News from King County Department of Transportation
Release date:  Dec. 21, 2006

Upper Preston road repairs completed three weeks early

Residents of the Upper Preston area in east King County have been battered by the storms of November and December, but they got some good news today when the King County Road Services Division fully restored road access to the community three weeks early.

A section of Upper Preston Road Southeast was closed during the week of Nov. 6 following heavy rainfall that caused a portion of the hillside supporting the road to fall into the Raging River – taking more than 300 feet of the southbound lane with it. Since the road is the only access into the community, residents were cut off and had to walk in and out of their neighborhood for several days.

Roads Services Division staff and the on-site contractor, Wilder Construction, built a temporary access road using the south shoulder of Interstate 90 within four days, but travel has been restricted while permanent repairs were made. The county originally thought the new roadway would not be completed until mid-January, but was able to accelerate the work. The total cost of repairs in the Upper Preston area is estimated at approximately $4 million.

One of the first steps the crews had to complete in November was stabilizing the Preston Frontage Bridge, which also suffered damage from high flows on the Raging River. Once the bridge was repaired, heavy equipment could be moved in to work on the road.

The entire hillside, approximately 55 vertical feet from the roadway down to the river, had to be rebuilt. Crews accelerated haul and placement of material, averaging 2,000 yards of rock per day for four weeks. The acceleration of the work and repairs was accomplished by bringing in extra staff and equipment.

The county rebuilt the hillside to provide a solid base for the roadway using rocks ranging in size from six feet in diameter to four inches, and then reconstructed the road on top. The total volume of rock used to reconstruct the roadway was in excess of 40,000 cubic yards.