Pier scour in Coarse bed and cohesive materials Research Paper

Pier scour in Coarse bed and cohesive materials - Research Paper Example This is the overall mission of the United States Department of the interior and the United States Geological Survey. The two mentioned departments are responsible for bridges and scours which this paper seeks to discuss. Studies have evidently determined that streambed scours are the leading cause of bridge failure in the United States. This results to approximately 60 percent of all bridge failures. The societal repercussions that are associated with failures and the costs that are 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 bridge site examination for scour. Purpose This paper therefore seeks to discuss pier scour in coarse bed and cohesive materials. The purpose of this paper is very open: to know how scour works and why bridges fall down. This is an issue that everyone could be interested in. Several bridges have been witnessed fall down and it has taken my attention to study how the whole process takes place. Bridges are normally built by technical experts and are expected to stay for maximum periods as prescribed by the civil engineers and architectures; however, scour has remained a disappointment to such expectations. Justas the aim of the paper: to discuss pier scour in coarse bed and cohesive materials, I am interested in understanding every single detail about the entire process of scour, types of scour, and its fundamental equations. Background on Scour Scour may refer to as remove by washing hard and rubbing and/ or rub hard with a cleansing rough material. Basically it accounts for a hole that remains behind when sand and rocks, sediments are washed away from the river bottom. Even though scour often occur at any particular time, the scour action is strong especially during flood season. This is because swiftly flowing water has much energy than slowly flowing calm 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 scoured by the river, it is most probably that the bridge could be very 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 Federal Highway Administration demanded that each state to specify bridges on the highway 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 d anger to highway bridges over water: Local scour: this occurs when sediments are swept away from around bridge piers and/ or abutments: the pillars that support bridges and those that support the end of the bridge. Flowing water past abutment or pier may scoop holes out in the sediment resulting into an