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S24 Mecânica dos Sólidos |
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Title:
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THE INFLUENCE OF REINFORCING STEEL BARS ON THE APPARENT LONGITUDINAL ULTRASONIC PULSE VELOCITY IN CONCRETE: A SIMPLE MATHEMATICAL MODEL
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Summary :
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LOW ULTRASONIC FREQUENCIES MUST BE USED IN NON-DESTRUCTIVE TESTING OF HETEROGENEOUS MATERIALS, SUCH AS PLAIN AND REINFORCED CONCRETE, CAST IRON OR TIMBER. WHEN FREQUENCIES ARE LOW ENOUGH, SIZE AND SHAPE OF TESTED BODIES MAY INFLUENCE THE MEASURED LONGITUDINAL PULSE VELOCITIES.
AN APPROACH WHICH IS NAMED "QUASI-FLUID" IS APPLIED TO DISCUSS THE LONGITUDINAL PULSE PROPAGATION IN REINFORCING STEEL BARS EMBEDDED IN CONCRETE. WAVE PROPAGATION IS DESCRIBED BY A SPATIALLY-AVERAGED DILATATIONAL FIELD.
AN APPROXIMATE FORMULA IS OBTAINED WHICH RELATES GROUP VELOCITY WITH AN EFFECTIVE RADIUS OF THE EMBEDDED BARS, WITH TRANSDUCER FREQUENCY, AND WITH THE ASYMPTOTIC P-WAVE VELOCITY IN STEEL AND CONCRETE, AMONGST OTHER PARAMETERS. THE EVOLUTION OF A TYPICAL ULTRASONIC PULSE IS DESCRIBED USING STATIONARY-PHASE METHODS.
SEVERAL KNOWN EXPERIMENTAL FACTS ARE THUS EXPLAINED.
FINALLY, COMMON-USE EMPIRICAL CORRELATIONS BETWEEN THE MEASURED LONGITUDINAL PULSE VELOCITY AND THE DIAMETER OF EMBEDDED STEEL BARS ARE DISCUSSED USING THE MODEL DEVELOPED IN THIS PAPER.
KEY WORDS: ULTRASOUNDS, WAVE PROPAGATION, NON DESTRUCTIVE TESTING,CONCRETE.
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Author :
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Suarez Antola, Roberto 0
Suarez Bagnasco, Diego 0
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Paper View :
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