Paper-Conference |

A continuous-time Markovian framework for performance-based earthquake engineering: integrated seismic risk and resilience assessment

Sat, 01 Aug 2026 00:00:00 +0000

Abstract

La valutazione dell’affidabilità sismica dei sistemi strutturali richiede sempre più spesso modelli che rappresentino congiuntamente l’evoluzione del danno e il ripristino. Tuttavia, la formulazione tradizionale del PEER PBEE non coglie la dinamica temporale delle riparazioni post-evento, e le moderne analisi di affidabilità si basano spesso su dati di ripristino scarsi o incerti, il che richiede metodi trattabili. Riformuliamo il framework PEER PBEE con un approccio Monte Carlo basato su catene di Markov a tempo continuo (CTMC), che modella in modo naturale le transizioni probabilistiche tra stati di danno e di ripristino sotto pericolosità sismica invariante nel tempo. I tassi di transizione incorporano funzioni di fragilità dipendenti dallo stato basate su metamodelli e i processi di ripristino, fornendo una rappresentazione unitaria degli effetti della pericolosità e dell’evoluzione del sistema. Sfruttando le proprietà analitiche delle CTMC, calcoliamo statistiche di prestazione a regime, come il tempo medio al collasso e il tempo trascorso in stati degradati, e definiamo un indice di resilienza adattato dal classico indice di affidabilità β. L’approccio è testato su un esempio semplice ma rappresentativo, mostrando che il framework PBEE arricchito dalle CTMC coglie la progressione temporale dal danno al ripristino in modo computazionalmente efficiente e flessibile rispetto ai dati.

Suggerimento

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A generalized autoregressive model for time-variant dynamical systems

Sat, 01 Aug 2026 00:00:00 +0000

Abstract

Surrogate models are a staple tool for the reliability analysis of complex engineering systems, because they enable the use of otherwise computationally prohibitive algorithms, such as Monte-Carlo simulation. Their prevalence in the context of nonlinear dynamic engineering systems, however, is significantly lower, because approximating their time-dependent response is generally considered more challenging than for their static counterparts. A powerful class of surrogate models is provided by autoregressive with exogenous input models, but their use is mostly limited to system identification tasks, as they tend to underperform in pure prediction tasks. Recent advances in data-driven autoregressive modeling, have vastly improved their prediction capabilities for engineering applications, but they still rely on the assumption of time-invariant dynamics at the core of NARX. In this contribution we demonstrate how the mNARX+ framework can efficiently handle time-variant dynamical systems, such as, e.g., civil or mechanical structures subject to plastic damage or fatigue accumulation, making it an ideal tool for their reliability assessment.

Suggerimento

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Adaptive regional seismic risk assessment under uncertainty: a case study in the Alto Garda area

Sun, 14 Sep 2025 00:00:00 +0000

Abstract

A reliable national and regional risk assessment is essential for researchers, practitioners, and decision-makers. Seismic risk assessment is crucial for evaluating earthquake-induced damage to structures, infrastructure, and society. However, it cannot be effectively performed without properly managing uncertainty. In this context, hazard models and vulnerability analysis are the two critical pillars that contribute most to improving risk management, infrastructure planning, and disaster response. In this work, we present an adaptive risk assessment framework for the Alto Garda area, located in northern Italy. Leveraging newly available microzonation data and advanced hazard analysis within OpenQuake engine, the study achieves high spatial resolution at a local scale. Historical earthquake records, cadastral data, open-source maps, and satellite imagery are integrated to (i) compile a comprehensive building taxonomy and (ii) dynamically refine vulnerability models. Additionally, both aleatoric and epistemic uncertainties are carefully considered using a logic tree approach applied to both hazard and fragility analysis. Moreover, an adaptive approach is implemented, meaning that as new information becomes available, updates are seamlessly integrated to enhance accuracy and refine models. By combining hazard and vulnerability maps, the study delivers a first semiquantitative risk evaluation for the region. This approach highlights the potential of adaptive methodologies in improving seismic risk mitigation strategies and strengthening decision-making under uncertainty.

