General Construction removed more than 203,000 cubic yards of contaminated sediment from Todd Pacific Shipyards.

Designated a Superfund site by the federal government in 1983, Todd’s shipyard was in need of a massive clean-up to remove more than 203,000 cubic yards of contaminated sediment.

General Construction was awarded the project in February 2003 and completed it in three years, more than two and half months ahead of schedule and $2.5 million under budget.

Major components included dredging and disposing of marine sediments to an upland receiving facility; under-pier capping of sediments that could not be dredged; and major slope armoring with rip-rap in order to establish habitat migration areas.

To eliminate the chance of off-site contamination by dredge spoils, the dredged material was transported to an off-load facility by hopper barges. General used a drop cloth dredging method in which the area was covered twice, reducing the risk of recontamination.

All buckets of material were taken by a decanting barge for dewatering prior to placement on the hopper barge, which significantly reduced the amount of water sent upland for disposal. This cost-saving method is being patented.

Photos courtesy AGC of Washington Part of General’s work included removal of 2,600 creosote piles.

By using a sand shooter welded to a steel frame and placed on a barge, the contractor was able to meet the strict requirements for accurate sand placement under the existing piers.

The project included demolition of more than 106,000 square feet of timber pier along with the removal of 2,600 creosote piles.

Working within an operational shipyard meant real-time project coordination with constant schedule adjustments in order to accomplish work during the Aug. 15 to Feb. 15 fish window.

Only one recordable accident, a spark from a welding torch that burned a worker’s ear, was logged in over 37,000 worker hours.