Application of Surface Wave Transmission Measurements for Crack Depth Determination in Concrete

10.14359/815 ◽  
2000 ◽  
Vol 97 (2) ◽  
Keyword(s):  
Surface Wave ◽  
Crack Depth ◽  
Wave Transmission ◽  
Depth Determination ◽  
Transmission Measurements

scholarly journals A Practical Guide to Source and Receiver Locations for Surface Wave Transmission Measurements across a Surface-Breaking Crack in Plate Structures

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3793
Author(s):  
Janghwan Kim ◽  
Seong-Hoon Kee ◽  
Jin-Wook Lee ◽  
Ma. Doreen Candelaria
Keyword(s):  
Surface Wave ◽  
Wave Transmission ◽  
Laser Vibrometer ◽  
Plate Structures ◽  
Reflected Waves ◽  
Practical Guide ◽  
Practical Guidelines ◽  
Transmission Measurements ◽  
Simulation Results ◽  
Surface Breaking Crack

The main objectives of this study are to investigate the interference of multiple bottom reflected waves in the surface wave transmission (SWT) measurements in a plate and to propose a practical guide to source-and-receiver locations to obtain reliable and consistent SWT measurements in a plate. For these purposes, a series of numerical simulations, such as finite element modelling (FEM), are performed to investigate the variation of transmission coefficient of surface waves across a surface-breaking crack in various source-to-receiver configurations in plates. Main variables in this study include the crack depths (0, 10, 20, 30, 40 and 50 mm), plate thicknesses (150, 200, 300, 400 and 800 mm), source-to-crack distances (100, 150, 200, 250 and 300 mm) and receiver-to-crack distances. The validity of numerical simulation results was verified by comparison with results from experiments using Plexiglas specimens using two types of noncontact sensors (laser vibrometer and air-coupled sensor) in the laboratory. Based on simulation and experimental results in this study, practical guidelines for sensor-to-receiver locations are proposed to reduce the effects of the interference of bottom reflected waves on the SWT measurements across a surface-breaking crack in a plate. The findings in this study will help obtain reliable and consistent SWT measurements across a surface-breaking crack in plate-like structures.

scholarly journals Surface-Wave Based Model for Estimation of Discontinuity Depth in Concrete

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2793 ◽  
Author(s):  
Eunjong Ahn ◽  
Hyunjun Kim ◽  
Sung-Han Sim ◽  
Sung Shin ◽  
John Popovics ◽  
...  
Keyword(s):  
Surface Wave ◽  
Crack Depth ◽  
High Strength ◽  
Depth Estimation ◽  
Wave Transmission ◽  
Spectral Energy ◽  
Estimation Model ◽  
Strength Concrete ◽  
Wide Range ◽  
Normal Strength

In this paper, we propose an accurate and practical model for the estimation of surface-breaking discontinuity (i.e., crack) depth in concrete through quantitative characterization of surface-wave transmission across the discontinuity. The effects of three different mixture types (mortar, normal strength concrete, and high strength concrete) and four different simulated crack depths on surface-wave transmission were examined through experiments carried out on lab-scale concrete specimens. The crack depth estimation model is based on a surface-wave spectral energy approach that is capable of taking into account a wide range of wave frequencies. The accuracy of the proposed crack depth estimation model is validated by root mean square error analysis of data from repeated spectral energy transmission ratio measurements for each specimen.

Determination of Depth of Surface Cracks in Asphalt Pavements

2003 ◽  
Vol 1853 (1) ◽  
pp. 143-149 ◽  
Author(s):  
Shane Underwood ◽  
Y. Richard Kim
Keyword(s):  
Surface Wave ◽  
Wave Velocity ◽  
Ultrasonic Testing ◽  
Kernel Method ◽  
Direct Method ◽  
Velocity Ratio ◽  
Crack Depth ◽  
Asphalt Pavements ◽  
Quantitative Prediction ◽  
Processing Techniques

Nondestructive measurement of crack depths of asphalt pavements in situ could be a valuable tool for engineers in rehabilitation planning. Such measurements currently must be made by first coring or trenching a pavement and then measuring the crack by hand. Two methods for performing this task nondestructively are presented. The two methods, surface wave and ultrasonic, use the slowing effect that a crack has on a wave. Two signal-processing techniques were used to analyze the surface wave method—the fast Fourier transform (FFT) and the short kernel method (SKM). The FFT method provided a frequency spectrum that was used to find the energy carried by specific frequencies. The percent energy reduction (PER) was computed and plotted at each crack depth; this plot revealed that PER values increase as crack depth increases. The SKM method showed the wave velocity to decrease as the crack depth in creased. By comparing the wave velocity of the cracked pavement with that of the undamaged pavement, a phase velocity ratio plot was developed and was shown to be adequate for predicting crack depth. Ultrasonic testing proved to be a simpler and more direct method than surface wave testing. It was not necessary to know the wave properties of an undamaged pavement with this method, and a quantitative prediction of crack depth was obtained. While encouraging results were observed with both methods, ultrasonic testing showed the most promise for application because of the commercial availability of ultrasonic meters and the direct prediction of crack depth.

Crack-Depth Determination by a Neural Network with a Synthetic Training Data Set

1993 ◽  
pp. 803-810 ◽  
Author(s):  
M. Takadoya ◽  
M. Notake ◽  
M. Kitahara ◽  
J. D. Achenbach ◽  
Q. C. Guo ◽  
...  
Keyword(s):  
Neural Network ◽  
Crack Depth ◽  
Training Data ◽  
Data Set ◽  
Depth Determination ◽  
Synthetic Training Data
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