Failure analysis of a rock anchor made of stainless steel in marine environment

Anchors made of stainless steel have been widely used for rock anchoring in marine environments. The presence of the corrosive environment, the tightening induced stresses and the susceptibility of the anchor material to stress corrosion cracking are the most critical parameters that may influence the longevity of the anchor. Failure investigation was carried out on fragments of a broken rock climbing anchor. Optical and scanning electron microscopy for structural and fractographic evaluation along with numerical modeling are used as the principal techniques in the context of the present investigation. Failure analysis findings suggest that the failure was caused by stress corrosion cracking. The anchor experienced extensive cracking during its lifetime and eventually broke when an unsuspected climber attempted to hang from it.