An Impact-Echo Experimental Approach for Detecting Concrete Structural Faults

Table 4

Measurement point results of plate No. 2.

Measuring point	Working condition	ftest	ftheory	ᅀf (%)	Ftest	Ftheory	ᅀF (%)
3	1/3	5409	6381	15.2	16280	17403	6.5
	2/3	5882		7.8	18943		8.8
4	1/3	5304		16.8	15986		8.1
	2/3	5943		6.9	15874		8.7

Notes. The above frequency unit is kHz. f_test—the test value of plate thickness frequency. f_theory—the theoretical value of plate thickness frequency. F_test—the test value of defect frequency. F_theory—the theoretical value of defect frequency.