A structure that
is held up by a
series of frames
like a house
Solid structures
A Structure that
is held up by
itself and
supports its own
weight (mostly)
Shell structures
A structure that
is held up by an
outer shell and
is usually hollow
inside
What The Strength of a
Structure Depends on
Materials used in
making the structure matter.
Strong materials like iron would be
good for building a structure that has
to take a lot of weight and load. This
is because the material can hold more
load and withstand more forces acting
on it. This means the structure will not
fail as easily.
Weak materials such as wood and
glass break easily, and may look
pleasing but will not hold up and
will undergo structural stress and then failure.
Shapes used
to make the
strutures
Triangles are the
strongest because they
form a fixed rigid shape
and because the angles at
their corners can not
change unless you
change the length of the
sides.
Circles are generally thought of as the weakest
shape to put into a structure. This is only true
sometimes. Sometimes they are good though. For
example, an airplane's windows crack and shatter if
they are square. This is because of the 90° angle in
the squares. The pressure from the air outside
causes structural failure. They are not the best
choice because they have to corners. This is a bad
thing because there are no easy points to put a
support beam for example.
Squares are not the best
choice because of the 90°
angle on each corner. A 90°
angle is quite easily snapped
or broken.
Form is the shape
that a structure takes,
and is highly
dependent on the
materials used in the
making of the item
(ie.) a bridge
Forces
A force is
something that
executes pressure
on a structure by
pushing or pulling it.
External forces
Winds and earthquakes
Wind usually bends or
something or causes
torsion. For example,
this picture to the left.
Earthquakes are a force
that cause compression
to an object. For example,
the picture to the left.
Gravity & loads
The imaganary line
representing the force of
gravity, should pass through
the base of the structure.
Symmetry follows the
rule of the center of
gravity
Structures are often made symmetrical to
make them aesthetically pleasing and used to
distribute the weight evenly in order to make
the structure more stable.
If the center of gravity is too
high, the structure is less
stable. Like the Leaning
Tower of Pissa
If the line of gravity is
outside the base, the
structure will be
unstable.
Load puts pressure on the
structure and if the structure is
not built properly, may cause it
to fail.
Internal forces
Tension
Torsion
Shear
Compression
The effect of force
depends upon its amount,
direction in which it acts on
that structure and the point
that it is applied.