Awesome Arch Bridges!

We're learning about Arch Bridges today.

The easiest type of bridge to recognize is the arch bridge. 

List of Supplies:

• Card stock paper
• Ruler
• Pen/Pencil
• Chair, table, books, etc. to use as abutments

This is also one of the oldest type of bridges, and it has an extraordinary strength due to its shape.

Unlike a beam bridge, the load on an arch bridge is pushed outward.

The load is carried along the curves of the arch to the support structure at the ends of the bridge called abutments.

The abutments spread out the load from the bridge and keep the ends of the bridge from pushing out and collapsing.

Arch bridges carry all loads in compression. The stones in arch bridges stay together by the force of their weight and compressive force transferred between them. So, the arch bridges don't need much mortar to keep the stones in place.

The size of the arch directly affects the effectiveness of the arch, and most modern arch bridges span between 100 - 1,500 feet.