Several scopes were part of the DPI (Distributed Protocol Interface) project, including Entry & Exit Pits, TBM/Bore Recovery, and Casing Removal. Both entry and exit pits for the Clearwater River crossing presented challenges that Arch Engineers solved by working closely with the contractor. At the entry pit, the sheet piles struck boulders during installation, splitting apart and leaving gaps in the shoring. The gaps were patch welded, and a row of walers was added to prevent deflection. Struts were also added but needed close coordination with the installation of the thruster machine.
Additional DPI-related adjustments were required at the exit pit, where boulders caused deformation of the sheet piles and prevented full-depth installation. Arch Engineers adapted with a soldier pile design to complete the pit excavation to depth.