2. For my first bridge I took a piece of paper and
folded the edges to the middle. Next I took
the sides and folded those straight up. Finally
I took the middle and folded it straight up. On
the ends I put the paper clips.
4. Suspension bridges used
to be made of twisted
grass but usual though
twisted grass does not
last long. Today only
one bridge made from
twisted grass is still
there. It is in Andes.
Measuring 90 ft or
27 meters
Golden gate bridge.
The golden gate bridge is built in San Fran
Cisco. It was built there because people
wanted a way across the water with out having
to take a ferry. The bridge was final built
and open for use on may 27 1937
Suspension Bridges suspend cables by towers that
support a majority of weight. Weight pushes down on
the suspension bridges deck then the compressions
travels up the cables or chains. It then goes into the 4
tower and is dissipated directly into the earth.
5. Arch bridges
The semicircular shape distributes weight onto two
componets of the bridge that directly take on all the
pressure. The curve of the arch thought allow it to
dispute the force outward greatly reduces the effects
of tension on the underside of the arch.
Mongomery Meigs
The bridge was completed in 1863 and was the
longest masonary arch in the world. It held for a
record 40 years. The main arch has a span of 220
feet. And is 57 ft above a creek. This bridge was
designed as a part of the Washington Aqudect.
Fun fact
These bridges are a popular choice
because they offer all the
advantages of a suspension bridge
just that they cost less,are
faster to build, require less
steel cables and incorporate more
precast concrete 5
6. Beam bridge
The beam bridge is very simple. To build a beam bridge you need
horizontal structure and two supports. One at each end.
Although the on the beam bridge the
bridge endures both tension and compress
ion. This is caused by adding weight it
causes the bridge to bend so
you need steel to handle the load.
Is the longest bridge in the world.
It on the Lake Pontchartain Causeway
in Louisiana. It
is aproximently 24
miles long and is supported
by more then 9,00 pilings.
This lake was built so that
travlers would not have to go
all the way around the lake.
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7. Cable stay bridges
The tower of cable-stay bridges are responsible for dealing
with compressional forces. The cables attached to the rodeway
in various ways. In a radial patter cables extend from several
points onto the road to a single point at a tower. Like a bunch
of fishing lines attached to one pole. In a parrel patter the
cables attach to both the radway and the towr at several
points.
The longest cable stay bridge is the Cooper River Bridge in
Charslton south Carolina. It open in the summer of 2005 and is
2.5 miles long and 186 ft above a river. It was built because
the town of River Creek needed to cross the Cooper River.
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8. I chosse an arch bridge. I chose this because it holds
up well and has a very pretty look to it. I used white
clay to make the platform and tooth picks as the
railings. Cups for the support forms and popsicle
sticks on the side to help keep its form. i could put all
the pennies and
staples on the bridge and it
did not budge.
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