The foundations for the piers and main span towers are six-foot-diameter driven steel-pipe piles and eight-foot-diameter drilled shafts. The bridge is the second longest cable-stayed bridge in North America and, at the time of its completion, its 200-foot width made it the widest bridge in the world.

Shannon & Wilson provided geotechnical and earthquake engineering recommendations to the project's Design-Build team. The exploration program included mud rotary and sonic core borings, and cone penetration tests at each of the 26 piers. The deepest explorations extended more than 250 feet.  Working 24 hours a day, seven days a week, our team finished all explorations-8,000 feet of drilling-in one month.

By providing soil-time histories every six feet for the length of each pier's deep foundation, we developed equivalent linear and non-linear effective stress-site response models to provide ground motions that considered modulus degradation and pore-pressure development.