Adding splice plates is a commonly used technique to repair fatigue cracks. The crack tip is drilled out before the splice plates are add. In some cases, however, a new fatigue crack initiates from the drilled hole. Because the drilled hole is entirely covered by the splice plates, it is impossible to measure its strain that can be used to assess the crack generation from the drilled hole. The purpose of this study is to propose a method to estimate the strain of the drilled hole by using a reference strain on the splice plate. By conducting parametric FE analyses and loading tests, the location for the reference strain which is strongly correlated with the strain in the drilled hole was proposed.
