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In spite of the enhancements related to building construction, many regions still present a major level of seismic risk as a consequence of the high vulnerability of the urban configuration of their cities. An improved method to assess the seismic vulnerability of buildings in urban areas is proposed in this contribution in order to advance the management of seismic emergency scenarios. The methodology, mainly based on the cadastral database, allows for a more standardized implementation as a function on the typological, structural, and urban parameters of the buildings, reducing the level of uncertainties linked to these methodologies and giving continuity to the different RISK-UE published works. The generalization of the method to any urban area has also been improved by means of removing the parameters whose calibration is associated with a specific area. The methodology has been put into practice in the urban area of the city of Lorca (SE Spain), in the aftermath of the earthquake of 11 May 2011, due to the availability of well-documented data reported from this seismic event. The proposal, when it is combined with Geographic Information System (GIS) techniques, provides valuable information for the planning and management of post-earthquake emergency situations.

The definition of strategies for the preservation and protection of cultural heritage is a topical issue, especially in view of the increasing relevance of the theme of seismic risk mitigation and ...

This article presents a methodology for the seismic vulnerability assessment of current buildings, suitable for the study of historical centers at the regional scale. The applicability is demonstrated with reference to four case studies: the historical center of the city of Foggia (Italy) and three other small towns of this province, for a total of 4519 housing units. Field data were collected by several teams of technicians by means of a survey form, provided in electronic format. The subsequent data processing and drawing of vulnerability maps was performed using geographical information system (GIS) technology. The collected data were used also for the validation of the algorithm, by comparing the results with those of the methodology used by the Gruppo Nazionale per la Difesa dai Terremoti (GNDT [Italian National Group for Defense Against Earthquakes]), which is widely adopted in Italy. The results of the research study and the application showed some critical points, related to the poor natur...

This paper addresses seismic vulnerability assessment at an urban scale and more specifically the capacity curves involved for building damage prediction. Standard capacity curves are a function of predefined building typology and are proposed in the Risk-UE LM2 method for computation of the corresponding damage grades. However, these capacity curves have been mainly developed for building stock of southern European cities and the accuracy of their application with different building features, such as the ones of cities of northern Europe should be assessed. A recent research project of seismic scenarios for the cities of Sion and Martigny in Switzerland provided the opportunity to check the capacity curves of Risk-UE LM2 method. Within the framework of this project, a detailed analysis was achieved for more than 500 buildings. These buildings were typical Swiss buildings and were composed of both unreinforced masonry buildings with stiff floors and reinforced concrete buildings. The construction drawings of each building were collected in order to have the most accurate information about their main structural characteristics. The typological classification that has been adopted was developed in a recent research project. Based on the individual features of the buildings, individual capacity curves were defined. Results of the seismic assessment applied to the 500 buildings compare very well with those obtained by using Risk-UE LM2 method for unreinforced masonry buildings with stiff floors. A slight improvement may be proposed for buildings with three stories through their introduction to the category of low-rise instead of mid-rise buildings. By contrast, accuracy for reinforced concrete buildings with shear walls is very poor. Damage prediction using related capacity curves of Risk-UE LM2 method does not correspond to reality. Prediction is too pessimistic and moreover damage grades increase with the height category (low-rise, mid-rise and high-rise) of these buildings which is in contradiction with the observed damages for this type of buildings. Improvements are proposed to increase the accuracy of the seismic vulnerability assessment for northern European building stock. For unreinforced masonry buildings, a slight modification of the limits of the height category of buildings using the ones defined for RC buildings improves the damage prediction. For reinforced concrete buildings with shear walls improved capacity curves derived from the typological curves of the specific typology C are proposed.

The present paper deals with the dynamic characterisation of a historical masonry chimney aimed at identifying the structural damage and assessing its seismic performance. The structure was severely damaged by a lightning accident and in-depth repair works were executed to re-instate its sound configuration. The case study is fully detailed, including the aspects of survey, inspection, diagnosis, and evolution of the dynamic properties of the system throughout the structural intervention. Considering the explicit dependence of the power spectral densities of measured nodal processes on their frequency content, a spectrum-driven algorithm is used to detect and locate the damage. The paper shows that the eigenparameters obtained from the decomposition of the response power spectrum matrix are sensitive to system's changes caused by evolutionary damage scenarios, thereby resulting excellent indicators for assessing both the presence and position of structural vulnerabilities. The results are compared with the ones from other modal-based damage identification methods and the strengths/limitations of the tools currently available in literature are extensively discussed. Finally, based on the crack pattern surveyed before the repair works, the weakest links of the chimney are identified and the most meaningful collapse mechanisms are analysed to verify the seismic capacity of the structure. According to the results of the kinematic analysis, the chimney does withstand the maximum site peak ground acceleration., info:eu-repo/semantics/publishedVersion

U radu se istražuje seizmička osjetljivost ab okvira ojačanog s CFRP-om (polimer armiran ugljičnim vlaknima). Proveden je program eksperimentalnih istraživanja kako bi se utvrdilo na koji način ojačanje CFRP-om utječe na čvrstoću betona. Poboljšana svojstva modelirana su za razne čvrstoće betona i u tu je svrhu korišten program temeljen na metodi konačnih elemenata. Na temelju rezultata analize izvedene su krivulje seizmičke osjetljivosti neojačanih i ojačanih okvira. Dobivene krivulje pokazuju da su nakon ojačanja ostvarena znatna poboljšanja neojačanih armiranobetonskih konstrukcija., Seismic vulnerability of a Reinforced Concrete (RC) frame retrofitted with the Carbon Fibre Reinforced Polymer (CFRP) is analysed in this paper. An experimental programme was conducted to determine the way in which concrete strength is affected by CFRP. The improved properties were modelled for different levels of concrete strength using a finite element based software. Using the results obtained during analysis, seismic vulnerability curves were derived for the unstrengthened and strengthened frames. The curves show significant improvement in the performance of unstrengthened RC structure after retrofitting.

