The cellar level for this project was significantly constrained by the 100 year flood zone, the curving nature of the High Line, and the existing High Line foundations. It was decided that removing the existing foundations and extending the High Line columns through the cellar would result in a much more efficient cellar layout. This required the design and installation of an extensive and complex temporary support system to carry the High Line loads.
The Solutions Unearthed
- Non-destructive parallel seismic testing indicated that the existing High Line piles were relatively short and would need to be removed to construct the cellar.
- GEODesign designed a unique structural temporary steel beam and girder grillage system supported on steel columns/caissons that were socketed into rock.
- GEODesign developed a complete jacking sequence for transferring the existing High Line column loads to the temporary support system.
- GEODesign included several measures to minimize High Line movements, including staggering caisson installation locations, requiring the contractor to improve their soil plug management, and installing additional temporary support measures.
- The High Line park remained open to pedestrian traffic during all foundation construction activities.
Client: HFZ Capital