Arch Bridge : The Bridge

Bridges have been used for thousands of years, beginning with natural formations, such as huge rock arches (Appendix A). The first bridges made by humans were most likely simple spans of wooden tree trunks laid across streams, or planks, such as rafts tied together (Gascoigne, 2001). These simple designs evolved over time, as new materials became available, to form the hundreds of bridges we use today. Some basic bridge designs include truss, arch, beam and suspension bridges. The most basic of these is the beam bridge (Appendix B1), which consists of a deck, spanning a relatively short distance, that is held up by a pair of abutments (vertical supports at either end). When weight is placed on

Initially, suspension bridges before 1940 were made of piers, towers, wires, anchorages, and roadways. Piers were the main foundation for the suspension bridges. There usually were two of them, which were made out of cement and were entrenched in ground underneath the body of water that the bridge was spanned across. Towers were built on top of the piers to provide a means of connection for the roadways and wires. Wires were connected to the towers, roadways, and anchorages to provide tension support for the weight of the bridge. The anchorages were large cement platforms that were planted into the ground on either side of the land so that the wires could be connected to it. Lastly, the roadways were the main point of the suspension bridge. They usually were wide enough to provide four lanes of traffic and stretched from one side of the bridge to the other. This was the basic design of the suspension bridges

These materials were used to build specific structures and technology. First of all, whenever they had to have water travel across valleys or other open landscapes, the Romans built bridges made of arches. These arches saved materials and money, as it took less to build arches than to build a solid wall. Also, arches were much more stable than a wall and were easily repairable. It was easy for pedestrians and vehicles to pass through the arches, too. However, when

The Pratt truss bridge was originally founded by Caleb and Thomas Pratt in 1844. It is mainly used to carry trains. The biggest advantage of this bridge was its low costs for construction and the materials to construct a truss bridge are minimal. It also use materials that is cheaper and light in weight. We can easily identify a pratt truss by detecting its diagonal members, which (excluding for the very end ones) all slant down and in toward the center of the span. The pratt truss was designed by applying few laws that related to the mechanics of materials concept. The bridge is mainly built using steel girders to support the construction of the structure. The below part of bridge weight is high so, it need an enough support to prevent from

building much more reliable bridges. In conclusion, the importance of concrete and arches in ancient

We choose design #1 because the truss bridge is a bridge whose load bearing superstructure is composed of a truss, a structure of connected elements forming triangular units. The stressed from tension, and compression helps carry heavier masses. We chose the truss bridge, for it is a very rigid structure and it transfers the load from a single point to a much wider area. A truss is an arrangement of structural members that are connected together to form a rigid frame work. Modern trusses are made of structural steel. All bridges have 4 main characteristics: form, span, material, and travel surface in relation to the structure. A truss bridge is one form that a bridge can take and there are at least 30 different kinds of truss

The arch enabled them to cover large amounts of land due to weight disbursement as the shape reduces the stress incurred by the structure (Kamm, n.d.). In addition, the Romans used triumphal arches to commemorate achievements both in battle and

The Roman arch held incredible importance regarding architecture. It was a supporting structure in a building that could carry a lot of weight. They achieved this not so much through the shape but rather the composition of these arcs. Furthermore, the Roman arch was significant in that the Romans (with their arcs) were then able to build massive structures like aqueducts. This feat of architecture freed architects to explore various different structures.

One of Roman Engineering’s greatest accomplishments was the use of the arch. The arch shape is very strong, able to support great amounts of weight. This allowed Romans to build massive structures that would stand for many centuries. The Romans adapted the arch design to fit many purposes. The barrel vault is merely an elongated arch; this was used for buildings tombs and sewers. The dome is an adaptation of the arch. The dome is an arch revolved on its vertical axis. The best example of the dome in ancient Rome is the Pantheon. The basic arch was used in almost every large building in Rome. Romans also used

The Roman Empire was one of the strongest empires and one of the ways that they were able to show that power was with their architecture. One of the most interesting pieces of architecture from the Roman period is the Pont Du Gard. The Pont Du Gard serves as an aqueduct to transport water from the springs to the city. The impressive part is that it is still standing today and it was made very precisely using stones. If you did not know it serves as an aqueduct it could very easily be a magnificent structure with the arch’s serving as the viewpoint. The arches are used to support the structure but they also help beautify the structure and make you think why they added arches and also why they are all different sizes. The very bottom of the structure

It is shaped in a way to transfer weight to the towers and anchors with its tension (O'Connor, 1971, p. 372). Cables are made of high strength wires spirally bound to form a rope (O'Connor, 1971, p. 372). Vertical cable suspenders that are fastened to the main cables hang the actual roadway. Stiffening girders and trusses are along the side of the bridge to distribute concentrated loads and help to keep the motion of the bridge at a minimum (Troitsky, 1994, p115).

The bridge has a strong tower keeping the bridge away from collapsing, while the web trusses were used to hold up the deck and the road from breaking and snapping but also a resistant to shear forces and torsion. In today’s bridge structures, they often fail under strong winds, therefore there is a supporting system beneath the bridge called a deck truss. This reinforces the bridge’s deck and it decreases the tendency of the roadway to wave and move. However, the dead loads are the external forces that are acting on the bridge are the gravity and the materials that were used to build, it also refers to the weight of the bridge itself as a dead load. The live loads are the carts, cars, trains and even humans are the external forces that the

The history of building truss bridges in the United States goes back to the late eighteen century, when in 1792, Timothy Palmer built in Massachusetts, his Newburyport Bridge, across the Merrimack River, thus proving the possibility of “fast and inexpensive” construction of a bridge. Very quickly, the “new” idea of bridge design was incorporated into repertoire of many designers, and a number of truss bridges, mostly across the Eastern coast of a country, was built. The majority of early truss bridges were single span, statically determinate structures, built out of timber, with the design aspect based mostly on the engineering intuition of their creators. Throughout the next two centuries, many types of truss bridges were designed and built,

Arch The arch consists of two supports, called piers, each topped by a platform called an impost. Angled blocks of brick or stone, called voussoirs . These are placed on the imposts in an arched, curved pattern that is capped by the central block of the arch called the keystone. A row of arches is called an arcade. Arches allowed the Romans to create wider, taller, and lighter structures. They also learned that they if they built arches entirely inside the walls of their buildings that this would make the walls even stronger.

Superstructure bears the load that is being passed over the bridge and it transmits the forces caused by the same to substructure. Load received from the decking is transferred on to the substructure by Bearings. They also distribute the load evenly over the substructure material as it may not have sufficient strength to bear the superstructure load directly. Piers and Abutments are the vertical substructures which transfer the load to the earth in the foundation. Wing walls and returns are constructed as the extension of