Design & Technology - Winter 1980 - 44
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http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1967Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1967May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1967Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1966Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1966Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1966May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1966Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1965Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1965Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1965May
http://www.nxtbookMEDIA.com