Publications

Disaggregation of the seismic hazard has become a popular technique to convey information on the main sources contributing to the hazard at a particular site. Recently published work adopts geographic disaggregation analysis of seismic hazard as a tool to identify dominant rupture scenarios for municipalities in Mainland Portugal. The authors conclude that the seismic hazard in South and Central Portugal is dominated by the seismicity that takes place offshore, around 70km WSW of Cape S. Vicente, both for the return periods of 475 years and 975 years. Whilst recognizing the merits of the approach taken and the utility of the tools developed, we take issue with this last conclusion.We consider that the proposed disaggregation returns a picture of the biases in the hazard analysis, more than any real feature of the distribution of relevant seismogenic sources.

Ao longo da sua história, a cidade de Lisboa tem sofrido os efeitos devastadores de diversos sismos que foram responsáveis por danos e perdas relevantes no seu parque edificado e seus habitantes. Os objectivos do presente artigo englobam a identificação, a análise e a avaliação do risco sísmico deste concelho, cumprindo-se, desta forma, algumas das etapas do processo de gestão do risco. Efectuou-se a análise de risco para uma perigosidade sísmica regida por mais do que um cenário probabilístico de ocorrência de sismos. Para o efeito, caracterizou-se a perigosidade sísmica das 53 freguesias de Lisboa, considerando dois cenários de ocorrência construídos sobre os mesmos pressupostos em que se fundamentou a acção sísmica que serviu de base ao Anexo Nacional do Eurocódigo 8. Avaliou-se ainda a exposição do parque habitacional e habitantes deste concelho, classificou-se e caracterizou-se a vulnerabilidade sísmica dos elementos expostos, traçaram-se as curvas de risco sísmico para a cidade de Lisboa e estimaram-se os valores esperados anuais das perdas económicas e sociais nas freguesias desta cidade. Da análise efectuada ressalta que as perdas totais são condicionadas essencialmente pelo cenário de acção sísmica próximo, que as freguesias mais antigas são aquelas em que o risco relativo esperado anual é mais elevado e que as freguesias responsáveis pelos maiores valores de risco absoluto são as que apresentam a vulnerabilidade sísmica mais elevada e os maiores valores de exposição.A apreciação do risco sísmico efectuada para Lisboa permite concluir que o risco de morte anual devido a sismos a que os habitantes desta cidade estão expostos se situa na zona ALARP (As Low As Reasonably Practicable).

Decisions to mitigate seismic risk require a consistent approach to evaluate the effects of future earthquakes on population, on civil engineering structures and infrastructures. The mathematical and probabilistic methods that are the support to those approaches are generally called Risk Analysis; in the particular case of seismic events and mitigation strategies it will be named Seismic Risk and Mitigation Analysis, SRMA. The paper will address the subject of estimating the seismic risk and evaluate mitigation strategies for the existing building stock of the metropolitan area of Lisbon by describing the methods and showing preliminary results obtained with LNECloss numerical tool. Even though such a sophisticated tool needs validation on some parameters to become more reliable, it is shown that it is possible to compare results of different mitigation strategies.

The paper addresses two complex case studies of modal and structural identification of monuments in Portugal: the Clock Tower of Mogadouro and the Church of Jero´nimos Monastery, in Lisbon. These are being monitored by University of Minho with vibration, temperature and relative air humidity sensors. Operational modal analysis is being used to estimate the modal parameters, followed by statistical analysis to evaluate the environmental effects on the dynamic response. The aim is to explore damage assessment in masonry structures at an early stage by vibration signatures, as a part of a health monitoring process that helps in the preservation of historical constructions. The paper presents the necessary preliminary dynamic analysis steps before the monitoring task, which includes installation of the monitoring system, system identification and subsequent FE model updating analysis, automatic modal identification and investigation of the influence of the environment on the identified modal parameters.

