Bridge Designs Bridges are often built over huge landmasses or bodies of water. Their design depends on their function and location. We will take you through all the different types of bridges. Tacoma Narrows Bridge Bridges intended to carry lesser traffic may use simple beams while those meant to handle larger traffic make use of trusses or box girders.

What is a Bridge? The word bridge represents the idea of crossing over large spans of land or water, thus 'bridging' the gaps spanning long distances. A bridge connects two far-off points reducing the distance between them and bringing them within reach. What does it take to construct this 'idea'? It takes ingenuity!

Types of Bridge Designs Can you name all of these types based on you previous research? BeamCantilever ArchSuspension

Span The horizontal space between two supports of a bridge structure. Also refers to the structure itself. The Akashi- Kaikyō Bridge aka the Pearl Bridge, has the longest central span of any suspension bridge at 6,532 ft. It is located in Japan and was completed in 1998.

The distance between two bridge supports is called the? 1. Arch 2. Span 3. Spread 4. Space Bridges are differentiated by the distance they can cross, also known as their span.

Span Types

Beam Bridge Highway overpasses, flyovers or walkways are often beam bridges. A horizontal beam supported at its ends. The construction is the simplest of all types. The top surface of this bridge is compressed and the bottom surface is under tension, helping the beam remain strait. Quick Fact: The longer a beam bridge, the weaker it is! Typically, beam bridges are not more than 250 feet long.

Beam Bridge A beam Bridge is arguably the most basic bridge. Modern steel beam bridges often use I- beams or box girders and concrete in their construction. The beam bridge must be designed so it does not bend under load.

Cantilever Bridge Cantilevers bridge structures are supported on one end only. In a typical cantilever bridge, cantilever arms extending from opposite ends meet at the center. The Forth Bridge in Scotland is a railway bridge is one of the oldest known cantilever bridges. Quick Fact: The 1800 feet Quebec Bridge of Canada holds the record of being the world's longest cantilever bridge.

Cantilever Bridge A cantilever bridge is a modified form of a beam bridge. The support is in the middle of the arm, not at the end. The advantage to a cantilever bridge is its ability to span wide spaces without the need of extensive and expensive support while under construction. The Greater New Orleans Bridge

Arch Bridge The second oldest bridge type. The arch doesn't require piers in the center. Arches use a curved structure. Provides high resistance to bending forces. Arches can only be used where the ground is solid or stable.

Arch Bridge Styles

Truss Bridge A truss bridge is built by connecting straight elements with the help of pin joints. Triangular units connected at joints form the skeleton of a truss bridge. Truss bridges came to be commonly constructed from the 1870s to the 1930s. Truss is the oldest form of modern bridge design. Deck truss railroad bridge that extends over the Erie Canal is one of the many famous truss bridges Quick Fact: Quebec Bridge, the longest cantilever bridge span, has a riveted steel truss structure.

Truss Bridge The truss is a simple skeletal structure. In theory, the individual parts of a simple truss are only subject to tension and compression forces but not bending forces. Trusses are made up of small beams that when put together can support large amounts of weight and can also span great distances.

Basic Truss Styles

Other Truss Bridges Styles

Howe Truss Styles

Warren Truss Styles

Pratt Truss Styles

Arch Bridge Arch-shaped w/ supports at both its ends. The weight of an arch-shaped bridge is supported by the supports at its ends. The Mycenaean Arkadiko Bridge in Greece of 1300 BC is the oldest existing arch-shaped bridge. But the Romans were foremost in discovering the use of arches in bridge construction. Quick Fact: The Chaotianmen Bridge in Chongqing, Southwest China is the largest arch bridge in the world. It is 1741 meters in length.

What gives an arch bridge its strength? 1. its shape 2. its size 3. its material Due to their curved shape, arch bridges don't need any additional supports or cables; they're naturally strong bridge structures.

Bridge Styles Cable-stayed Bridge

Bridge Styles Suspension Bridge

Bridge Forces

Forces Squeezing - Compression Stretching - Tension Bending Sliding - Shearing Twisting – Torsion Forces Lab

Shapes Square Arch Triangle Shapes Lab

Examples

Which of the following is not one of the two major forces bridges deal with? momentum compression tension Correct! Compression is a force that acts to compress or shorten the object it's acting on; tension is a force that acts to expand or lengthen the object it's acting on. These are the two main forces that bridges must contend with. Which part of a suspension bridge receives the most compression? the cables the deck the towers Correct! A suspension bridge's cables transfer the bulk of the compression to the towers, which dissipate the compression directly into the earth where they're buried. What force is responsible for most bridge failures? torsion compression weather Oops! Wrong Answer. While the danger of other forces has been largely eliminated through better design, weather forces are much harder to combat. The rotational or twisting force that bridges face is called: torsion resonance fusion Correct! Torsion has been eliminated in most bridges, but larger suspension bridges can still be affected by it because of the fact that they're suspended and vulnerable to strong winds.