Seismic and Energy Retrofit of Apartment Buildings through Autoclaved Aerated Concrete (AAC) Blocks Infill Walls

Abstract

All around the world, a huge amount of buildings have been built before the enforcement of specific codes for seismic resistance and energy efficiency. Particularly in Italy, over 74% of residential buildings were constructed before 1980, when only 25% of the territory was classified as seismic, and nearly 86% were built before 1991, when the first restrictive regulation on energy efficiency was issued. This means that most buildings need both seismic and energy renovation actions to improve their sustainability level. The proposed combined retrofit strategy for reinforced concrete framed buildings is based on the replacement of the external layer of double-leaf infill walls, made of hollow bricks, with high-performing AAC blocks: this solution can be implemented by operating mainly from the outside of the building, thus reducing occupants’ disruption during retrofitting. The generally neglected structural contribution of masonry infill panels is here considered using a recently developed macro-element modeling approach. The results suggest that, from a structural viewpoint, the proposed intervention involves the highest improvement at the damage limitation limit state, while lower upgrades are recorded at life safety limit state and near-collapse limit state. In regards to the energy issues, the energy demand can be reduced by 10% and 4% for heating and cooling, respectively, just by replacing the outer layer of blocks; further savings can be achieved through the application of a supplementary insulation layer.

Decision Support System for the Sustainable Seismic and Energy Renovation of Buildings: Methodological Layout

“…Other authors have analyzed the effect of adding dissipative braces to the structure [21,22], which increase the building stiffness and energy dissipation capacity, with the aim of minimizing damage at the occurrence of small earthquakes. Manfredi and Masi [23], instead, proposed replacing the external infill walls with new panels with better structural and thermophysical properties; a similar strategy has been applied by Artino et al [24], proposing to use autoclaved aerated concrete blocks infill panels. For mid-low hazard areas, this technique could imply a full rehabilitation with regards to both seismic and thermal requirements, in compliance with the regional specific rules.…”

Comparison of Different Solutions for a Seismic and Energy Retrofit of an Auditorium

“…Despite the necessity of both refurbishments, structural and energy interventions usually follow their own paths and join only towards the end of the process. Therefore, only in recent years have some researchers focused on combined seismic and energy retrofitting approaches to the problem of singular components such as masonry walls [11,12] or reinforced concrete (RC) building envelopes [13]. Few examples of an integrated methodology have been developed in recent years; it can also be remarked that simultaneous investigations and modeling can optimize the costs for the design of the energetic and structural improvements [14].…”

An Integrated Approach to Improve Seismic and Energetic Behaviour of RC Framed Buildings Using Timber Panels

“…In the last few years, several integrated retrofit solutions that included different materials and techniques have been studied all over the world. For example, integrated solutions based on the use of independent multi-purpose exoskeletons [17,18], timber prefabricated panels [19], or autoclaved aerated concrete blocks [20] have been proposed.…”