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The art. 5 of the Regional Law 33/2015 provides that "the works referred to in article 93 paragraph 1 of the Presidential Decree fall within the scope of application of this law. 380/2001...". This article states “1. In the seismic zones referred to in article 83, anyone who intends to proceed with construction, repairs and elevations is required to give written notice to the one-stop shop, which will send a copy to the competent technical office of the region, indicating their domicile, name and the residence of the designer, the construction manager and the contractor.”

The Technical Construction Standards ed. 2018 provide, in addition to the case of new construction, the distinction into:

• local intervention;
• improvement;
• adjustment.

Therefore, interventions involving structures made of any material (reinforced concrete, steel, aluminium, wood, laminated wood, structural glass...) require the filing of the documentation required by Regional Law. 33/2015 and reporting in accordance with the provisions of the art. 65 of the Presidential Decree 380/2001. 

By way of example, it should be noted that the construction of new staircases, new mezzanines, changes in the rigidity of the horizontal elements for the creation of double volumes and similar interventions also require seismic deposition.

It is important to specify that even if these are interventions that go beyond the adaptation or safety assessment of the entire building, this type still requires the obligation to verify not only the intervention which is the object of the practice but also the parts of the structure interacting with it. For clarification, paragraphs 8.4.1 of the NTC2018 and C.8.4.1 of the Explanatory Circular are reported:
“8.4.1 Local repair or intervention. “Interventions of this type will concern individual parts and/or elements of the structure. They must not significantly change the overall behavior of the construction and are aimed at achieving one or more of the following purposes:

• restore, compared to the configuration prior to the damage, the initial characteristics of damaged elements or parts;
• improve the resistance and/or ductility characteristics of elements or parts, even if not damaged;
• prevent local collapse mechanisms;
• modify an element or a limited portion of the structure. 

The project and safety assessment may refer only to the parts and/or elements involved, documenting the structural deficiencies found and demonstrating that, compared to the configuration prior to the damage, degradation or variant, no substantial changes are produced to the behavior of the others parts or of the structure as a whole and that the interventions do not lead to a reduction in the pre-existing safety level... omitted"
C8.4.1 Local repair or intervention.

Interventions that do not significantly alter the overall behavior of the building fall into this category; the objective on the basis of which the admissibility of the intervention is assessed is an increase in the safety of at least a portion of the construction, or, in the case of damage suffered, that of maintaining or increasing the original structural effectiveness of the damaged portion .

This category includes interventions for the restoration, reinforcement or replacement of structural elements or parts of them that are not suitable for the function they must perform (for example beams, architraves, roofs, decks or portions of decks, pillars, wall panels). In particular, strengthening interventions must favor the development of ductile mechanisms or in any case improve local ductility, so as to favor the development of the overall ductility of the structure. The restoration or reinforcement of existing connections between individual components or between parts of them or the creation of new ones
connections (for example between masonry walls, between walls and beams or floors, also through the introduction of chains/tie rods, nailing between wooden elements of a roof or a floor, between prefabricated components) fall into this category. Finally, the modification of a limited part of the structure (e.g. the opening of a space in a wall, accompanied by appropriate
reinforcements) can fall into this category, provided that it is demonstrated that the set of interventions does not significantly modify the stiffness, resistance to horizontal actions and deformation capacity of the structure... ...omissis". 

FAQ SUE n. 7 - Published on 6 March 2020