1. By Damien Griego Period 5
Do You Know Bridges?
By Damien Griego
Period 5

2. Different Types of Bridges
There are a total of six bridges types, but there are four types that are mainly used.
Arch Bridges- An arch bridge is a bridge that forms an arch. It works by transferring the weight of the bridge throughout the bridge. It is one of the most well known bridges.
Beam Bridges- these bridges are known as the most simple kind of bridges. Beam bridges need to be stiff and it needs to resist twisting and bending under heavy pressure. When a lot of weight is on the bridge, the surface is compressed down and the bottom is stretched out.
Cantilever Bridge- these bridges first appeared in the 19th century. The main elements of these bridges are structures that are anchored at only one end while the other projects horizontally toward the sky.
Suspension Bridge- this type od bridge is where the deck is hanging below suspension cables on vertical suspenders. This bridge was also introduced in the early 19th century.

3. Arch Bridges
Arch bridges are very unique and very interesting. It is one of the most popular types of bridges. It was first introduced over 3000 years ago. They entered their height of popularity during the industrial revolution. While other bridges have been introduced and some have become popular, arch bridges remain in use.
The bridges work because they have abutments at each end which gives the bridge its curved shape. They transfer the weight of the bridge and its loads into the horizontal thrust which is held in place by the abutments at the end of it.

4. Beam Bridges
Beam bridges actually have one of the simplest ways it works. The beam bridges have a rigid horizontal structure and two supports. One at each end and the bridge rests on them. These beams and materials directly support the downward weight of the bridge and any weight on it.
These bridges also endure both compressional and tensional stress They are very cool and very useful bridges.

5. Cantilever Bridges
Cantilever bridges are awesome bridges! They use pairs of cantilevers back to back with a short beam bridge in between. These bridges have been around for a good amount of time. The first one was completed in They are very dependable bridges even they are not very well known.

6. Suspension Bridges
Some of the most famous bridges in the world, such as the Golden Gate Bridge, are suspension bridges. They suspend the roadway by cables, ropes or chains that are on two tall towers. These two towers support the majority of the weight as they compress and push down on the deck of the bridge. Then they travel up the ropes and transfer compression. The supporting cables receive the bridges tension forces. These cables run horizontally. These bridges are incredibly strong and last for a long time if made right.

7. Forces Acting Against Bridges
Compression Compression is a force that is pushing. The shorter something is the less compression it can hold. Compression is very dangerous problems for bridges if they are not made correctly.
Weather
Natural disasters can really destroy a bridge. Tornadoes, hurricanes or earthquakes can level it. If the bridge has anything wrong with it, it has a real chance of going down. That’s why we always have to check the bridges and make sure that they are working right.

8. Shear Force
Shear force is very different and it is a very interesting force. This force happens when two opposing forces are acting upon the same point. For example, if you hold a piece of wood and push up with one hand and down with the other hand, you are applying shear force to that object. This force is very dangerous and something that is very tough on bridges. Shear force is truly unique and different than any other kind of force.

9. Forces Acting Against Bridges
Tension
Torsion
Tension is another huge threat to bridges. Tension is a pulling force. In order to be a material used in a bridge you have to be able to resist tension. Tension has no different effect on objects bigger or smaller. It does no matter. A short material can take as much tension as a big object.
Torsion is a twisting force. When you wring out a cloth for example, you are applying torsion. Bridge designers must watch for torsion and they must use materials that will keep the torsion damage down to a minimum.

10. The Different Loads Dead Loads Human Loads
Human loads is all the weight humans put on the bridge. Such as body weight. This can add up and the bridge needs to be very strong to hold this, on top of the other loads.
Dead loads are the permanent or stationary loads which are transferred to structure throughout the lifespan. Dead load is due to self weight, permanent equipment, and the weight of different materials. This weight will always be there.

