DSI Supports Washington State Department of Transportation during the Construction of its Tallest Soil Nail Wall
The University of Washington in Bothell, approximately 20km north of Seattle, is one of the newest universities in Washington State. Due to its popularity with students, the university plans to increase its enrollment from 3,000 to 10,000 full time students. According to an ordinance by the city of Bothell, an expansion of the university is only possible if a new access to the campus is constructed.
The new exit is being constructed on highway SR 522 and offers a direct connection to the south entrance of the campus. In addition to considerably relieving traffic at the university’s north entrance, this project will also permit traffic towards Bothell to flow more smoothly.
One of the signature portions of the project was the construction of an approximately 4,180m² retaining wall selected to stabilize the hillside adjacent to the new south entrance. The owner, the Washington State Department of Transportation (WSDOT), designed an approximately 29m tall soil nail / shotcrete wall shoring system. It is the tallest soil nail wall ever constructed by WSDOT.
DSI USA supplied approximately 387 #8, Gr 75 Epoxy Coated DYWIDAG Soil Nails in lengths of 4.9m and approximately 1,470 type 1-3/8" Gr 150 Ksi Double Corrosion Protected DYWIDAG Soil Nails in lengths of 26m, which were installed by the contractor, Northwest Cascade, Inc.. Afterwards, an approximately 13cm thick temporary shotcrete facing was applied on the soil nail wall.
DSI is pleased to have contributed to an improvement of traffic flow around the University of Washington.