Shake table testing of a pre and post-retrofitted unreinforced masonry structure: Preliminary experimental and numerical results

The paper presents the results of an experimental campaign on a ¾-scaled unreinforced masonry structure subjected to bidirectional shaking table tests carried out at the L.E.D.A. Laboratory of the Kore University of Enna. The study investigates the impact of progressive retrofitting and repair strategies for the as-built structure, which was designed to represent a heritage residential building of central Italy. Three sequential shaking table tests were carried out. In the first test, the as-built configuration was tested up to the early damage achievement. In the second test, prior stiffening and strengthening of the floor slabs was performed, also including improved connections of the floor slabs with the perimeter walls. For the third test, the structure was repaired by the application of internal and external FRCM layers to the masonry walls. A detailed 3D finite element model of the three configurations of the specimen was developed with the STKO software platform for OpenSees to reproduce the experimental tests and complement the interpretation of the experimental results. The preliminary results shown in the paper illustrate the influence of the progressively introduced retrofit interventions by assessing structural performance in terms of damage onset and propagation, and capability of the retrofitting systems in repairing prior seismic damage.