Vulnerability analysis of buildings in areas affected by slow-moving landslides and subsidence phenomena

2015 - 2016Slow-moving landslides and subsidence phenomena yearly induce huge damages both direct (on structures and/or infrastructures with them interacting) and indirect (corresponding to the associated economic losses). For this reason, studies aimed at analyzing and predicting the aforementioned damages are of great interest for Scientific Community and Authorities in charge of identifying the most suitable strategies for the land-use planning and management of urban areas affected by slowmoving landslides and subsidence phenomena. However, carrying out the activities related to the pursuit of those goals is not straightforward since it usually requires high costs due to the great amount of data to be collected for setting up reliable forecasting models as well as the development of proper procedures that take into account i) the identification and quantification of the exposed elements; ii) the definition and estimation of an intensity parameter; iii) the prediction of the damage severity level (generally associated with the attainment of a certain limit state). In this PhD Thesis some original procedures are proposed. In particular, on the basis of empirical and numerical methods, fragility and vulnerability curves are generated in order to predict the damage to buildings in subsidence- and slow-moving landslide-affected areas. The proposed empirical procedures, based on the joint use of DInSAR data (provided from the processing of images acquired by Synthetic Aperture Radar via Differential Interferometric techniques) and information on damages suffered by buildings (recorded and classified during in situ surveys), were tested on case studies in The Netherlands, affected by subsidence phenomena, and in Calabria Region (southern Italy) for slow-moving landslide-affected areas. The procedure based on the adoption of a numerical method was applied on a structural model representative of a single building. With reference to subsidence phenomena, the analyses were carried out for a densely urbanized municipality following a multi-scale approach. In particular, at medium scale, the subsiding areas that are most prone to ground surface settlements along with their spatial distribution and rates, were preliminarily detected. The above ground surface settlements (here considered as subsidence intensity parameter) combined with the results of an extensive damage survey on masonry buildings, allowed first retrieving, at large-scale (on building aggregates) and at detailed scale (on single buildings), the relationships between cause (settlements/differential settlements) and effect (damage severity level); then, empirical fragility curves were generated for structurally independent single buildings. These latter were validated via their comparison with fragility curves generated, with reference to two others densely urbanized municipalities, for buildings with similar structural typology (masonry) and foundation type (shallow or deep). Finally, fragility and vulnerability curves for masonry buildings were generated by using the entire database of damages. As for slow-moving landslides, the analyses were carried out at large scale. In particular, the joint use of DInSAR and damage surveys data allowed analyzing the consequences induced on the buildings (either of masonry or reinforced concrete) with shallow foundations by retrieving the causeeffect relationships and generating empirical fragility and vulnerability curves. Finally, the numerical analyses carried out on a structural model representative of a single masonry building, allowed to go in-depth in the different aspects contributing to the onset and development of building damages as well as to quantify the uncertainties inherent to the addressed issue. The obtained results highlight the huge potential of the fragility and vulnerability curves generated according to the proposed procedures that, once further calibrated/validated and jointly used with a continuous monitoring of the intensity parameter via conventional (e.g., inclinometers, GPS, topographic leveling) and/or innovative (e.g., SAR images processed via DInSAR techniques) systems, can be valuably used as tools for the analysis and prediction of the damage to buildings for land-use planning and urban management purposes in subsidence- and slow-moving landslide-affected areas. [edited by author]Le frane a cinematica lenta e i fenomeni di subsidenza causano annualmente ingenti danni sia diretti (su strutture e/o infrastrutture con essi interagenti) che indiretti (quali si configurano le associate perdite di natura economica). Per tale ragione, gli studi volti ad analizzare e a prevedere i predetti danni sono di indubbio interesse per le Comunità e gli Enti impegnati nella individuazione delle più idonee strategie di pianificazione e di gestione delle aree urbanizzate affette dai suddetti fenomeni. Tuttavia, lo svolgimento delle attività connesse al perseguimento dei predetti obiettivi è tutt’altro che agevole in quanto richiede costi elevati, dovuti alla grande quantità di dati da acquisire per la generazione di modelli previsionali affidabili, nonché lo sviluppo di procedure che contemplino i) l’identificazione e la quantificazione degli elementi esposti, ii) la definizione e la stima di un parametro di intensità e iii) la previsione del livello di severità del danno (generalmente associato al raggiungimento di uno stato limite). La presente Tesi di Dottorato propone alcune procedure originali che, sulla base di metodi empirici e numerici, conducono alla generazione di curve di fragilità e vulnerabilità quali strumenti di previsione del danno a edifici in aree affette da frane a cinematica lenta e fenomeni di subsidenza. Le procedure empiriche proposte, basate sull’integrazione congiunta di dati DInSAR (ovvero derivanti dalla elaborazione di immagini acquisite da radar ad apertura sintetica montati su piattaforme satellitari mediante tecniche interferometriche differenziali) e sul danno subito da edifici (a sua volta classificato sulla base degli esiti di rilievi in sito dei quadri fessurativi esibiti dalle facciate), sono state testate con riferimento a casi di studio dei Paesi Bassi, affetti da fenomeni di subsidenza, e della Regione Calabria (Italia meridionale), interessati da frane a cinematica lenta. La procedura basata sull’impiego di metodi numerici è stata, invece, applicata su un modello strutturale rappresentativo di un edificio singolo. Con riferimento ai fenomeni di subsidenza, le attività svolte con un approccio multi-scalare hanno consentito preliminarmente di rilevare (a media scala) le aree che risultano essere maggiormente predisposte a cedimenti dovuti a fenomeni di subsidenza. La conoscenza della distribuzione spaziale e della entità di tali cedimenti è stata, poi, combinata con i risultati di un esteso rilievo del danno agli edifici in muratura di un’area comunale in modo da i) risalire – sia a grande scala (su aggregati di edifici) che a scala di dettaglio (singoli edifici) – alle relazioni funzionali che si stabiliscono tra causa (cedimenti assoluti/differenziali) ed effetti (livello di severità del danno) e ii) generare per singoli edifici strutturalmente indipendenti curve di fragilità su base empirica. Le curve di fragilità così calibrate sono state, poi, validate operandone un confronto con curve di fragilità generate, con la medesima procedura, per altre due aree comunali caratterizzate dalla presenza di edifici con la stessa tipologia strutturale e fondale (superficiale o profonda). Si è, infine, provveduto alla generazione di curve di fragilità e di vulnerabilità di edifici in muratura utilizzando l’intero campione di dati a disposizione. Per quanto riguarda le frane a cinematica lenta, le analisi sono state svolte esclusivamente a grande scala, dove l’uso congiunto dei dati DInSAR e del rilievo del danno a edifici in cemento armato e in muratura con fondazioni superficiali ha consentito, ancora una volta, di risalire alle relazioni causa-effetto e di generare curve di fragilità e di vulnerabilità su base empirica. Infine, l’analisi numerica effettuata su un modello strutturale rappresentativo di un singolo edificio in muratura con fondazioni superficiali ha consentito di approfondire il ruolo esercitato da alcuni fattori nella generazione e nello sviluppo del danno nonché di quantificare le incertezze che intervengono nel problema esaminato. I risultati ottenuti evidenziano l’enorme potenzialità delle curve di fragilità e vulnerabilità ottenute che, laddove ulteriormente calibrate e validate, possono essere impiegate congiuntamente con tecniche di monitoraggio in continuo dei parametri d’intensità – sia di tipo convenzionale (quali, ad esempio, inclinometri, GPS, livellazione topografica) che innovative (come quelle derivanti dall’elaborazione di immagini satellitari mediante tecniche DInSAR) – per la messa a punto di modelli previsionali utili alla pianificazione territoriale e alla gestione di aree urbane affette da frane a cinematica lenta e fenomeni di subsidenza. [a cura dell'autore]XV n.s

