I-90 Richards Road to Winery Road VIC Seismic Retrofit

Project Summary

The project provided seismic retrofit improvements to existing concrete and steel bridges along Interstate 90 between Bellevue and Issaquah, Washington. Retrofit improvements included: concrete girder stops, concrete infill walls between bridge piers, concrete bolster add-ons, steel column jacketing, FRP column jacketing, concrete catcher block walls, and demo and replacement of steel cross framing.

By The Numbers:

  • 395 working days
  • 42,000 square feet of concrete forming
  • 2,000 cubic yards of concrete poured
  • 72 total girder stops at 5 different bridges
  • 19 infill walls, ranging from 10 feet to 28 feet tall and on average 20 feet wide at five different bridges
  • 14 bolster add-ons, suspended 10 feet to 28 feet off the ground at four different bridges
  • 39 welded steel column jackets, ranging from 10 feet to 28 feet tall and 4 feet in diameter
  • Five FRP column jackets
  • Demolition and replacement of steel cross framing at 14 bents with an average four girder bays per bent
  • 9,400 square feet of 6-inch OC by ½-inch depth spall pattern roughening
  • 6,630 drill 7/8-inch diameter by 9-inch depth hole and epoxy dowels



King County, WA (Various Locations)


Washington State Department of Transportation

Contract Amount

$6 Million


Washington State Department of Transportation


January 2009 - April 2010