The document discusses different types of bridges throughout history. It begins by explaining how arch bridges, one of the oldest designs, use curved structures for support and were originally built from stone. Beam bridges are also very common as they are inexpensive and strong over short distances, though not as aesthetically pleasing. Cantilever bridges extend beams out over the water and can support more weight than beam bridges. Cable-stayed bridges are similar to suspension bridges but are cheaper to construct and are aesthetically pleasing and modern designs.

1. BRIDGING THE GAPLisa-Jayne Heading
For this practical we will be researching,
building and testing a range of designs of
bridges. Bridges are a very important in
modern society; we use them to go over
rivers, valleys and get anywhere with more
convenience. Bridges have been around
since the simplest of bridges like a fallen
log over a creek. It was only when the
romans started building bridges from
stone is when they became a part of
civilized society.
The Arch Bridge
Arch bridges are one of the oldest types of bridges,
have been around for thousands of years and have
great natural strength. An arch bridge uses a
curved, semi-circular structure for support. They
are are one of the most stable bridges and one of
the most used because they’re very attractive and
grand however, the construction of an arch bridge
can be fairly difficult since the structure is
completely unstable until the two spans meet in
the middle. They were originally built of stone or
brick,as seen in the picture below of the ‘Pond De
Gard’, but these days are built for reinforced
concrete or steel and due to the introduction of these new materials arch
bridges could be built over longer
distances.
Brooklyn Bridge
Pond De Gard (south of
France)
Example of a stone Arch
Bridge built by the romans
over two thousand years ago

2. The Beam Bridge
The beam bridge is one of the most commonly used bridges along with
arch bridges and is most effective over short
distances. They are very common due to the fact
they’re cheap and easy to build and they are very
strong over short distances as opposed to other
types. However the drawbacks of this type of
bridge are that they’re weak over long distances
and are not as pleasing the eye as some other
bridges such as Arch or Suspension.Beam
bridges can be made out of basically any
material.
The Cantilever Bridge
The Cantilever bridge is basically a variation of a beam bridge. The
roadway of the bridge is held in place by cantilevers, which are longpieces
going out into the water, but which are only anchored at one end. The
positives of a Cantilever Bridge is
that its able to carry large amounts
of weight and the span can be
greater thanthat of a simple beam,
because a beam can be added to the
cantilever arms.However the
construction of this bridge can be
challenging and expensive.
The Cable-Stayed Bridge
The cable-stayed bridge is a type of suspension bridge using its cables to keep it
up. Even this bridge is very similar to the suspension bridge its a lot cheaper. Along
with this there are a lot of other positives including the fact this bridge is
aesthetically pleasing and very modern looking, strong temperatures don’t affect
the cables in any way and the bridge has a low center of gravity which makes it less
venerable to earthquakes. There are negatives though, which includes the constant
maintenance needs of the cables and the bridge is easily affected by the wind.
A basic beam bridge
Longest Cantilever Bridge in the world
in Quebec