Beam Bridge in Action!

Human beings first made bridges using wooden logs, planks and lashing together sticks, bamboo poles and tree branches. These were the first beam bridges, and they are everywhere!

List of Supplies:

• Sponge
• Permanent Marker
• Ruler
• Something to create a gap for the bridge

Draw lines 1/2" apart on the bridge, front and back.

Lay the sponge across a gap to create a bridge.

Now, press down on the middle of the sponge bridge, and see what happens.

These bridges are the simplest and the least expensive bridges to build. A beam bridge consists of a horizontal beam that is supported at the ends by land, columns or piers, just like the logs that sit across a stream.

On a beam bridge, the weight of the beam (bridge) and any additional weight (cars, people or whatever else) on the bridge is transferred to the supporting structure on the bottom.

When a load (weight) is placed on the beam bridge, the top of the bridge is pushed down by a compressive force and tensile force stretches the bottom of the bridge.

    

For heavy car and railroad traffic, the beam bridges are replaced by stronger truss bridges. 

For information and project ideas on truss bridges, please check out - 

Truss Bridge Information

Foam Truss Bridge Project

Straw Truss Bridge Project

Have a great day!