A multi-scale methodological approach for slow-moving landslide risk mitigation in urban areas, southern Italy

Several urban areas in Euro-Mediterranean countries are affected by slow-moving landslides that, even if rarely associated with the loss of human life, can cause damage to structures and infrastructure. In such contexts, the progressive decay of the built environment can bring along a generalized increase of the physical vulnerability and, as a result, slow-moving landslide risk increases over the time. Under these conditions, as long as suitable risk mitigation measures are lacking, the level of risk (also related to earthquakes) could turn out to be no longer acceptable within an a priori unknown time interval. This problem has a relevant social-economic impact, thus requiring the adoption of risk mitigation strategies that need to be effective and, at the same time, sustainable for the involved stakeholders. In this regard, this paper proposes a multi-scale methodological approach—based on the joint use of satellite-derived displacement monitoring data and the results of building damage surveys—whose applicability is tested with reference to urban areas affected by slow-moving landslides in Calabria region (southern Italy)

Empirical fragility curves for settlement-affected buildings: Analysis of different intensity parameters for seven hundred masonry buildings in The Netherlands

The analysis and prediction of damage to buildings resting on highly compressible fine-grained "soft soils" containing (organic) clay and peat are key issues to be addressed for a proper management of subsidence-affected urban areas. Among the probabilistic approaches suggested in literature, those oriented to the generation of empirical fragility curves are particularly promising provided that a comprehensive dataset for both the subsidence-related intensity (SRI) parameters and the corresponding damage severity to buildings is available. Following this line of thought, in the present paper, a rich sample of more than seven hundred monitored (by remote sensing) and surveyed masonry buildings – mainly resting with their (shallow or piled) foundations on soft soils – is analysed in four urban areas of The Netherlands. Probabilistic functions in the form of fragility curves for building damage are retrieved for three different SRI parameters (i.e., differential settlement, rotation and deflection ratio) derived from the processing of Synthetic Aperture Radar (SAR) images by way of a differential interferometric (DInSAR) technique in combination with the severity levels of the damage recorded from the visual inspection of over 700 masonry buildings. As a novelty with respect to earlier similar studies, the work points out the methodological steps to be followed in order to identify the most appropriate SRI parameter among the selected ones. Thus, the objective of the paper is to improve the existing geotechnical forecasting tools for subsidence-affected urban areas, in order to target areas that require more detailed investigations/analyses and/or to select/prioritize foundation repairing/replacing measures

