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Beam Bridge
Do you enjoy building structures with toy blocks? Most kids enjoy stacking toy blocks into creative shapes to build houses, toy cars and even bridges. Typically, when children build a toy bridge, they take two blocks and stand them straight up and down in a vertical position. Then, they place one horizontal block across the top of the two vertical blocks. This set of blocks is designed similar to a beam bridge. A beam bridge is a bridge that is made of two or more strong towers that support one or more horizontal beams, or long sturdy pieces of wood or metal.
Who Designs Beam Bridges?
Engineers are scientists who design beam bridges, among other structures. They must be very smart and talented in the areas of math and science to design and oversee the construction of beam bridges. Engineers have to think about a variety of factors when designing a beam bridge. Some questions they ask themselves include:

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  Will the beam bridge be short or long?
  
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  Will the beam bridge be designed for people to walk or bicycle across?
  
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  Will cars and enormous 18-wheel trucks travel over it?
  
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  Will it go over water?
  
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  What is the climate in the area where the beam bridge will be located?
  

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Truss Bridges
A truss bridge is one that is built when a bridge must span a very large distance. Truss bridges are built using lots and lots of very small beams, which can be made out of wood or metal. The beams are put together in triangular patterns, so the final bridge looks like a cool geometric design.
Bridges allow us to cross safely over rivers, lakes, and valleys. There are many different kinds of bridges, including arch bridges which are made with rounded archways, and drawbridges that can rise to allow boats to pass through. Truss bridges are made with beams placed in triangular patterns, and cable-stayed bridges connect flexible cables from the bridge to towers.