pdf 2017 Edward Timm Currents and Stresses Report

An Investigation into the Effect of Near Bottom Currents on the Structural Stability of Enbridge Line 5 in the Straits of Mackinac

Author: Edward Timm, PhD, PE

Author Affiliation: Independent Investigator

Journal: Internet Published Technical Report; 3/5/2017

Abstract: The Straits of Mackinac is a four mile wide channel that connects Lakes Huron and Michigan. Resting on the bottom of the Straits is Enbridge Line 5, a twinned crude oil pipeline that was designed and constructed by Bechtel Corporation in 1953 for the Lakehead Pipeline Company. This was a unique engineering project at the time of construction and the designers attempted to account for the forces on unsupported sections of the pipe resulting from underwater currents. Recent research has shown the currents in the Straits of Mackinac to be stronger and more complex than originally contemplated by the designers of line 5. This paper reviews recent underwater current data for the Straits of Mackinac and draws conclusions about the implications of deficiencies in the original design basis for Line 5.