We are currently working on a multi-year highway widening and improvement project by the Washington State Department of Transportation (WSDOT) to provide engineering construction support to the rock slope designer Wyllie & Norrish Rock Engineers. This massive project is currently the largest re-grade and rock excavation in the State, spanning several miles of rock slope excavations over 100 feet high. You can find more details in our section; Rock Slopes.
We recently completed engineering input for the contractors' geotechnical firm, providing our professional services for final design of the permanent retaining walls and overpass lids along the new segment of 520. This highway segment stretches from the east end of the 520 Floating Bridge at Lake Washington to the north-south interchange at SR 405. Our input included static and seismic design of; cut/fill slopes, reinforced earth walls, lid structures, detention ponds and retaining walls. This was an exciting and fast paced project with a well integrated design-build team we were lucky to be part of from the early stages. You can learn more about the 520 project at the following Washington State Department of Transportation site: