Grouting Defect Detection of Lapped Bar Connections Based on Impact-Echo Method

Table 4

Results of parametric analysis.

Buried depth (mm)	50	75	100	125	150
f1 (kHz)	9.166	8.83	8.66	8.83	9.166
Amplitude (10^−8)	4.48	3.45	2.37	2.00	1.93
Back-calculated depth based on f1 (mm)	207.38	215.27	219.42	215.27	207.38
f2 (kHz)	38.50	25.50	19.83	15.50	12.66
Amplitude (10^−8)	0.08	0.19	0.45	0.78	0.38
Back-calculated depth based on f2 (mm)	49.37	74.54	95.85	122.60	150.14