Experimental study on one-way arching masonry specimens under monotonic and cyclic loads

Characterizing the behavior and the mechanical properties of masonry assemblies subjected to out-of-plane static loading is a fundamental step towards the understanding of their response to more complex loading scenarios. The more challenging case is that of arching walls where the load resistance mechanism couples bending and axial components. This study presents a combined experimental and theoretical effort aiming at gaining insight into the behavior of such arching walls. The experimental phase is conducted on small-size one-way specimens that are comprised of two or four masonry units loaded in a four-point-bending scheme. The experimental methodology aims at collecting new quantitative data on the response under monotonic and cyclic loadings. The 2-block configuration mimics the basic form of arching walls and focuses on the interaction between the masonry units and the mortar layer, features that are essential for any quantitative, analytical or numerical assessment of such walls. The 4-block configuration mimics the more complex response when additional mortar joints are part of the structural system. Along with the global load–displacement curve, the experiments also monitor the arching force, as well as local aspects such as the axial deformations at the tensed and compressed extreme fibers of the mortar joints. The latter aims at studying the constitutive behavior of the mortar joints. The complete set of test results is then used as a benchmark for comparison with an analytical model. The comparison examines the model capabilities, reveals further aspects of the physical behavior, and explores the cracking process, the deformation profile, and the effect of inelastic behavior of the mortar material. The combined experimental and theoretical findings reveal the spectrum of phenomena governing the behavior of masonry walls and highlight the role of the arching mechanism through macro and micro perspectives.