Anibal Costa | Universidade de Aveiro (original) (raw)

Papers by Anibal Costa

Vernacular Heritage and Earthen Architecture, 2013

The development of a framework for the quantification of the seismic vulnerability of churches is... more The development of a framework for the quantification of the seismic vulnerability of churches is presented. Given the advantages of having different areas of expertise contributing for the assessment of vulnerability, the proposed framework involves a multidisciplinary approach for the definition of the vulnerability of churches. The general scope and the conceptual definition of the proposed framework are discussed and it is established that vulnerability assessment must be carried out with respect to three fundamental components: the building, the collections and the building surroundings. Implementation details of the framework are then presented for the specific case of church heritage under seismic hazard. The applicability of the vulnerability assessment approach is illustrated using real case scenarios.

Ligação à página Inicial, This Page in English Saltar para: Menu Principal, Conteúdo, Opções, Log... more Ligação à página Inicial, This Page in English Saltar para: Menu Principal, Conteúdo, Opções, Login, Atalhos. Ajuda Contextual, Autenticar-se. IBM CAS - Portugal recruta estudantes de Doutoramento e Pós-Doutoramento. Você ...

Arabian Journal for Science and Engineering, 2012

ABSTRACT Although seismic design codes are often subjected to improvements after each earthquake ... more ABSTRACT Although seismic design codes are often subjected to improvements after each earthquake disaster, old constructions are left unprotected by new technology. The purpose of this paper is to promote public welfare and safety by reducing the risk of death or injury that may result from the effects of earthquakes on existing reinforced concrete (R/C) building stock in Egypt. It aims to evaluate seismic vulnerability of the most commonly used type of multi-story RC buildings. Special attention is placed upon examining R/C buildings with vertical irregularity. The seismic vulnerability assessment for existing R/C buildings is assessed through examining two types of damage indicators: damage index and inter-story drift limit state. A sample building set is selected to reflect existing construction practice including regular buildings and those with vertical irregularities. The effects of vertical irregularity at different floor levels are examined by developing fragility curves of medium-rise gravity load designed R/C buildings. Fragility curves of the investigated building set are determined by nonlinear time history analysis to evaluate the damage state. These curves are used to represent the probabilities that the structural damages, under various levels of seismic excitation, exceed specified damage states by means of earthquake intensity damage relations. The analytical damage evaluation in this study shows that the seismic effects of earthquakes experienced in Egypt may be significant. Moreover, it shows that some of the earthquakes may impose excessive displacement demands on the investigated buildings. The results also show that the irregular buildings are more vulnerable than the regular ones.

URBSIS avaliação da vulnerabilidade e gestão do risco sísmico à escala urbana URBSIS URBSIS proje... more URBSIS avaliação da vulnerabilidade e gestão do risco sísmico à escala urbana URBSIS URBSIS project A qualidade de vida nos núcleos urbanos constitui uma meta dinâmica, fortemente e das infraestruturas. Nos núcleos urbanos do conforto e de salubridade, num equilibrio que se quer, sustentado e sustentável, com ś mica, a grande maioria deste ń dole social, tem levado facto, muitos destes edifićios necessitam vulnerabilidade siśmica, particularmente siŕ isco sić onteúdo vem sublinhar a necessidade de da vulnerabilidade siśmica, particularmente hierarquizadas e acauteladas. PREÂMBULO Este livro resulta da compilação do trabalho de investigação científica desenvolvido no âmbito do projeto I&D "URBSIS-Avaliação da Vulnerabilidade e Gestão do Risco Sísmico à Escala Urbana", financiado pela Fundação para a Ciência e Tecnologia (FCT) e apoiado institucionalmente pela

Proceedings of the 4th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2013), 2014

