Tetra Tech INCA provided engineering and survey services for design and prepared contract drawings and specifications for a new concrete apron at Terminal 30 for the Port of Seattle. The project included installation of 400 linear feet of new concrete aprons, demolition of the existing apron, design of a new concrete apron, and design of an electrical substation and rails for a new 100-kip operating load crane. INCA prepared a 15% cost estimate and updated it throughout the design to assure the owner that the budget would be met.

This $6 million apron contract included pretensioned concrete deck panels placed over water, a five-foot-diameter drilled shaft system to resist lateral earthquake loads, underwater dredging of contaminated and clean soils, underwater pile driving and riprap placement, ship and barge moorage load design, concrete pretensioned piles driven under water, underwater surveying, and sonar mapping.