Problem:

After starting a remodeling project in a wing of the Sprint Campus, located in Overland Park, KS two large cracks were discovered when the carpet was removed. The first crack was approximately 80 feet in length. The existing saw joint had expanded to close to 1/2" in width. The second crack proved to be more disturbing. This crack was not along any joints and was a structural concern. Sprint promptly contacted an engineering consulting firm to assess the situation. After review, the consulting firm needed to determine if voids between the slab and underlying soil caused the problem and determine how bad the voids were.

Solutions:

• The consulting firm would take core samples to determine voids, and poorly compacted soils.
• Perform a GPR scan in 3D to identify voids underneath the slab.

Results:

• In this project both solutions were applied in order to validate the radar results to the building management. After Construction Solutions performed a full 3D scan of the floor, core samples were taken to determine areas of voids. After the GPR scan was processed the results coincided perfectly with the core samples taken. The scan showed that the worst voids were occurring along the south wall. These voids were up to 1" in size.

*Dashed lines represent cracks in slab, which coincide with voids below slab. Colors represent distance void is from surface of slab (Yellow=shallow, Red=deeper).