Fatigue tests of plates with gussets welded to the plate edges were fatigue tested under plate bending type of loading. When fatigue cracks initiated and propagated from the gusset ends, Impact Crack Closure Retrofit treatment, ICR treatments, were applied to the cracks in order to stop or to reduce further fatigue crack propagation. The ICR treatment is the technique to produce plastic deformation near the fatigue cracks to close opening of the crack, and thus reduce stress intensity factor. Fatigue test results showed significant improvement of remaining fatigue life after ICR treatment.
