Repair methods for the fatigue crack in steel bridges depend on the size of the damage. Therefore, in order to perform the appropriate repair for fatigue damage, it is important to know the crack depth.
In this study, we investigated a method to estimate the crack depth for semi-elliptical surface crack based on the stress intensity factor. First, we conducted a numerical analysis to verify a method to estimate the stress intensity factor for semi-elliptical surface crack and the crack depth. From the numerical analysis results, it was shown that the crack depth could be estimated within an error of ±15%. Secondly, in order to verify the effectiveness of the proposed method, fatigue tests were conducted using tensile specimens. From those fatigue test results, the crack depth could be estimated using the estimated stress intensity factor within an error of ±28%. In addition, we examined the index to evaluate the pasting accuracy of the gauge from the measured strain data.
