Pier scour in coarse bed and cohesive materials Research Paper

Pier scour in coarse bed and cohesive materials - Research report ExampleThis results to approximately 60 percent of all twosomework failures. The societal repercussions that argon associated with failures and the costs that be linked to repair are amplified in Alaska, alternate routes of ground transportation between several cities are not in existence. Bridge culvert damages cost a lot to the economy, for example, in 2002 the damage in Kenai Peninsula was estimated at about 19 million dollars. This led to twain site examination for scour. This paper indeed seeks to discuss the background of scour, its description, the pier scour, and its equation. Scour Scour is a hole that re primary(prenominal)s behind when common sense and rocks, posits are washed away from the river stooge. Even though scour often occur at each particular time, the scour action is strong especially during flood season. This is because swiftly flowing peeing has overmuch energy than slowly flowing ca lm water to lift and wash away sediments from the river bottom. Scour is of a great concern to bridges. This is because if rocks or sediment on which bridge is supported or rest is seek by the river, it is most probably that the bridge could be actually unsafe for travel purposes. For example, in 1987 when the interstate Highway bridge over Schoharie Creek in the state of New York collapsed following a flood, the national Highway Administration demanded that each state to specify bridges on the avenue over water that are likely to experience problems of scour and to have the bridges with severe scour identified. This knowledge of bridge sites in which there are potential scour problems will enable the States to improve and monitor the bridge conditions ahead of time before they pose danger to travelers. Types of scour There are three main types of scour that affect bridges. The following are the major types of scour that may pose danger to highway bridges over water Local scour this occurs when sediments are swept away from approximately bridge piers and/ or abutments. Piers in this particular case are the pillars that support bridges, while abutments are the ones supporting the closedown of the bridge. Flowing water past abutment or pier may scoop holes out in the sediment resulting into scour holes. contraction scour this type of scour occurs the sediments are swept away from the sides and bottom of the river. Contraction scour is majorly caused by an increased speed in water flow as it flows through an initiation of a bridge which is narrower than the natural channel of the river. Degradation scour this is a general removal of back and rocks, sediments from the bottom of the river by the flow of the river. This is often a natural process of sediment removal that lowers the bottom of the river resultantly. In most cases, the process removes large quantities of sediment with time. Pier scour Piers scour is the removal of sediments around the pier. T his occurs when rocks and sand in which the bridge rests are removed by flowing water. This is very dangerous to travelers and may cause high magnitude accidents. Adequate definition of potential pier scour at piers is very essential to a proper construction, design, and maintenance of bridges. Designing cost effective and safe bridge depends on accurate estimate of the depth of scour. Thus, underestimating the depth of the scour can place both human life-time and structures at risk. On the other hand, consistent