Probabilistic seismic hazard for Mainland Portugal was re-evaluated in order to perform its disaggregation. Seismic hazard was disaggregated considering different spaces ofrandom variables, namely, univariate conditional hazard distributions of M (magnitude), R (source-to-site distance) and

Probabilistic seismic hazard for Mainland Portugal was re-evaluated in order to perform its disaggregation. Seismic hazardwas disaggregated considering different spaces of random variables, namely, univariate conditional hazard distributions of M (magnitude), R (source-to-site distance) and

N/A

Decisions to mitigate seismic risk require a consistent approach to evaluate the effects of future earthquakes on population, on civil engineering structures and infrastructures.The mathematical and probabilistic methods that are the support to those approaches are generally called Risk Analysis; in the particular case of seismic events andmitigation strategies it will be named Seismic Risk and Mitigation Analysis, SRMA. The paper will address the subject of estimating the seismic risk and evaluate mitigation strategies for the existing building stock of the metropolitan area of Lisbon by describing the methods and showing preliminary results obtained with LNECloss numerical tool. Even though such a sophisticated tool needs validation on some parameters to become more reliable, it is shown that it is possible to compare results of different mitigation strategies.

This paper describes the shaking table tests, and their main results, of an asymmetric limestone masonry building, under different reinforcement conditions. The work was performed in the aim of the project

No âmbito de um projecto denominado

A methodology to improve the earthquake design of R/C building is presented. This methodology idealizes the decision-making processes in the design of a building and the effects of future earthquakes. The concept of a design process is put forward as directly related to decision-making and only as indirectly related to structural performance under earthquake vibration; this concept is illustrated through a discussion of the

Nesta comunicação faz-se uma primeira abordagem da influência da distribuição das resistências dos elementos verticais, nas exigências de ductilidade em pórticos de betão armado sujeitos á ação sísmica, quando se aplica os coeficientes de comportamento previstos na regulamentação portuguesa para o projeto de estruturas de ductilidade normal.

Esta comunicação apresenta o desenvolvimento e implementação computacional de uma subrotina especificamente desenvolvida para o estudo das relações histeréticas forças-deslocamentos, observados nos ensaios de elementos de betão armado sujeitos á flexão, provocadas por cargas alternadas.Neste algoritmo procurou-se reproduzir além dos efeitos provocados pelo esforço normal, os devido á degradação de rigidez e resistência, tendo-se por isso desenvolvido uma subrotina de caracter geral e aplicável a uma vasta gama de estudos dinâmicos não lineares de estruturas de betão armado.São também apresentados alguns exemplos de aplicação que atestam aspetos relevantes do funcionamento da subrotina.

In this paper we present results obtained in the 3-D dynamic analysis of standard case studies referring the 60, 150 220 and 400 kV electric busbars under seismic loading, reflecting the experience gained by the authors in the past few years. A set of recommendations for the structural design, some practical guide lines for the preliminary computation of seismic response based on a simplified 2-D analysis, and a brief reference to the effects of electromagnetic forces, are also presented.

In this paper results obtained in the seismic analysis of the EN1 Águeda Bridge are presented. This bridge was analyzed according to the prescriptions of the new Portuguese Code for Safety and actions in Building and Bridge Structures, which requires an extensive dynamic analyses that includes the consideration of the spatial variability og ground motion. The basic ideas of the adopted structural design, which seeks to minimize the effects of seismic actions, and the corresponding detailing are also presented.

Progress in engineering seismology and gathering of data taking place in recent years in the different fields related to tectonics, mechanisms of generation, propagation of seismic waves and historical seismicity, indicate that seismic hazard maps should be updated in a continuous manner.This paper is dedicated to the analysis of improvements made in the last four years and studies their influence on the final hazard estimates: (i) earthquake catalogue was extended from 1900 back to 1300, (ii) earthquake source-zones slightly modified to accommodate new evidences of fault activity and (iii) attenuation curve, allowing anisotropy, fit in a better way the macroscopic observation of several quakes. A comparison with previous hazard curve is made for several sites explicating the contributions of distant and

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.

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

A non

N/A

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

O presente estudo teve como objetivo a caracterização dinâmica e do comportamento mecânico da estrutura do edifício Sede I da EDP, para uma adequada simulação do seu comportamento sísmico. Neste relatório descrevem-se os ensaios de identificação dinâmica in situ realizados, com base em vibrações ambiente e em vibrações forçadas, com o objetivo de recolher informação sobre as propriedades dinâmicas da estrutura como um todo e das suas lajes dos pisos elevados em particular. Foi efetuado o registo e a análise dos sinais de aceleração devido a vibração ambiente, medidos em diversos pontos do edifício, bem como devido a vibrações forçadas impostas num dos pisos enterrados do edifício. São também apresentados e analisados os ensaios de caracterização do comportamento mecânico de componentes estruturais relacionadas com a ligação das lajes mistas dos pisos elevados às paredes dos núcleos resistentes de betão armado do edifício. Estes consistem em ensaios destrutivos de troços de laje mista ligados aos núcleos, por meio de varões selados à parede, e em ensaios de arrancamento desses varões, tendo como objetivo caracterizar os materiais e componentes dos elementos estruturais. Esta informação é essencial para a posterior calibração dos modelos numéricos da estrutura e para uma realista simulação do seu comportamento sísmico, bem como para uma eventual deteção de anomalias estruturais decorrentes de patologias que possam comprometer o desempenho do edifício face à ocorrência de sismos.

