Structural Health Monitoring of Precast Concrete Box Girders Using Selected Vibration-Based Damage Detection Methods

Table 5

Error in predicted damage location by each method, listed as a fraction of measurement point spacing, when two and three modes were used in combination with 15 measurement points.

Method	2 modes				3 modes
	Max. error	Avg. error	Stand. dev.	% ambig*	Max. error	Avg. error	Stand. dev.	% ambig*
CMS	0.50	0.14	0.09	2.5	0.50	0.14	0.09	0
DI	0.70	0.28	0.17	2.5	0.50	0.25	0.15	2.5
MCF	0.70	0.20	0.15	27.5	0.50	0.19	0.13	15

*indicates the percentage of the 40 cases that produced a second peak that was either at least 75% of the magnitude of the highest peak, or nearer to the damage location, including near support damage cases.