Existing Pile Foundation Evaluation for a Pier Upgrade

The Pier 3 upgrade project at the Port of Tacoma was completed in anticipation of super-post-Panamax size container ships. The primary goals of the project were to maintain the existing 64-foot-gauge crane rail and to accommodate a new 100-foot-gauge crane rail for new higher capacity container cranes. The upgrade includes adding piles to the outboard crane rail and upgrading the existing wharf to support both existing container cranes and new, larger container cranes. The new crane rail is supported on a combination of the original concrete piles installed in the 1980s and new concrete piles installed as part of this upgrade project. The project geotechnical engineers evaluated the as-installed resistances of existing piles using data from the initial construction. By evaluating each existing pile individually, the design team justified increasing the allowable axial resistance of select individual existing piles. This limited the number of new piles required for the upgrade and reduced the over-all project cost.