Seismic assessment of existing heritage buildings remains a challenging task. There is a high level of complexity and uncertainty compared with the assessment of standard buildings. Heritage masonry churches are usually prone to partial collapses during earthquake due to local loss of stability, and exhibit particular seismic vulnerabilities. An important step in the seismic analysis of heritage masonry buildings is the detection of local mechanisms. The Italian Building Code provides a simplified approach (LV1-churches) to assess the vulnerability of heritage churches evaluating and comparing 28 potential mechanisms. A general index of vulnerability and hierarchy between mechanisms is thereby provided. Verification of safety against local mechanisms can also be carried out using the kinematic approach. This procedure is based on evaluating the horizontal action needed to activate out-of-plane collapse mechanisms. Based on a full-scale study (Sion Cathedral), this paper evaluates the reliability of the “LV1-church” approach and of the kinematic approach through a comparison with the results obtained with a complex 3D model using the Applied Element Method.

Kao dio mediteransko–transazijskog pojasa, područje Republike Hrvatske se odlikuje izraženom potresnom aktivnošću te se jača podrhtavanja tla događaju svakih 20 do 30 godina. Iako su mnoge zgrade projektirane u skladu s propisanim zahtjevima norme Eurocode 8 za proračun potresno otpornih zgrada, još uvijek postoji značajan broj starijih zgrada koje su izgrađene ne slijedeći nikakve norme. Najdetaljnija ispitivanja su propisana za tzv. zgrade izvan kategorije, kojoj pripadaju i osnovne škole te je shodno tome, u primjeru ovog rada, odabran ravninski model armirano–betonske (AB) okvirne konstrukcije osnovne škole Augusta Šenoe u Osijeku. Osnovna škola Augusta Šenoe je projektirana 70tih godina prošlog stoljeća u skladu s tadašnjim jugoslavenskim standardom o tehničkim uvjetima za projektiranje. Studija provedena u ovom radu se zasniva na procjeni potresne oštetljivosti ravninskih armiranobetonskih okvirnih konstrukcija niske duktilnosti. Za procjenu potresne oštetljivosti je korištena tzv. ''State of the Art'' metoda, odnosno nelinearna dinamička analiza inkrementalnog tipa (IDA) na numeričkom modelu zgrade, čija se konfiguracija sastoji od čistog AB okvira. Obradom podataka dobivenih IDA analizom dolazi se do zaključka da su ovakve konfiguracije (čisti AB okviri) najviše izložene dosezanju postavljenog graničnog stanja ili u krajnjem slučaju, rušenja konstrukcije. Pri provedbi IDA analize, numerički model AB okvira je izložen akcelerogramima stvarnih potresnih zapisa, točnije setu od sedam potresnih zapisa. Postavljena su četiri granična stanja oštećenja na osnovi kojih su definirana stanja oštetljivosti AB okvirne konstrukcije. U konačnici, kao rezultat analitičkog istraživanja, definirane su IDA krivulje vjerojatnosti oštećenja i matrice vjerojatnosti oštećenja za set od sedam potresnih zapisa., As part of the Mediterranean–transasian belt, the Croatian territory is characterized by a pronounced earthquake activity, with the strong ground motion occuring every 20 to 30 years. Although many buildings are designed in accordance with Eurocode 8 provision for earthquake resistant buildings, there is still a significant number of older buildings constructed without following any norms. The most detailed seismic tests are prescribed for so–called ''building without category'' to which they belong and school buildings and accordingly, the case study applied in this paper is 2D model of reinforced–concrete (RC) frame structure of primary school ''August Šenoa'' in Osijek. The primary school ''August Šenoa'' was designed in 70s of the last century in accordance with former Yugoslavian standards on technical conditions for design. The case study in this paper is based on seismic vulnerability assessment of low ductility reinforced–concrete 2D frame structures. For the seismic vulnerability assessment is used so– called ''State of the Art'' method, respectively nonlinear dynamic analysis of the incremental type (IDA) the numerical model of the building, whose configuration consists of RC frame. The interpretation of data obtained IDA analysis leads to the conclusion that these configurations (RC frames) are the most exposed to reaching the set limit state or, ultimately, cause construction collapse. In the implementation of IDA analysis, numerical model of RC frame is exposed to real time histories accelerogramms, or more precisely – the set of seven real time histories accelerogramms. There are four limit states of damage based on which damage states of RC frame structure are defined. Eventually, as a result of analytical resarch, IDA fragility curves and damage probability matrices for set of seven real time histories were defined.

As an approach to the problem of seismic vulnerability evaluation of existing buildings using the predicted vul-nerability method, numerical models can be applied to define fragility curves of typical buildings which represent building classes. These curves can be then combined with the seismic hazard to calculate the seismic risk for a building class (or individual buildings). For some buildings types, mainly the unreinforced masonry structures, such fragility analysis is complicated and time consuming if a Finite Element-based method is used. The FEM model has to represent the structural geometry and relationships between different structural elements through element connectivity. Moreover, the FEM can face major challenges to represent large displacements and separations for progressive collapse simulations. Therefore, the Applied Element Method which combines the advantages of FEM with that of the Discrete Element Method in terms of accurately modelling a deformable continuum of discrete materials is used in this paper to perform the fragility analysis for unreinforced masonry buildings. To this end, a series of nonlinear dynamic analyses using the AEM has been per-formed for two unreinforced masonry buildings (a 6-storey stone masonry and a 4-storey brick masonry) using more than 50 ground motion records. Both in-plane and out-of-plane failure have been considered in the damage analysis. The dis-tribution of the structural responses and inter-storey drifts are used to develop spectral-based fragility curves for the five European Macroseismic Scale damage grades.