Suggerimento

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UQ based state-dependent framework for recovery and seismic risk assessment

Sun, 14 Sep 2025 00:00:00 +0000

Abstract

Recovery processes and seismic risk assessment represent a critical and challenging frontier in engineering risk analysis under uncertainty. Despite growing attention, the problem remains inherently complex, shaped by nonlinear system behaviours and high-dimensional stochastic spaces. These difficulties are compounded by the limited availability and often confidential nature of recovery data, highlighting the urgent need for modelling approaches that are not only efficient, but also flexible enough to adapt to real-world constraints. In this work, we introduce a novel framework that explicitly integrates recovery into state-dependent seismic risk assessment. The approach combines fragility modelling, recovery processes, and hazard evaluation into a cohesive structure, enabling holistic and reliable risk analysis. Designed for flexibility, the framework draws from the state-of-the-art in different disciplines, such as structural engineering, recovery modelling and probabilistic seismic modelling, and focuses on balancing adaptability and computational efficiency. At the core of the methodology is a state-dependent seismic risk model that embeds recovery through a Continuous-Time Markov Chain (CTMC) framework. This enables the joint evaluation of damage progression and recovery over time. Spectral analysis of the reduced transition matrix allows for reliability-based metrics. The framework is applied to a full-scale industrial steel frame from the European SPIF project, tested under seismic loading at EUCENTRE, demonstrating its ability to capture resilience dynamics with computational efficiency.

Suggerimento

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Bayesian Approach for Main Frequency Identification on Extremely Under-Sampled Signals

Wed, 02 Jul 2025 00:00:00 +0000

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State-dependent seismic fragility functions for bolted flange joints on special-risk industrial substructures

Sun, 28 Jul 2024 00:00:00 +0000

Abstract

Seismic vulnerability assessment of industrial plants and process equipment has gained attention lately. However, the complexity of the problem and its modelling, combined with a general scarcity of available data on industrial systems, contributed to limiting or developing risk assessment methods based on extremely simplified models. On these premises, a new methodology that combines limited data from finite element (FE) models with cutting-edge machine learning techniques is developed to generate state-dependent fragility functions for critical components mounted on archetypical industrial substructure modules. Specifically, referring to the classical forward uncertainty quantification scheme, a physics-informed FE model, calibrated on the results of a comprehensive shake table test campaign of a real-scale industrial braced-frame (BF) steel substructure, is considered. Time histories of seismic event sequences generated by a site-based ground motion model compose the input provided to the FE model. The uncertainty is then propagated through Monte Carlo analysis on inexpensive-to-run polynomial chaos expansion (PCE) metamodels set for each starting damage level condition measure. As a result, empirical state-dependent fragilities are evaluated, assuming the lognormal distribution.

Suggerimento

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Risk analysis of the Alto Garda area by means of microzonation and structural characterisation of buildings mapping

Tue, 02 Jul 2024 00:00:00 +0000

Abstract

A reliable seismic risk assessment at national and regional scales has become a major focus for researchers and practitioners, as well as decision-makers and territorial stakeholders. The two primary components of risk assessment, i.e., hazard models and vulnerability analysis, have been the subject of extensive study. In fact, they play a critical role in improving risk management strategies, planning infrastructure and engineering facilities, and supporting disaster response management at a regional scale. Within this framework, a detailed regional risk assessment for the Trentino Alto Garda region, in northern Italy, is presented herein. The recently completed microzonation of the studied area is considered for the hazard analysis contributing to improving the assessment at the local scale and with high spatial resolution. Additionally, data mining of structural building information databases and statistical models of the building asset that take advantage of the main building characteristics evaluated by means of seismic noise measurements and analysis, are used to develop exposure maps. As a result, the hazard and exposure maps are integrated to derive a first semiquantitative seismic risk assessment for the case study area.

Suggerimento

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State-dependent seismic fragility functions for vertical tanks installed on major hazard industrial substructure module

Mon, 01 Jul 2024 00:00:00 +0000

Abstract

Suggerimento

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Experimental investigation on the seismic performance of a multi-component system for major-hazard industrial facilities