Geology, slow-moving landslides, and damages to buildings in the Verbicaro area (north-western Calabria region, southern Italy)

This paper presents a mass movement inventory map at 1:5000 scale of the Verbicaro area (about 13 km2) located in the Calabria region (southern Italy). The Main Map results from the visual interpretation of aerial photographs, multi-temporal geomorphological field surveys, and field investigations of damage suffered by buildings. Some 53% of the study area is affected by a total of 252 landslides, comprising different types, state of activity, and size. The mapped landslides, mainly complex type, involve low-grade metamorphic rocks; among these, 15% are active and slow-move on pre-existing sliding surfaces. Moreover, out of 492 surveyed buildings, 347 are located on landslide-affected areas and experienced damages covering a broad range of severity levels. The Main Map can represent a useful tool for authorities in charge of land-use planning and urban management and can be used to pursue landslide risk analyses

Mediterranean river buffalo oxytocin-neurophysin I (OXT) gene: structure, promoter analysis and allele detection

Oxytocin (OXT) is a very abundant nonapeptide neurohypophysial hormone implicated in several aspects of reproduction, including social, sexual and maternal behaviour, induction of labour and milk ejection. The nucleotide sequence of the whole OXTneurophysin I encoding gene (OXT) in Mediterranean river buffalo was determined, plus 993 nucleotides at the 5’ flanking region. Buffalo oxytocin gene sequence analysis showed two transitions in the promoter region (C→T in position – 966 and G→A in position – 790) and one transversion G→T at the 170th nucleotide of the second exon, responsible for the Arg97→Leu aa substitution which identifies an allele named OXT B. A PCR-RFLP based method for a rapid identification of carriers of these alleles has been developed

DNA polymerase alpha inhibition by aphidicolin and fragile site expression in prometaphase chromosomes of the Italian Mediterranean River Buffalo (Bubalus bubalis, 2n=50)

The present study reports on the expression and localization of "fragile sites" (FS) on prometaphase chromosomes of two groups of river buffaloes (Bubalus bubalis, 2n=50; Mediterranean Italian breed), reared in two different farms, with the aim to characterize chromosome fragility in this species. Totally, 400 aphidicolin induced breakages were identified and localized on the standardized ideogram of the river buffalo karyotype. Preliminary results can be synthesized as follows: (a) aphidicolin showed a remarkable decondensing effect on chromosome structure, enabling further studies at high resolution level; (b) the chromosomal expression of the breakages was not different in the two groups of animals; (c) the most fragile chromosomes were the inactive-X, chromosomes 9, 8 and active-X, showing 42, 32, 31 and 30 breakages, respectively; (d) the breaks were localized in the RBG-negative bands (corresponding to eterochromatic regions) or at the band-interband regions; (e) the chromosomal distribution of the break sites was not random and only partially related to chromosome length. The study is in progress to determine the relative incidence of the fragile sites at chromosomal band level, in order to construct a 'fragile-site map' of river buffalo, which could be utilized for genetic improvement programs of the species

Lista bibliografica

Questa lista bibliografica contiene il secondo aggiornamento della bibliografia della Lisy e deriva dall’assemblaggio da parte della redazione (M. Serdoz ed E. Panfili) dei contributi parziali stilati dai gruppi regionali

Notulae to the Italian alien vascular flora: 14

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. materia

Notulae to the Italian alien vascular flora: 14

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. material

Building damage assessment and settlement monitoring in subsidence-affected urban areas: case study in the Netherlands

Buildings in subsiding areas may suffer from settlements causing damages of different severity levels with high impact in terms of yearly economic losses. In these contexts, a systematic damage assessment jointly with continuous monitoring of relevant parameters (e.g. settlements exhibited by points located on the roof) can be extremely useful to control the building behaviour and develop forecasting models. In this regard, the paper presents the results of an integrated analysis carried out on a subsidence-affected urban area in the Netherlands where the availability of multi-temporal building damage surveys and a long DInSAR monitoring dataset allowed both retrieving quantitative empirical relationships between the cause (magnitude of the selected intensity parameter, IP) and the effect (recorded damage severity level, DL) and generating empirical fragility and vulnerability curves. The results pointed out the importance of considering the exact dating of the onset of building damage and the corresponding magnitude of the considered IP in the generation of quantitative forecasting models