Rethinking the role of the connections to improve the sustainability of the retrofit actions

Integrated interventions, possibly holistic and assembled outside the building, have been acknowledged as an effective solution to tackle the multifaceted needs of the existing buildings (structural, energy, and architectural). To guarantee true economic, environmental, and social sustainability throughout the building life cycle, besides mandatory objectives, such as energy efficiency and structural safety, other performance objectives must be targeted. LCSE principles, such as design for durability, reparability, for reuserecycle, might remarkably improve sustainability. In this scenario, re-thinking the role of the connections, targeting standardization and modularity, might be key in improving the sustainability of any innovative and traditional retrofit actions. At the construction stage, the connection conceptual design should be aimed at reducing the construction time, facilitating the assembly of prefabricated components of the retrofitting exoskeleton, accommodating construction tolerances, and guaranteeing the envisioned stiffness and strength through modularity of its components. At the use stage, it should be aimed at lumping damage enabling the fast replacement in case of an earthquake (fuse of the structure), its possible adoption in the implementation of incremental rehabilitation retrofits and improving adaptivity to future uses of the building through plug-andplay installation and activation mode. At the end-of-life stage, connections could be fundamental in guaranteeing selective dismantling, and through standardization, they could effectively improve the reusability of the retrofit components. In the paper, the conceptual design of the existing building-to-exoskeleton connection is presented. A standardized, modular connection is proposed.