Tue, 13 Jul 2021 00:00:00 +0000

Abstract

Past earthquakes demonstrated the high vulnerability of industrial facilities equipped with complex process technologies leading to serious damage of the process equipment and multiple and simultaneous release of hazardous substances in industrial facilities. Nevertheless, the design of industrial plants is inadequately described in recent codes and guidelines, as they do not consider the dynamic interaction between the structure and the installations and thus the effect of seismic response of the installations on the response of the structure and vice versa. The current code-based approach for the seismic design of industrial facilities is considered not enough for ensure proper safety conditions against exceptional event entailing loss of content and related consequences. Accordingly, SPIF project (Seismic Performance of Multi-Component Systems in Special Risk Industrial Facilities) was proposed within the framework of the European H2020 - SERA funding scheme (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe). The objective of the SPIF project is the investigation of the seismic behaviour of a representative industrial structure equipped with complex process technology by means of shaking table tests. The test structure is a three-story moment resisting steel frame with vertical and horizontal vessels and cabinets, arranged on the three levels and connected by pipes. The dynamic behaviour of the test structure and of its relative several installations is investigated. Furthermore, both process components and primary structure interactions are considered and analyzed. Several PGA-scaled artificial ground motions are applied to study the seismic response at different levels. After each test, dynamic identification measurements are carried out to characterize the system condition. The contribution presents the experimental setup of the investigated structure and installations, selected measurement data and describes the obtained damage. Furthermore, important findings for the definition of performance limits, the effectiveness of floor response spectra in industrial facilities will be presented and discussed.

Suggerimento

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Shake table testing for a multi-component prototype industrial plant: input and system modelling issues

Tue, 13 Jul 2021 00:00:00 +0000

Abstract

Recent destructive earthquakes in China (Sichuan, 2008 and Yushu, 2010), Japan (Tohoku, 2011) and Italy (Emilia, 2012) highlighted the social and the political consequences of seismic risk due especially to industrial facilities. More precisely, critical interactions between the supporting structure and process components reveal to be extremely vulnerable in a seismic scenario and capable to lead serious damage of process equipment and potential release of hazardous substances. This latter circumstance, underestimated by current codes, in addition to loss of production, pose a serious danger to humans and the surrounding environment. Based on these premises, the SPIF project - Seismic Performance of Multi-Component Systems in Special Risk Industrial Facilities - was proposed within the framework of the European H2020 - SERA funding scheme. In greater detail, the goal of the project is the investigation of both the seismic behavior and the dynamic interactions of a representative industrial substructure equipped with complex process technology by means of shaking table tests. A full-scale mock-up composed by two single-bay moment resisting frames with three floors equipped with tanks, flanges, pipes, cabinet etc. was built and tested using a unidirectional shaking table activated with several earthquake levels. More precisely, the salient features investigated by shaking table testing are: i) the interaction between a primary moment resisting frame steel structure and secondary process components that influence the performance of the whole system; ii) input and system modelling capable to faithfully reproduce the seismic response of SPIF tested structure. The comprehensive testing campaign demonstrated a clear dynamic interaction between the primary steel structure and secondary process units that emphasizes the need of further investigations and studies.

Suggerimento

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Seismic performance of multiple-component systems in special risk industrial facilities

Fri, 18 Sep 2020 00:00:00 +0000

Abstract

Past earthquakes demonstrated the high vulnerability of industrial facilities equipped with complex process technologies leading to serious damage of the process equipment and multiple and simultaneous release of hazardous substances in industrial facilities. Nevertheless, the design of industrial plants is inadequately described in recent codes and guidelines, as they do not consider the dynamic interaction between the structure and the installations and thus the effect of seismic response of the installations on the response of the structure and vice versa. The current code-based approach for the seismic design of industrial facilities is considered not enough for ensure proper safety conditions against exceptional event entailing loss of content and related consequences. Accordingly, SPIF project (Seismic Performance of MultiComponent Systems in Special Risk Industrial Facilities) was proposed within the framework of the European H2020 - SERA funding scheme (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe). The objective of the SPIF project is the investigation of the seismic behavior of a representative industrial structure equipped with complex process technology by means of shaking table tests. The test structure is a three-story moment resisting steel frame with vertical and horizontal vessels and cabinets, arranged on the three levels and connected by pipes. The dynamic behavior of the test structure and installations is investigated with and without base isolation. Furthermore, both firmly anchored and isolated components are taken into account to compare their dynamic behavior and interactions with each other. Artificial and synthetic ground motions are applied to study the seismic response at different PGA levels. After each test, dynamic identification measurements are carried out to characterize the system condition. The contribution presents the numerical simulations to calibrate the tests on the prototype, the experimental setup of the investigated structure and installations, selected measurement data and finally describes preliminary experimental results.

