Types, Purpose and Historical Background of Bridges - Research Paper Example

Bridges – Types, Purpose and Historical background Introduction Bridge refers to the structure that is built for the purpose of spinning any physical obstacle or space like water, valley or road. The bridges are basically built to provide passage over these obstacles (Wardhana and Hadipriono, 2003). These are different types of bridges that are built to perform varying functions. The method and material used in the construction of the bridges also varies according to their purpose and type. With the advent of advanced construction technology and architectural enhancements the building of the bridges has also experienced significant level of improvement and the bridges built during different time period stand as symbol of architectural expertise of that era (Biezma et al, 2007). The following paper intends to trace the historical origins of construction of the bridges and describes the major types and function of the bridges to explain the purpose and significance of constructing the bridges. Historical Background The building of the bridges could be traced back to thirteenth century when the wooden logs and stones were used to cross the stream or river. In fact, the basic idea of bridge has been bestowed by the nature in form of simple logs fallen across a stream or river. The human mind gradually refined the idea and employed its creativity and architectural skills and capabilities to give this idea an enhanced and modified form (Wardhana and Hadipriono, 2003). The human beings started building the bridges using the cut pieced of wooden logs and pranks. After which they started using the wooden stones to support the crossbeam arrangements. The use of tress and bamboo poles was also started by the Americans for crossing the small caverns and well that allowed them getting one place to another (Biezma et al, 2007). The proper bridges were started building in the 13th century BC by the Greeks however, the ancient Romans gained proficiency in the building of the bridges by constructing various arches and aqueducts. During the Greek Bronze Age an arch bridge was constructed between Tiryns to Epidauros in Peloponnese named Arkadiko Bridge. This old arch bridge still existed whereas several other intact arched stone bridges built during that era could be found in different locations in Southern Greece (Wardhana and Hadipriono, 2003). The Romans built numerous bridges that were constructed using the techniques to overcome the problems faced with the early bridges. Some of the bridges built by the Romans even stand today like the Alcantara Bridge that was constructed over the Tagus River in Spain and existed at present. The Romans also started the use of cement for the construction of the bridges because they want to overcome the variations of the strength of different natural stones. The created a cement Possolana that was consisting of water, lime, sand and volcanic rock. In this way the Romans give the idea that the bridges could also be constructed with the modified material along with the usage of natural stones and wooden logs to add strength to the bridges (Nath, R. (1982). After the roman era, the use of the bricks became popular for the construction of the bridges. The use of the cement was suspended for sometime after the Roman era when mostly the brick and mortar bridges were built. The use of the bridges was soon become popular and spread all over the world. In different countries of the world, the construction of the bridges was initiated for military and commercial purposes. In India the Mughals built several bridges using the plaited bamboos and iron chains. These bridges were also very strong and were widely visible in India until the fourth century (Wardhana and Hadipriono, 2003). Chinese have also done some remarkable developments in the field of bridge construction. Earlier Chinese built some wooden bridges and then started the construction of the stone bridges. For instance, Zhaozhou Bridge was built from stones on China from 595 to 605 AD during the period of the Sui Dynasty. The bridge has been regarded as the world largest open spandrel arch bridge. In Europe the construction of the bridges using stones and wood was initiated as early as in 2nd century AD. After the stone, wooden and brick the construction of the bridges was also done using the ropes that allowed building the suspension bridges in the 16th century. The construction of the bridges witnessed major developments and enhancements during the 18th century when several architects worked for brining innovations to the designing of the bridges. In 1716, the architect Hubert Gautier wrote the first book on the bridge engineering and provided guidelines and new ideas for the construction of the bridges (Nath, R. (1982). In 1779, there was major revolution witnessed in the construction of the bridges along with the invention of usage of cast iron in the arches. It was the major breakthrough of the technology that enhanced the field of bridge construction when