Operativna modalna analiza za određivanje svojstava povijesnih građevina

Assessing and reducing the seismic risks associated with historical structures require an appropriate knowledge of structural behaviour and characteristics, as suggested by recent national and international guidelines concerning cultural heritage. However, historical structures are characterised by a high level of uncertainty, which affects material properties and structural schemes and is related to deterioration processes or previous interventions and structural modifications. The level of knowledge can be increased by experimentally evaluating a structure’s dynamic properties, and the resultant data can be used to refine and update numerical models that are representative of the real structural behaviour. Moreover, the periodic monitoring of relevant parameters can help identify eventual deterioration phenomena. Thus, dynamic tests, in conjunction with model updating, are becoming reliable tools for non-destructively assessing historical structures. In this article, a brief discussion of the basic principles of dynamic identification under operational conditions is presented. Two tests with historical structures are then presented, and the main results are reported. The high performance of operational modal analysis techniques and the interesting opportunities these techniques provide for the structural assessment of historical structures are discussed.Ocjena i smanjenje seizmičkog rizika kod povijesnih građevina, zahtijevaju odgovarajuće poznavanje značajki ponašanja takvih konstrukcija, kako to sugeriraju nedavno objavljene nacionalne i međunarodne smjernice za građevine koje spadaju u kulturnu baštinu. Doduše, povijesne građevine su velika nepoznanica što se tiče svojstava materijala i konstrukcijskih sustava, a usto su podložne izmjenama, propadanju te promjenama tipa konstrukcije. Bolji uvid se može dobiti s procjenom dinamičkih svojstava modela konstrukcije, a dobiveni rezultati mogu se upotrijebiti za povećanje preciznosti i kvalitete numeričkih modela za realne konstrukcije. Štoviše, povremeno opažanje relevantnih parametara može pomoći identifikaciji možebitnih procesa propadanja. Zbog toga, dinamički pokusi, povezani s proračunskim modelima, postaju pouzdan alat kao nerazorne metode procjena stanja povijesnih građevina. U članku se razmatraju osnovna načela dinamičke identifikacije u uvjetima upotrebe konstrukcije. Opisana su dva pokusa na modelima povijesnih građevina, a prikazani su i najvažniji rezultati. Raspravlja se o velikoj djelotvornosti tehnike operativne modalne analize te o interesantnim mogućnostima koje ta tehnika pruža za procjenu povijesnih građevina

In-situ procjena zidanih svodova: Dinamička ispitivanja i numerička analiza

This paper concerns the structural identification of historical masonry buildings with reference to a case study, which is discussed in detail. The building is located in Southern Italy (Lecce). It has an ancient vaulted roof that is complex and commonly found in old masonry structures. This study takes advantage of extensive historical and structural investigations of the building. Preliminary activities have been conducted to obtain information about the current state of the structure including the geometry, morphology, structural details, material properties, prior interventions, and existing damage. This process was supported by an historical investigation into the conceptual background and construction methods used to build the structure. After the historical investigation, a series of experiments, including dynamic tests, were conducted on a number of the vaults to determine their dynamic response characteristics under operational conditions. A numerical model was also determined. In this paper, the primary dynamic test results and modelling assumptions are reported. Comparisons between numerical and experimental results are discussed.U ovom se članku razmatra konstrukcija jedne kulturno-povijesne zidane zgrade, detaljno obrađena još u jednoj ranijoj studiji. Zgrada se nalazi u Južnoj Italiji (Lecce). Zgrada ima složenu konstrukciju krova, sa svodovima, kakva je česta kod starih zidanih zgrada. U članku se uzimaju u obzir ranija opsežna povijesna i statička istraživanja. Ta ranija istraživanja bila su usmjerena ka dobivanju informacija o prethodnim ispitivanjima te o sadašnjem stanju konstrukcije, uključujući geometrijske karakteristike, oblikovnost, konstruktivne detalje, svojstva materijala i oštećenja zgrade. Pri tome su pomogla i ranija istraživanja o koncepciji i načinu gradnje zgrade. Nakon ovih istraživanja, obavljene su serije ispitivanja, između ostalog i dinamički pokusi na mnogim svodovima da se ustanove svojstva njihovog dinamičkog odziva u uvjetima standardne uporabe. Postavljen je i numerički model. U ovom su članku prikazani rezultati prvih dinamičkih ispitivanja i svojstava modela. Diskutira se odnos rezultata dobivenih numerički i eksperimentalno

