BRIDGES

BEAM, ARCH, SUSPENSION, AND CLAPPER. WHAT IS THE DIFFERENCE?

BASIC STRUCTURE

The basic principle of arch bridge is its curved design, which doesn’t push load forces straight down, but instead they are conveyed along the curve of each arc to the supports on each end. Supports (called abutments) carry the load of entire bridge and are responsible for holding the arch in the precise position. Conveying of forces across the arch is done via central keystone on the top of the arch. Its weight pushes the surrounding rocks down and outward, making the entire structure very rigid and strong.


Beam bridges are supported by abutments or piers on each end. The beam bridge is one of the simplest types of bridges there are, which makes the structure of the bridge.


A suspension bridge is a bridge that suspends a roadway using huge cables connected to towers secured by anchorages (ANCHORAGES MEANING: The action of securing something to a base or the state of being secured).


The basic structure of a clapper bridge is large slabs of rock laid across stone pillars.

WHEN AND WHERE?

Possibly the oldest arch bridge existing is the Mycenaean Arkadiko Bridge in Greece from about 1300bc. It was built to join the highway between Tiryns, Mycenae, and Epidaurus cities of ancient Greece.


In 1847, Virginia was when the first suspension bridge was made and used.

FAMOUS EXAMPLE

The Anji Bridge was built in Zhaoxian, Shijiazhuang, Hebei, China. The arch bridge was chosen for that specific place because they needed a type of bridge to cross a river easily, the arch bridge was the most suitable type of bridge they could have used at that time.


The Bonghai Bridge (A.K.A The East Sea Grand Bridge) is the longest sea crossing bridge and it is used as a connection between mainland China and Yangshan, off-shore deep water port.


The Alcantara Bridge was built over the Tagus River, so you could walk over the river with no danger of stepping on a rock or any other object hidden in the water.

MATERIALS

The materials an arch bridge is typically made of iron, timber, or concrete. They can be made all different types of materials but these are the most common materials used.

Beam bridges are usually made of steel or iron.

They were originally made of rope and wood, but are now made with high tensile strength cables.

Made of large flat slabs of granite or schist.

LIMITATIONS

Arch bridges have to be very rigid, need to be a certain distance above the water to allow water traffic (e.g. Boats) to travel safely under the bridge, they have to have a high resistance to bending forces. The main limitation to most arch bridges is the cost of construction.

Beam bridges are very simple to make but they aren’t that reliable. For a good beam bridge you need to have strong soil at either end of the water for the bridge to stay up. It has limited span sizes because of the bending

forces.


Suspension bridges require large machinery and a high level of experience. Suspension bridges cannot be built in Cambodia; they do not have either an experience of building them or they large machinery to build.

THE DIFFERENCES

Bridges may seem the same and you might think they are but really they are very different. They are different in lots of obvious ways (e.g. the name, shape, etc.) and some not so obvious ways (e.g. how the bridge distributes the load of weight, how you make them, etc.). You might not even know that there is different names for bridges (the type of bridge) until you actually look and research the types of bridges.


There are some popular bridge types that most people have heard of or know, but there also some that people don't usually hear or know about. You cant say there isn't a lot of bridge types because it is a true fact that there are quite a lot of bridge types.