Arches can be used as doorways or can be left as an opening in the wall to decrease the amount of area exposed to wind, which is a dynamic force.
if the centre of gravity falls outside of the bases of support, the structure will become unstable.
The more live loads placed on a structure, the higher the compression force will be.
the centre of gravity must stay within the bases of support for the structure to remain stable.
If the person was just sitting in the chair, it would be a static live load, but if the person was bouncing up and down, it would be a dynamic load
If a structure is faced with to much commpression force, then the structure may buckle and become unstable.
To increase the stability of a structure, you can add an extra base of support.
triangles are used to increase stability.
Compression and tension often work together because when there is tension at the bottom of the structure, there will be compression at the top.
Using corrigation or lamination is a great way of keeping the dead load (and the price) low because instead of one large heavy piece you have multiple smaller pieces or empty space in the middle.
Trusses and gusstets also create triangles.
Structural Stregnth and Stability

Structural Stregnth and
Stability

STABILITY

Stable

A structure will remain stable if it has the
ability to remain on it's base when faced
with forces it is designed to withstand.

Unstable

a structure will be unstable if it's unable
to remain on it's base when faced
with elements that it is desgined
to withstand.

Centre of Gravity

The center of gravity is the place where
the mass of the object is concentrated.

Base of Support

the bases of support are every point of
contact that a structure makes with it's
supporting surface.

LOADS

Dynamic Loads

dynamic loads are caused by forces
other than gravity and can change
rapidly.

Static Loads

static loads are caused by the force
of gravity.

Live Loads

Live loads are caused by anything that is not permanantly attached tothe structure.

Dead Loads

Dead loads are caused by the force of
gravity on the structure itself. They do
not change.

EXTERNAL FORCES

Plane of Application

The plane of application is the angle at which the
force is being applied.

Point of Application

the point of application is the spot on the structure
that the force is being applied to.

Direction

the effect of the force on the structure is determined
by the direction of the force

Magnitude

the magnitude of a force measures how strong a
force is. every force has a magnitude.

Stregnthening Structures

Triangles

Using triangles is one very effective way
to stregthen structure, as they are the
strongest shape found in nature.

Truss

A truss is a frame that takes advantage
of the stregnth of structures. they do this
by putting many of them together.

There are 3 different types of trusses : a
pratt truss, a warren truss, and a howe
truss. pratt truss's use right angle triangles,
warren trusses use equilateral triangles, and
howe trusses are often used on the inside of
roofs.

this image depicts a howe truss.

Gusset

Gussets are made of solid materials and
used to reinfore a seam or a joint.

Gussets are also used to resit the forces
of tension, compression, and torsion.

you could insert these in corners to increase
stability.

Curves

Simalirly to triangles, curves are also often
used to stregnthen a structure.

Arches

Arches are built to form a very strong
support. They transmite the compression
force from each piece to the next. One
piece arches also exist.

Ties and Struts

Ties

Ties are used to resist the forces of tension.
they help to hold up the top side of a
structure.

Struts

struts are used to resist compression forces.
They help to support the underneath of a
structure.

Corruigation

Corrugation is a series of pleated arches
used to stregnthen material alike to
carboard. this is why cardboard is such
a great packing material.

Lamination

Lamination is the process in which multiple
thinner pieces of a material are bonded
together to create a piece that is more
lightweight or less expensive. The material
can also be made waterproof in the
process of lamination.

INTERNAL FORCES

Torsion

Torsion is createde by applying opposite rotational
forces to different parts of a structure. structures
that are under torsion twist.

There are two different types of torsion. It is created
when opposite rotational forces are applied to a
structure, but is is also created when a rotational force is
applyed to one end of an anchored project.

Shear

Shear is created when parallel forces acting in
opposite directions are at work on a part of a
structure.

There are also two different types of shear. Shear
is always created with parallel forces, 1 type pushing
toward each other, and the second type pushing in
opposite drections.

Compression

compression is the squeezing force that
occurs when large amounts of force are
applied to structures.

Tension

tension is the pulling or streching force that
is applied to a structure when large amounts
of force are introduced.