Delamination Detection of Reinforced Concrete Decks Using Modal Identification

Table 3

Comparison of natural frequencies of the undamaged and delaminated concrete decks for numerical example under SS-F-SS-F support condition.

Mode	Undamaged		1/8 delaminated		1/6 delaminated		1/5 delaminated		1/4 delaminated		1/3 unsymmetrical delaminated		1/3 symmetrical delaminated		1/2 delaminated
	Mode Shape	Freq	Freq	Difference	Freq	Difference	Freq	Difference	Freq	Difference	Freq	Difference	Freq	Difference	Freq	Difference
		(Hz)	(Hz)	(%)	(Hz)	(%)	(Hz)	(%)	(Hz)	(%)	(Hz)	(%)	(Hz)	(%)	(Hz)	(%)
1	1st bending	18.88	18.70	−0.94	18.63	−1.32	18.57	−1.65	18.43	−2.40	17.67	−6.39	18.29	−3.10	13.28	−29.64
2	2nd bending	22.69	22.42	−1.20	22.30	−1.70	22.19	−2.18	21.90	−3.46	20.60	−9.19	22.08	−2.68	18.67	−17.72
3	3rd bending	37.01	36.50	−1.38	35.91	−2.96	34.56	−6.63	29.77	−19.57	24.35	−34.21	26.87	−27.39	21.81	−41.06
4	4th bending	57.64	52.79	−8.42	42.31	−26.59	37.87	−34.29	35.76	−37.96	33.28	−42.26	38.76	−32.76	27.53	−52.24
5	5th bending	73.47	56.89	−22.57	55.36	−24.66	54.07	−26.40	51.22	−30.28	43.50	−40.79	47.21	−35.75	27.89	−62.04
6	6th bending	76.44	73.42	−3.95	71.58	−6.35	68.91	−9.84	59.98	−21.53	45.70	−40.21	51.12	−33.12	37.55	−50.87