Abstract:
The Long Slip Canal is located in Hoboken, New Jersey. To mitigate future flooding and build up the site for future rail facilities, New Jersey (NJ) Transit constructed an extension to the Combined Sewer Overflow (CSO) and filled in the canal. A significant challenge of the site was the compressibility of the soft marine clay in the canal during backfilling and impacts to adjacent CSO structures due to lateral spread. To limit impacts to the aforementioned structures when backfilling, NJ Transit’ s designer conceptually designed soil mix ground improvement to be designed by the contractor. The contractor elected to Value Engineered (VE) the ground improvement with a pile-supported concrete Load Transfer Platform (LTP) to be constructed in the wet. Since the VE design bounded structures designed by NJ Transit’ s designer, emphasis was placed on the impact of the VE on adjacent structures. This paper will cover the unique aspects of this VE design and construction including: comparison of the 2D and 3D Finite Element analysis, use of concrete to function as a more traditional LTP for underwater construction, limitations of existing geotechnical code used for traditional LTP design and use of ACI building code for concrete used in a non-traditional application, and construction challenges in soft marine clays.
Keywords: load transfer platform, wet construction, marine clay, canal