Introduction of Non destructive testing methods, IS Code provision for NDT testing, Necessity

1. Presented by,
Ms. Varsha G. Jadhav
M.E.- Structural Engineering,
Civil Engineering Department
Jawaharlal Nehru Engineering College
Aurangabad

2.  Nondestructive testing (NDT) is the process of
inspecting, testing, or evaluating components
without or partial damage
 It analyses and suggests appropriate repairs
and retrofitting measures required for the
buildings to perform better in its service life.
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3.  The issue of Structural Audit has been a
growing interest across all sectors.
 Most buildings in Aurangabad City are over 30
years old.
 The National Crime Records Bureau, in a data-
report states that in the last 10 years, up to year
2012, there has been 448 building collapses, in
Maharashtra, killing over 425 people
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4.  Structural Auditing for all types of R.C.C. Structures
(Residential, Commercial and Industrial)
 Conduction of various workshops for training for
students and consultants in the area of structural
auditing.
 Useful for Projects of B. Tech. and M. Tech. students
 Research and development in the domain of
structural engineering
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5.  Test on actual structure at several location
 Assessment of uniformity of concrete
 Location of cracks, voids & honey combs
 Detection of location damaged due to
overloading or other impacts
 Quality in relation to the IS requirement
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6. 1. Rebound Hammer
2. Ultrasonic Pulse Velocity Meter
3. Half Cell Potential Meter
4. Core cutter
5. Profometer
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7.  To asses quality of concrete in relation to the
standard results
 To estimate compressive strength of concrete
with correlation between rebound index and
compressive strength
 To delineate regions of poor quality concrete
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8.  Calibration:
 The calibration factor is
obtained by testing the
hammer against Steel
having Brinell
Hardness of about 5000
N/mm2
 Co-relation:
 Data is analyzed for 3
positions of Rebound
Hammer (i.e. -90⁰, 0⁰
and 90⁰) to derive
equation of co-relation
between the Rebound
number and
Compressive Strength
 Eg
For 0 deg
Y = 0.013x2 + 0.723x – 5.642
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9.  Consider the following example
 The following 6 values are obtained in a Rebound
Hammer Test for 0⁰ position of Hammer
 29, 31,29,28,28,29 (After considering outliers as per IS
8900)
 Average = 29
 Calibration Factor = 1.036
 Average x Calibration Factor = 29 x 1.036 = 30.044
 Substituting in the co-relation equation
 Y= 0.013(30.0442)+ 0.723(30.044) – 5.642
 = 27.82 N/mm2
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10.  To assess homogeneity & uniformity of
concrete
 To assess quality of concrete in relation to IS
requirement
 Detection of the presence and approximate
extent of cracks, voids
 Measurement of changes occurring with time
in the property of concrete
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11.  Working Principle: The
equipment consist of
transmitter and receiver
probe (20 kHz to 150 kHz)
and time measuring device.
 The transmitter and receiver
probes are pressed against
the concrete surface.
 The physical distance (L)
between the probes are
measured in mm
 The Time (T) required to
traverse the ultrasonic pulse
from transmitter to receiver
is recorded in microsecond
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12.  Less Time required to
traverse through
uniform concrete
 More Time required
to traverse through
damaged/uneven
section
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13.  Velocity (V) is determined by dividing the Length (L) by Time (T)
 V = L/T
 Quality Parameter as per IS 13311-Part 1
Velocity (km/s) Grade
V > 4.5 Excellent
3.5 to 4.5 Good
3.0 to 3.5 Medium
Below 3.0 Doubtful
 Uniformity Parameter (empirical)
Range (Diff between Max and Min) Quality
Less than 0.5 km/sec Uniform
Greater than 0.5 km/sec Doubtful
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14.  This is electrochemical process to detect
corrosion in the reinforcement bar.
 This instrument measures the potential and the
electrical resisistance between the reinforcement
and the surface to evaluate the corrosion activity
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16.  Core Cutting: Core should be cut from
hardened concrete having ends reasonably
even and perpendicular. A core which, before
capping has a maximum height of less than
95% of dia or after capping height less than its
diameter shall not be used.
 Capping: The cut core shall be capped with
suitable material (compressive strength greater
than the compressive strength of concrete and
shall not depart by more than 0.05 mm)
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17.  Correction Factor: For specimen of
height/diameter ratio other than 2. Correction
factor shall be applied as per (Fig 1) of IS 516
 Equivalent Cube Strength of the concrete shall
be determined by multiplying the corrected
cylinder by 5/4
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18.  Dia: 68mm
 Height: 136mm
 Height/Dia: 2:1 (Correction factor 1)
 Failure Load: 45.8 kN
 Area of Core: 3631.68 mm2
 Equivalent Cube Strength: = (5/4) x Load/Area
= (5/4) x 45.8x1000
3631.68
= 15.76 N/mm2
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19.  To assess diameter
 Location of reinforcement
 To asses cover
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20. THANK YOU
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