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The diffusion of seismic structural health monitoring systems, evaluating the dynamic response of engineering structures to earthquakes, is growing significantly among strategic buildings. The increasing availability of valuable vibration data is being backed by continuously evolving techniques for analysing and assessing structural health and damage. Within this framework, the paper proposes a novel model-driven vibration-based methodology to support the assessment of the damage level in masonry buildings hit by earthquakes. The leading idea is to exploit, in the pre-event phase, synthetic equivalent-frame modelling and nonlinear dynamic analyses to systematically relate the gradual reduction of natural frequencies to increasing levels of structural damage. The resulting behavioural chart (seismic chart) of the building, constructed by employing computational tools and robustly defined on a statistical base, may provide the theoretical expectation to ascertain a certain level of seismic damage, based on the decrease in vibration frequency experimentally identified in the post-event phase. The methodology is firstly formalized, integrating common identification techniques with a novel damage grade estimation procedure, and finally exemplified for a monitored strategic masonry building damaged by the 2016–2017 Central Italy earthquake sequence. The outcomes of this application confirm the operational validity of the methodology, which can be intended as effective support for the decision-making process regarding structural usability and safety in the post-earthquake scenario. [ABSTRACT FROM AUTHOR]

A close relationship between civil protection organizations and scientific community is widely recognized today at international and European level as being of paramount importance for the effectiveness of research products in their application for disaster risk management. In this perspective, European research projects on risks are more and more focused on application oriented outcomes, requiring the involvement of civil protection organizations, and creating a well-structured knowledge network within a European civil protection framework. For about forty years, the Italian civil protection has been relying upon the contribution of the scientific community to find the best solutions based on the most advanced and consolidated knowledge, for activities that concern the management of the entire disaster risk cycle. The interactions between civil protection and scientific community in Italy are mainly based on the so-called Competence Centers, i.e. the scientific operational partners of the Civil Protection Department (DPC), and on the Major Risks Commission, i.e. the technical-scientific advisory body of DPC. They both work with an interdisciplinary, multisectoral and, when necessary, multi-hazard risk approach. This paper aims to describe how Competence Centers presently operate, in a way that has evolved over the years. The focus will be on scientific activities and products related to the earthquake and structural engineering science, emphasizing the way of operating and collaborating of Competence Centers, consistently with the principles of the Italian Civil Protection Code. [ABSTRACT FROM AUTHOR]

ShakeMap is the tool to evaluate the ground motion effect of earthquakes in vast areas. It is useful to delimit the zones where the shaking is expected to have been most significant, for civil defense rapid response. From the earthquake engineering point of view, it can be used to infer the seismic actions on the built environment to calibrate vulnerability models or to define the reconstruction policies based on observed damage vs shaking. In the case of long-lasting seismic sequences, it can be useful to develop ShakeMap envelopes, that is, maps of the largest ground intensity among those from the ShakeMap of (selected) events of a seismic sequence, to delimit areas where the effects of the whole sequence have been of structural engineering relevance. This study introduces ShakeMap envelopes and discusses them for the central Italy 2016–2017 seismic sequence. The specific goals of the study are: (i) to compare the envelopes and the ShakeMap of the main events of the sequence to make the case for sequence-based maps; (ii) to quantify the exceedance of design seismic actions based on the envelopes; (iii) to make envelopes available for further studies and the reconstruction planning; (iv) to gather insights on the (repeated) exceedance of design seismic actions at some sites. Results, which include considerations of uncertainty in ShakeMap, show that the sequence caused exceedance of design hazard in thousands of square kilometers. The most relevant effects of the sequence are, as expected, due to the mainshock, yet seismic actions larger than those enforced by the code for structural design are found also around the epicenters of the smaller magnitude events. At some locations, the succession of ground-shaking that has excited structures, provides insights on structural damage accumulation that has likely taken place; something that is not accounted for explicitly in modern seismic design. The envelopes developed are available as supplemental material. [ABSTRACT FROM AUTHOR]