Training on improved resilience and sustainable reconstruction of cultural heritage areas
YADES aims to efficiently train a network of fellows on the field of the resilience of Cultural Heritage (CH) areas and historic cities against Climate Change (CC) and other types of hazards. Towards this direction, YADES aims to introduce a research framework for downscaling the created climate and atmospheric composition as well as associated risk maps down to the 1×1 km (historic area) scale, and specific damage functions for CH materials. Applying atmospheric modelling for specific CC scenarios at such refined spatial and time scales allows for an accurate quantitative and qualitative impact assessment of the estimated micro-climatic and atmospheric stressors. YADES will perform combined structural/geotechnical analysis of the CH sites and damage assessment under normal and changed conditions, based on the climatic zone, the micro-climate conditions, the petrographic and textural features of building materials, historic data for the structures, the effect of previous restoration processes and the environmental/physical characteristics of the surrounding environment. The data coming from installed monitoring system will be coupled with simulated data (under our cultural heritage resilience assessment platform- CHRAP) and will be further analysed through our data management system, while supporting communities’ participation and public awareness. The data from the monitoring system will feed the DSS so as to provide proper adaptation and mitigation strategies. The produced vulnerability map will be used by the local authorities to assess the threats of CC (and other natural hazards), visualize the buily heritage and cultural landscape under future climate scenarios, model the effects of different adaptation strategies, and ultimately prioritize any rehabilitation actions to best allocate funds in both pre- and post-event environments. To train the fellows, the project will make use of extensive workshop ad training sessions, as well organise summer schools.
Project Funding
EU Research Executive Agency
Marie Sklodowska-Curie Reseasrch and Innovation Staff Exchange
H2020-MSCA-RISE-2019
Collaborators
National Technical University of Athens – NTUA
UAB Metis Baltic
Resilience Guard GmbH
Environmental Reliability and Risk Analysis
Geomatics (Cyprus) Limited
Aristotelio Panepistimio Thessalonikis
Technologiko Panepistimio Kyprou
Red Spa
Politecnico di Milano
Ilmatieteen Laitos
Time Period
Jan 2020 – March 2025
Relevant Publications
Karaferi E., Chatzidaki A., Solstad J., Vamvatsikos D. (2025). Quantitative assessment of the impact of climate change to the tourism of Tønsberg, Norway. International Journal of Disaster Risk Reduction, 120: 105351.
Abstract | A model is developed to assess the impact of a changing climate to the tourism of the town of Tønsberg, offering data suitable for evaluating the downstream implications to related business sectors. The methodology comprises downscaled data from EuroCORDEX scenarios, weather station observations, and records of visitors to museums of the municipality. To achieve this, correlation patterns are sought between the weather station observations and monthly/yearly visitor numbers. The highest correlation was found to be provided by the mean temperature over the weekends, which complies well with the nature of Tønsberg as a short (sub-daily) visit destination over weekends, without overnight stays. By developing a regression model and tying it to local weather predictions derived from EuroCORDEX, we are able to quantify the probabilistic distribution of yearly visitors and observe the potential effects of a changing climate. Assuming all else remains as is, this shows benefits for the tourism of Tønsberg, befitting its northern coastal (non-alpine) nature. The methodology presented is general enough to be applicable to other cities as long as sufficient data is available.
[paper]Gerontati A., Vamvatsikos D. (2025). Intensity Measures for Short-Period Structures and Their Non-structural Components. Earthquake Engineering and Structural Dynamics, 54(5): 1361-1375.
Abstract | Selecting (near) optimal intensity measures (IMs) for seismic fragility assessment is fundamental for the accurate and unbiased assessment of risk. While moderate/long-period structures benefit from a variety of well-established options, short-period structures and their non-structural components (NSCs) present a more ambiguous scenario. Mainly driven by nuclear power plant studies, it is the peak ground acceleration (PGA) that has long been the default choice. Challenging this notion, we test IM candidates ranging from single-period spectral acceleration (Sa) ordinates to geometric averages over a range of periods (AvgSa). Featuring both on-ground NSCs and on-structure ones, we encompass a spectrum of short-period structures and short-period components. Invariably, if one has the luxury of employing NSC-specific IMs, Sa at the fundamental period of the component tends to yield the best results. In the more general case, though, certain AvgSa options whose period range starts at 0.01–0.10s and ends at 0.40–0.50s, provide a consistently improved (or at worst equal performance) compared to PGA, for a wide variety of NSCs with periods ranging from 0.05 to 0.90s.
