Coastal Embankments and Dike Protection –Design and Conservatism

ABSTRACT: As a design-construction integrated team, Kiewit has been actively involved in the hurricane protection infrastructure in States that border the Gulf of Mexico. There, erosion protection and maintenance of dikes and levees involves high costs, since riprap like materials need to be transported for some 300 miles (500 km) to the site. With such a crucial component as rip rap protection for dikes and levees involving high mobilization cost, it puts the focus on the fundamentals of coastal protection design. In carrying out these designs, the existing condition consisting of one layer of large granite blocks 2 ft (600 mm) thick was assessed. With only one layer of protection, this assessment led a design criteria review as they relate to minimum mass (WMin) versus average mass (W50) or expressed as a diameter DMin versus D50. This paper will present the results of this review, which involved finding one of the first paper on the topic by Hudson (1959) and comparing it to some of the current practice guides by Hydro-Quebec (HQ), the United States Army Corps of Engineers (USACE) and the Bureau of Reclamation (Bureau) which are not aligned with one another and may lead to conservative designs.