December 2, 2020 ITS Money: Mike Paquette, P.E., MASCE

Mike Paquette, P.E., MASCE | Langan Engineering and Environmental Services, Inc.

Load Testing High Capacity Caissons in Manhattan

This presentation deals with the most expensive private development in US history: Hudson Yards. Encompassing six city blocks, it will become an entirely new neighborhood on the west side of Manhattan with 12 high-rise and several low- to mid-rise towers, some of which are being built on platforms over the Long Island Railroad’s west side rail yard. With over 600 caissons being drilled as deep as 140 feet to bedrock, pre-production load tests were used to justify shorter rock sockets and reduce the drilling times.

Findings

• The bi-directional load tests that were performed during the design phase cost approximately $600,000.
• The testing program provided much better insight in the actual skin friction on the caissons, resulting in a reduction of the socket lengths by 30%.
• The shorter sockets generated direct cost savings well in excess of the load test costs and also reduced the overall construction schedule.