Bridge Building: Focus: Structural Engineering Grades - Educational ...

Suspension BridgeAesthetic, light, and strong, suspension bridges can spandistances from 2,000 to 7,000 feet -- far longer than anyother kind of bridge. They also tend to be the mostexpensive to build. True to its name, a suspension bridgesuspends the roadway from huge main cables, whichextend from one end of the bridge to the other. Thesecables rest on top of high towers and are secured at eachend by anchorages.The towers enable the main cables to be draped over longdistances. Inside the anchorages, thecables are spread over a large area toevenly distribute the load and toprevent the cables from breakingfree.Suspension bridgeanchorageSuspension bridgeGolden Gate Bridge, SanFrancisco, CAArch BridgeArch bridges are one of the oldest types of bridges andhave great natural strength. Instead of pushing straightdown, the weight of an arch bridge is carried outwardalong the curve of the arch to the supports at each end.These supports, called the abutments, carry the load andkeep the ends of the bridge from spreading out. Alsodiscuss tension and compression.Arch BridgeBixby Creek Bridge,Monterey, CABeam BridgeA beam or "girder" bridge is the simplest and mostinexpensive kind of bridge. According to Craig Finley ofFinley/ McNary Engineering, "they're basically the vanillasof the bridge world."In its most basic form, a beam bridge consists of ahorizontal beam that is supported at each end by piers. Thebeam itself must be strong so that it doesn't bend under itsown weight and theBeam bridge14