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PS 200 Ferroscan

PS 200 Ferroscan. PS 200 Ferroscan. Measuring Systems. Application Knowledge. Application Knowledge. Rebar is added to concrete to increase its tensile strength. Concrete is very strong in compression, but very weak in tension

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PS 200 Ferroscan

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  1. PS 200 Ferroscan PS 200 Ferroscan Measuring Systems

  2. Application Knowledge Application Knowledge

  3. Rebar is added to concrete to increase its tensile strength • Concrete is very strong in compression, but very weak in tension • Loads placed on concrete are tension which may cause the concrete • to break • Rebar can be added to concrete for added strength

  4. Rebar placement and coverage information can be critical • Knowledge of rebar placement and the amount of concrete coverage can be critical to insure the integrity of the structure • Factors influencing rebar integrity: • Rebar Corrosion – weakening of the concrete • Fire Protection – rebar loses its strength • Rebar Verification for Load Changes – can a structure’s use be changed? • Safe and Fast Drilling – not hitting statically relevant rebar, less wear and tear on drills and bits

  5. Rebar corrosion weakens concrete structures Concrete surfaces sprayed repeatedly with salty water from the ocean or road surfaces during winter The salts penetrate the surface and soak into the rebar The rebar corrodes and expands The structure is weakened by the corroded rebar. In some instances, the concrete surface may blow off

  6. Rebar loses is strength in high temperatures, such as fires Concrete surface is exposed to fire over a long period of time The heat will penetrate the concrete Rebar that heats up loses its strength. Almost all strength is lost at about 932°F (500°C) and an average building fire temperature is 1500-1800°F (815°C-982°C). The deeper the rebar is in the concrete, the less it will heat up The rebar loses its strength and the structure can be damaged

  7. Knowing rebar placement and size can determine the load placed on it Changing loads on a structure … Can the structure’s use be changed?

  8. Knowing rebar location aids safe and fast drilling • Prevent cutting of statically relevant reinforcement • Increase life of drill and core bits • Reduce wear and tear on tool motors • Reduce time spent drilling

  9. Application / User / Scan Mode Matrix Required Information Who needs the information The Issue Scan Mode • Corrosion studies • Fire protection • General Contractors • Civil Contractors • Civil Engineers • Quickscan Recording • Change of loads on a structure • General Contractors • Civil Contractors • Civil Engineers • Imagescan • General Contractors • Diamond Specialists • Road, Bridge and Tunnel Contractors • Mechanical & Electrical Contractors • Quickscan Detection • Imagescan • Blockscan • Safe Drilling

  10. Detection Principle Detection Principle

  11. Magnetic field Radar waves There are 3 main types of detection tools Disadvantages Advantages 1. Induction – PS 200 • Instant, 3-D image • Can analyze the image on the jobsite • Easy operation • Can analyze large areas quickly • Very good depth accuracy • Can use on floors, walls or ceilings • Detects rebar and other ferrous objects only • Image depth limited to 7.1” (180 mm) depending on rebar size • Can see everything in the concrete • Can see very deep in the concrete with large, push behind equipment • Must be processed in an office • Very difficult to analyze • Very poor depth measurement • The size of the tool determines the depth it will read – the smaller tools don’t see very deep • Cannot work in a damp or wet environment 2. Reflection - Radar 3. Inflection – X-ray • Can see everything in the concrete • Very clear, 2-D image • Dangerous - the working area has to be cleared of people • No depth measurement • Must have access to both sides of the structure • Very slow to process image • Extremely expensive Transmitter Receiver

  12. The magnetic field produced by the PS 200 becomes distorted When the scanner is far away from rebar or ferrous metal it produces a perfect magnetic field When the scanner is placed over rebar the magnetic field becomes distorted The distortion creates a current around the 7 sensor coils and produces a signal the tool can interpret

  13. Radius End point Angle Start point Amplitude Other factors are considered in determining rebar diameter and depth Because the signal that is created around the sensor coils cannot determine rebar diameter or depth, other factors also have to be considered: • Signal strength alone cannot determine rebar size • - Two different sized bars can have the same signal strength • - The signal strength is always strongest at the surface • Additional factors that must be examined • - Start and end points of the signal • - Radius • - Angle • - Amplitude • The PS 200 is programmed to calculate the depth and diameter based on US and Canadian rebar standards

  14. The amount of signal generated does not indicate rebar size Two different sized boxes will make the same size shadow depending on the distance they are away from the light source A large rebar deeper in the concrete produces the same signal as a smaller bar near the surface

  15. The software analyzes the data to determine rebar position, depth and diameter The software uses mathematical analysis to determine the number and approximate position of the rebar Next, it separates the signals into individual rebars Last, the software determines the bar size and depth Location, coverage and diameter

  16. Other factors also influence what the PS 200 can detect Based on the magnetic principle of locating, determining diameter and depth of rebar, there are other factors that influence what the PS 200 is able to detect: • Rebar Spacing • - Rebar that is closely spaced together • The Shading Effect • Ferrous Metal Detection • - The PS 200 is designed to detect ferrous metal, specifically rebar that meets US and Canadian rebar standards

  17. Rebar Spacing can effect the PS 200’s ability to distinguish rebar Rebar must be spaced a minimum distance apart for the PS 200 to be able to distinguish individual bars The minimum rebar spacing is defined as the ratio S:C (Spacing:Coverage) and the bars must be at least 1” in the concrete • For image and depth of rebar, the ratio is ≥ 1:1 • To determine diameter, the ratio is ≥ 3:1 • Using Quickscan Detection, the ratio is ≥ 2:1 • Using Quickscan Recording, the ratio is ≥ 1:1 C = Coverage S = Spacing For example, to determine the image of rebar 4 in (100 mm) in the concrete, the rebars must be at least 4 in (100 mm) apart.

  18. The Shading Effect can also effect the PS 200’s ability to distinguish rebar The Shading Effect – the magnetic field from the first layer of rebar shades the second layer of rebar preventing detection of second layer. 1st Layer of rebar Shading 2nd Layer of rebar

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