Case history: Design of river crossings for the Trans-Alaska Fiber Optic Cable

Design and construction of a 1300-km fiber optic cable along the Trans-Alaska pipeline occurred in 1996 and 1997. This fast-track linear project crosses a wide range of terrain and man!: streams in a harsh arctic and subarctic environment. Stream crossing designs were developed to allow cost-effective crossings that protected the cable from damage by bottom scour and lateral channel migration. Most of the stream crossings were accomplished using horizontal directional drilling technology. The design reduced construction costs by reducing directional bore lengths wherever possible. A method of conveying the limits of fiber optic cable burial was presented in the form of an 'exclusion zone' that summarizes, in graphical form, the design at each crossing.