Spillatura A., Vamvatsikos D., Kohrangi M., Bazzurro P. (2024). Harmonizing Seismic Performance Via Risk Targeted Spectra: State Of The Art, Dependencies, And Implementation Proposals. Proceedings of the 18th World Conference on Earthquake Engineering, Milan, Italy.
Abstract | Structures are typically designed on the basis of ground motion spectral values associated to an “ultimate” limit state of reference, e.g., 10% in 50 years, which gives a measure of the hazard at the site of interest. However, this design approach does not guarantee that the risk will be uniform, even for buildings at sites that share the same design level, as measured, e.g., by the peak ground acceleration, mainly because of differences in hazard curve shape. Aiming to ensure a uniform collapse risk across different sites and buildings, Risk Targeted design maps were first introduced by ASCE7-10 to modify conventional design spectra by employing suitable adjustment factors. As there is more than one approach to define such factors, our objective is to test their effectiveness in matching a specific target risk or, at least, in harmonizing the risk of multiple buildings at different sites with respect to different limit states. To do so, we make use of simplified single-degree-of-freedom structures for several configurations of vibration period and ductility. Although risk matching is shown to be only theoretically possible and unachievable in practice, we claim that harmonization remains a viable and valuable target.
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Karaferis N., Gerontati A., Vamvatsikos D. (2024). From PGA To Anything: Fragility Curve Conversions For Nuclear Power Plant Applications. Proceedings of the 18th World Conference on Earthquake Engineering, Milan, Italy.
Abstract | There has been a lot of discussion on intensity measure optimality for conventional structures, touting the advantages of novel metrics of ground motion intensity to improve upon the efficiency and fidelity of seismic assessment. Yet, somehow this revolution of sorts has not transitioned to nuclear power plant assessments, which cling to the time-honored tradition of the peak ground acceleration (PGA). They do so for the simple reasons of stiffness and mass. That would be stiffness in the assets themselves, typically leading to periods of the order of 0.1 to 0.2sec for both the structures and their nested components, but also in the rigidity of regulations in an understandably ultra-cautious industry. Adding the mass (and cost) of engineering effort required to reassess already established fragilities for hundreds of standardized components, it is no wonder that there is too much inertia to allow moving away from PGA. Would it not be great if someone came along and offered a minimal-error approach for converting existing fragility curves from PGA to any intensity measure of choice? Interestingly, the response characteristics of nuclear power plants may actually favor an equivalent one/two-degree-of-freedom-model based procedure that allows disaggregating existing fragilities back into ground-motion-level constituents and reconstructing them anew with the desired intensity measure parameterization. There is little doubt that safeguarding the integrity of nuclear power plants would still require massive computations rather than rely on shortcuts, yet such an approach can give novel intensity measures a fighting chance to prove that they are worth the trouble for nuclear engineering.
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Karaferis N., Melissianos V.E., Vamvatsikos D. (2024). Seismic Fragility Assessment Of Spherical Pressure Vessels: The Effect Of Fill Ratio Variability. Proceedings of the 18th World Conference on Earthquake Engineering, Milan, Italy.
Abstract | Fragility curves are a seismic risk modeler’s bread and butter, relaying the probability of reaching or exceeding each limit state of interest given the ground motion intensity. Yet, as they convey essential information, they also hide assumptions, especially when used to characterize a group of similar or even seemingly identical structures. Chief among them is the concept that the dynamic properties of such structures are invariable and uncorrelated. However, the latter does not necessarily apply to groups of adjacent “identical” spherical pressure vessels, used for storing gaseous products in industrial facilities. The quantity of product contained within a vessel directly affects its dynamic response. Using an ensemble of four “identical” pressure vessels as a case study, a comprehensive set of fragility curves is developed, each corresponding to a different fill ratio of a single vessel. Then, different approaches are explored to combine said fragilities and assess the group of four. These include full-scale Monte Carlo simulation with or without filling level correlation, as well as the computation of a single “law-of-total-variance” fragility curve. The latter approach is decidedly simpler, yet its use cannot be justified without some knowledge of the facility’s operational profile in terms of day-today fluctuation of the filling level, as it can otherwise lead to unconservative and/or biased results.