The ongoing global transformation of human habitats from rural villages to ever growing urban agglomerations induces unprecedented seismic risks in earthquake prone regions. To mitigate affiliated perils requires the seismic assessment of built environments. Numerous studies emphasize that remote sensing can play a valuable role in supporting the extraction of relevant features for preevent vulnerability analysis. However, the majority of approaches operate on building level. This induces the deployment of very high spatial resolution remote sensing data, which hampers, nowadays, utilization capabilities for larger areas due to data costs and processing requirements. In this paper, we alter the spatial scale of analysis and propose concepts and methods to estimate the seismic vulnerability level of homogeneous urban structures. A procedure is designed, which comprises four main steps dedicated to: 1) delineation of urban structures by means of a tailored unsupervised data segmentation procedure with scale optimization; 2) characterization of urban structures by a joint exploitation of multisensor data; 3) selection of most feasible features under consideration of in situ vulnerability information; and 4) estimation of seismic vulnerability levels of urban structures within a supervised learning framework. We render the prediction problem in three ways to address operational requirements that can evolve in real-life situations. 1) To discriminate two or more classes based on labeled samples of all classes present in the data under investigation, we use the framework of soft margin support vector machines ( C -SVM). 2) To consider situations, where solely labeled samples are available for the class(es) of interest and not for all classes present in the data, we deploy ensembles of $\nu$ -one-class SVM ( $\nu $ -OC-SVM). and 3) To fit data with a higher statistical level of measurement (interval or ratio scale), we utilize a support vector regression (SVR) approach to estimate a regression function from the training samples. Experimental results are obtained for the earthquake-prone mega city Istanbul, Turkey. We use multispectral data from the RapidEye constellation, elevation measurements from the TanDEM-X mission, and spatiotemporal analyses based on data from the Landsat archive to characterize the urban environment. In addition, different in situ data sets are incorporated for Istanbul’s district Zeytinburnu and the residual settlement area of Istanbul. When estimating damage grades for Zeytinburnu with SVR, best models are characterized by mean absolute percentage errors less than 11%, and fairly strong goodness of fit ( ${{R}} > {{0}}.{{75}}$ ). When aiming to identify different types of urban structures for the remaining settlement area of Istanbul (i.e., urban structures determined by large industrial/commercial buildings and tall detached residential buildings, which can be considered here as highly and slightly vulnerable, respectively), results obtained with $C$ -SVM show a distinctive increase of accuracy compared to results obtained with ensembles of $\nu$ -OC-SVM. The latter were not able to exceed moderate agreements, with $\kappa$ statistics slightly above 0.45. Instead, $C$ -SVM allowed obtaining $\kappa $ statistics expressing substantial and even excellent agreements ( $\kappa > {{0}}.{{6}}$ up to $\kappa > {{0}}.{{8}}$ ). Overall, analyzes provide very promising empirical evidence, which confirms the potential of remote sensing to support seismic vulnerability assessment.

The majority of structures in seismic-prone areas worldwide are structures that have been designed either without seismic design considerations, or using codes of practice that are seriously inadequate in the light of current seismic design principles. In Cyprus, after a series of earthquakes that occurred between 1995 and 1999, it was decided to carry out an unprecedented internationally seismic retrofitting of all school buildings, taking into account the sensitivity of the society towards these structures. In this paper representative school buildings are analysed in both their pristine condition and after applying retrofitting schemes typical of those implemented in the aforementioned large-scale strengthening programme. Non-linear analysis is conducted on calibrated analytical models of the selected buildings and fragility curves are derived for typical reinforced concrete and unreinforced masonry structures. These curves are then used to carry out a feasibility study, including both benefit-cost and life-cycle analysis, and evaluate the effectiveness of the strengthening programme.

In this paper a procedure is described for quick seismic vulnerability assessment according to the EMS 98 classification. The criteria adopted by Ems 98 to assign the typological classes are mainly based on the vertical structure type. The proposed methodology aims to reduce the uncertainty in the class assessment using a set of parameters, related to typological features, that are identified as modifiers of the vulnerability level. The paper shows how the weight of each of these parameters is evaluated through the analysis of the seismic damages recorded during past earthquakes. A synthetic damage parameter is then defined in order to compare the seismic response of different sets of buildings under the same seismic intensity. Finally, the vulnerability assessment obtained on a set of buildings by the application of the methodology is compared with expert evaluations derived from the direct inspections on buildings.

