Modern Bridge Building essays

Modern Bridge Building essays Modern technology is advancing faster than we care to think. Our engineering marvels of the past are quickly becoming obsolete. Many bridges are built using classic designs which can be greatly improved with new technology. Modern technology allows bridges to be built from state of the art materials with superior strength and versatility (Wilson I). The arch is one of the older forms of bridge used in many Roman structures. It is like an inverted suspension bridge, with all the tensions replaced by compressions, and vice versa. The other great difference is in the stability of the system. You can drive heavy weight across an arch and cause it to flex, and it will always return to its original position, after movement. The girder bridge is made up of two or more large beams that can stretch across the length of the obstacle that it is built to overcome. Many cantilevers that pivot as the load on the bridge shifts are used to even out the stress on the entire structure. This is the most basic and most widely used design (Krinsiuns III). The box girder is a bridge that most engineers try to avoid because of the stress that is put on the beams during construction, which has lead to many collapses(Wilson I). It is made up of many trusses and boxed or round beams. The cable stayed bridge uses the support of many high tension cables that are attached to two large pillars. The bridge is very well balanced due to the many separate cables, which support themselves under high stress (Krinsiuns III). The suspension bridge is the most popular and well known bridge design used today. The most highly stressed parts of a suspension bridge are in tension not in compression. A cable, though flexible, is very stable against pressure, and only needs to be thick enough to withstand the tension, with a safety factor. A strut is unstable, and needs to be thick enough to prevent buckling. So an arch can never be as light as a suspension ...