WHY USE GSSI GPR

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WHY USE GSSI GPR?
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History of GPR

• GPR invented 1970
• Uses
• To Find Bedrock, Water Tables, and Geological
  Features
• Nuclear power industry 1980s

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Theory

• Electromagnetic Reflection (EMR)
• Ultra Wide Band frequency
• 300 MHz to 3 GHz
• 64 KHz repetition rate

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Characteristics

• Average radiated power - .004
  milliwatts
• Practical limits 15-18 in concrete with 1.6GHz
  antenna
• Up To 36 Deep with 900MHz antenna

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ADVANTAGES OF GPR

• EXTREMELY ACCURATE
• FAST
• REAL TIME TARGETING
• NON-DESTRUCTIVE
• ONE SIDE ACCESS (SLAB ON GRADE)
• NON-INTRUSIVE
• DIGITAL MEDIA STORAGE

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EXAMPLES2D 3DData
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Typical Slab on Grade
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GOOD CONCRETE
DETERIORATED
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Slab on Grade VS Structural Slab
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Plan-view Mapping
WIRE MESH
Rebar Mat
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DOUBLE REBAR MAT
Dbl Rebar Matt 2 D Dbl
rebar Matt 3D
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Advanced Mappingin Super 3D
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Identifying Conduit 2D

• A target that doesnt fit the rebar pattern is
  most likely a conduit and requires further
  investigation

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Identifying Conduit Slicing The Data
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Mapping Out Radiant Heating Lines In Slab
2-D Plan View
3-D Depth Slice
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BecausePicture worth a thousand words
Before Concrete
Results of scanning
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GSSI - Demonstration Fermi National Accelerator
Laboratories April 13, 2005

• Four Sites were chosen for the purpose to
  showcase GPR with known embedments inside the
  concrete of Fermi Labs.
• The Four Sites
• First Site IBC Cryostat Area (Side)
  Grid 002
• Second Site ICB Collaring Press Saw Cut Grid
  003
• Third Site ICB 2W Headquarters Conf Rm Grid
  005
• ICB Computer Area (Field Issues)
  Grid 006

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First Site IBC Cryostat Area (Side)
End of Wire Mesh
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First Site IBC Cryostat Area (Side)
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First Site IBC Cryostat Area (Side)
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First Site IBC Cryostat Area (Side)
New Roll of 4 Mesh
Curling End of Wire 4 Wire Mesh
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Second Site ICB Collaring Press Saw Cut
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Second Site ICB Collaring Press Saw Cut
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Second Site ICB Collaring Press Saw Cut
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Third Site ICB 2W Headquarters Conf Rm
Target Under Conf Table
Known Conduit See User Mark
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Third Site ICB 2W Headquarters Conf Rm
Wire Mesh
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Third Site ICB 2W Headquarters Conf Rm
Conf Room Wall
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Third Site ICB 2W Headquarters Conf Rm
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Fourth SiteICB Computer Area (Field Issues)
2.
3.
1.
The Bright white dots are the targets in the
concrete. This is a 2D side profile.
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Fourth SiteICB Computer Area (Field Issues)
3.
2.
1.
Conduits
Post Processing
On Screen
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Fourth SiteICB Computer Area (Field Issues)
Pinpoint targets in the 2D Profile view while
interactive cross-hairs are shown on the 3D Cube
above.
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Fourth SiteICB Computer Area (Field Issues)
Note The Mesh Depth Change
2x2ft Structure Scan Optic Pad Conduits in
Yellow
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Conclusion

• The four sites scanned by Structure Scan yielded
  excellent results.
• A. Near field conduits were evident.
• B. 4 wire mesh was shown clearly
• C. Conduits were seen deeper as well.
• D. Post Processing data helps exact target
• location with Super 3D.