The current thesis deals with the seismic vulnerability assessment of historical masonry buildings towards out-of-plane failure mechanisms, also denoted as out-of-plane local collapse mechanisms, by means of linear and nonlinear kinematic analysis. Damage analyses usually carried out after earthquakes demonstrated that one of the main sources of vulnerability for existing masonry buildings is associated to local failures, mainly due to the activation of out-of-plane collapse mechanisms. The issue of the structural safety of existing structures, with regards to local out-of-plane failure mechanisms, is already known and studied since a long time by architects and engineers. However the interest to the problem of the seismic vulnerability assessment of existing masonry buildings has increased in time, especially after the recent and catastrophic earthquake that affected Italy in the last years. This interest is strictly tied to the need to interface with the problem of the safety level and at the same time, the need to preserve the artistic-historical value of existing buildings, especially with regards to historical buildings characterized by an important artistic-historical value. The damages caused by earthquakes highlighted the real necessity to plan improvements interventions in order to avoid similar situations and similar damages in future. As anticipated, within intervention planning the special attention to historical buildings is related to the artistic value of these type of buildings and, as a consequence, to the relation with the preservation and restoration criteria. In this context the first step deals with the definition of the seismic vulnerabilities and criticalities of historical buildings. As a matter of fact only by means of the identification and evaluation of the vulnerabilities of the buildings towards seismic actions, it is possible to propose interventions for the preservation of the building and the increase of its safety level. Hence the evaluation of the seismic vulnerability is the first fundamental step of the design process. Experience showed that seismic actions can involve small or larger portion of the building, and hence can activate local or global collapse mechanisms. As already anticipated and as well documented in literature, it has been demonstrated that one of the main sources of seismic vulnerability deals with the activation of out-of-plane local collapse mechanisms, that bring to the overturning of masonry walls or portion of them out of the plane of the masonry. In the current thesis the attention is paid to the evaluation of the seismic vulnerabilities towards out of-plane collapse mechanisms. The seismic vulnerability has been assessed for some historical buildings following the prescriptions of the Italian building code (D.M.2008, Circolare del 02 febbraio 2009). The Italian building code, with reference to the Direttiva del Presidente del Consiglio dei Ministri, 12 Ottobre 2007 for historical buildings, proposes a calculation method for the seismic vulnerability assessment of historical buildings towards local out-of-plane collapse mechanisms by means of the application of linear and nonlinear kinematic analysis. The thesis work has been subdivided in several parts, starting from a general introduction to the problem, a description of the theoretical background of the calculation method applied, to the discussion of the results obtained. In the first part of the thesis an historical overview on the theory and the construction techniques of masonry buildings, with particular attention to the basis theory of the calculation method adopted in the thesis, is presented. Then the seismic behavior of existing masonry buildings and the main criticalities of these buildings, detected and listed after recent earthquakes, are reported. The description is mainly addressed to the survey and cataloging aspects of the seismic damages, necessary for the identification of the main criticalities in the perspective of the seismic vulnerability assessment. After a first introductive description of the most common seismic damages detected after earthquakes, the main geometrical and morphological features of existing masonry buildings and their vulnerabilities towards seismic actions are described. As already anticipated the seismic vulnerability of existing buildings can be related to both the activation of global collapse mechanisms and local collapse mechanisms, that can be respectively studied and calculated by means of global or local analyses. Hence the main calculation aspects and the theory background of global and local analyses are described, with particular attention to local analyses, applied in the thesis for the seismic vulnerability assessment of historical buildings towards out-of-plane collapse mechanisms. Within local analyses the theoretical aspect of linear and nonlinear kinematic analyses according to the Italian building code framework are in detail described. As anticipated the seismic vulnerability assessment represents the first step towards the planning of interventions that aim to increase the seismic safety level of the building. Hence the possible type of intervention plans, according to the Italian building code prescriptions are briefly described. Within existing building a fundamental aspect that precedes the seismic vulnerability assessment is related to the building knowledge process. In order to identify the criticalities and vulnerabilities of the building, it is in fact of great importance to get a knowledge level of the building as much complete as possible. A complete and clear knowledge of the building allows first of all the analyst to know the history of the building, especially related to the previous restoration interventions done on the building or on the previous damages suffered by the building during previous earthquake. Furthermore the knowledge process has to bring important information on geometrical and structural features and most of all on the crack pattern detected during in-place surveys. The historical, geometrical and crack pattern surveys are then the basis instruments for the identification of the vulnerabilities that identify the collapse mechanisms active in the building or that could be activated due to the criticalities detected by the survey. The knowledge level of the building can affect the results of the seismic analysis carried out: the lower the knowledge of the building, the higher the uncertainties related to the building itself. Hence, as a consequence, the higher the uncertainties of the building, the higher safety coefficients must be applied to the results obtained in order to supply to such uncertainties. The knowledge level of the building results in fact in safety coefficients, denoted as confidence factors, that has to be applied to the capacity of the building. In the evaluation of the seismic vulnerability of existing masonry buildings by means of kinematic analyses according to the Italian building code the capacity of the structure has to be compared to the seismic demand, for the seismic verification. In particular the capacity of the structure is calculated towards a particular local collapse mechanism applying the kinematic analysis while the seismic demand is evaluated according to code prescriptions. It is straightforward to deduce that the seismic verification is satisfied if the capacity of the structure is higher that the demand request by the seismic action. As a matter of fact if the capacity of the structure is higher that the seismic demand, the building analyzed is not vulnerable towards the local collapse mechanism analyzed for that particular seismic demand, otherwise the collapse mechanism analyzed is critical for that building. The capacity of the structure depends on the geometrical features of the portion of building analyzed, subjected or potentially subjected to that local collapse mechanism, while the seismic demand depend on the site characteristic where the building stands and the limit state analyzed. According to linear kinematic analysis the capacity of the structure and the seismic demand are evaluated in terms of acceleration. By means of linear analysis the only acceleration activation of the mechanism, to be compared to the acceleration demand, can be evaluated. On the contrary according to nonlinear kinematic analysis capacity and demand are evaluated in terms of displacements. Nonlinear kinematic analysis represents a higher level of refinement respect to linear kinematic analysis. According to nonlinear kinematic analysis in fact, since the capacity of the structure is evaluated in terms of displacements, the whole evolution of the collapse mechanism can be investigated, starting from the activation point to the collapse of the portion of building analyzed. By means of nonlinear kinematic analysis in fact the capacity of the structure is represented by a capacity curve, and not only by a value. The ultimate capacity, to be compared to the seismic demand, is then evaluated according to the Italian building code prescriptions. Hence nonlinear kinematic analysis takes into account for hidden capacity of the structure and for a more realistic behavior of the structure itself. In the thesis the seismic verifications results, for both linear and nonlinear kinematic analysis, are expressed in terms of a seismic safety index, defined as the ratio between the capacity and the demand. Hence, if the seismic safety index is higher than one, the seismic verification is satisfied, otherwise, it can be stated that the portion of building analyzed is vulnerable with respect to the collapse mechanism calculated. If so, an intervention plan can be proposed in order to increase the seismic safety level of the building towards the local collapse mechanisms analyzed. As anticipated, since local collapse mechanisms are investigated, the same building can be subjected to several local collapse mechanisms, and hence several seismic safety indexes can be associated to that building. The seismic safety index can be considered as an immediate representation of the seismic vulnerability level. The last part of the thesis deals with the presentation and the discussion of the results obtained. The seismic vulnerability assessment has been evaluated according to different refinement levels, starting from relatively simple analysis to more complex and refined analysis, in particular applying first linear and then nonlinear kinematic analysis . The different refinement level is strictly related to the aim to be pursued or to the different project phases. A higher complexity and refinement of the analysis carried out implies of course a higher computational burden to be faced with. Within the refinement level issue and the aim of the study, it has to be distinguished, in this particular context, if the analyses to be carried out are in the framework of a territorial scale evaluation or of a local scale evaluation, in particular if several buildings have to be analyzed or if a relatively low number of buildings has to be analyzed towards out-plane collapse mechanisms. Part of the thesis work is associated to activities researches that fit into a research program between the University of Parma and the Superintendence of Cultural Heritage for the seismic vulnerability assessment of several historical buildings, in order to produce an intervention priority list of the buildings analyzed. The first part of the work provides preliminary analyses, relatively simple, for the identification of recurrent criticalities and common local collapse mechanisms that aim to quantify the vulnerabilities detected. In this framework the analyses carried out are relatively simple and refer to linear kinematic analysis. Some historical buildings have been chosen as cases studies for the application of linear kinematic analysis and for the discussion of the preliminary results. In particular four buildings placed in Emilia Romagna region have been investigated. The buildings analyzed in the thesis have been chosen on the basis on common local out-of-plane collapse mechanisms identified, associated to commonly findable geometrical and morphological features and criticalities . The process of the evaluation of the seismic vulnerability, in particular for the determination of the seismic safety index, followed the knowledge process previously described. For each building a detailed survey allowed to collect useful historical information, to determine the crack pattern and to identify some critical situations. This first knowledge step was the basis for the individuation of already active or potentially active out-of-plane collapse mechanisms that have been then calculated by means of linear kinematic