Diagnostic Campaign Aimed at Assessing the Seismic Vulnerability of Existing Buildings Applied to Strategic Buildings in Trentino Alto Adige (Northern Italy)

Abstract

In order to assess the seismic vulnerability of existing buildings, the Italian structural codes require that the geometric characteristics of the structural elements and the mechanical characteristics of the materials shall be determined through diagnostic investigations. The level of deepening of the investigations carried out depends on the Level of Knowledge (LC) achieved; on this basis it is determined a Confiance Factor (FC) which must be applied in the subsequent verification activity to reduce the mechanical characteristics determined for the materials in the diagnostic way. Furthermore the legislation identifies the buildings that are “strategical” because of the effects consequent the seismic events: on these buildings the vulnerability assessment is mandatory. The paper describes the diagnostic activities carried out on some buildings located in Trentino Alto Adige (Northern Italy) built between the mid-19th c. and the first decades of the 20th c., which were originally intended for the headquarters of the Judicial Prisons and the Court (in Rovereto) and for the Casa del Fascio (in Bolzano). Currently they are aimed for public offices (state offices, barracks of the financial guard and police). These are very common situations in Italy: historic buildings, built with different construction techniques (both masonry and Reinforced Concrete and mixed techniques) and subject to multiple functional transformations over time, even linked to the repair of war damage. The analysis carried out involved the geometric and material survey, the historical analysis of the events and interventions undergone, the mechanical characterization of the materials, foundations and foundation soil. In particular, given the architectural interest of the building and the need to minimize disturbance to users, the tests that have a limited impact on the construction (e.g. sampling on the concrete and tests with flat jacks on the masonry) were accompanied by non-destructive tests (endoscopies, sonic and ultrasonic tests, penetrometric tests on mortars, sclerometric tests and magnetometric investigations) in order to extend the results and guarantee their representativeness. It was thus possible to reach the Level of Knowledge LC3 (the maximum expected level) and apply the Confiance Factor FC = 1 (the minimum value), operating with the best compliance with the real state of the building. It was of particular interest also the building up of a BIM (Building Information Modeling) model, implemented from the laser scanner survey and carried up to the appropriate Level of Development (LOD = 300) which allowed to embed in the model all the acquired structural diagnostic information and to develop the consequent static and seismic assessment.