Arch Bridges

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A Little History 


Arch bridges are one of the oldest types of bridges. They were originally made of stone or bricks. Currently they are made of concrete or steel, but many argue that stone or bricks is the most structuraly sound way of making this form of bridge because of the way compression makes the bridge more sturdy. Possibly the oldest existing arch bridge is the Mycenaean Arkadiko bridge in Greece from around 1300 BC. The stone corbel arch bridge is still used by the local populace. Although true arches were already known by the Etruscans and ancient Greeks, the Romans were, the first to fully realize the potential of arches for bridge construction. Thus, many different things were created from arches, such as the wall of arches in the picture below.

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Structural Analysis


The Arch Bridge is always under compression. These bridges have very little tension, mostly compression, unlike most bridges. Compression is precisely what makes the bridge work. The more compression, the tighter the stone and the more sturdy it is. The force of the compression is spread about the curve of the arch, pushing them closer together, and the supports at each end. The supports are called abutments (a structure for absorbing tensions from reinforcing strands for concrete being prestressed). The abutments keep the weight and keeps the bridge from breaking. The tension in an arch is negligible. The original curve of the arch and its ability to spread the force outward majorly reduces the effects of tension the underside of the arch.
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To watch an informational and interesting video about arch bridges click here: http://www.teachersdomain.org/asset/phy03_vid_bbarch/
This video will tell you about how Arch Bridges work and how they are designed and made

In the search box below, type in 'Bridge Thing' and try and create an arch bridge for yourself. It is alot harder than it looks.

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