Suggerimento

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Ground motion model for seismic vulnerability assessment of prototype industrial plants

Sun, 19 Jul 2020 00:00:00 +0000

Abstract

Relationships between seismic action, system response and relevant damage levels in industrial plants require a solid background both in experimental data, due to the high level of nonlinearity and seismic input. Besides, risk and fragility analyses depend on the adoption of a huge number of seismic records usually not available in a site-specific analysis. In order to manage these issues and to gain knowledge on the definition of damage levels, limit states and performance for major-hazard industrial plant components, we present a possible approach for an experimental campaign based on a real prototype industrial steel structure. The investigation of the seismic behaviour of the reference structure will be carried out through shaking table tests. In particular, tests are focused on structural or process-related interactions that can lead to serious secondary damages as leakage in piping systems or connections with tanks and cabinets. The aforementioned test program has been possible thanks to the adoption of: (i) a number of artificial spectrum-compatible accelerograms; (ii) a ground motion model (GMM) able to generate a suite of synthetic time-histories records for specified site characteristic and earthquake scenarios. More precisely, GMM model parameters can be identified by matching the statistics of a target-recorded accelerogram to the ones of the model in terms of faulting mechanism, earthquake magnitude, source-to-site distance and site shear-wave velocity. As a result, the stochastic model, based both on these matched parameters and on filtered white-noise process, can generate the ensemble of synthetic ground motions capable of capturing the main features of real earthquake ground motions, including intensity, duration, spectral content and peak values. Moreover, the synthetic records are selected to target specific damages and limit states in industrial components. Finally, by means of the combination of artificial and synthetic accelerograms, a seismic vulnerability assessment of both the whole structure and relevant industrial components

Suggerimento

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A ground motion model for seismic vulnerability assessment of prototype industrial plants

Wed, 24 Jun 2020 00:00:00 +0000

Abstract

Relationships between seismic action, system response and relevant damage levels in industrial plants require a solid background both in experimental data, due to the high level of nonlinearity, and in knowledge of seismic input due to large uncertainty. Besides, risk and fragility analyses depend on the adoption of a huge number of seismic records usually not available in a site-specific analysis. In order to manage these issues and to gain knowledge on the definition of damage levels, limit states and performance for major-hazard industrial plant components, we present a possible approach and discuss results of an experimental campaign based on a real prototype industrial steel structure. The investigation of the seismic behaviour of the reference structure has been carried on through shaking table tests, focusing in particular on the structural or process-related interactions that can lead to serious secondary damages as leakage in piping systems or connections with tanks and cabinets. This has been possible thanks to the adoption of a ground motion model (GMM) able to generate a suite of synthetic time-histories records for specified site characteristic and earthquake scenarios. In fact, model parameters can be identified by matching the statistics of a target-recorded accelerogram to the ones of the model in terms of faulting mechanism, earthquake magnitude, source-to-site distance and site shear-wave velocity. Hence, the stochastic model, based both on these matched parameters and on filtered white-noise process, generates the ensemble of synthetic ground motions capable to capture the main features of real earthquake ground motions, including intensity, duration, spectral content and peak values. Finally, by means of the combination of a high-fidelity and a low-fidelity FE model as well as the stochastic input generated by a GMM, a seismic vulnerability assessment of both industrial components and the global structure can be carried out.

Suggerimento

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Investigation of the seismic behaviour of structural and non-structural components in industrial facilities by means of shaking table tests

Wed, 04 Mar 2020 00:00:00 +0000

Abstract

Industrial facilities consist of a primary load-carrying structure and of process components, such as vessels, tanks, piping and cabinets, that can be seriously damaged by earthquakes. Within the SPIF project (Seismic Performance of Multi-Component Systems in Special Risk Industrial Facilities), funded by the European H2020 SERA Transnational Access programme, a full-scale three-storey industrial steel frame equipped with vertical and horizontal vessels, a cabinet and connecting pipes was tested on the shaking table of the EUCENTRE laboratories in Pavia, Italy. This contribution presents the test structure, its installations and the measurement plan, with accelerations and relative displacements of the components and pipe sections recorded at increasing peak ground acceleration levels, with the aim of supporting design recommendations for the seismic performance of vessels, pipes and their connections.

Suggerimento

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