2. Introduction
Structural Principles
Leaning barn.
Some forms are
inherently weak:
• Squares
• Rectangles
• Rectangular solids
Other forms achieve
stability quite naturally:
• Triangles
• Pyramids
• Arches
• Cylinders
• Domes
• Spheres
3. Introduction
Structural Principles
Types of structures.
• Post and lintel – A horizontal beam (lintel) is supported by columns (two posts.)
• Arch - An arched bridge can span approximately four times the distance and support
more weight than a flat beam bridge.
• Truss - An extremely sturdy structure is created when triangles are repeated to form
an extended configuration.
Shigeru Ban. Paper Bridge. Remoulin, France. 2007.
4. Structural Economy
Efficient Form
There is not a particle to spare in natural structures.
— Ralph Waldo Emerson
Extremely tall towers use efficient vertical trusses and guy wires to
connect them to the ground.
Radio transmission tower near Houma, Louisiana.
5. Geodesic domes rely on a web of triangles, spreading the load evenly and efficiently
throughout the entire structure.
Buckminster Fuller. Biosphere of Environment Canada. 1967. Montreal, Quebec, Canada.
Structural
Economy
Efficient Form
6. Tension is the force that stretches.
Pulling each end of a rubber band places it
under tension — tension acts to expand.
Compression is the application of pressure.
If you stand on a stack of books, squeezing
it downward, it is being compressed.
Can you recognize which kind of force is
acting on each of the elements in this
sculpture?
Tension and Compression
Physical Forces
Santiago Calatrava. Bou. 2007. Palma, Spain.
7. Tension and
Compression
Physical Forces
Spider webs are only under tension.
They work because the silk has high
tensile strength – the ability to be
stretched without failing
Stone, concrete, and wood have low
tensile strength.
Spider web.
8. Tension and
Compression
Physical Forces
In suspension bridges,
such as the Brooklyn
Bridge, the steel cables
are under tension, and
the stone towers are
under compression.
In this way, all
suspension bridges
find their equilibrium.
Brooklyn Bridge. John A. Roebling, designing
engineer. New York, NY.
9. Joinery
Structural Connection
Joinery refers to how parts of a form are held together, how elements are attached.
One of the challenges of the designer or artist is to find the appropriate method for the
task at hand.
• Nails, screws, staples, bolts
• Rivets
• Clamps
• Binding
• Tape
• Adhesives
• Welding
• Soldering, brazing
• Heat-sealing
• Mechanical splicing
Ben Franklin Bridge. Philadelphia, PA.
10. Joinery
Structural Connection
Woodworkers utilize many kinds of joints: miter, spline, dovetail, tongue and groove,
and dado are just a small selection. Some joints require glue or epoxy, and some can
do without.
Richard Deacon. Kiss and Tell. 1989. Epoxy, plywood, steel, timber,
5' 9 1⁄3” x 7' 5” x 8' 10 1⁄3". Collection, Arts Council of Great Britain, London.
Woodworker fitting dovetail joint.
11. Transformers
Collapsible and Expandable Structure
Form is not simply a static mass; it can be
collapsible, expandable, inflatable, and foldable.
These transformations are usually a result of
function or efficiency, as illustrated by the decoy
that can be disassembled for easy carrying.
Blue Heron decoy. Assembled, right. A rendering of the decoy unassembled, left.
12. Transformers
Collapsible and Expandable
Structure
The toy pictured is not simply an
amusement, but the sphere employs
ingenious folding mechanisms that have
led the designer to major projects
involving rapidly deployable tents and
adaptive buildings with roofs that open
and close and facades that retract.
Portable dwellings such as tents, igloos
and huts, are a necessity for nomadic
people or traveling events.
Raumlaborberlin, Art and architecture collective. Portavilion 2010:
Rosy (the ballerina).
Hoberman Sphere. Toy. Expanded and contracted views. Chuck
Hoberman, designer. Plastic, 9"–30".
