Beck Drive Spec #3 Floor Slab Investigation

JPR was hired to complete a Forensic Structural Investigation on the floor slab of a 150,240-square-foot building. This new industrial building experienced significant floor slab frost heave – before the walls, roof, and heating system were completed. The purpose of the investigation was to identify the cause of the frost heave, as well as potential detrimental impacts to the future use of the building.

The investigation encompassed a range of testing and analysis, and detailed coordination with the contractor was essential for scheduling testing that was sensitive to vibration and obstructions. The investigation included surveying elevations, geotechnical soil boring and laboratory testing analysis, floor flatness and levelness testing, and ground penetrating radar. It also included the review of provided slab construction images and videos, building and site construction plan drawings, and previous soil borings performed by the contractor. Documentation review of the slab construction materials testing and the inspection of visible and measurable impacts of frost heave was also completed. Interviewing project contractors and stakeholders, collecting representative photographs, and preparing an Investigation Report was also a part of the process.

The Report found that the contractor failed to adhere to crucial construction plan specifications. This, in combination with construction taking place during unsuitable weather conditions, led to frost heave occurring before the building could be closed.

It was also found that the imported soil constructed beneath the slab was susceptible to frost heave and a specified aggregate subbase was intentionally omitted by the contractor. Immediately below the imported soil, widespread native soils with significant organic content were found to remain, even though the organic content had been indicated at the same depths on the soil boring logs performed by the contractor. Additionally, the ground penetrating radar located areas of high moisture and voids under the slab correlating with the frost heave areas.  

Furthermore, the floor flatness and levelness testing showed areas below industry standards. Based on the Report findings, and despite the frost heave settling to near plan elevations upon enclosing the building and adding interior heating, the owner/developer and contractor negotiated a settlement for the contractor to be responsible for an extended 10-year warranty for the performance of the floor slab and related construction.

The tenant moved into the building and began manufacturing operations. However, JPR recommended ongoing monitoring of the slab for possible issues until the warranty expires.  

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