Correlation between sonic pulse velocity and flat-jack tests for the estimation of the elastic properties of unreinforced brick masonry: Case studies from Croatia

Historic urban cores in southern Europe are characterized by a significant number of existing unreinforced masonry structures that are known for their seismic vulnerability. The first step in the preservation of such damaged buildings is condition assessment and characterization of the mechanical properties of the masonry, which can be achieved using non-destructive, semidestructive and destructive methods. In this paper, the emphasis is on determining the modulus of elasticity of unreinforced masonry through flat-jack and sonic pulse velocity tests. Both methods are explained in detail and results from eight different case studies are presented. The results are compared and correlations among the techniques are observed, showing that both methods can be suitable for estimating the elastic properties of existing masonry. The paper provides a wide set of experimental data that has been made available. Finally, a sensitivity analysis was performed. Differences between static and dynamic modulus of elasticity and operational and practicability issues regarding on-site testing are discussed.