Arch faced a rapidly changing project scope and had to design concepts under extreme time pressure with partial information. The final scope included geotechnical analysis, structural design, and sheet pile shoring for an 8.5m deep pit on both riverbanks. Each pit exceeded 50m in length and 9m in width, providing space for a large HDD unit and a 500mm pipe installed with pipelayer machines.
As Engineer of Record, Arch also designed an aqua dam sheet pile shoring wall to isolate the river during in-water work. Design options considered sandbags and lock-blocks.