analysis. It has been highlighted that a fundamental role in the definition of seismic vulnerability assessment towards out-of plane mechanisms is played by the connection level between orthogonal masonry walls and between the masonry wall with the floor. It is in fact well known that the connection level between structural parts of the building is one of the main aspects for the definition of the structural behavior. If all the masonry walls and the walls with the floor are well connected to each other, the building can assume a “box” behavior, that is the building behaves like a box and out-of-plane mechanisms are avoided, thanks to the good connection level. On the contrary if the structural parts are not well linked to each other, they behaves like independent elements, activating in the buildings local out-of-plane collapse mechanisms. Another fundamental aspect that leads to the activation of local out-of-plane collapse mechanisms is the effect of horizontal static force generated by arches and vaults not countered by tie rod. The lack of tie rod that counter horizontal forces in arches and vaults is in fact a common and dangerous criticality detected in existing masonry buildings. It is important to underline that most of the times simple and non invasive interventions, like steel tie rod placed in arches and vaults or linking of the floor to the masonry walls, can significantly increase the safety level of the structures. Especially for historical buildings with a certain artistic-architectonic value to be preserved, it is very important that the interventions plan increase the safety level of the building but at the same are not invasive for the building itself, following the restoration and sustainability concepts and respecting the “minimum intervention criterion”. For this reason the intervention plan has to be adequately calibrated and hence the preliminary phase of identification and evaluation of the seismic vulnerability appropriately calculated. A second part of the results deeps some aspects of the calculation process that proved to have significant influence on the preliminary results. Hence the second part of the results indirectly deals with the transition from the territorial scale to the local scale, focusing on some numerical aspects of the calculation process. This leads to increase the refinement level of the analysis. The second part of the results in fact mostly deals with calculation parameters strictly related to nonlinear kinematic analysis. In the second part of the results an analytical model for the evaluation of the structural capacity of historical buildings in the framework of kinematic analysis is presented. The analytical model has been implemented during the thesis work in Excel spreadsheets. This part of results is not directly related to a particular case study but aim to provide indications as much general as possible, with relation to the field of application investigated. The analytical model focuses on some parameters of high influence on the results obtained in the calculation of out-plane collapse mechanisms and aim to take into account, in a relatively simplified way, these parameters in the calculation process. In particular the analytical model has been validated through a parametric study in which the basis hypothesis related to the geometrical and mechanical parameters investigated have been combined and varied in order to cover a relatively wide range of cases. The parametric study starts from a “base case study”, that has been chosen as reference case study to which the variations have been applied for the parametric study. The base case study refer to the simple overturning of a masonry walls characterized by continuous masonry from the ground to the roof and wooden floor. The parameters mostly investigated in the case study refer to the friction developed at the floor-wall interface, to the internal masonry friction, to the position of the pole around which the masonry wall overturns, to the influence of transversal masonry walls participating to the mechanisms, to the influence of the floor warping and to the type of forces acting on the building. In particular, referring to the friction developed at the floor-wall interface, a friction model that takes into account the progressive decaying of the friction coefficient from a static to a dynamic value and the progressive extraction of the floor has been implemented. In the model it has been considered the possibility of floor extraction, that means that as the wall rotates, the floor loses support length on the walls and progressively slides on the wall, extracting from the wall itself. Regarding the internal masonry friction, both simple and composed mechanisms have been considered in the model. Simple mechanisms refer to simple overturning walls while composed mechanisms refer to masonry wedges, transversal to the main overturning wall, participating to the mechanism. Within composed mechanism it has been taken into account the internal friction developed between the overturning masonry wedge and the remaining stable part of the transversal wall. It must be reminded that, since according to kinematic analysis the overturning masonry walls are considered as rigid bodies, in simple overturning mechanisms the internal friction is not relevant. The internal masonry friction has been taken into account in the model by means of a fiber mode, according to which the transversal masonry wall is subdivided into vertical fibers that generate an internal friction at the interface between the overturning wedge and the remaining stable part. Even in case of internal friction it has been considered that the friction coefficient trend decreases from a static value to a dynamic value. Furthermore it has been considered that, as the wall overturns, the transversal masonry wedge participating to mechanism, detaches from the remaining stable part of the wedge, and hence it is subjected to both horizontal and vertical displacements. Hence, since as the wedge vertically detaches from the remaining stable part as the friction effect vanishes, it has been considered that the friction also reduces due to the uplift effect. This aspect has been considered in the model by reducing the friction forces through an uplift coefficient. Again related to composed mechanisms, different masonry texture quality have been taken into account. As a matter of fact bad texture quality leads to define a lower inclination angle of the transversal masonry wedge and hence a smaller transversal wedge portion, while good texture quality leads to define a higher inclination angle and hence a bigger transversal masonry wedge portion. For each composed mechanisms two inclination angle values have been considered in calculation. Regarding the position of the pole around which the wall overturns, it has been considered that, since for example due to cracks eventually plastered through time, it is not always easy to determine the exact position around which the wall rotates and the mechanism activates. Hence, for each combination of the parametric study the pole of the overturning wall has been placed at the basis of each floor. Finally particular attention has been paid to the type of forces acting on the overturning wall: constant forces or variable forces. Constant forces are forces that remain constant during the whole mechanism evolution while variable forces are forces that, for some reasons, stop to act at a certain step of the mechanism evolution. Referring to the case analyzed variable forces refer to the possibility of floor extraction. As a matter of fact, if the floor is not well connected to the overturning wall, it can extract from the wall: in this case, as soon as the floor loses its support on the wall, the floor weight and its related friction force immediately stop to act on the wall. This aspect is particularly important in the definition of the structural capacity. As a matter of fact, locally incompatible situations, like the extraction of the floor, affect the capacity of the wall itself. Hence particular attention has been paid to this aspect. As anticipated the proposed analytical model allows to determine the structural capacity of the analyzed portion of building subjected to out-of-plane collapse mechanism through linear and nonlinear kinematic analysis. The seismic safety verification are then carried out according to the Italian building code prescriptions. The model has been validated through a parametric study: each variation of the parametric study corresponds, in effect, to a single collapse mechanism associated to a seismic safety index. The analyses showed the great variability of the results obtained depending on the basis hypotheses adopted in the calculation, in particular on the calculation parameters effect previously described. These parameters are associated to uncertainties related to the effective knowledge of the building and hence to the knowledge level of the building itself. Hence the importance of the knowledge level of the building is again underlined by the variability of the results obtained in the parametric study. The aim of the study is also to underline how important is to improve the refinement level of the analysis in order to obtain reliable and at the same time safe results and to trust, as much as possible, the results obtained. This is an important step in the perspective of the planning, in a more targeted way, of the intervention for the increase of the safety level in the sustainability and minimum intervention criterion framework. The analytical model proposed hence well fits with both research and practical requirements. It is in fact of interest, from a research point of view, the deepening of numerical aspects and the of mechanical models that describe, in a rather simplified but efficient way, some physical aspects that proved to influence the structural response. From a practical point of view it is useful to face with a calculation instruments that help analysts in the seismic vulnerability assessment of existing masonry walls towards out-plane collapse mechanisms, according to codes prescriptions. Furthermore, although the great attention paid by researchers to the theme of the seismic vulnerability assessment of historical buildings, well documented by several works available in literature, the topic of the seismic vulnerability assessment towards out-of-plane collapse mechanisms has not yet been well addressed in European codes. The Italian building code is the only code that provides a relatively simple calculation method for the evaluation of the seismic vulnerability towards out-of-plane collapse mechanisms, by means of linear and nonlinear kinematic analysis. For this reason the Italian building code is in advanced with respect to other international standards. The research carried out can be considered as a starting point for future research developments. As a matter of fact it must be underlined some limitations of the research carried out to the application field, that can be extended in future researches. First of all, since the aim of the study was also to provide useful indications to be applied in the current design process, standard and conventional calculation methods have been applied to the cases study analyzed, mostly following the codes prescriptions. Remaining in the respect of standards prescriptions, it would be of interest deepening some aspects of the calculation procedure proposed by the standards, like for example the calibration of safety coefficients or the determinations of ultimate limit values, by means of more refined and addressed analyses. Furthermore the analytical model proposed only deals with limited cases of out-plane collapse mechanisms. As a matter of fact the study has been carried out on simply overturning masonry walls characterized by wooden floor. Future researches aim to extend the analytical model and the associated parametric study to further types of out-of-plane collapse mechanisms, like for example the out-of-plane bending of masonry walls, and to deal with the influence of further mechanical aspects related for example to the horizontal forces effect generated by arches and vaults. The aim is then to get a complete scenery of the main criticalities of historical buildings, implemented in an analytical model that allows to determine, in a rather refined but at the same time safe way, the structural capacity of portion of buildings subjected to out-of-plane collapse mechanisms, for the seismic safety verifications. This allows to have useful calculation instruments in the daily design process for the identification and the evaluation of the most common seismic vulnerabilities of existing masonry buildings.