11. The Different Loads Imposed Loads Environmental Loads
Imposed loads are either movable or moving loads with out any movement or acceleration. These loads are assumed to be produced by the intended use or occupancy of the building including weights of movable parts. Some things that are imposed loads are Assembly buildings, business and office buildings, and storage rooms.
Weather can have a huge impact on bridges , as we all know. Storms and winds can take a bridge down and we have to be aware of the weather in an area before we build a bridge there. We have to be aware of the environment or else we can put people in danger by building a bridge in a bad spot.

12. The Different Loads Live Loads Dynamic Loads
A live load is the moving weight the bridge will hold, such as traffic. Traffic can be very heavy, when you can consider the weight of all the goods and the cars that are transporting the good. The bridge needs incredible strength and materials to work.
Dynamic loads are outside forces that can not be accurately measured, such as wind or extreme other circumstances. We can not exactly calculate the force of these things but they are obviously very dangerous. That’s why these are dangerous because we don’t know exactly what they are.

13. Thermal Load
When a structure expands or shrinks with the temperature, it is experiencing thermal load. The temperature causes the beams and columns to change shape and push and pull on other parts of the structure. This can change the bridge so this is how important the materials are to the bridge. This effects the bridge because it totally changes the structure of it, when the weather changes so it’s a very dangerous load for a bridge to withstand.

14. Commonly Used Shapes: Rectangle
Rectangles are a commonly used shape in building bridges. When a rectangle is not supported by anything else, it is very wobbly, but when support is added, it becomes strong. It is able to distribute weight and is very reliable. When building a bridge with the shape of a rectangle in it, you must reinforce the rectangle and give it some extra support so the rectangle will not fall or make the bridge fall.

15. Commonly Used Shapes: Archs
When an arch by itself is pushed on, the sides of the arch are pushed out and they in a way, expand. However when you add support to the arch, it will try to spread out when force Is applied, however the reinforcement will not let it. This is great for bridges as it will keep bridges made with arch shapes very strong. It will be very hard to knock down a bridge if it is made with care and if it uses correct arch and support for the arch.

16. Commonly Used Shapes: Triangles
When a triangle is pushed on, the outer edge squeezes together. The inner edge will pull apart. When one of the sides has or experiences these two forces at the same time. It bends. The weakest part is the side. When you poke the top of the triangle though, it doesn’t not bend because the weight is being evenly distributed throughout the entire triangle, which is basically like adding support. It makes it much more stable and it makes it a very reliable source.

17. Golden Gate Bridge
The Golden Gate bridge is one of the most famous bridges in the entire world. It is located in San Francisco, California. The length of this great bridge is 8,981 feet long. This is a huge bridge! The Strauss Engineering Corp designed this bridge. It was there best make by far. It is a suspension bridge that is made of metals and suspension cords that support the whole bridge. This makes the design of the bridge very good and makes it look very cool. The bridge was made on January 5, It has been around for a long time and has lasted. It’s a great of example of a good bridge. The golden gate bridge took 4 years to build!

18. Brooklyn Bridge
The name of the bridge, as the title says is the Brooklyn Bridge. It is located in Brooklyn. The length of the Brooklyn Bridge is 5,989 feet. This is a pretty long bridge. John Augustus Roebling was the created of the amazing Brooklyn Bridge. It was a suspension bridge that used steel for its cable wire. It was the longest suspension bridge in the world. It was built on January 3, That’s a really long time ago to create the quality of work that they made. It took 13 years to build this bridge. It took this long because the technology they had was not very good. This bridge is a true beauty.

19. Seven Mile Bridge
The Seven Mile Bridge is an amazing bridge. It is located in Florida. It is 35,370 feet long which is just absolutely incredible. It is one of the longest bridges in the Unites States and in the world. Henry Flagler was the creator of this wonderful bridge. What an amazing thought he had that day! It cost 45 million dollars to make which was very expensive at the time. It was made in 1978 and opened in It took 4 years to create so the bridge and it is absolutely amazing. It is an incredible bridge even though it isn’t very well known across the world.