Underpinning & Foundation Skanska was awarded a contract to install more than 5,500 150-ton and 200-ton capacity piles to support the 44,000-foot-long guideway structure on AirTrain.

In order to execute the project in the most efficient and cost effective manner, Underpinning invented a new pile type using a tapered steel lower section and steel pipe upper section. This pile, called the Tapertube, allowed for faster pile installation, with no pile failures and higher design capacities.  It features a tapered bottom section that helps build up ground stresses as it is driven

The work was performed using state-of-the-art hydraulic pile driving equipment built in Finland to Underpinning’s specifications. The high mobility of the pile rigs, combined with highly efficient hammers, allowed for rapid installation in the tight confines of the existing airport roadway system and in the center median of the heavily traveled Van Wyck Expressway.

The new pile features a tapered bottom for the first 25 feet with the rest of the 45-foot to 75-foot pile being ordinary pipe. Tapertube piles are 50 percent thicker than a monotube pile, allowing them to be driven to higher driving resistances at lower stresses. The idea for the new piles required a "contractor willing to take a very big risk," in putting the cost in to develop and use the pile. The heavier steel also allows the piles to be driven quicker once work is under way, an important consideration on a job where all work was completed without disrupting traffic on the Van Wyck Expressway. The piles support 515 poured-in-place concrete columns, which in turn support the precast guideway over which the train will travel. The project combines the biggest scope in precast concrete segmental work and DBOM contracting ever let in New York City.