Application of Non-destructive Testing Techniques for Condition Assessment of Wall Ties in Masonry Construction

Experimental modal analyses on masonry structures have proven effective in damage identification, particularly in detecting cracks and defects on single-leaf masonry walls and identifying damage locations using non-destructive, vibration-based methods. However, limited studies have been conducted on investigating damage caused by deterioration of wall ties within masonry veneer and cavity walls using this methodology and the assessment of wall ties often relies on intrusive and destructive means. An experimental program consisting of 8 full-scale veneer and cavity walls  was proposed and finite element models were constructed. This present work discusses the results of preliminary numerical modelling of veneer and cavity walls with the influence of wall tie deterioration. The proposed experimental program is planned to verify the effectiveness of modal analysis in assessing conditions of wall ties within veneer and cavity walls based on changes in modal parameters. Based on results from preliminary numerical modelling, a clear trend of natural frequency reduction was observed when the cross-sectional area of wall ties was reduced.