DYNAMIC ANALYSIS OF THE OUT-OF-PLANE BEHAVIOUR OF MASONRY FACADES USING RIGID BEAM MODEL

In this work, a simple and effective Rigid Beam Model originally introduced for studying the dynamic behaviour of ancient freestanding stone columns and recently extended to the case of cantilever unreinforced masonry walls subjected to out-of-plane loading, is further extended to simulate the out-of-plane behaviour of loadbearing façades. Such structural elements are characterized by the presence of at least one or two slabs and roofs, which transfer further vertical loads to the façade and represent additional masses that can be activated by ground acceleration. The proposed model assumes the wall vertically subdivided in equal portions modelled as rigid beam elements and each interface between portions is assumed as a node. Considering no sliding along the interfaces and small displacements of blocks, rocking can be simulated by a bi or tri-linear moment rotation non-linear constitutive law. Monolithic façades with different levels of additional mass on top are modelled and subjected to different in magnitude and frequency harmonic loading. From the analysis results, it is found that monolithic walls can overturn with acceleration magnitudes larger than their corresponding static load multipliers, if input frequency values increase. On the other hand, results converge to static load multipliers for decreasing input frequency values.