Concrete Scanning at the Harrah’s Hotel & Casino in Atlantic City, NJ

Concrete scanning enables visualization of major structural components within concrete. It is used to inspect concrete slabs or columns before coring or drilling in renovations and new construction projects using Ground Penetrating Radar technology (GPR). Trained technicians can locate rebar and post-tension cables within the concrete, accurately detect electrical and communications conduits, locate voids – air gaps between the sub-grade or any other commodity within or beneath the concrete surface. Structural reports can be also made including concrete slab measurement and rebar spacing.

It is important to accurately find and identify these objects. Hitting an electrical line, conduit or other buried features within concrete can be extremely dangerous, potentially causing immediate structural failure and injuring or killing those on site. Damage to electrical services within the concrete can cause electrocution or death. It can also be costly, leading to work delays, emergency repairs and a loss of production. Therefore, it is important that technicians are highly skilled and knowledgeable so that they can confidently instruct contractors where they can drill without the risk of hitting any of the objects and thus avoiding many of the related costs and problems. It is a precise step by step process that must be undertaken with the utmost diligence.

The following is a glimpse of what this process entails.

Massett Building Company hired GPRS for this Concrete Scanning project and the job was completed by project managers, Dave Sansone and Zach Strang, on March 23, 2020.

The contractor’s goal was to locate all utilities/conflicts in the concrete slab in two-bathroom areas (approximately 12’x12’) at the Harrah’s Hotel & Casino that were being renovated and retrofitted in Atlantic City, NJ. Once arriving onsite, GPRS Project Managers David Sansone and Zachary Strang walked floor number four with the onsite contact. When the site walk was completed, Dave and Zach filled out a job hazard analysis report which is used to ensure safe working practices onsite. Information was then gathered from the site contact, specifically that the concrete slab was previously identified as a post tension cable structure elevated slab. Electrical/ Mechanical rooms were then located on floors three, four, and five to identify nearby floor penetrations. Dave and Zach organized a plan that best utilized their skills to efficiently work within the clients time frame.

Zach began the job by connecting to each floor penetration with an electromagnetic detector (EM) and scanning both 145 sq ft areas and alerted Dave if any targets were detected. Once this was completed Zach performed passive scans which utilized radio and power waves to locate and mark potential utilities/conflicts. Dave began scanning the area with a 1400 MHz GSSI antenna and marked all post tension cables, rebar, and conduits found to be within and below the elevated slab. The 1400 MHz antenna is designed specifically to locate in concrete slab utilities, rebar, voids, and anomalies. Conflicts that were just below the slab also were marked due to the core drilling activities of the contractor. Typically, core drill locations are only scanned in a 2’x 2’ areas, however the whole floor was scanned at the request of the contractor to achieve greater flexibility of core drilling location placement. All markings were applied to the concrete slab via crayon initially, then were painted for better visibility/durability. Each marking was then communicated to the onsite contact and best areas were given to perform core drilling safely without the risk of damaging a utility, cable, rebar, or conflict. Depths were recorded on the surface for additional information. Pictures were then taken to include in the provided job summary report deliverable so the client would be able to reference and access the job for present and future use.

All GPRS Project Managers are highly skilled and trained in the field of concrete scanning and utility locating. However, it does not end there, numerous clients are helped to identify underground storage tanks (USTs), footings, and identify voids onsite. As a nationwide company, GPRS covers all 50 states. The 24-hour rapid response program guarantees that the project will get covered within a 24-hour window of a client’s call, text, or email.

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