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Karaferi E., Kohrangi M., Spillatura A., Tsarpalis D., Vamvatsikos D. (2024). Seismic Risk, Direct, And Indirect Losses For The Historic City Of Rhodes. Proceedings of the 18th World Conference on Earthquake Engineering, Milan, Italy.
Abstract | A risk assessment model is developed for the historic city of Rhodes, Greece, with a focus on the buildings, residential and commercial, that are at risk from earthquakes, the main hazard that the city faces. The structural integrity of the buildings of Rhodes is tested under a stochastic event set of spatially correlated ground motion fields. They are generated with the OpenQuake platform via an event-based probabilistic seismic hazard analysis for 10,000 years using the 2020 European Seismic Hazard Model. All commercial or mixed-use buildings are assigned to corresponding lines of business according to census data and expert opinion, while using data from the 2020 European Seismic Risk Model to determine vulnerability functions, and from HAZUS-MH to assess the related downtime. The assessment takes as input the exposure model, the hazard, and the vulnerability of the assets to return the direct and the indirect losses per line of business. This allows the determination of the direct consequences to the city, translated to the economic losses to rebuild or renovate the damaged buildings. Stemming from the direct losses and especially the downtime, a mesoeconomic model is employed to determine the losses caused by business interruption on an event-by-event basis. By thus providing a comprehensive assessment of the risk faced by the city, the model can be used to develop a socioeconomic impact model and support the development of financial mitigation tools.
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Gerontati A., Karaferis N., Vamvatsikos D., Bazzurro P., Droszcz C. (2024). A Bare-Bones Nuclear Power Plant Case Study To Test Uncertainty Propagation And Correlation Effects. Proceedings of the 18th World Conference on Earthquake Engineering, Milan, Italy.
Abstract | The safety of a nuclear power plant is influenced by both aleatory randomness and epistemic uncertainty, as well as the potential inter-component and intra-component correlations. Aleatory randomness arises from inherent variability in the data, while epistemic uncertainty stems from limitations, or incomplete knowledge in models or data. Component correlation refers to the extent to which the properties of various components within a Nuclear Power Plant (NPP) are interdependent and how they may co-vary within a single component (intra-component correlation) or among similar/identical ones (inter-component). Evaluating their effects to completion is a non-trivial operation that requires a full model of the power plant and its components, as well as the overall fault tree. When the goal is the evaluation of alternative approaches to safety assessment, one need not set the bar so high. In this, we offer a pared-down model, comprising simplified models of the reactor building and of one or more non-structural components, together with a simplified fault tree that leads to loss of core cooling capacity. As an example, three alternative cases of perfect, partial, and no correlation are employed to test common causes of failure. Uncertainty is propagated using a Monte Carlo simulation with either classic or progressive Latin hypercube sampling, using the simplified model as an efficient benchmark for NPP-compatible applications.
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Gerontati A., Karaferis N., Sipcic N., Vamvatsikos D., Bazzurro P., Droszcz C. (2024). A Minimalistic Computational Testbed For Evaluating Fragility Assessment, Record Selection, And Intensity Measure Optimality For Nuclear Powerplants. Proceedings of the 27th International Conference on Structural Mechanics in Reactor Technology (SMiRT27), Yokohama, Japan.
Abstract | Recent advances in Performance-Based Earthquake Engineering (PBEE) have followed their own revolutionary path over the past two decades. Focusing on the assessment of conventional buildings and infrastructure, several innovative proposals on improving fragility assessment have appeared over the years, focusing on record selection, improved intensity measures, as well as novel uncertainty propagation approaches. Whether these are also useful for nuclear powerplant assessment remains a question. Partially owing to the well-established practice and guidelines, introducing novelty in such procedures faces significant hurdles in terms of modeling, computational power, and complexity. In an effort to overcome said difficulties in the context of the METIS Euratom project, we propose a minimalistic computational testbed comprising simplified models of a building, one or more components, and a bare-bones fault tree
to tie them together and propagate uncertainties. The METIS simplified testbed is realized in open source, using Python and OpenSees to offer a fast assessment platform, whereby one can test any number of ideas in a setting that resembles a real case study. Among them are important questions, such as the influence of aftershocks, or clustered seismicity in general, new uncertainty propagation techniques, the use of hazard consistent record selection approaches in place of selection based on the uniform hazard spectrum, as well as the use of new intensity measures that can potentially reduce the aleatory uncertainty in the estimates of risk. Focusing on the latter, we present an example of application of the testbed and its results.
