Roads, Highways, Bridges, and Retaining Walls

Sea-Tac Third Runway

HNTB/Port of Seattle
Seattle-Tacoma International Airport, Washington

Hart Crowser was the geotechnical and hydrogeologic consultant for this extraordinarily complex project. The new 8,500-foot-long runway required construction of an embankment built from 17,000,000 cubic yards of compacted earth fill. A key part of the project involved design of Mechanically Stabilized Earth (MSE) reinforced retaining walls up to 135 feet in height. MSE walls of this height are rare—only one other in the world is taller than 135 feet.


I-405 Kirkland SR 520 to SR 522 Stage I Design Build

Washington State Department of Transportation
Kirkland, Washington

WSDOT is working for more capacity, more predictable travel times, and improved safety on I-405. We are supporting WSDOT’s goals by providing geotechnical design for this 2-mile, design-build project. It includes new lanes and shoulders, new pavement and resurfacing, a bridge and abutment, retaining walls, noise walls, stormwater treatment and detention facilities, and a new fish passage tunnel.


I-5/SR 18/SR 161 Triangle Improvement

BERGER/ABAM Engineers Inc./Washington State Department of Transportation
Federal Way, Washington

Hart Crowser worked closely with WSDOT, project team members, and other stakeholders to develop innovative approaches to geotechnical issues such as bridge foundations, a retaining wall/ embankment for wetland protection, and an approach embankment.