Publications

In order to promote an effective approach to the prevention of and preparedness for disasters, the countries participating in the Union Civil Protection Mechanism (UCPM) shall develop risk assessments, risk management capability assessments and disaster risk management planning at national or appropriate sub-national level. The European Commission is providing scientific support to the countries participating in the UCPM, publishing updated guidelines to facilitate the development of their National Risk Assessments (NRAs). Earthquake is among the most common hazards considered in NRAs prepared by the countries participating in the UCPM. Indeed, in 2018 NRAs, more than 20 countries performed risk assessment for earthquakes, and some considered cross-border and cascading effects, such as tsunami, landslides, disruption of infrastructure and industrial accidents. This paper surveys and summarises the current state of research that can be utilized for national seismic risk assessment. It aims to facilitate the development of consistentNRAs with respect to earthquakes and ensure their utility in seismic risk management planning. It also aims to support the use of the new reporting guidelines on disaster risk management among countries participating in the UCPM. The seismic risk assessment process is described as outlined in ISO 31000: 2018. A wealth of hazard, exposure, vulnerability and damage-to-loss models, methodologies and tools are presented to serve the purpose of conducting national seismic risk assessment. References to relevant European research projects, good practices, and software to support the assessment are also provided.

The metropolitan area of Lisbon is the region of Portugal with the highest seismic risk, given the coexistence of moderate-to-high hazard with highpopulation density and building stock exposure. The present work addresses the seismic risk assessment of pre-code masonry buildings in this region, accounting various typological classes and conservation states in order to evaluate the consequences in terms of economic losses. The analyses are conducted through a seismic probabilistic approach, considering the sitespecific ground motion through a non-stationary stochastic method. The results can serve as a useful guide for decision-making in developing regional seismic risk mitigation strategies.

Given the 516 Arouca pedestrian suspension bridge

Azores Islands are seismically active due to the tectonic structure of the region. Since the 15th century, they have been periodically shaken by approximately 33 moderate to strong earthquakes, with the most recent one in 1998 (Mw = 6.2). Nonetheless, due to insufficient instrumental seismic data, the region lacks a uniform database of past real records. Ground motion simulation techniques provide alternative region-specific time series of prospective events for locations with limited seismic networks or regions with a seismic gap of catastrophic earthquake events. This research establishes a local ground motion model (GMM) for the Azores plateau (Portugal) by simulating region-specific records for constructing a homogeneous dataset. Simulations are accomplished in bedrock using the stochastic finite-fault approach by employing validated input-model parameters. The simulation results undergo validation against the 1998 Faial event and comparison with empirical models for volcanic and Pan-European datasets. A probabilistic numerical technique, namely the Monte-Carlo simulation, is employed to estimate the outcome of uncertainty associated with these parameters. The results of the simulations are post-processed to predict the peak ground motion parameters in addition to spectral ordinates. This study uses XGBoost to circumvent the difficulties inherent to linear regression-based models in establishing the form of equations and coefficients. The input parameters for prediction are moment magnitude (Mw), Joyner and Boore distance (RJB), and focal depth (FD). The quantification of GMM uncertainty is accomplished by analyzing the residuals, providing insight into inter- and intra-event uncertainties. The outcomes demonstrate the effectiveness of the suggested model in simulating physical phenomena.

The characteristic values of temperature corresponding to the maximum and minimum shade air temperature with an annual probability of being exceeded 0.02, used in the European construction standard for thermal actions (EN 1991-1-5:2003), are usually assessed at a country level and included in the National Annexes to that Eurocode part.The paper aims to support national authorities on elaborating maps for thermal actions using publicly available datasets, consistent at a European level, and harmonised modelling approaches. In addition, these datasets are continuously updated, reflecting the current climate and capturing potential global warming variations.The work investigates how updates in data and modelling could affect the characteristic values currentlyadopted in the Italian National Annexes to the Eurocodes. The main results show that: (i) the currently adoptednumber and locations of the weather stations result fairly representative of the patterns detected by exploitingadditional datasets; ii) the statistical method plays an essential role in the assessment of characteristic values, i.e., the method adopted in the current Italian standard evaluates more conservative characteristic values of maximum temperature than Gumbel or Generalized Extreme Value distributions, but could err on the unsafe side for minimum ones; (iii) both E-OBS and ERA5-Land datasets represent two optimal products to be used as a common source of temperature values at European scale; (iv) moving towards an updated period for temperature data results on an increase of characteristic values of maximum temperature and limited variations in spatial extent and magnitude of characteristic values of minimum ones.

