PSI - Issue 44

Giacomo Iovane et al. / Procedia Structural Integrity 44 (2023) 1870–1876 Giacomo Iovane et al. / Structural Integrity Procedia 00 (2022) 000 – 000

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elements, as well as strengthening of the members cross sections and reinforcement of timber floors.

3.2. Global interventions As far as the global interventions are concerned, timber-based endoskeletons and exoskeletons are recognized as seismic and energetic retrofitting systems. Deriving the terminology from the field of biology, endoskeletons and exoskeletons consist of added structural systems connected to the existing building respectively from inside and from outside. Both systems are able to modify the structural behavior of the existing structure, involving increment of strength, stiffness and ductility. Both endo and exoskeletons can be provided with additional seismic energy dissipation devices, enhancing also the global dissipative behavior of the construction. In Figure 2 possible types of global timber based interventions for RC and masonry buildings are shown.

RC buildings

Masonry buildings

E NDOSKELETON

2D// endo,RC,Wall

2D// endo,RC,Braces

2D// endo,M,Wall

2D// endo,M,Braces

E SOSKELETON

2D// exo,RC,Wall

2D// exo,RC,Braces 2D ⊥ exo,RC,Wall 2D ⊥ exo,RC,Braces 2D// exo,M,Wall

2D// exo,M,Braces

2D ⊥ exo,M,Wall

2D ⊥ exo,M,Braces

3D exo,RC,P,Wall

3D exo,RC,P,Braces 3D exo,RC,P,Reticular

3D exo,M,P,Wall

3D exo,M,P,Braces

3D exo,M,P,Reticular

3D exo,RC,S,Wall

3D exo,RC,S,Braces 3D exo,RC,S,Reticular

3D exo,M,S,Wall

3D exo,M,S,Braces

3D exo,M,S,Reticular

Fig. 2. Types of global interventions on RC and Masonry buildings with timber-based elements.

Endoskeletons are particularly attractive when it is difficult or it is not possible to work from the outside of the building due to physical or geometrical issues, city-planning and architectonic matters, mostly in case of heritage and protected buildings. Endoskeletons are generally bi-dimensional (2D) systems placed in parallel (2D// endo ) to the masonry walls or RC frames. They can be made with CLT walls, light timber frame or timber bracing systems (X, V concentric braces and eccentric braces), which play the role of seismic-resistant system (Fig. 2). In particular, for RC structures endoskeleton is generally applied as infill wall within the framed structure (Fig. 2), which it needs to be properly connected to. Besides, for masonry structures it is superimposed to the internal surface of the walls (Fig. 2). Exoskeletons, due to installation from outside of the building, allow to use the building also during the working phases. This represents a particular advantage in case of strategic public buildings (such as hospital or barracks). In