Experimental and Numerical Analysis of Historical Aseismic Construction System

Timber frames have been used in masonry buildings since a very early age to enhance their seismic performance. Several construction techniques have been conceived over the centuries for this purpose; among them, the so-called casa baraccata is relatively unknown and yet relevant as it has been employed since the 17th century in Calabria, a region in Southern Italy historically characterized by frequent and powerful seismic sequences. After a particularly devastating earthquake nearly destroyed the two cities of Reggio Calabria and Messina in late December 1908, Calabrian engineer Pasquale Frezza patented an anti-seismic construction technique that further improved the casa baraccata by embedding fictile tubules in its masonry walls. Those are hollow clay bricks, employed since the Roman Empire in buildings all around the Mediterranean Sea, that allow for a reduction of participating mass of the structure, hence helping its resistance to dynamic loads. This paper investigates the seismic effectiveness of the construction technique patented by Frezza. First, a diagonal compressive test is carried out on a specimen wall built according to Frezza’s recommendations, with the aim of evaluating its shear strength. Then, a numerical analysis is performed in the commercial FE software Abaqus to simulate the experimental test and validate its results. The shear strength measured from the experimental test is higher than the usual values for ordinary and historical masonry walls, and the numerical results are able to grasp the overall behavior of the wall as resulting from the diagonal compressive test.