The present work analyses the wind load effects on the 516 Arouca bridge, the world's longest pedestrian suspension bridge in 2020. Computational fluid dynamics (CFD) was used to model a range of wind incidence angles between -8

The safety and resilience of school buildings against natural disasters is of paramount importance since schools represent a reference point for communities. Such significance is not only related to the direct consequences of collapse on a vulnerable part of the population, but also due to the importance of schools in the post-disaster recovery. This work is focused on the risk and resilience assessment of school buildings in Lisbon (Portugal) under seismic events. The results of this study, in which a subset of 32 schools are analyzed, are used to define a prioritization strategy to mitigate the seismic risk of the Lisbon City Council school building portfolio and to assess the overall resilience of the school network. Numerical modeling of the school buildings is performed in order to estimate losses in terms of the built-up area of the schools and recovery times associated with different seismic scenarios, which are probabilistically defined specifically for the sites of the buildings, accounting for the local soil conditions and associated amplification effects. Based on the obtained risk estimates, which are compared to reference values established on international guidelines and specialized literature, the Lisbon City Council and LNEC jointly defined a short- and medium-term risk mitigation plan, starting with a detailed inspection and assessment of the most vulnerable school buildings and continuing to the implementation of retrofitting measures.

Probabilistic seismic hazard assessment (PSHA), despite its deep criticism, is still the most common tool used to decide on the acceptable seismic risk and corresponding mitigation measures. We propose two consistency tests to address the variability of earthquake generation models found in PSHA studies: (i) one rule-of-thumb test where the seismic moment release from the model is converted to an average slip on a typical fault and compared with known plate kinematics or GNSS deformation field and (ii) a test where using a neotectonic model the computed deformation is converted into seismic moment release and to a synthetic earthquake catalogue. We apply these tests to W and SW Iberia slowly deforming region, where two earthquake source areas are investigated: (1) the Lower Tagus Valley, one of the largest seismic risk zones of Portugal; and (2) the offshore SW Iberia area, considered to be the source for the 1 November 1755 event (M

Procuram-se sintetizar neste artigo os principais aspetos relacionados com a avaliação e a reabilitação sísmica de edifícios existentes de alvenaria, compatibilizando a NP EN 1998-3:2017 com os respetivosAnexo C, específico para edifícios de alvenaria, e Anexo Nacional, específico para Portugal.A avaliação sísmica é um procedimento quantitativo através do qual se verifica se um edifício existente, danificado ou não, satisfaz os requisitos de desempenho, definidos por uma combinação de um estado limite com um nível de ação sísmica, através de critérios de conformidade. Neste procedimento estão envolvidos a definição da ação sísmica, a modelação da estrutura, os métodos de análise para determinação dos efeitos das ações e as verificações de segurança. São abordados os métodos de análise, dois lineares e dois nãolineares, aplicáveis a edifícios existentes de alvenaria, bem como as recomendações específicas do Anexo C e as informações complementares do Anexo Nacional.

The response of three full-scale unreinforced masonry buildings, without specific seismic detailing, as observed in shake table testing at LNEC for a seismic action representative of induced seismicity, is presented. The first building specimen simulated the upper floor and roof of the end-unit of a two-storey terraced house, built with unreinforced cavity walls, a reinforced concrete slab and a pitched timber roof. The second specimen was a replica of the roof of the first building. The third specimen represented instead a one-story detached pre-1940

This paper presents the las developments on seismic hazard analysis directed to the computation of strong ground motion parameters to be applied to nonlinear structural analysis (Campos Costa,1992). It follows the Ishikama and Kameda approach (1988), and makes an application to the Lisbon site. Inhere, the methodology and the most probable seismic scenarios are presented. In an accompagning paper (Duarte et al, 1992), time series generation is obtained for a long distance and short distance earthquake scenarios.