A avaliação da segurança sísmica de edifícios existentes tem como quadro de referência o Eurocódigo 8

Nos estudos probabilísticos para avaliação da perigosidade sísmica, são estabelecidas zonas de geração sísmica (zonas sismogénicas), representando regiões que partilham as mesmas caraterísticas sismológicas, tectónicas e geológicas e definidas as relações entre a frequência com que aí ocorrem os sismos e as respetivas magnitudes, num dado período de tempo. Em 2006, para o Anexo Nacional do Eurocódigo 8, foram consideradas e caraterizadas 11 zonas Sismogénicas para Portugal continental, adaptadas de estudos previamente elaborados em 1996. Entre 2008 e 2009, no âmbito dos projetos ERSTA e SHARE, foram propostas novas zonas sismogénicas, e estimados os respetivos parâmetros da lei de frequência - magnitude. Estas diferentes propostas resultaram em diferentes mapas de perigosidade sísmica para Portugal continental. A SPES, Sociedade Portuguesa de Engenharia Sísmica, espelhando a inquietude existente na comunidade científica face às diversas expressões da perigosidade sísmica em Portugal, e consciente da necessidade de um consenso perante os agentes decisores, considerou urgente a realização de um estudo criterioso acerca das opções tomadas, nos diferentes estudos, e suas implicações. É nestecontexto que surge este trabalho, que pretende fazer uma análise crítica e comparativa dos resultadosobtidos nos diferentes estudos mencionados e as suas implicações ao nível dos períodos de retorno para sismos de maior magnitude. Numa parte II, serão estudadas as implicações em termos de valores da perigosidade sísmica, para vários períodos de retorno e frequências espetrais.

O presente relatório, elaborado no âmbito de um estudo em curso no LNEC sobre a segurança sísmica das construções nas intervenções de reabilitação, sintetiza os instrumentos jurídicos e os conceitos relevantes para a análise do atual regime jurídico da reabilitação urbana (RJRU), e do regime excecional de reabilitação urbana (RERU).

This document reports the outcomes of the research project

This document reports the outcome of the seismic test on the Rusticasa building, the first in a total of four buildings included in the TIMBER BUILDINGS Project. This building is a log house system (LHS). The goal of the tests was to assess the seismic performance of the building, panel elements and steel connectors, defined in terms of relative displacements and hold-down forces.

This document reports the outcome of the seismic test on the LegnoCase building, the second in a total of four buildings included in the TIMBER BUILDINGS Project. This building is a platform frame system with sheathing assembled by means of OSB panels (PF-OSB). The goal of the tests was to assess the seismic performance of the building, panel elements and steel connectors, defined in terms of relative displacements and hold-down forces.

This document reports the outcome of the seismic test on the RubnerHaus building, the third in a total of four buildings included in the TIMBER BUILDINGS Project. This building is a platform frame system with sheathing assembled by means of gypsum fibre panel (PF-GF). The goal of the tests was to assess the seismic performance of the building, panel elements and steel connectors, defined in terms of relative displacements and hold-down forces.

This document reports the outcome of the seismic test on the TUGraz building, the fourth in a total of four buildings included in the TIMBER BUILDINGS Project. This building is a cross laminated system (CTL). The goal of the tests was to assess the seismic performance of the building, panel elements and steel connectors, defined in terms of relative displacements and hold-down forces.

The TIMBER BUILDINGS Project, led by the University of Trento, included testing of four full scale multi-story timber houses with a realistic horizontal plan and three types of timber housing systems: platform frame system (PFS), log house system (LHS) and cross laminated timber (CLT). The tests were carried in the LNEC-3D shake table under different levels of excitation and different conditions of the structure.The tests were carried with the goal of assessing the seismic performance of the buildings, panel elements and steel connectors, defined in terms of relative displacements and hold-down forces.The results were presented in separate reports, one for each building. This document contains information common to the remaining four reports.

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