Enhancing seismic and climate resilience of existing buildings through low-damage external exoskeletons

Abstract

In recent years, devastating earthquakes and climate-induced events have raised societal awareness of the urgent need to enhance resilience against extreme hazards. This becomes crucial when dealing with existing buildings. Many of these structures were built before the enforcement of modern seismic codes and energy regulations. Consequently, existing buildings are exhibiting a lack of resilience not only during earthquakes but also in case of extreme climatic conditions. Moreover, the energy inefficiency of the building stock should not be viewed solely as a problem related to its thermal vulnerability. It also requires an unprecedented effort to meet the goals outlined in the European Green Deal, specifically targeting energy savings and decarbonization by 2030 and 2050, respectively, to increase environmental sustainability. This work explores the feasibility of employing external low-damage exoskeletons consisting of rocking-dissipative structural connections for seismic strengthening. The implementation of exoskeletons is nowadays crucial, given the possibility of carrying out the intervention from the outside with limited disruption for occupants. Moreover, the exoskeleton serves as a support for a “double-skin” facade system offering opportunities to enhance the envelope energy performance, thereby enabling an integrated (i.e., seismic and energetic) rehabilitation. This paper discusses the advantages of using external exoskeletons compared to more traditional strategies (e.g., seismic local interventions combined with thermal coatings) by a case study application. The overall performance of as-built and retrofitted configurations is assessed through seismic and energy dynamic analyses as well as integrated loss modeling for resilience evaluations. The findings provide evidence of the efficiency of the proposed strategy and its potential.