Conservation and Enhancement of the Pietrabbondante Archaeological Site between History, Geology and Emerging Crowd-Based Digital Technologies

Attention to the condition assessment and conservation of cultural heritage is increasing due to growing sensitivity to the preservation of the built and natural environment and awareness of the risks associated with natural hazards. In this context, a comprehensive approach to the conservation and valorization of cultural heritage requires the combined action of different skills to achieve reliable assessment of the conditions of valuable assets and sites based on qualitative and quantitative indicators. This paper explores the issues of conservation and sustainable management of archaeological sites, considering humanistic and technical aspects. It reviews the current rules and practices concerning the maintenance and administration of archaeological heritage and outlines the implementation of a novel procedure, based on low-cost tools, to assess and describe the current condition of archaeological assets. Specific attention is paid to the interaction between experts and researchers operating in both humanistic and technical fields and to the knowledge and data contribution available on modern web-based platforms to implement reliable and low-cost data acquisition for the development of worthwhile plans for the conservation and enhancement of cultural heritage. The Samnite complex of Pietrabbondante, Molise, South Italy, is employed to apply and check the proposed tools in the real world

structural and seismic monitoring of the cardarelli hospital in campobasso

Abstract Recent earthquakes occurred in Italy and throughout the world have once again emphasized the critical role of health facilities for post-earthquake emergency management. Due to earthquake, several hospitals (L'Aquila 2009, Amatrice 2016) have lost their functionality because of damage to structural as well as non-structural members, equipment and installations. The primary role of hospitals after hazardous events requires the development of specific analysis and monitoring strategies aimed at quickly assessing their health conditions. Turning a hospital into a "Smart Health Facility" (SHF) allows remote assessment of the structural health; moreover, it can effectively support the mitigation of administrative and organizational vulnerability by acting on preparedness of the medical staff and supporting management and maintenance of structural as well as non-structural subsystems over time. Continuous monitoring of health and performance of hospitals can support the formulation of disaster mitigation plans and the definition of investment priorities to ensure the overall safety. In the present paper, some results of an on-going monitoring project for the main hospital in Campobasso (Southern Italy) are presented, focusing the attention on the response of the structure in operational conditions and after seismic events. Moreover, the results of experimental as well as operational modal analysis tests on a drug dispenser are discussed in order to assess their applicative perspectives for qualification of medical equipment in view of their seismic vulnerability assessment as non-structural elements

the role of the modal assurance criterion in the interpretation and validation of models for seismic analysis of architectural complexes

Abstract The seismic vulnerability assessment of historical buildings is usually a very complex task because of the large number of uncertainties in the characterization of their structural behaviour. The unique structural configurations, the adoption of old construction techniques and the presence of stratified structural modifications occurred over the centuries make the definition of an appropriate and reliable numerical model very challenging. The available analysis approaches distinguish the local response of selected macro elements from the global response of the structure. The problem of discriminating if the investigated structure shows a global behaviour or a local response has been often reported in the literature. However, the definition of a quantitative measure to discriminate the global modes from the local ones and, in the latter case, the associated macro elements, is currently missing. The Modal Assurance Criterion is a vector correlation index frequently used in experimental dynamics to quantify the similarity of mode shapes. In the present paper, it is used to define an original and quantitative approach to the discrimination between local and global modes. Results of application of the proposed procedure to an explanatory case study are reported, pointing out how the proposed method can guide towards the selection of the most appropriate analysis method

Some Remarks on Experimental Estimation of Damping for Seismic Design of Civil Constructions

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Some reflections on the seismic upgrading and regeneration of existing buildings in the Italian regulatory framework

In recent years, rehabilitation of the built heritage has increased, while construction of new buildings has decreased. A powerful impulse toward the combined structural upgrading and energy demand reduction has been given to the construction sector by means public investments associated with a fiscal incentives. Design exercises and real execution of interventions highlighted the role of the building envelope not only in the case of energy demand reduction, but also in the case of increase of structural and seismic performance of the buildings. This paper moves from an interdisciplinary research on the role and opportunities offered by multifunctional exoskeletons in the regeneration of buildings in urban areas. Herein the attention is focused on the relation between structural solutions for seismic upgrading, the technical standards related to the structural design and the regulatory framework concerning existing buildings and their relations with the urban environment. Some reflections on clashes generated by innovative and effective structural solutions for performance upgrading of existing buildings are also reported with the aim of defining some needs of integration and coordination of some crucial aspects of current regulatory provisions in the field of architecture and building engineerin