Meadowbrook Bridge No. 1726A King County Landmark Bridge at Snoqualmie River Snoqualmie Valley, Washington Back to Project List   Vibratory Ground Improvement Dry bottom feed stone columns reduce the potential impacts of liquefaction on the landmark bridge. Project Overview: The King County landmark bridge was built in 1921. In order to preserve the historical bridge, King County decided to seismically retrofit the bridge structurally and to implement ground improvement at the approach embankments to meet the current building code and standards. To reduce the potential impacts of lateral spreading and liquefaction on the slopes supporting the approaches of the landmark bridge, underlying soils were improved using vibro-compaction and vibro-replacement techniques. Layne GeoConstruction installed over 5,800 linear feet of stone columns to depths of up to 65 feet using the dry bottom feed method. In addition, compaction grout columns were installed to a depth of 55 feet. The compaction grout columns were installed to create a buffer wall for the protection of the existing piers from the soil densification work and potential damage or settlement due to the vibrations generated during the installation of the stone columns.   Value of Work Performed: $650,000 Project Duration: 3 months Project Completion Date: July 2005 Project Reference: General Contractor Wilder Construction, Inc. Phil Bogardus (425) 551-3100