The paper describes a simplified methodology for the evaluation of the seismic retrofit intervention types to be performed on clusters of multi-span masonry arch bridges, on the basis of the main bridges’ geometrical characteristics. The structural behaviour of the analysed sample bridges has been evaluated in their main directions highlighting the potential local and global vulnerabilities and the related retrofit intervention typologies that need to be selected. The main aim of this study is to take the form of an useful tool for the identification of the best retrofit strategies for each masonry bridge structure in function of its geometrical characteristics and thus planning rationally the management of these bridges belonging to railway networks.

Structural assessment of historical constructions is a particular issue as these structures were built with technical knowledge and construction methods based on in-field experience and on the observation of previous failures and successes of similar buildings. Their structural behavior is influenced by numerous aspects, sometimes not completely known (geometry, structural schemes and details, material mechanical properties), which often results in historical structures inadequate to achieve the safety level required for new constructions. In the case of earthquakes, these structures can suffer heavy local or global damages that sometimes lead to collapse. Thus static and seismic vulnerability assessment of historical buildings should therefore be performed by proper methodologies that differ from those used for new constructions. In Italy, an official document (Direttiva del Presidente del Consiglio dei Ministri [DPCM] 2007, revised in 2011) was released, defining a step-by-step procedure for data acquis...

Mestrado em Construções Civis na Escola Superior de Tecnologia e Gestão do Instituto Politécnico de Viana do Castelo O estudo dos danos resultantes de abalos sísmicos em estruturas de pontes permitem verificar a necessidade da consideração do comportamento não-linear na análise e no dimensionamento sísmico destas estruturas. A partir da definição das leis do comportamento material do betão e do aço, a partir do seu funcionamento isolado em condições de carregamento monotónico e cíclico, permitem depois idealizar o comportamento não linear dos elementos de betão armado. É efetuada a descrição dos conceitos teóricos relativos à aplicação das modelações de análise sísmica, abordando dois modelos de análise numérica, modelo de fibras e modelo de rótulas plásticas. É mencionada também uma breve abordagem sobre a avaliação da segurança sísmica de pontes envolvendo funções de vulnerabilidade possibilitando determinar assim a probabilidade de ruina de modo a avaliar a sua segurança e permitir assim efetuar o estudo comparativo entre as metodologias abordadas. Para o estudo comparativo do comportamento sísmico de pontes de betão armado através da análise dinâmica foram considerados quatro viadutos em betão armado com diferentes configurações, cujo comportamento do material foi modelado com a não-linearidade distribuída ao longo do elemento estrutural pelo modelo de fibras. Obtiveram-se os valores de probabilidade de ruina para cada ponte, calculada através da metodologia probabilística e foi efetuada a discussão dos resultados obtidos entre as duas modelações estudadas. The study of damage from earthquakes in bridge structures to monitor the need for consideration of nonlinear behavior analysis and seismic design of these structures. From the definition of the laws of the material behavior of concrete and steel, from its operation in isolated conditions of monotonic loading and cyclic, then allow idealize the nonlinear behavior of reinforced concrete elements. Complete legal description of the theoretical concepts related to the application of modeling seismic analysis, addressing two models of numerical analysis, model and fiber model plastic hinges. It also mentioned a brief approach to the evaluation of seismic safety of bridges involving vulnerability functions enabling thus determine the probability of ruin in order to assess its safety and to thereby make a comparative study between the methodologies discussed. For a comparative study of the seismic behavior of reinforced concrete bridges by dynamic analysis were considered four bridges of reinforced concrete with different configurations, whose material behavior is modeled according to the nonlinearity distributed along the structural element model of the fibers. We obtained values of probability of ruin for each bridge, calculated using the probabilistic approach and discussion is made of the results between the two modulations studied.

