The project involves upgrading the Sterling Highway from milepost 45 to 60 near Cooper Landing, Alaska. The purpose of the project is to bring the highway up to current standards for a rural principal arterial to efficiently and safely serve traffic needs.
Alaska Department of Transportation, DOWL, Landslide Technologies, Crux Subsurface
Crux provided geotechnical drilling and instrumentation for a proposed new stretch of highway, including a new bridge. The initial scope included 7 boreholes up to 300 feet in depth, but was ultimately expanded to 42 boreholes ranging from 30 to 300 feet. Instrumentation included inclinometer casing installed in 8 of the borings and vibrating wire piezometers in 14.
Access to 39 of the borings was highly challenging due to the rugged terrain and condition of available access roads. None of these sites were accessible by pickup. Crux utilized custom Morooka track carriers to transport equipment. Upon arriving at the site, the drill and drill platform were disconnected from the Morooka and stabilized. Crew access was accomplished by a combination of utility task vehicle (UTV) and hiking.
Challenges included 24-hour drilling to complete the first 7 borings, which were located at the east abutment site for the proposed bridge. These borings were on an expedited schedule as the client needed to start monitoring data from instrument installs as soon as possible. Additional challenges included congested yards and site access due to multiple contractors working on the project simultaneously.