Torin recently presented on nondestructive evaluation of stone anchor corrosion effects at the 2022 TMS Annual Meeting held October 12-15, 2022, in Denver, Colorado.
Historic stone masonry often has embedded metal anchors connecting facing stones to masonry backup materials. Anchor corrosion causes damage to surrounding stone at metal anchor embedments, and the typical approach is to repair stone damage after it manifests itself as visible cracks or spalls. A new approach has been developed to evaluate subsurface damage before it becomes visible, thereby identifying potentially dangerous conditions and reducing the scope of repairs. The method uses an ultrasonic pulse-echo array system to identify subsurface cracks at anchor positions located using surface penetrating radar or pachometer equipment. Case studies are included showing how the method successfully located damaged anchorages at stone and cast stone materials, including one project where results were validated with a series of probe openings. Recommendations will be provided for using the approach with different materials and conditions.