When relating to hazards such as earthquakes, a primary task of a resilience approach is to evaluate vulnerability in an integrative manner by taking into account the most relevant indicators. Focused on Iasi, one of the major Romanian cities which are exposed to the earthquakes originating in Vrancea area, this study aims to assess seismic vulnerability using a multi-criteria analysis of buildings infrastructure and social vulnerability. Several indicators are taken into account, such as physical (related to the characteristics of buildings and terrain) and social indicators (related to population and economic income), as well as the accessibility from/to emergency services/hospitals. The indicators were processed by standardization (Z score), processed and correlated using the principal components analysis (PCA) and integrated within an Analytical Hierarchy Process (AHP). By summing the weighted values of the standardized indicators, a (integrated) seismic vulnerability index was obtained. It is a pre-assessment of the seismic vulnerability in Iasi City and also a prerequisite for the identification of the necessary prevention measures to be taken in compliance with the identified spatial patterns of vulnerability as a part of a resilient approach.

This study assesses the seismic vulnerability of ductile reinforced concrete frames with masonry infill walls, utilizing nonlinear dynamic analysis of building models. The evaluation is based on structures designed and detailed according to Eurocodes. The research quantifies the effect of presence and configuration of masonry infill walls on the seismic collapse risk using Incremental Dynamic Analysis within the performance-based framework. Seismic vulnerability assessment indicated that of the configurations considered (bare, partially-infilled and fully-infilled frames), the fully-infilled frame had the lowest collapse risk and the bare frame is found to be the most vulnerable to earthquake-induced collapse. The study compares seismic vulnerability of reinforced-concrete frame structures with- and without infill. An Incremental Nonlinear Dynamic Analysis of the model planar reinforced-concrete frames exposed to a set of recorded ground motions was performed in order to evaluate their seismic vulnerability.

The seismic vulnerability that characterizes the architectural heritage requires methods applicable at territorial scale, simplified but reliable for a proper risk assessment and subsequent planning of intervention strategies. For this purpose, in the present work a model for the seismic vulnerability evaluation at territorial scale was developed in order to analyze the buildings built in Italy between 1930 and 1940, belonging to the architectural movement of Italian Rationalism. Starting from the vulnerability model, based on the European Macroseismic Scale ( Grunthal, 1998 , Giovinazzi and Lagomarsino, 2004 ), the proposed methodology provides new parameters related to specific vulnerabilities of the Rationalist architectural heritage. The analysis of these buildings, represented by a sample geographically contextualized to Ligurian region (Italy), pointed out that the vulnerability is related to two main issues. The first is the formal characteristics, related to the research of lightness, transparency and boldness that characterized the new architectural language which, in those years, was developing in Italy, as in the rest of Europe. At the base of the formal choices is the use of reinforced concrete, a “new” construction technology: if the use of this material was a valuable tool for the formal renovation in architecture, it is true that it is, at the same time, the second cause of the vulnerability that characterizes the buildings belonging to the Italian Rationalism. In fact, it is necessary to take into account that the construction technique was in its “first step” at the beginning of the last century, and that, therefore, had not yet fully mastered, causing structural problems, in some cases, already from a static point of view. The scores of vulnerability, assigned to the parameters identified, have been calibrated through parametrical analysis on a building “prototype”, from a real case study, selected as representative of certain recurring characteristics in the sample.

Earthquakes do not kill people, buildings do. Transforming existing cities in earthquake resilient systems should be the main goal for researchers in the field of the seismic analysis of entire towns. Providing means for realistic disaster risk scenario can help decision makers in pre- and post-earthquake management and save lives and goods. Two main challenges regarding seismic resilience at urban scale are linked to determining seismic vulnerability before earthquakes and residual capacity following a seismic event. In this way, ambient-vibration measurement is an interesting and non-destructive data source for the seismic vulnerability assessment of towns. It can help in the detection of the real seismic behavior of structure and in the introduction and definition of new construction types in regions with very limited construction data prior to an earthquake. A second measurement after the shock provide information about the possibility of occupancy of damaged buildings.

PELL, Public Energy Living Lab, is a platform conceived to support the Public Administration in Italy towards the definition and implementation of interventions on public buildings, aiming to jointly pursue their seismic safety, energy efficiency and environmental certification. This paper presents the on-going activities for the development of the platform PELL-Schools, focusing, in particular, on the “Seismic-Response” module that aims to become a standardized and interoperable database for the collection and collation of relevant data for the seismic vulnerability assessment and for the seismic monitoring of Italian schools. In order to test, tune and modify, if necessary, the proposed PELL-School Seismic-Response module and to contribute to its implementation on Italian school buildings a Working Group has been set up involving several Italian municipalities and stakeholders. The paper concludes with a call to action in viting researchers working on the seismic vulnerability assessment and monitoring of strategic buildings to join the Working Group to contribute their knowledge towards the commo n goal of guarantying the seismic safety of schools and other strategic buildings in Italy

