Bridge construction is a branch of civil engineering that utilizes strong manpower and various construction materials. The kings of construction include a clamshell dredge, a concrete truck, a pile driver, a submerged arc-welder, and steel cables (Brown, 1993). According to Brown (1993), types of bridges depend on traffic volume expected to use the way and the nature and type of water transport taking place on a surface in question. Though super bridges have been constructed using modern technologies, various issues, however, still surrounds the branch of civil engineering. The major bridge construction problem is natural deterioration (Waddell& Low, 1916). This paper explores natural deterioration, as a bridge construction issue, by reviewing already published literature.
Waddell& Low (1916) explains natural deterioration of bridges to include slow but continuous processes that weakens strength and efficiency of materials used in bridge construction. Raton (2003) points out three processes that make construction materials non-functional. The processes include corrosion, stress, and aging. Corrosion is a consequent of both acidic rains and under surface water lapping over the steels. Corrosion physically reduces sizes of construction steels making an entire bridge deficient. Corrosion has made mega bridges to collapse or rendered weak. Minneapolis Bridge is an example of super bridge that collapsed due to corrosion (Brown, 1993). Stress on the construction materials significantly lowers quality of strong bridges. Bridge stresses are attributed to heavy trucks using bridges not designed for them as well as increased volume of traffic. According to Agrawal (2010), road damage caused by a one 40-ton truck is equivalent to road damage caused by 9,600 cars. Similar to corrosion and stress, aging also makes bridges weak. Aging is a threat in bridge construction especially when proper maintenance practices are not applied.
Several solutions have been proposed to curb natural deterioration as a bridge construction problem. Modern solution involves application of anti-corrosion devices that withstand salty waters (Raton, 2003; Waddell& Low, 1916). The devices range from the construction steels, cables, and the concrete. The devices, which operate as giant hair dryers, are fitted in the suspension cables of a bridge. Application of Ultra-High Performance Concrete pi-girders, also extends life time of a bridge. However, these modern technologies face a challenge of lack of enough funds. High cost of the devices makes civil engineers to use sub-standard construction materials. It is, therefore, imperative that adequate funds be allocated to the engineering sector to ensure quality structures. Enough funds, in addition, ensure that proper maintenance practices are done on already constructed bridges (Raton, 2003). Adequate funding is, hence, an indirect solution to corrosion and bridge aging.
Corrosion is also reduced by reducing steel surfaces in contact with water. The solution specifically reduces corrosion caused by water lapping on the bridge surface. The procedure is done by maximizing the distance between water and bridge surfaces. Brown (1993), however, criticizes the solution for it does not effectively control corrosion caused by acid rains. Proper measures that regulate traffic flow are also solutions stress caused on bridges. Having maximum number of vehicles that use a bridge per given time prevents over-utilization of bridges. Effectiveness of traffic control procedures has been questioned because it results to congestion of traffic at certain points of roads. Raton (2003) proposes that control of traffic volume should go in hand with expansion of lanes. Expansion lanes is, however, not only expensive, but will also result to population congestion because much space will be occupied by roads. It is, thus, evident that if the solutions are inappropriately applied, they have negative impacts than positive ones.
Bridge construction is a concept that was first applied the Romans (Brown, 1993). Ancient bridges were made from large stone blocks, which were wedged against one another to form an arch. Different advances and improvements have taken place on the branch of civil engineering. The improvements have not only been on expertise used, but also on construction materials. Today, four major types of bridges exist. The types of bridges include a truss bridge, an arch bridge, a suspension bridge, and a cantilever bridge. The advances are, however, associated with certain problems. Natural deterioration is an issue that raises eyebrows of civil engineers while constructing bridges. The essay has outlined three processes that deteriorate quality of bridges. The processes include corrosion, stress, and aging.
Corrosion is a result of continuous contact between water and construction steels. Acidic rains also significantly contribute corrosion. The process eats away construction steels and cables making the entire structure weak. Stress is a problem largely caused by increased traffic volume and frequent usage of bridges by heavy trucks. Stress similarly shortens life of a bridge. Aging, as a bridge construction problem, becomes significant when poor maintenance practices are implemented. Maintenance practices mainly include replacement of weak and/or substandard construction materials. As a solution to natural deterioration problem, use of anti-corrosion devices improves quality of bridges and extends life of the structure. Traffic regulation and having specific bridges for vehicles is a sure solution to stress caused by moving vehicles on bridges. The solutions are only feasible if adequate funds are set aside by various nations. In other words, a country need to assess its current and estimated future financial flow before adopting any of the steps to have long-lasting bridges.
Agrawal, A. K. (2010). Supplemental Data Features for the Manuscripts Submitted to the Journal of Bridge Engineering. Journal of Bridge Engineering, 2010, Vol.15, no. 2, p.121
Brown, D. (1993). Bridges. New York: Macmillan Reed International Books.
Raton, B. (2003). Bridge Engineering: Seismic Design. FL : CRC Press
Waddell, J., & Low, J. (1916). Bridge Engineering. New York : J. Wiley Press.