the first Iron Bridge was built in England that crosses the river Severn. The industrial revolution of the nineteenth century also complemented the process of the bridge construction and the truss system of wrought iron was developed to be used for the construction of the larger bridges. However, it was also found that iron was not capable enough to support the large loads on the bridges. After the invention of steel the construction of the large bridges become easier because the problem of tensile strength was resolved with the use of steel in bridges(David, 2005). Along with the advancements in the technology, the construction of the bridges was also improved. In 1927, the first welded road bridge of the world was designed by Stefan Bryla who was the pioneer of the welding. The bridge was later built actor the Sludwia Maurzyce river in Poland. At present, the use of welded steel has become very popular for the construction of the bridges and the architects all over the world use to employ their creativity skills to design the bridges of different types with unique and attractive designs (Wardhana and Hadipriono, 2003). Types of Bridges The designing of the bridge has witnessed significant improvement from time to time and various types of bridges have been designed to meet their unique purposes and functions. The types of the bridges could also be understood according to their use (Nath, R. (1982). For instance, the aqueducts are the bridges meant to carry water whereas viaduct links points of equal heights. A road-rail bridge is built to carry the road and rail traffic (Charles, 2003). There are six major types of bridges including beam, arch, suspension, cantilever, cable stayed and double decked bridge. Each of these types of bridges has their own significance and purpose as described below Beam Bridge: The beam bridge is the type of bridge that is supported at each end with the help of the abutments. In architectural language this bridge has been called as the name of simply supported bridge. If the bridge is designed in a way that there are more than one span in the bridge then the supports are called piers. The beam bridge is an early form of the bridge when the simple wooden logs were used to cross the streams and simple structure. Along with time, the technology advancements have changed the material used in the beam bridge and in modern days, the beam bridges are made in form of large box steel girder bridges (Wardhana and Hadipriono, 2003). The bridge is designed in a way that the weight is placed on the top of the beam that is pushed straight down on any of the side of the abutment. Now the beam bridges are mostly made from the wood or metal. The beam bridges could be built up to the height of 76meters and the typical beam bridge do not exceeds this limit because as the height of the bridge is increased the bridge becomes weaker. The longest bridge of the world is Lake Pontchartrain Causeway Bridge that is built in Louisiana with the individual span of 17 meters (Romesh, 2000). Cantilever Bridge: The cantilever bridges are designed with the help of the cantilevers. Cantilevers are the horizontal beams in which the support is given only on one end. Most of the cantilever bridges are constructed using pair of continuous spans. These spans are extended to the opposite side of the supporting pears in a way that they meet at the centre of the object or obstacle that the bridge intends to cross (Biezma et al, 2007). These bridges are much similar to the beam bridge because almost similar technique and material is used to build this type of bridge however, the height of this type of bridge could be greater than that of the beam bridge. The largest cantilever bridge is Quebec Bridge constructed in Quebec Canada. The length of this bridge is 549 meters (Charles, 2003). Arch Bridge: The arch bridges are designed in a manner that they have abutment at each of the end. The arch bridges are among the oldest type of bridges because the evidences show that the arch bridges were built by the Greeks. The example of Greek era bridge Arkadiko is also an arch bridge. The bridge is designed in a way that the weight is thrust in to the abutment at any of the side. The largest arch bridge of the world is being constructed in Dubai that is expected to be completed in year 2012(David, 2005). Suspension Bridges: The suspension bridges are designed with the help of the cables that works to suspend the bridge over the area of the obstacle. Earlier the suspension bridges were made from the ropes or vines that were covered with the pieces of bamboos. However, in the modern age the designing of the suspension bridges has changes a lot and mostly cables are used for the construction of these bridges. The cables are hanged from the towers and the towers are attached to the caissons or cofferdams implanted in the deep floor of river or lake. The Akashi Kaikyo Bridge of Japan is 3909meter long suspension bridge that is the longest suspension bridge of the world (Cass, 1983). Cable Stayed Bridge: The cable stayed bridges are very