Scantec GPR Services has been scanning thousands of slabs in Calgary to help clients determining the type of slabs, thickness, reinforcement information and location of critical objects embedded within the slabs prior to doing any cutting or coring through.
This week we completed a scanning project for a general contractor at a busy shopping centre during a store renovation. It was on a waffle slab (Figure 1) with varied beam sizes and rebar on the top slab. It is noted that there was no access to the slab bottom as there were other active stores on the below level and the ceiling was completely covered.
Figure 1. An example of waffle ceiling slab which was scanned with GPR in this project (Source Internet). We were not able to access to the slab bottom for an actual picture of the site.
The contractor redesigned the store and planned to core 30 new locations through the slab for new mechanical, plumbing and electrical lines. After initial scans, we determined the slab type and other structural information. The top slab was estimated 7 in thick on top of dense beams/ girders which were more than 20 in thick. The girders could be up to 3 ft wide with columns below. We were not surprised when we found out half of the proposed locations were initially put on the beams. However, we expanded the scanning areas in order to find safe locations to redesign the cores.
Figure 2. Picture of a location with a clear area in the middle of the scan. The top slab was 8″ thick with one layer of rebar and the beams were 2′ apart in both directions.
Figure 2 shows an example of the findings where we were able to draw accurate guide marks indicating exactly where the rebar lay in the concrete, the location of the beams and the contractor was able to bore through the floor without disturbing the structural integrity of the slab.
We provided the critical information needed to take the next steps during the project while saving cost and time for the property owner and the contractor by avoiding any damage to people and property. In addition, we were always able to arrive after a short notice, to perform the nondestructive GPR survey. to establish the location, extent, and depth to any known/ unknown objects.
We can establish the location, extent, and depth to any known/ unknown objects below the concrete surface such as:
- Quick and accurate inspection of concrete slabs, walls, decks, balconies, slab on grade etc to a depth of 20 inches or more with multiple antennas available.
- Location of reinforcement such as rebar, post-tensioned cables, conduits, PVC pipes etc with depth and size measurements.
- Location and extent of voids
Ground penetrating radar is also a great tool for locating underground utilities. Scantec also provides locating service for water, gas, power, phone, sewer, and other objects prior to excavating. Please contact us to schedule for your next project or if you have any questions regarding GPR applications or limitations.
Edmonton:780-246-2486
Calgary: 587-917-1486
Email: info@scantecGPR.com