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Existing road and railway system often incorporate bridges, part of the historical heritage, that need careful attention not only for their operational safety and safeguard. For this reason, the approach to the inspection and to the constructional knowledge require the integration and coordination of phases like the analysis of primary sources to in-situ characterization of local and global performance of components and materials. The management of infrastructures has to exploit digital technologies, both in the data collection phase and in the decision-making process. The paper deals with the e-conservation paradigm and discusses the results of an investigation on the potentialities offered by parametric models of historic bridges. It also checks and validates the introduction of the approach advised by recent National regulations in the framework of the Historic Bridge Information Modelling (HBrIM) combining safety and conservation knowledge instances.

The structural and seismic fragility assessment of minor historical centers of the Inner Peripheries of Italy is a key phase of the preservation process of the historical and cultural features of a portion of the Italian building stock, whose reuse is crucial for the reversal of shrinking trends and the stimulation of population growth. In this framework, the opportunities offered by digital crowd-sourcing technologies with respect to performing probabilistic structural safety assessment at a large scale are investigated herein. The objective of this research was to exploit data and information available on the web such that the key building features of an area of interest are collected through virtual inspections, historical databases, maps, urban plans, etc. Thus, homogeneous clusters of buildings identified in the area of interest are catalogued and associated with specific building classes (chosen among those available in the literature), and the buildings’ levels of seismic fragility are determined through the development of fragility curves. The research outcomes show that the proposed approach provides a satisfactory initial screening of the seismic fragility level of an area, thus allowing for the identification of priority zones that require further investigations or structural interventions to mitigate seismic risk.

Structural safety assessment of urbanised areas exposed to seismic risk is a complex task and can be approached at different scales. Fragility functions are the most effective tool to perform an estimation of the structural risk, since they describe the exceeding probability of the limit state of interest given a level of ground shaking. The formulation of a fragility function is based on the selection of an Intensity Measure of the ground shaking, commonly represented by peak-ground or spectral parameters or by macroseismic intensity grades. In the present paper, a novel approach to estimate the seismic vulnerability at a large scale of urbanised areas is presented. The scenario earthquakes are selected according to the current formulation of the seismic hazard disaggregation provided by National and International codes, i.e. through the disaggregation in terms of magnitude (M), epicentral distance (R) and number of standard deviation from the median ground motion (ε). To this aim, a vectorial seismic Intensity Measure is assumed to compute structural safety at large scale, and a change of variables is made to turn the traditional fragility curve into a matrix. Typological fragility matrices are processed and combined to define the so-called Urban Fragility Matrices, representative of the vulnerability of selected urban sectors. The procedure is then implemented and validated referring to the city of Pozzuoli (Southern Italy) and its effectiveness validated with reference to the damage survey relative to the 4th October 1983 seismic event which struck the city, resulting a good matching between predicted and observed scenarios.

The paper deals with the description of detailed non-destructive in-situ tests and the analysis of the dynamic behaviour of the Santa Maria Maddalena church, located on the Ischia isle and partially damaged by the seismic event of August 21st, 2017. This church is a very special type of structure built in 1896 according to a mixed ‘baraccato’ constructive technique, based on tuff masonry walls strengthened by thin iron profiles in the main parts and timber elements in its back part. After the seismic event, a detailed survey of the church was done and passive thermography imaging as well as dynamic tests under operational conditions were carried out afterwards. The paper outlines a methodological approach where data and information collected from in-situ tests and surveys about geometry, masonry texture, crack patterns and vibration properties are collectively analyzed for the non-destructive structural assessment and finite element modelling of the church. The paper first describes how the experimental outcomes allowed to enhance the knowledge about the “baraccato” construction system specific to this church and its dynamic response under operational conditions. Setting of a three-dimensional finite element model of the whole church is described afterwards, considering the experimental results, to have a deeper insight into the dynamic behaviour of the structure under different assumptions, mainly regarding the constraint conditions at the roof levels and the values of Young’s modulus and unit weight of masonry. Specific analyses have been also carried out aimed at quantitative discrimination of the numerical vibration modes as ‘local’ or ‘global’. The obtained results remarked the importance of accurately planning dynamic tests on similar structures characterized by significant complexity in their structural organization to achieve a reliable assessment of their dynamic behaviour.