ANIDIS - L'ingegneria Sismica in Italia, ANIDIS XIX & ASSISi XVII - 2022

Dimensione del carattere:  Piccola  Media  Grande

Innovative Method for Masonry Columns Confinement

Alberto Viskovic, Claudio Valente, Alice Di Primio, Rossella Brescia

Ultima modifica: 2022-09-05


The Italian cultural heritage is largely composed by masonry structures. This type of structures is particularly sensitive and scarcely resilient to earthquakes. The technical and scientific communities devoted their attention to the problem since several decades and important achievements have been reached meanwhile. Nonetheless, much work should still be done in different fields among which the strengthening improvement of masonry columns is one of the main concerns. In this case masonry confinement is commonly resorted to. Proposals range from invasive FRP warping to hooping to confine the mortar joints. The paper deals with the presentation of a novel confinement approach capable to overcome the drawbacks of the existing techniques either in terms of mechanical behavior or technological aspects. The purpose of the work is to study the improvements of the performances of masonry columns reinforced through non-conventional hooping system using "Dyneema ribbons". Apart strengthening, this system is endowed with ease of installation and removal, as compared with steel or FRP based systems, and is fully compliant with the requirements of fitting, deformability and reversibility. The research develops along with two main phases: numerical (completed) and experimental (in progress). The numerical models are realized using 3D solid f.e. with dimensions adjusted to fit the deformation gradients. The nonlinearity is concentrated at the mortar-brick joints. The bonding between ribbons and mortar is modelled using appropriate interface elements aimed at reproducing the stress transfer during installation and in working condition. A device has been properly designed to install the ribbons with the correct hooping traction. Incremental non-linear static-equivalent analyses have been performed. The numerical results, compared to similar solutions but with different strength and stiffness (Nylon ribbons), allow to draw the following conclusions: (i) the Dyneema ribbon offers better mechanical performances than Nylon ribbon, (ii) the hooping provided by the ribbons noticeably increases the stiffness and the load carrying capacity of the column, (iii) the failure mode tends to change from brittle to ductile. 

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