Studio numerico-sperimentale sul comportamento ciclico di telai in c.a. tamponati

Under seismic loads the interaction between masonry panels and the concrete structure of infilled frames (a very diffuse structural type in Italy) may generate stress and strain concentrations in r.c. elements (particularly in columns) and brittle failure behaviour can be detected due to these mechanisms. The non-linear constitutive models for masonry, currently available, are calibrated to predict accurately the global response in terms of forces in masonry panels, and not to analyze local and global failure interaction mechanisms of panels and r.c. frames. Through an experimental investigation information about the real behaviour of masonry infilled frames under seismic action have been gathered; with special attention on stresses and forces, but also on global and local failure mechanisms. Experimental tests performed at the Laboratory of experiments on materials and structures of the University Roma Tre, on bricks, mortar, single and double infill walls and finally on bare and infilled r.c. portals, are described and discussed. In parallel with the experimental activity non linear fiber structural models representative of the considered structures by means of triple strut nonlinear cyclic models for masonry panels have been set up. The accuracy of the models has been assessed through comparison with experimental results obtained form cyclic tests of frames.