Identifying Rebar Patterns in cement columns

Ground Penetrating Radar Systems, Inc. was contracted to identify the rebar pattern around the tops of multiple columns at the Macy’s and Bloomingdale’s project in Long Island City, NY. NYC project manager George Psihoules conducted the on-site work. Our client needed to be certain they would not hit rebar while drilling anchor bolts for steel insertion. Using our concrete palm antenna (2400 MHz), we then performed long scans of the area, using a grid pattern, to determine reinforcement patterns. To describe, ground penetrating radar, or GPR, is a form of non-destructive testing which allows GPRS, Inc. to detect subsurface items within the concrete slab. Once detected, GPRS can trace out, then mark out the layout of the reinforcement mat within the concrete slab so that the client could look to avoid as much rebar and/or conduits as possible when drilling and/or anchoring. Finally, we marked out our findings in tape, at the client’s request. Preliminary scans indicated the slab was reinforced with two separate (Top and Bottom) layers of rebar. Additionally, our equipment detected layers of top and bottom rebar running in both directions. To make the separate layers of rebar easily distinguishable, we marked each as either a top or bottom bar. Furthermore, we determined the approximate depth of all rebar and the approximate thickness of the slab. Our job is not complete before thoroughly communicating our findings to our client and answering any questions. At GPRS, safety is our highest priority. We take great pride in providing our clients with as much information as possible prior to beginning their work.

Getting every job scanned prior to saw cutting, core drilling, and excavating is a best practice that is growing in acceptance. At a national level, it is estimated that utility strikes have caused $1.7 billion in damages in the last 20 years and have resulted in 1,906 injuries with 421 fatalities. Locating utilities prior to concrete removal is a growing industry standard, as it can save time and money, and prevent injury and loss of life.

If you are saw cutting, drilling, or excavating, we would love to serve you on your next project located in New York City or the surrounding areas, please contact Jim Bell at 540.272.9162 or for more information on scheduling and costs.

GPRS does not provide geophysical, geological, land surveying or engineering services. If you need such services, please contact an appropriate professional.