Seismic retrofit of residential buildings

A huge number of r/c buildings were strongly damaged by the Italian 2009 L'Aquila earthquake. Many of these buildings, designed and built more than twenty years ago, are characterized by insufficient resistance against lateral forces, as well as by insufficient ductility and resistance due to inadequate structural configuration and inadequate structural detailings.

For many buildings, Numeria, based on its long-term experience, proposed retrofit interventions based on the use of base isolation and provided consultancy services for effective design and intervention.

The base isolation option was considered by Numeria engineers as the preferred solution since the very beginning of the design, whenever it was possible to carry out most of the works at the basement level. Thanks to the insertion of seismic isolators, almost no strengthening works on the buildings' elevation were needed despite the generalized low seismic-resistant capacity of the primary structural system.

The following interventions have been successfully proposed by Numeria and safely and easily implemented by the contractors: cutting of the top portions of the columns at basement level, insertion of isolating devices, strengthening of the columns below the isolators, strengthening of the beam joints above the isolators, demolition and reconstruction of the first flight of the stairs, creation of a seismic gap.

As far as the building elevation (existing superstructure) is concerned, after the insertion of the seismic isolators, the resistant sections of beams and columns have been proven to be sufficient to sustain the stresses induced by the earthquake.

Base isolation application in retrofit of r/c structures has been proven to be effective and economically convenient compared to conventional retrofit intervention.