South 196th Street Bridge

(Kent, WA)  Landau Associates provided geotechnical and environmental engineering services to the City of Kent for the South 196th Street Corridor Project (West Valley Highway to East Valley Highway), which is part of a major east-west transportation corridor across the Kent valley that crosses over Union Pacific and BNSF railroad tracks and the Western Processing Superfund site.

Project elements included:

  • 1,200-foot long, four-lane steel bridge with a concrete deck, with spans greater than 200 feet, supported on deep six- and eight-foot diameter drilled shafts extending 80 to 90 feet below the surface
  • Two approach embankments, up to 35 feet in height
  • 2,800 feet of improved roadway to connect the bridge to West Valley and East Valley Highways
  • Relocation of Puget Sound Energy’s (PSE) east-west power distribution line from overhead to underground
  • Raising two of PSE’s 230kV steel transmission towers and raising two 115KV transmission lines 50 ft to accommodate the new bridge
  • Relocating a major telecommunications line (both copper and fiber optic)
  • Constructing a 230 ft-long, 18 ft diameter culvert to carry Mill Creek beneath the west approach embankment
  • In a unique public-private partnership, integrated the design and construction of the west approach embankment with the design and construction of a cap and slurry wall containment system that was a part of the remediation of the Western Processing Superfund site

Landau Associates developed geotechnical engineering recommendations and conclusions for seismic design, drilled shaft foundations including vertical and lateral capacities, drilled shaft construction, east and west approach embankments, stone columns to mitigate the potential for soil liquefaction, foundation support of bridge abutment footings, roadway subgrade preparation, and installation of new utilities. We coordinated with a diverse stakeholder group that included the City of Kent, Washington State Departments of Ecology and Fish and Wildlife, U.S. Environmental Protection Agency, Puget Sound Energy, the Western Processing Trust, Union Pacific Railroad, and Burlington Northern Santa Fe Railroad.

Landau Associates received an Engineering Excellence Award from the American Council of Engineering Companies (ACEC) – Washington for the South 196th Street Corridor.