This paper presents, in the light of LNEC experience in Earthquake Engineering studies, the limitations and advantages of shaking table testing of reinforced concrete and masonry structures. It starts with a general assessment of the contribution of shaking table facilities to the mitigation of earthquake risks and proceeds with a discussion of some specific problems of shaking table performance and testing procedures, like shaking table design alternatives, self-tuning control and numerical evaluation.

A methodology for the definition and quantification of behaviour coefficients to be used in the earthquake design of structure is presented. These coefficients are defined for specific design methods and are quantified by a target value of the probability of collapse. The methodology is quantified through the analysis and safety checking of structures defined by single variable models.

Nesta comunicação apresenta-se uma metodologia de quantificação de coeficientes de ductilidade de edifícios em betão armado que apresentam irregularidades em planta, e que possuem uma dada probabilidade de ruína.Foram considerados edifícios de 8 pisos com dimensões em planta 20x15 m2, os elementos resistentes a forças horizontais são pórticos planos e paredes estruturais, sendo a determinação dos valores resistentes elásticos limites feito em função de um dado processo de dimensionamento.Posteriormente, recorrendo a algoritmos de integração passo a passo, acedeu-se ao comportamento inelástico dos edifícios sob a ação sísmica intensa. Deste modo, obtiveram-se os valores máximos das ductilidades impostas, definidas em termos das relações momentos-curvaturas nas secções extremas dos elementos de barra, e para valores crescentes de ação sísmica.O cálculo dos coeficientes de ductilidade foi efetuado tendo em atenção quer os valores das probabilidades de serem excedidas as ductilidades disponíveis quer os potenciais mecanismos de colapso de cada edifício.

This report analyses the influence of masonry infills in the earthquake behaviour of buildings with a reinforced concrete frame structure, four storeys high and a plan dimension of 20x15m2. Nonlinear analysis are performed using an ensemble of ground motions. Maximum ductility demand distributions are obtained. The values of the ductility coefficients are evaluated in terms of the vulnerability functions of the buildings and by comparison with the responses obtained in bare frame analyses and taking into account the probabilities of collapse.

Apresenta-se uma metodologia bayesiana para estimar a relação não-linear ações efeitos das ações (função de vulnerabilidade) para efeitos de cálculo de probabilidade de ruína; embora a metodologia seja geral, ela é apresentada para o caso das ações sísmicas. Esta metodologia assenta numa quantificação não informativa de probabilidade á priori no espaço das funções de vulnerabilidade e o seu resultado é uma distribuição de probabilidade para o valor da probabilidade de ruína, as diversas etapas do cálculo são otimizadas por análise pré-posterior.

The objective of this paper is to characterize the earthquake behaviour of asymmetric buildings, with the purpose of assessing values of the behaviour coefficients and associated probabilities of failure. Buildings with a plan dimension of 20x15m2 and 8 storeys high are considered; their resisting elements are R/C frames and shear walls. The resistances of those elements were defined according to a given design processe and their nonlinear behaviour under earthquake actions was computed by step-by-step procedures and assessed by the maximum ductility demand defined in terms of moment curvature relations and by the probability of occurring prescribed global or local collapse mechanisms.

Apresenta-se nesta comunicação o desenvolvimento de um modelo analítico adequado ao estudo do comportamento de estruturas reticuladas de betão armado preenchidos com paredes, não se pode considerar que os modelos já existentes resolvam completamente este problema de análise. Com efeito, o desenvolvimento de qualquer modelo analítico depara com a dificuldade que existe em simular a grande complexidade destas estruturas, devido à necessidade de modelar, por um lado, as paredes de alvenaria, material não homogéneo anisotrópico, e por outro, as condições de fronteira das paredes com os elementos dos pórticos que influenciam o comportamento global destas estruturas, quando sujeitas a ações horizontais alteradas.

Definem-se coeficientes de ductilidade locais no contexto dos

Apresenta-se neste trabalho uma metodologia para o cálculo de coeficientes de comportamento de estrutura, a serem usadas na verificação da segurança em relação á ação dos sismos. Estes coeficientes são definidos em relação a métodos de dimensionamento específicos e quantificados com base no valor da probabilidade de ruína que se pretende atingir. Exemplifica-se esta matéria através da análise de dimensionamento e verificação de segurança de estruturas univariáveis. Indica-se a metodologia a seguir para casos mais gerais.