Italian territory is particularly sensitive to seismic actions. The Amatrice earthquake on August 24th 2016 confirmed this aspect. Such an event, nothing but extraordinary, has been able to cause huge and tragic damages. The direct knowledge of building features is the only prior measure to face seismic events. In order to get a realistic scenario of the urban damage distribution, the determination of useful seismic vulnerability assessment tools at urban scale becomes a priority. The widespread application of seismic vulnerability assessment sheets and the related data transformation into urban damage distribution plans is exactly what municipalities need. Main advantages are both in the chance of prior knowing the most affected areas to focus on for retrofitting interventions and in the possibility of organizing optimal emergency plans. In European framework, in the last decade, the Risk-UE project has played an important role. The Risk-UE project has proposed two methods for vulnerability assessment at urban scale: LM1 method (macroseismic) and LM2 method (mechanical). The two methods provide, with different approaches, seismic vulnerability ssessment of existing buildings. In LM1, seismic input is simulated by a given seismic intensity. In LM2, seismic input is given by a predetermined response spectrum. On the basis of the two proposed methods, many countries have adjusted their evaluation forms. Seismic vulnerability assessment in Italy is carried out through the application of appropriate forms (level 0, level 1, level 2), prepared by GNDT. The three gradually more detailed forms provide all the core information for seismic assessment of analysed buildings. The two methods proposed by Risk UE project are particularly advanced and founded on solid theoretical basis. Their application over the last few years and, in particular, a recent detailed study on the reliability of the methods, carried out by Canton of Valais (Switzerland), together with local research centre Crealp, University of Genova and École Polytechnique Fédérale de Lausanne, have shown some nebulous aspects that deserve further studies. The paper deals with the main features of the two methods and tries to point out the aspects that need to be improved for a better reliability of results.

This paper addresses seismic vulnerability assessment at an urban scale by focusing on the displacement demand determination for building damage prediction. The study is based on the comparison of urban seismic damage distributions obtained by the displacement demand computed using non-linear time-history analysis (NLTHA) with three simplified methods. These methods include the N2 method, the Lin & Miranda proposal and an optimized version of the N2 method. Comparing the different damage distributions from the three simplified methods with the one obtained by time-history analysis helps understanding the reliability of displacement demand determination. The study is carried out on Sion and Martigny, two typical Swiss cities. For the case of Sion, results clearly show that using N2 method may lead to significant overestimation of damage grade distribution. The use of Lin & Miranda method and optimized version of N2 improves the damage prediction in both cases. For the other studied case of Martigny, N2 method and Lin & Miranda proposal are not accurate. The optimized version of N2 method provides stable and reliable results.

This paper contains a seismic assessment at urban scale of the cities of Sion and Martigny in Switzerland. These two cities have been identified for the present research based on their importance regarding size and the characteristics of the building stock for which information was available. Moreover, microzonation investigations are available for both cities. This results in a more accurate characterization of local expected ground shaking, which is expressed through specific response spectra. Sion and Martigny represent, respectively, the capital and second largest city of the canton of Valais. This region is characterized by the highest seismicity within Switzerland. The paper focuses on the assessment using Risk-UE methodology, namely the empirical method LM1 and the mechanical method LM2. The obtained results are compared in order to assess the related accuracy. Firstly, buildings of the two cities were surveyed in order to collect main structural characteristics in a database. Building stock is typical of that region and can be found similar to many other medium-sized Swiss cities. Around half of the buildings are unreinforced masonry buildings, while several others are reinforced concrete buildings with shear walls. Results show the most vulnerable part of the cities regarding earthquake. There are significant differences in global results between LM1 and LM2 methods. The mechanical LM2 method is more pessimistic since it predicts damage grades of about one degree higher than LM1 method. However, the main drawback of the empirical LM1 method is that an a priori determination of an adequate value of the macroseismic intensity is required. Nevertheless, LM2 method may lead to a global overestimation of damage prediction.

In the present research work, the effect of ground motion vertical component in case of near-source excitations on masonry buildings has been analysed. To this purpose, an investigation has been made on the Banloc Castle, a historical masonry construction damaged by the Banat-Voiteg earthquake occurred on December 1991 in the Romanian Region of Banloc. A FEM model of the building, setup using DIANA FEA analysis software, has been analysed in the non-linear dynamic field. In particular, the records have been referred to the Banloc site, characterized by a moment magnitude of 5.5 and a focal depth of 9 km. In order to estimate the influence of the vertical seismic motion on the case study building in terms of both displacement and internal forces, two different scenarios have been examined. The first scenario has taken into account the horizontal component only, whereas the second one has studied the simultaneous effects of three components of the seismic action. The comparison between the two scenarios has shown that the vertical ground motion significantly modifies the structural behaviour of the inspected building. Finally, numerical damage patterns have been plotted and compared to the real cracks detected in the case study after the considered seismic event., (undefined)

Among natural disasters, seismic activity which can cause earthquakes is a serious risk for human activities and most importantly their lives. Seismic risk assessment requires knowledge to evaluate existing buildings and their expected response against earthquakes. In a large scale assessment, it is not possible to analyze each one of them individually. Instead, each building is associated to a certain type to group them under similar behaviour. The literature already gives the parameters characterizing the vulnerability of these types. In the first part, this project focus on an advanced technique to determine the building type of the whole canton of Basel. By using data mining to have a list of features for the buildings and implementing a machine learning algorithm to interpret them, each building has a type attributed. A visual survey is also performed to validate the results from the machine learning method. To understand the taxonomy of buildings in Switzerland, the supervised algorithm called Random Forest (RF) was trained during another project with several swiss cities such as Neuchatel, Yverdon-Les-Bains and Solothurn. The results obtained by this method being close to the ones from the visual survey, this allows us to approve the first attempt of this methodology to try it on the whole country. In the second part, the risk assessment is performed using the European Risk-EU basis composed of two methods. Firstly, the empirical method (LM1) whose calculation of damage grade is based on past earthquakes. And secondly, the mechanical method (LM2) whose calculation of damage grade is based on the mechanical behaviour of buildings corresponding to their group. It consists in computing the lateral displacement in function of the lateral force at the base due to the seismic acceleration (those are called capacity curves). An optimization of the N2 method, used in the LM2 method to better compute the displacement demand was also considered. Several scenarios were considered to analyze the damage on the city of Basel and create seismic vulnerability maps.