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L
OCATING
REINFORCEMENT
BARS
R
• The signal strength indicator bar on the display will increase in length.
• The depth of cover on the display will show a number.
• The LED on the search head will start to glow.
The search head is aligned directly over a reinforcement bar when:
• The pitch of the sound is at its highest.
• The signal strength indicator bar is at its maximum.
• The depth of cover is at its minimum.
• The LED is glowing at its most intense.
9. Record the position of the reinforcement bar (using chalk or similar).
5.3 To locate two layers of reinforcement bars
Layers of reinforcement bars are typically orientated at right angles to each other. To locate
individual layers of reinforcement bars, carry out the procedure in section 5.2 for each layer.
If the bars in the two layers are of similar size (Figure 10):
Search for the nearer layer first; it gives a stronger signal, and is least influenced by the other bars.
Then search for the second layer, this time scanning the head in lanes between the previously
located positions of the first layer of bars.
•
The first scan locates the nearer (top) layer.
•
The second scan locates the second (bottom) layer.
Figure 10. Scanning layers of bars of equal size
If the bars in the nearer layer are thin compared with those in the deeper layer (Figure 11):
Search for the deeper layer first; it gives a stronger signal, and is least influenced by the other bars.
Then search for the nearer layer, this time scanning the head in lanes between the now-known
positions of the deeper layer of bars.
•
The first scan locates the second (bottom) layer.
Second scan
First scan
331.book Page 19 Thursday, March 12, 2009 9:46 PM