This book presents a selection of the best papers from the HEaRT 2015 conference, held in Lisbon, Portugal, which provided a valuable forum for engineers and architects, researchers and educators to exchange views and findings concerning the technological history, construction features and seismic behavior of historical timber-framed walls in the Mediterranean countries. The topics covered are wide ranging and include historical aspects and examples of the use of timber-framed construction systems in response to earthquakes, such as the gaiola system in Portugal and the Bourbon system in southern Italy; interpretation of the response of timber-framed walls to seismic actions based on calculations and experimental tests; assessment of the effectiveness of repair and strengthening techniques, e.g., using aramid fiber wires or sheets; and modelling analyses. In addition, on the basis of case studies, a methodology is presented that is applicable to diagnosis, strengthening and improvement of seismic performance and is compatible with modern theoretical principles and conservation criteria. It is hoped that, by contributing to the knowledge of this construction technique, the book will help to promote conservation of this important component of Europe

The applications of discrete elements models based on rigid block formulations to the analysis of masonry walls under horizontal out-of-plane loading is simplified block pattern are addressed. Two procedures for creating irregular block systems are presented, one using Voronoi polygons, the other based on a bed and cross joint structure with random deviations. A test problem provides a comparison of various regular and random block patterns, showing their influence on the failure loads. The estimation of manual frequencies of rigid block models, and its application to static pushover analyses, is addressed. An example of application of rigid block model to wall capacity problem is presented.

The overall aim of Sub-Project 10 (Earthquake disaster scenario predictions and loss modelling for urban areas) has been to create a tool, based on state-of-the-art loss modelling software, to provide strong, quantified statements about the benefits of a range of possible mitigation actions, in order to support decision-making by urban authorities for seismic risk mitigation strategies. A further larger aim has been to contribute to a seismic risk mitigation policy for future implementation at European level. Among the European cities for which loss estimation studies have been carried out are Istanbul, Lisbon and Thessaloniki, and tools, using GIS mapping, have been developed by research teams in each of these cities; these were made available for further development to examine mitigation strategies within SP10. Related research studies

Much work in Earthquake Engineering was devoted to the improvement of earthquake resistant design of new structures. One European result is EN 1998, which will be in several years the main seismic code for all European countries. But it is well known, that older existing structures cause in many large earthquakes much more casualties and damages than new structures. It is certainly not possible to retrofit all existing structures, but agreement exists, that assessment and retrofit of safety - critical - structures and lifeline structures must have priority. In September 2004 the European Integrated Research Project LESSLOSS on Risk Mitigation for Earthquakes and Landslides was started. The project will run for three years and comprises 13 Sub-Projects (SP´s). The consortium consists of 46 partners (see http:\\www.lessloss.org). LESSLOSS SP5 is on In-situ Assessment, Monitoring and Typification of buildings and Infrastructure. The project partners of SP5 are ARS, CESI, LNEC, RWTH and VCE. This Sub Project focuses mainly on the assessment of important existing structures and tries to integrate experimental methods into the assessment procedure. The progress of SP5 obtained in the first year is summarized in this paper. Highlights presented by all partners are mentioned and the assessment of Hospital Innsbruck is presented in more detail. The most innovative task of LESSLOSS/ SP5 is Update of vulnerability estimates via monitoring, which was also started in the first year.

In order to study the behavior of bridge structures in relation to traffic, wind and seismic loads, it is extremely important to know their actual dynamic properties (natural frequencies, vibration mode shapes and damping). The experimentally identified dynamic properties of bridge structures are also an effective way to characterize their actual global structural behavior. Whether included in the reception load tests of recently built bridges, before they are opened to the traffic, or as part of the inspection works of bridges already in service, LNEC has performed modal analysis studies based on the results of ambient vibration tests. Some of the studies carried out recently in important bridges are reported in this paper.