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Dasiou M-E., Lachanas C.G., Melissianos V.E., Vamvatsikos D. (2024). Seismic performance of the temple of Aphaia in Aegina island, Greece. Earthquake Engineering and Structural Dynamics, 53(2):573-592
Abstract | The seismic performance assessment of the ancient Temple of Aphaia in Aegina island, Greece, is presented. The Temple of Aphaia was erected around 500BC using porous limestone and is one of the most characteristic examples of Doric architecture. The assessment is performed within a performance-based framework using state-of-the-art tools of earthquake engineering. In the first part, the seismic hazard of the site was calculated using the European Seismic Hazard Model and hazard-consistent records were selected. Then, the Temple was scanned by drone and the point cloud was used to develop the numerical structural model. The Temple was analyzed using the discrete element method. Appropriate engineering demand parameters and limit state thresholds were defined. Fragility curves for the structural elements, namely, columns and architraves, of the Temple were computed via multi-stripe analysis. Finally, the seismic risk of the Temple was evaluated using long-term estimates in terms of return periods of exceeding limit states and total loss. The outcomes of the study offer valuable information to engineers, architects, and archaeologists regarding the current status of the monument in terms of identifying its most vulnerable elements and allowing the prioritization of short- and long-term restoration actions.
Reggiani Manzo N.R., Vassiliou M., Lachanas C.G., Vamvatsikos D. (2022). Α Risk-Based Design Procedure for Negative Stiffness Bilinear Elastic Systems. Proceedings of the 3rd International Conference on Natural Hazards & Infrastructure ICONHIC 2022, Athens, Greece.
Abstract | This paper presents uniform risk spectra for systems with lateral negative stiffness, such as free-standing, restrained or curved-end rocking blocks. The spectra are constructed using a simplified system, the Zero Stiffness Bilinear Elastic system, which can satisfactorily predict the response of different systems with negative lateral stiffness. The paper offers the step-by-step methodology for the construction of the spectra. It presents the construction and discussion of the spectra for a site in Athens, Greece using two distinct intensity measures: Peak Ground Velocity and Peak Ground Acceleration.
[paper]
Reggiani Manzo N., Lachanas C.G., Vassiliou M.F., Vamvatsikos D. (2021). Uniform risk spectra for negative stiffness systems. Proceedings of the COMPDYN2021 Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Athens, Greece.
Abstract | This paper presents uniform risk spectra for negative stiffness systems that do not exhibit hysteretic damping, named Negative Stiffness Bilinear Elastic (NSBE) systems. The NSBE oscillator can be used to describe the dynamics of deformable rocking systems with or without restraining systems flexible enough to lead to an overall negative stiffness. It can also be used to describe rocking systems equipped with curved extensions at their base. It has been shown that the response of an NSBE system can be well predicted using the response of a Zero Stiffness Bilinear Elastic (ZSBE) system, which is a bilinear system of constant restoring force. The ZSBE system is a single parameter system; therefore it is simple to construct design spectra for it. For a wide range of ZSBE system strength values, this paper employs Incremental Dynamic Analysis using 105 ordinary (non-pulse-like, non-long-duration) ground motions to obtain the fragility functions for predefined limit-states of the ZSBE seismic response. Fragility functions per limit-state are convolved with the seismic hazard to compute the Mean Annual Frequency of exceedance (MAF). For this study, the seismic hazard curve for a site at Athens Greece is used as it is obtained via probabilistic seismic hazard analysis. Finally, uniform risk spectra per limit-state are obtained by computing the MAF for all the ZSBE oscillators. These spectra can be used for the design of NSBE systems, including rocking oscillators.
YADES Members
