Construction of the Sound Transit University Link Light Rail Extension Project in Seattle, Washington. The purpose of this project was to bore two tunnels to connect University of Washington to downtown Seattle via a 3.15-mile extension of Sound Transit's current light rail system. 

The project consisted of constructing and excavating the future University of Washington Husky Station Box, which acted as the launching shaft. Two 21.5-foot diameter, Earth Pressure Balance (EPB) Tunnel Boring Machines were launched to excavate twin 11,400-foot tunnels to Capitol Hill Station. These tunnels were lined with Precast Concrete Tunnel Segments. Sixteen cross-passages were constructed using the Sequential Excavation Method (SEM) and completed with cast-in-place concrete segments to connect the twin tunnels. Placing tunnel concrete inverts and walkways as well as installing electrical systems and fire standpipe were also completed.