O sismo de Northridge ocorreu na parte norte da área metropolitana de Los Angeles, Califórnia, às 4:31 h do dia 17 de janeiro, uma segunda-feira coincidente com dia de feriado nacional, tendo atingindo uma magnitude de 6.6 na escala de Richter. O número total de vítimas mortais cifra-se em 57, havendo para cima de 8 000 feridos e 20 000 desalojados.As estimativas de perdas totais, feitas em meados de fevereiro de 1994, apontavam para valores de 15 biliões de US dólares, tendo o Estado da Califórnia apresentado um impacto económico total de ordem dos 30 biliões de dólares, perto do valor do Orçamento Geral do estado Português para 1994. Os prejuízos infligidos na indústria e no comércio são também surpreendentemente elevados, exigindo longos períodos de interrupção das atividades económicas.

Within the realm of natural hazards, geohazards are recognised as being particularly complex and often having the potential of triggering disasters. This complexity has led to increased political commitment and interest in engaging multi-stakeholder and citizens in disaster risk management. The AGEO project explored new forms to foster collaboration between civil society and authorities, using the rapidly developing field of citizen science and its innovative tool of citizens

Communicating science within disaster risk reduction using methods that encourage two-way dialogue between scientists and laypersons is a challenging task. This paper aims at presenting a methodological strategy of communicating risk and non-structural seismic protection measures through participatory approach. Such methodological strategy is part of a pilot experience of risk communication in two schools in Lisbon (Portugal) under the EU project KnowRISK (Know your city, Reduce seISmic risK through non-structural elements). The efficacy of education for seismic safety is often inhibited by an incomplete understanding of the process by which individuals decide to protect themselves from harm (Becker JS, Paton D,Johnston DM, Ronan KR. Nat Hazards 64(1):107

Most of the Lisbon 18th century timber-framed masonry

Good performance of non-structural elements can be decisive in saving lives and costs when an earthquake strikes. The European project KnowRISK aims to educate and encourage households to take the necessary precautionary measures to protect people, houses, and contents. Preparedness and prevention act on community resilience. Within the KnowRISK project, the idea of a Practical Guide has been conceived suggesting seismic mitigation solutions for non-structural components to non-experts stakeholders. It is intended to guide people into the first steps of prevention in a straightforward manner, minimizing or avoiding injuries, damage, and long-term financial consequences. The novelty of the Guide belongs to his philosophy: a path through increasing challenges corresponds to a growing level of safety. The idea is that anyone can mitigate seismic risk in its own environment by adopting simple and low cost measures. The Practical Guide may contribute to increase risk awareness. This kind of initiatives if undertaken at larger scales may also enhance social resilience.

When one of the dimensions of a structural member is not clearly larger than the two orthogonal ones, engineers are usually compelled to simulate it with refined meshes of shell or solid finite elements that typically impose a large computational burden. The alternative use of classical beam theories, either based on Euler-Bernoulli or Timoshenko

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This text reflects the first of the four lectures that the author has presented at Udine, Italy, at CISM

Um dos principais problemas e interesses da engenharia sísmica é a caracterizaçãoda acção sísmica, envolvendo a estimativa da intensidade, conteúdo em frequência,duração e variabilidade espacial dos movimentos intensos do solo mais gravosos, emtermos dos seus efeitos nas estruturas, que pode ocorrer num local.O presente trabalho de investigação desenvolve e aplica a metodologia estocástica etécnicas de modelação de fonte

Os sismos são encarados frequentemente como desastres naturais inevitáveis. Todavia,deveriam ser considerados fenómenos naturais, cujos efeitos adversos podem ser minimizadoscaso se proceda a uma gestão efectiva do risco sísmico.O objectivo principal do presente trabalho de investigação é o de avaliar o risco sísmicoem Portugal Continental.Sendo um tema de natureza multidisciplinar, apresentam-se e discutem-se modelos deavaliação probabilística da perigosidade sísmica e sua desagregação, de vulnerabilidade efragilidade sísmicas de tipologias construtivas, de danos e de perdas económicas e humanas.Aplica-se a análise probabilística da perigosidade sísmica, e sua desagregação, aPortugal Continental, obtendo-se cenários modais capazes de reproduzir os níveis deperigosidade que os condicionam. Apresenta-se o inventário do parque habitacional e seushabitantes, descriminado por factores de vulnerabilidade, e classifica-se a sua vulnerabilidadesegundo os modelos de dano. Procede-se à actualização e aferição de uma metodologia parasimulação de cenários sísmicos, integrada num Sistema de Informação Geográfico. Avalia-seo risco sísmico, seguindo diversas abordagens, comparando-se os resultados com o risco deoutros países.Construiu-se assim uma ferramenta de avaliação de perdas devidas a sismos, queconstitui uma primeira contribuição para o desenvolvimento de um processo de gestão dorisco sísmico aplicado ao Continente Português.

