BRIDGES UNIT

TYPES OF BRIDGES

Draw this chart in your Bridges Packet

Beam bridges are the oldest and simplest bridge design consisting of vertical piers and horizontal beams. - e.g. just a simple plank or stone slab. They are suitable only for short spans but can used for larger crossings by adding additional piers.

 Strengths: simple to build and not expensiveWeaknesses: become weak when longer

BEAM BRIDGES

Arch bridges were built by the Romans and have been in use ever since. They are often chosen for their strength and appearance. The forces created by the load are transferred down through the arch into the ground.

Strengths: they are very strong and can be built from many materialsWeaknesses: cannot be very long

ARCH BRIDGES

Suspension bridges are made by a pair of main suspension cables stretching over two towers. They are attached at each end to an anchor buried deep in the ground. Smaller vertical suspender cables are attached to the main cables to support the deck below.

Strengths: strong and can span long distancesWeaknesses: expensive and complex to build

SUSPENSION BRIDGES

Cable Stay Bridges also have towers supporting cables that are attached to be main deck of the bridge. The cables carry the load of the bridge to the towers and down to the ground.

Strengths:  good for medium distances and are more stiff than the suspension bridge

Weaknesses: more expensive

CABLE STAY BRIDGES

Truss Bridges are structures built up mainly on triangles because of their rigidity. They are very strong and can support heavy loads.

Strengths: They are very strong and use materials wiselyWeaknesses: More difficult to build

TRUSS BRIDGES

FAMOUS BRIDGESSydney Harbor Bridge is one of Australia’s most well known and photographed landmarks. It is the world’s largest (but not the longest) steel arch bridge with the top of the bridge standing 134 meters (440 feet) above Sydney Harbor. It took eight years to build and opened in March 1932.

FAMOUS BRIDGES

Crossing the Tagus River at Alcántara in Spain, the Alcántara Bridge is a masterpiece of ancient Roman bridge building. The bridge was built between 104 and 106 by an order of the Roman Emperor Trajan in 98 AD, who is honored by a triumphal arch in the center of the bridge and a small temple at one end.

FAMOUS BRIDGES

The Akashi-Kaikyo Bridge, also known as the Pearl Bridge, is the longest suspension bridge at 1,991 meters (6,532 feet) in the world. It spans the Akashi Strait in Japan connecting Kobe on the mainland and Iwaya on Awayi Island. The bridge took almost 12 years to build and was opened for traffic in 1998.

FAMOUS BRIDGES

The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the strait between San Francisco and Marin County to the north. The bridge took seven years to build, and was completed in 1937.The famous red-orange color of the bridge was specifically chosen to make the bridge more easily visible through the thick fog that frequently shrouds the bridge.

FAMOUS BRIDGES

The Millau Viaduct bridge is a cable stay bridge in Millau, France. A cable stay bridge is a bridge that consists of one or more columns (normally referred to as towers or pylons), with cables supporting the bridge deck. 

FAMOUS BRIDGES

The Manchac Swamp Bridge is located in Louisiana is the 7th longest bridge in the world which carries Interstate 55 across the swamps. The engineering structure of this bridgeare concrete trestles which are two pillared. The total length of the bridge is 22.80 miles The cost of one single mile amounted to $7 million.

FAMOUS BRIDGES

The Chain of Rocks Bridge is a truss bridge that spans the Mississippi River on the north edge of St. Louis, Missouri. The eastern end of the bridge is on Chouteau Island (part of Madison, Illinois), while the western end is on the Missouri shoreline. The bridge was privately built as a toll bridge in 1929.