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Spotlight
Radio programs in 'Specialized English'

Script Title:  Building Bridges

(Program number: 662)

Different Bridges | Forces | Connecting People

Thank you for listening to Spotlight.  I’m Sara DeKoster.

And I’m Rebekah Schipper.  Spotlight uses a special English method of broadcasting.  It is easier for people to understand, no matter where in the world they live.

Today’s Spotlight is on Bridges!

The Ashaki-Kiakyo Bridge.  This bridge connects the city of Kobe on the mainland of Japan with Awaji on Awaji Island. It was completed in nineteen ninety-eight.  The Ashaki-Kiakyo is the longest bridge of its kind in the world - almost four thousand metres long!  It can withstand winds of up to eighty metres per second.  And it can resist earthquakes measuring over eight points on the Richter scale.

The Sydney Harbor Bridge.  This bridge has become one of Australia’s most well known international symbols.  It is the largest steel arch bridge in the world.  Its surface area is about the size of sixty football fields.  It has huge hinges that combat the pressure of the bridge when the hot sun expands it.

Le Ponte De Normandie.  The French built this bridge to connect the cities of Honfleur and Le Havre.  When it was completed in nineteen ninety-five, it broke the record for the longest cable stayed bridge in the world.  Thousands of small white cables hold this bridge up one hundred sixty five feet above the water.  It is one of the most interesting bridges to look at because of its form and design.

The Brooklyn Bridge.  This beautiful old bridge in downtown New York City was completed in eighteen eighty-three, well over one hundred years ago.  It is held up by four large cables.  Each cable can carry twelve thousand tons!  People say that walking over this bridge makes you feel one with the city of New York.

The earth’s surface is over seventy percent water!  So it is no surprise that some of the most important landmarks in the world are bridges!

There are three kinds of bridge structures.  Most bridges these days are made by people.  But these three kinds of bridges were all found first in nature.

The first is called a beam bridge.  A beam bridge is the most simple bridge structure.  A straight piece of wood or metal connects two points.  Nothing supports the middle of the beam from the bottom or top.  It just lies across the space supported by the land on either side.  A tree fallen across a stream of water forms a natural beam bridge.

The second kind of bridge is called an arch bridge.  An arch bridge has supports in the shape of a half circle.  The Roman Aqueducts are an example of an arch bridge.  These bridges are found in nature in rock formations.  An arch bridge is a very strong bridge structure.

The third kind of bridge is a suspension bridge.  A suspension bridge is supported by cables that hold it in place.  With strong cables, a suspension bridge can be very long.  Vines hanging from trees can form a suspension bridge in nature.

Building a bridge is not an easy job.  Many different forces act on a bridge.  Tension is the force that stretches or pulls apart.  Compression is the opposite force.  It squeezes or pushes together.  A shear force is a sliding force.  And torsion is a force that twists or turns.  Maybe you remember a time when you were on a bridge and you felt it move.  These different forces are always trying to move the bridge.  But a good bridge will be able to stand strong.

These forces are all created by the different kinds of loads that bridges carry.

Bridges are designed to carry three kinds of loads.  The first is the dead load.  Dead load is the weight of the bridge itself.  A bridge must be able to support its own weight before it can support any other weight.

Bridges are also designed to carry live load.  Live load is the people, cars, trains or any other moving objects that will cross the bridge.  A bridge for people to walk across has a lot less weight to carry than a railway bridge.

The third kind of load a bridge has to carry is environmental load.  Environmental load involves all of the natural forces that act on a bridge.  A bridge must be able to resist strong winds and other weather.  And many bridges are built in places that have earthquakes.  A bridge must be very strong to resist an earthquake.

Bridges are very useful.  Think of how difficult travel would be without them!  A lot of science and technology goes into making a strong bridge.  But bridges can also be very beautiful.  Bridge building is a mix of science and art.  A beautiful bridge can stay in your memory forever.  I still remember the first time I crossed the Golden Gate Bridge in San Francisco, California, USA.  It was much larger than I imagined it.  The tallest points stood up higher than the clouds of hazy fog.  And the red iron cables looked beautiful against the dark blue water.

Bridges play a very important part in our lives.  Bridges connect pieces of land.  But they also connect people.  They make it easier for us to travel.  And because of that, they make it easier for people to communicate with each other.  People have been able to share food products, natural resources, manmade goods and many other material things easier because of bridges.  But they have also been able to share themselves by visiting with others.

Being able to communicate is an important thing.  Often, we use the idea of bridge building when we talk about understanding other people.  We can build bridges between different cultures, religions and people groups.  Building bridges helps us get to know each other better.  It can help us to build good relationships with people.  It can even help to bring peace between nations.

The next time you cross a bridge, think about all the work that went into building it.  And think about how you can build your own bridges in life by reaching out to communicate with other people.  The hard work will be worth it!

This program was written by Sara DeKoster.  The voices you heard were from the United States.  Computer users can hear these programs, read our scripts and see our wordbook on our website at www.radio.english.net.  This program is called Building Bridges.

We love to hear comments and questions from our listeners.  You can write to us care of this station.  Or, our email address is radio@english.net   We hope you can join us again next time for Spotlight.  Good-Bye!!

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