The corner mechanism in masonry structures is one of the out-of-plane modes that may frequently occur under dynamic actions such as earthquakes. The three dimensional motion, in principle complex to treat, can be simplified into a two-dimensional problem, where a prismatic equivalent block is associated to the corner mechanism. This paper provides a method to treat the corner mechanism in two dimensional rocking analysis, taking into account the roof actions -especially the roof thrust that acts as destabilizing force in the preliminary phases of motion -and the boundary conditions such as the transverse walls. A case study is taken as benchmark to perform rocking non-linear analyses and discuss the role of geometry, energy dissipation and boundary conditions. It is shown the relevant influence of the geometry and of the coefficient of restitution on the stability conditions, whenever the oscillation produce horizontal displacement values of some cm. The results of the case study, subjected to the Central Italy earthquake, are compared to the actual response of the corner mechanism, which collapsed during this seismic swarm, showing that the rocking analysis on the equivalent block correctly predicts the collapse occurred.

Wall-to-horizontal diaphragm connections play a crucial role in the global stability of historical buildings under seismic actions. When these links are ineffective or absent, engineered measures should be considered to enhance the earthquake-resistant box-type behavior. Besides the great variety on the construction systems and materials, common damages were observed in recent seismic events showing the high vulnerability of local mechanisms promoted by the lack of structural integrity. Although the acknowledged importance of connections, this topic has been practically neglected over time among the research community and practitioners and only few of them focused on the influence of diaphragm-to-wall connections on the dynamic behavior of the building as a whole.

This paper examines the dynamic behaviour of timber framed buildings under wind and dynamic loads, focusing on the role of connections being experimentally tested. The main aim of this manuscript is to analyze the in-service dynamic behaviour of a semi-rigid moment-resisting dowel-type connection between timber beam and column. For this purpose, two laboratory tests have been performed, the first on a connection and another one on a portal frame. The results are used to validate a numerical model of the simple portal frame, analyzed in OpenSees. The obtained relationships are also discussed and compared with Eurocode rules. The main result is that the joint stiffness is calculated through the Eurocode (EC) formulation underestimates the experimental one. A mutual agreement is obtained between the numerical model, validated from the experimental stiffness value for the connections, and the experimental results on the portal frame.

This paper presents an innovative anti-seismic device for controlling the out-of-plane rocking motion of masonry walls with traditional tie-rods, called LInear COntrolled Rocking Device (LICORD). LICORD is a low-impact box connected to the extremity of the traditional tie-rod designed to mitigate rocking for medium–high intensity earthquakes. Additionally, the paper widens the knowledge about the dynamic behavior of rocking walls through the interpretation of the results of an extensive experimental campaign performed on masonry specimens composed by clay brick and cementitious mortar. Firstly, the LICORD’s single components are tested to identify their stiffness and damping properties. Secondly, free vibration tests provide actual values of coefficients of restitution on free-standing walls and walls restrained by LICORD, where the walls vary for the height to thickness ratio. For the stockier wall, the ratio of experimental/analytical coefficient of restitution varies from 88 to 98%, whereas for the slender wall, the results are less scattered, with a minimum value of 95% and a maximum value of 96%. The restrained walls are characterized by coefficients of restitution from 5 to 25% less than the values found for unrestrained walls, depending on the equivalent viscous coefficient of the shock absorbers. Moreover, LICORD demonstrated to properly absorb and damp the oscillations of the wall and control its rocking motion, strongly reducing the number of impacts and the rotation amplitudes up to 70%. Considerations about the effect of one-sided motion on the assessment of coefficient of restitution are also given. The equivalent viscous damping coefficients are observed to be on the range 4% (unrestrained wall) and 7–20% for walls restrained by LICORD.