Masonry walls with multi-layer bed joints subjected to cyclic shear: Analytical modelling

An analytical rheological model capable of describing the loading speed dependent in-plane shear behavior of the unreinforced masonry (URM) walls with a multi-layer bed joint subjected to static-cyclic shear loading is presented. Such joints consist of a core soft layer protected by two thin extruded elastomer membranes, which in turn are placed in a bed mortar joint. The extruded elastomer membranes are employed to prevent and/or limit the deterioration of the core soft layer during the cyclic action. Joint behavior is assumed to be linear elastic-perfectly viscoplastic and has been captured by a uniaxial model consisting of three elements: an elastic spring connected in series with the frictional slider and a dashpot (viscous damper). Assuming a linear elastic behavior of masonry, the model was able to describe the in-plane horizontal force-displacement behavior of URM walls with multi-layer bottom bed joints and was validated against the experimental results.