GEODesign was retained to provide geotechnical engineering services for a new 12-story building. The subsurface conditions included uncontrolled fill, up to 10 feet of organic clay, and rock at a depth of approximately 35 feet. Consideration was initially given to a mat foundation bearing on the organic clay; however, the building settlement amount was not acceptable. Recommendations were given for a mat foundation bearing on the soil below the organics, a pile foundation, or a mat foundation bearing on improved soil.
The Solutions Unearthed
- A 24 inch diameter soil mix column program was designed to improve the strength and settlement characteristics of the organic soils.
- A variable and cost efficient column spacing was developed based on the bearing stresses within the mat, as calculated by the structural engineer.
- A construction sampling and testing program was developed and implemented by the contractor and their engineer. The testing results indicated that the soil mix columns achieved the required compression strength of 150 psi.
Client: 399 Hudson Yards LLC