Concrete Scanning used to Locate Pre-Stressed Cables Prior to Core Drilling Holes inside a Nursing Home in Ann Arbor, MI

It’s always essential to have as much information as possible prior to making any floor penetrations. There are many unknowns prior to core drilling holes in an elevated slab such as what type of reinforcing steel is present, potential for beams being in the area & embedded conduits possibly passing through proposed coring locations. Ground Penetrating Radar (GPR) is an excellent source to provide some answers to those unknowns.

A general contractor had a project inside a nursing home being renovated in Ann Arbor MI where they had to core drill numerous holes in an elevated slab. The nursing home was being transformed in to an updated space for the residents. The new plans had bathrooms, sinks & janitor closets that were going to be added along with numerous floor boxes. The contractor had to connect the new plumbing to the existing plumbing on the floor below. They also had to connect new electrical for the floor boxes. Before making any floor penetrations, the contractor needed to know the type of floor that was present & if any existing utilities were in the slab. Ground Penetrating Radar Systems of Ann Arbor MI was contacted to scan the areas for the future floor penetrations. While scanning in real time, GPRS was able to determine the concrete slab was of hollow core construction. That was important information since hollow core slabs have pre-stressed cables that run in the grouted portions of the slab. It’s essential to avoid cutting any pre-stressed cables when core drilling since doing so would compromise the structural integrity of the floor & could potentially injure the drillers. GPRS was able to mark the hollows directly on the surface & explained to the plumbers to core drill in the hollow portions (labeled by the H). The project was able to continue without having any setbacks.

It’s always a good practice to scan prior to core drilling or saw cutting concrete structures. 

Please contact Regional Manager of Michigan, Thaddeus Bullock, for more information on the capabilities of GPRS at 734.377.4551 or


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