Olympic Sculpture Park
Seattle Art Museum
This 8.5- acre facility for the Seattle Art Museum included an exhibition facility, two pedestrian bridges, several mechanically stabilized earth (MSE) walls, and stabilization of the park’s seawall.
The geotechnical engineering design for the pedestrian bridges that cross Western and Elliott Avenues took into account the need for the bridges to support the weight of emergency vehicles.
A critical design feature for the 212-foot bridge over the Burlington Northern Santa Fe railroad tracks was the potential for liquefaction and lateral ground spreading during a design level seismic event.
Lateral spreading was also an issue with respect to the design of the Elliott Avenue overpass abutment. Along Elliott Avenue, the approach fills terminate in abutments constructed of MSE walls more than 20 feet high.
For the deteriorating seawall, we evaluated alternatives that would allow for earthen buttress fills immediately offshore to provide additional support.
Sustainability. Sustainable practices were integrated into our geotechnical design by importing 250,000 cubic yards of needed soil from another nearby Hart Crowser project site. We were aware that soil scheduled to be excavated from the site of the new Russell Investments Center met the Superfund fill requirements for the park site. This greatly reduced the amount of trucking required, eliminated off-site disposal of the excavated “waste” soil, and eliminated the need for disturbance of an off-site quarry.We provided construction oversight and compaction testing for the fill material.
Prospective Purchaser Consent Decree Negotiation and Cleanup Plan
Initially the Seattle Art Museum was reluctant to purchase the property for the $85 million project due to unknown environmental liabilities. Hart Crowser assisted the musuem in negotiating a Prospective Purchaser Consent Decree with the Washington State Department of Ecology. We demonstrated that hydrocarbons associated with residual free phase product and soils would not impact Elliott Bay, and would not require certain costly remedial actions. This enabled the land purchase to go forward. We also developed a cost-effective cleanup plan for the site.