similar to the suspension bridges because these are also hangs up with the help of the cables. However, there were different from the suspension bridge because there is lesser amount of cable required in the construction of the cable stayed bridges because the towers holding the cables are kept relatively shorter. The history of the cable stayed bridges is also very old and could be traced back to the eighteenth century when the first cable stayed bridge was designed by Loescher in 1784. After this experiment, the construction of the cable stayed bridges became very popular all over the world. At present the longest cable stayed bridge of the world is present in China names Autong Bridge that has been built over the Yangtze River (Wardhana and Hadipriono, 2003). Double-decked Bridges: The advancements in the construction technology paved the way towards the invention of several advanced type of bridges and the engineers seek the ways through which they would attain the purpose of the bridges with maximum capacity and options. The double decked bridges are designed in two levels (Romesh, 2000). In some countries, the upper level is used for the road transport whereas the lower level is allocated for the Metro trains or for the pedestrians. The first double decked bridge was constructed in 1849 that was built across the Tyne River in Newcastle. The upper level was allocated to the railway whereas the lower level of the bridge was set for the road traffic (Charles, 2003). The construction of the double decked bridges has now become very popular all across the globe and in different countries of the world; the double decked roads are built for pedestrians, railways and road traffic like the San Francisco-Oakland Bridge in USA, Kap Shui Mun Bridge in Hong Kong, Prince Edward Viaduct in Canada and Washington Avenue Bridge (Cass, 1983). Functions of Bridges The basic function of the bridge is to provide path to crossover the obstacle like water or land where finding the path is difficult. However, the bridges also perform several other functions due to which they have become an important focal area for the architects and engineers (Romesh, 2000). The bridges add to the beauty of the site. In some cases the bridges are made much taller than the necessary height with the purpose of creating a beautiful image. These garden image bridges are also called moon bridges because the architects try to evoke rising full moon through the design of the bridge (Charles, 2003). Bridges are not only meant to provide path where there is any obstacle but the bridges also provide path to travel where the traffic or human mobility exceeds beyond the capacity due to the growing population. For instance, in many of the metropolitan cities the pressure of the traffic on the roads has massively increased and it often becomes difficult to manage the huge traffic on the roads. At such sites, the construction of the bridges is planned so that the pressure of the traffic could be reduced by diverting some of the traffic to the bridges. Moreover, in some cases the bridges also make the path shorted and connect two faraway placed where the travellers are not required to go through the long road ways but they could reach their destination through the bridges in lesser time and with great convenience. Sometimes, the bridges are also used to manage the traffic according to the weight. The light weight traffic is directed to the bridges and the heavyweight traffic is allowed to pass through the normal roads or vice versa. In this way, the management of traffic become easier (Charles, 2003). In some bridges special installations are also added to add to the beauty and impression of the bridges for instance, the Movy Most Bridge in Bratislava carries a restaurant in its tower that gives people unique experience of dining and travelling. However, the core function of the bridge is to provide a path or alternate way of moving from one place to another where the mobility becomes impossible or difficult due to any hurdle, problem or security issue. Sometimes, the bridges are also used for the monitoring of the situation from height whereas the bridges are also used by the elites to carry on their journey without becoming part of the usual traffic (Wardhana and Hadipriono, 2003). References David, B. J. (2005), Bridges: Three Thousand Years of Defying Nature, Richmond Hill, Ontario: Firefly Books Biezma, María Victoria, Schanack, Frank (2007), Collapse of steel bridges". Journal of Performance of Constructed Facilities 21: pp398–405 Cass, S. R. (1983), Bridges. An Easy-read modern wonders book. New York: F. Watts. Charles, W. S. (2003), Bridges of the World: Their Design and Construction. Mineola, NY: Dover Publications Nath, R. (1982). History of Mughal Architecture. India: Abhinav Publications Romesh, C.D. (2000). A History of Civilisation in Ancient India: Vol II. London: Routledge Wardhana, K. and Hadipriono, F. (2003), Analysis of Recent Bridge Failures in the United States". Journal of Performance of Constructed Facilities 17: pp144–150 Read More