O parque habitacional de Portugal Continental contém algumas tipologias construtivas deelevada vulnerabilidade sísmica em relação às quais urge actuar no sentido de reduzir o riscosísmico a elas associado. No projecto de investigação

A caracterização da ação sísmica, para efeitos de projeto e verificação de segurança das estruturas de engenharia civil, é realizada para valores de intensidade sísmica elevados quando comparados com os valores de intensidade sísmica sentidos frequentemente. Tais valores elevados são compatíveis com os níveis de segurança exigidos para as estruturas, que usualmente são considerados implícitos nas regras de dimensionamento e verificação de segurança de estruturas contempladas nos códigos em vigor.

O presente relatório, elaborado no âmbito do projecto de investigação para a Fundação para a Ciência e a Tecnologia intitulado

Os sismos são fenómenos naturais que apenas poderão ter consequências desastrosas se afetarem uma região habitada do globo. Sem dúvida que os piores efeitos de um desastre sísmico são as perdas de vida humana envolvidas.A redução das perdas de vidas humanas é assim um dos grandes objetivos das políticas de prevenção e proteção sísmica e do domínio de investigação da engenharia sísmica.Para se ter uma ideia da dimensão do problema refira-se que apenas no século XX (entre 1900 e o fim de 1992), o montante oficial de vítimas mortais em 1 100 sismos muito severos, atingiu o total de 1 528 000. Perto de metade deste número de vítimas ocorreu num único país, a China, e as principais contribuições para este.

O presente relatório, elaborado no âmbito do projeto de investigação PRAXIS XXI

O presente relatório, elaborado no âmbito do projeto de investigação para a Fundação para a Ciência e a Tecnologia intitulado

The present progress report describes the research developed by LNEC under the ENVIRONMENT project ENV4-CT97-0548, entitled

O presente estudo tem por objetivo apresentar uma metodologia para a avaliação dos efeitos da propagação das ondas sísmicas em condutas de água enterradas. Essa avaliação é efetuada em termos do campo de deformações (extensões axiais e curvaturas), a serem impostas nas condutas, para diferentes valores máximos de aceleração e velocidade da ação sísmica associados a diferentes períodos de retorno.A metodologia desenvolvida é aplicada à cidade de Lisboa considerando as características locais do terreno, diversos diâmetros de tubagens e ambas as situações de condutas contínuas ou com juntas.

As part of ECOEST European research activities, this report describes the experimental programme carried out at the new LNEC seismic simulator facility. It is reported a detailed characterization of the frequency response of the shaking table and the results from an assessment of its control fidelity. This information will act as a benchmark, against which the performance of future tests at this facility could be gauged.A part of the description of the procedures and results of the test programme carried out, it was also compiled descriptive material about the entire facility.

O presente relatório descreve os estudos efetuados no LNEC, que visaram o desenvolvimento e implementação computacional de um algoritmo representativo das relações histeréticas forças-deslocamentos generalizados observados em ensaios de elementos de betão armado sujeitos á flexão.Foi dado um carater geral à implementação do modelo, de forma a poder ser usado em trabalhos futuros de análise dinâmica em regime não linear de estruturas de betão armado, sujeitas á ação dos sismos.O algoritmo computacional resultante é suficientemente versátil uma vez que através da introdução de alguns parâmetros pode reproduzir diferentes comportamentos estruturais, tais como: degradação de rigidez e resistência, efeito de

Análise dos registos históricos de eventos climáticos e o seu impacto no setor da energia da AML, para identificar o grau em que este setor foi afetado por estímulos relacionados com o clima. Avaliação de capacidades adaptativas.

Análise da forma das edificações nas ações do vento

As condicionantes arquitetónicas e de urbanização na ventilação natural

Caracterização do vento. Ações sobre estruturas. Ensaios em túnel de vento