Lessons Learned from Pile Driving at the Central Artery/Tunnel Project

Five contracts from the Central Artery/Tunnel Project (CA/T) in Boston, Massachusetts were reviewed to document issues related to the design and construction of driven pile foundations. Given the soft and compressible marine clays in the Boston area, driven pile foundations were selected to support specific structures including retaining walls, abutments, roadway slabs, transition structures, and ramps. This paper presents the results of a study to assess the lessons learned from pile driving on the CA/T. This study focused on an evaluation of static and dynamic load test data and a case study of significant movements of an adjacent building during pile driving. The load test results showed that the piles have more capacity than what they were designed for. At the site of significant movement of an adjacent building, installation of wick drains and preaugering to mitigate additional movements proved ineffective. Detailed settlement, inclinometer, and piezometer data are presented.