Dynamic elastic properties of brick masonry constituents Nirvan Makoond ∗ , Luca Pel` a, Climent Molins Department of Civil and Environmental Engineering, Universitat Polit` ecnica de Catalunya (UPC-BarcelonaTech), Jordi Girona 1-3, 08034 Barcelona, Spain Abstract When subjected to dynamic loading, materials can exhibit a mechanical behaviour quite different from its static counterpart. The evaluation of dynamic properties is thus very useful in the assessment of existing masonry structures. This paper presents results of an experimental campaign to determine both the dynamic Young’s modulus and the shear modulus of brick masonry constituents through two non-destructive testing methods. Following a discussion on the reliability of the methods, a robust procedure is described and tested on a variety of samples. The results show that the techniques can be successfully applied to provide reliable estimates of the dynamic elastic properties of brick masonry constituents. Keywords: Brick masonry, Non-destructive testing (NDT), Impulse excitation of vibration (IEV), Ultrasonic pulse velocity (UPV), Elastodynamics, Young’s modulus, Shear modulus, Poisson’s ratio Link to formal publication: https://doi.org/10.1016/j.conbuildmat.2018.12.071 1. Introduction Static elastic properties of masonry constituents are in general well understood. Indeed, a considerable amount of information is available in literature on the determination and estimation of such properties. For instance, the European Committee for Standardisation (CEN) has approved a European Standard on the determination of the static elastic modulus for natural stone since 2005 [1]. Tests to determine static elastic properties rely mainly on measuring deformations while applying controlled loading. Hence, the modified 5 application of recommendations from standards designed for other materials such as concrete is, at least in theory, relatively straightforward. As a consequence, several authors such as Binda et al. [2–5], Oliveira et al. [6–8] and Pel` a et al. [9] have explored testing procedures to determine these properties for masonry constituents and assemblages. Many of these studies have shown that although the theory behind the eval- uation of static elastic properties is well understood, the scatter of results in experimental studies remains 10 high in many cases, often due to the difficulties related to measuring deformations in the elastic range of brittle materials such as those typically used as constituents in brick masonry constructions. Nevertheless, a considerable amount of information is still available, not only on best testing practices, but also on the range of expected results for different types of bricks and mortar, as well as on the effects which can influence the estimates of static elastic properties for brick masonry constituents. 15 Dynamic elastic properties refer to the constants that define a material’s behaviour in the elastic range under vibratory conditions. When subjected to dynamic loading, experiments have shown that materials can feature a mechanical behaviour quite different from its static counterpart. A possible physical cause of this empirically known inequality between measured static and dynamic elastic moduli may be found in the 20 different inelastic contributions to stress-strain which behave as a function of strain amplitude and frequency (energy and strain rate) [10]. Most of the studies available in literature focus on the relation between static and dynamic elastic properties of rocks in a geophysical context [11–14]. As such, although some authors, notably Totoev and Nichols [15, 16], have explored this relationship for specific types of bricks, it is still not * Corresponding author Email addresses: nirvan.makoond@upc.edu (Nirvan Makoond), luca.pela@upc.edu (Luca Pel` a), climent.molins@upc.edu (Climent Molins) Preprint submitted to Construction and Building Materials November 8, 2018