PSI - Issue 44

Franco Braga et al. / Procedia Structural Integrity 44 (2023) 331–338 Franco Braga et al. / Structural Integrity Procedia 00 (2022) 000–000

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activation of which is mainly related to the effectiveness of the floor connections and connections at masonry intersections. 2. The data sample The sample covered refers to seismic improvement and reconstruction projects in the historic centers of L'Aquila and its hamlets. Each project relates to a Minimum Unit of Intervention (hereinafter UMI), normally corresponds to the urban block and is divided into one or more structural units according to the provisions of Circular January 21, 2019 , No. 7 C.S.LL.PP. "Instructions for the application of the "Update of the "Technical Standards for Construction" referred to in Ministerial Decree January 17, 2018" and the Manual of the Sheet and the "Technical Manual for the compilation of the AeDES formability sheet." Where the urban block has been found to be particularly large, on the "L'Aquila Reconstruction Plan" it is stipulated that the same be divided into several UMIs, whose projects are to be coordinated by a single technical figure according to the indications given in the aforementioned D.P.C.M. February 4, 2013. The data refer to 572 UMIs consisting of 1666 structural units, of which 1476 are in aggregate, 190 UMIs consist of a single structural unit (hereinafter US). As shown in Fig. 1, the structural units are mostly masonry, of which about 13% are subject to monumental protection under the Cultural Heritage Code.

Fig. 1. Distribution of surveyed structural types (left) and damage assessed according to EMS 98 scale of surveyed buildings (right).

Damage and seismic vulnerability, on the basis of which the public contribution for the implementation of interventions is calculated, are calculated according to simplified models implemented on the Sheet managed through a web-based application accessible from the Internet. As a preamble to the numerical computations illustrated in the remainder of the document, it should be noted that: • the sample of buildings used, as far as it was possible to detect, was not affected by statistically significant disintegrative phenomena. The historic masonry of L'Aquila, while not having high strength characteristics on average, was not subject to masonry disintegration except for a few sporadic cases referable to localized mechanisms; • in order to limit the effects of foundation soils on the extent of damage, only the 865 structural units in masonry or with similar structure having the seismic amplification coefficient for stratigraphic effects Ss between values 1 and 1.2 (soil categories A and B) and the amplification coefficient for topographic effects equal to unity were taken into account.