Aladdin GPR Case Studies

Case Study One: A-Shed Wharf Fremantle WA

This data was collected at the A-Shed at Fremantle Port. The wharf deck was scanned to locate the reinforcing and map its arrangement within the slab. The wharf deck is a 300mm thick Bondek slab (i.e. metal lining on the soffit). Because of this access to beneath the slab was not possible. Data was collected bi-directionally at 100mm spacing over a 1m x 1m area. The challenge was to accurately map the bottom reinforcing.

B-Scans

Figure 1: B-Scan with Top and Bottom Reinforcing Indicated

The B-Scan above has been processed and we can clearly see 5 top reinforcing bars as well as 3 bottom reinforcing bars (Indicated with coloured circles).

C-Scans

Figure 2: C-Scan of Top Reinforcing

The C-Scan in Fig 2 indicates the top reinforcing. The reinforcing viewed horizontally has slight kinks due to offset start points during data collection.

Figure 3: C-Scan of Bottom Reinforcing

The C-Scan in Fig 3 indicates the bottom reinforcing. It is almost completely resolved even with a relatively wide 100mm spacing between B-scans.

3D Images of Reinforcing

Figure 4: Scan Area from Above Showing Both Layers of Reinforcing

Fig 4 image shows all of the reinforcing from both layers viewed at the same time. The reinforcing was placed by picking the top of each reinforcing bar reflection and using the target acquisition mode. The colour coding from the B-scan relates directly to the colours used in this image.

Figure 5: Scan Area shown from Angle

Fig 5 is the same image shown from an offset angle. It demonstrates the relative depth of each of the layers.

Figure 6: Side view of area Showing Definite Tilt in top Reinforcing

This last image (Fig 6) shows clearly that the top reinforcing has a server dip down to the bottom reinforcing level. This in itself could be picked from the B-Scans. It made creating the C-Scans difficult because the top reinforcing was at multiple levels.

Additional Information

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