R.C. shear walls in seismic retrofitting of buildings

The paper describes the seismic retrofitting of two R/C frame buildings in one of the areas most damaged by the moderate earthquake that on December 13th 1990 struck the southern part of eastern Sicily causing intense damage in some localized areas and the loss of 19 human lives. The damage potential of the earthquake, evaluated using strong motion data and damage indices, turned out to be low and compatible with the seismological data. The adopted retrofitting solution is the addition of shear walls, which increase stiffness, resistance and capacity of energy dissipation. The use of shear walls lead generally to a good seismic behaviour, as also observed during many earthquakes in the world, for instance in Chile, Argentina, Colombia, Japan, USA and Turkey. In fact, complete collapse hardly occurs when shear walls are present. Moreover, the insertion of shear walls represents an economically sustainable retrofitting intervention.