The Job
This Secaucus lightweight fill project is located just across the Hudson River from Manhattan. It’s part of a completely gut of an existing 100,000 square foot distribution and logistics building. While the ground in Secaucus is terrible, the real estate is valuable because of its close proximity to New York City, and also at the core of the dense, urban North Jersey market.
The Challenge
Since original construction in the 1970s, the floor of the building has settled nearly two feet. This is due to underlying compressible, organic soils. As the underlying soils consolidated, and the floor settled, two subsequent floors were poured on top of the existing floor. Varying thicknesses of recycled concrete and other base materials were used to level over the differentially settled previous floors in preparation for the new floor pours.
The goal of the full gut was to build a food grade space. This is to bring the building into a more profitable sector. To do this, minimizing the amount of future settlement was important. Reports from multiple consulting geotechs in the past recommended undercutting and lightweight fill placement as a viable option for achieving this goal. The CMAR reached out to CJGeo about designing and implementing an undercut and lightweight fill program. This was based on our experience on similar projects in the Secaucus area.
The Solution
CJGeo’s inhouse geotechnical engineer worked with the CMAR’s geotechnical consultant. We used RocScience’s Settle 3 program to design an undercut program that would bring anticipated settlement to no more than 1.5 inches. Given the global subsidence of the area, along with rising ground water levels and increasing flood chances, buoyancy was also a design consideration. The total system (floor, base stone & lightweight fill) had to have a minimum 1.1 factor of safety against uplift in fully inundated condition. As an added measure of safety, given the very large footprint of the fill, limited permeability soils immediately below the lightweight fill, and disruptions associated with any buoyancy, CJGeo recommended not factoring infiltration into reduced buoyancy.
The final design includes a 42 inch undercut, followed by placement of 32 inches of CJFill-Ultra Lightweight foamed concrete fill. CJGeo mobilized a single dry batch plant to the site, and placed approximately 8,500 cubic yards of CJFill-Ultra Lightweight material. Production was as high as 1100 cubic yards per day.
Speak With An Expert
Facing a similar challenge to this Secaucus lightweight fill project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
