Shivan Giroti
Ms. Page
Honors Life Science P6
10/2/15
Statement of Purpose
The purpose of this experiment is to see how someone can use less materials to make safe bridges that work well. The controls are the material of the bridge, the model of the bridge, the cargo, and the surface. The manipulated variable is the distance between the support structures.
Hypothesis
If the support structures are each 1/4 away from each other then the bridge will hold the most cargo.
Background Research
A bridge is a structure that usually allows people to walk or drive over a canyon, busy highway, or a body of water. Bridges can span for miles or even …show more content…
This is a simple bridge because the ends of the girders are on top of the pier and abutments. The span of a girder bridge can go up to 1,000 feet. Truss bridges are bridges that are supported by trusses. The trusses are set in a triangular pattern. A truss bridge can have a span of over 1,000. Every truss is a triangle formed by wood or steel. Engineers prefer a girder bridge because it looks better, however it uses more materials. Arch bridges are another common type of bridge. Each span of an arch bridge forms an arch. The spans can go up to 1,800 feet. Arch bridges are one of the oldest bridges in history. Old arch bridges used to be made out of large stone blocks. Nowadays, arch bridges are made out of wood and concrete. Cantilever bridges have one, two, or several cantilever beams. Cantilever bridges can span about 1,800 feet. The cantilever bridge has two sections that go from the abutment to the pier. Those sections are called anchor arm and cantilever arm. A lot of cantilever bridges have truss like structures. Most are made of steel or pressed concrete. Suspension bridges are the most famous bridges and the ones that stand out, for example the Golden Gate Bridge. They have roadways that are supported by metal cables that hang on to two tall towers. A suspension bridges span can range up to 4,000 feet and sometimes even beyond that! They only need two piers two hold them up. A suspension bridge sometimes sways in