Na literatura da especialidade podemos encontrar diferentes abordagens de esquemas de ensaio de p... more Na literatura da especialidade podemos encontrar diferentes abordagens de esquemas de ensaio de pilaressujeitos a flexao composta, com esforco axial constante e flexao ciclica. A principal dificuldade naimplementacao destes sistemas de ensaio experimental esta na forma como se aplica a accao axial, que devemanter-se vertical e sem grandes variacoes de intensidade, apesar das deformacoes provocadas pela flexao. Esteproblema agrava-se em ensaios de pilares sujeitos a flexao desviada, que e o caso para o qual se projectou econstruiu o sistema de ensaios actualmente em uso.O sistema de ensaio desenvolvido pelo grupo de investigadores do LESE FEUP (Laboratorio de EngenhariaSismica e Estrutural da Faculdade de Engenharia da Universidade do Porto), pensado para possibilitar o ensaiode pilares associando a aplicacao de carga axial as cargas horizontais aplicadas em duas direccoes ortogonais,recorre a uma placa de deslizamento de atrito reduzido aplicada da cabeca do pilar que permite a tran...

Bulletin of Earthquake Engineering, 2015

Stone masonry is one of the oldest and most worldwide used building techniques. Nevertheless, the... more Stone masonry is one of the oldest and most worldwide used building techniques. Nevertheless, the structural response of masonry structures is complex and the effective knowledge about their mechanical behaviour is still limited. This fact is particularly notorious when dealing with the description of their out-of-plane behaviour under horizontal loadings, as is the case of the earthquake action. In this context, this paper describes an experimental program, conducted in laboratory environment, aiming at characterizing the out-of-plane behaviour of traditional unreinforced stone masonry walls. In the scope of this campaign, six full-scale sacco stone masonry specimens were fully characterised regarding their most important mechanic, geometric and dynamic features and were tested resorting to two different loading techniques under three distinct vertical pre-compression states; three of the specimens were subjected to an out-of-plane surface load by means of a system of airbags and the remaining were subjected to an out-of-plane horizontal line-load at the top. From the experiments it was possible to observe that both test setups were able to globally mobilize the out-of-plane response of the walls, which

This work mainly aims at a comparative study between several numerical methods for non-linear cyc... more This work mainly aims at a comparative study between several numerical methods for non-linear cyclic behavior simulation of reinforced concrete members, namely the continuum damage, the fiber and the concentrated plastic hinge models, in order to establish the applicability of each numerical tool. The damage model is based on 2D or 3D finite element representations, adopting two scalar damage variables for the simulation of non-linear concrete degradation mechanisms under tension and compression, and using the well known Giuffré-Menegotto-Pinto model to simulate the cyclic behavior of steel. The well known fiber model, computationally lighter than the previous one, resorts to 1D constitutive laws for both concrete and steel to simulate the non-linearity of fibers. Finally, the lightest model herein considered is the concentrated plastic hinge model: it is essentially a global element model for RC members, such that each is represented by an elastic central zone plus two finite-length plastic end-zones where non-linear behavior is simulated through cross-section level Takeda type moment-curvature global laws. The study was performed using these methodologies for simulating tests carried out at the Laboratory of Earthquake and Structural Engineering of the Faculty of Engineering of University of Porto (LESE-FEUP) regarding two types of elements, viz building solid columns and hollow-section bridge piers. The analyses allowed assessing each methodology advantages/limitations in simulating the cyclic behavior of the referred elements for different failure situations, particularly emphasizing those where shear failure is observed.

Advances in Civil Engineering, 2013

The seismic vulnerability of a historical Basilica church located in Italy is studied by means of... more The seismic vulnerability of a historical Basilica church located in Italy is studied by means of limit analysis and nonlinear finite element (FE) analysis. Attention is posed to the failure mechanisms involving the façade of the church and its interaction with the lateral walls. In particular, the limit analysis and the nonlinear FE analysis provide an estimate of the load collapse multiplier of the failure mechanisms. Results obtained from both approaches are in agreement and can support the selection of possible retrofitting measures to decrease the vulnerability of the church under seismic loads.

Recent earthquakes demonstrated a significant contribution of the masonry infill walls in the str... more Recent earthquakes demonstrated a significant contribution of the masonry infill walls in the structural response of the existent reinforced concrete buildings. When subjected to seismic actions, they tend to interact with the surrounding RC frames, which can result in different failure modes depending on the combination of the in-plane and the out-of-plane behaviour. From the surveys on damaged and collapsed RC buildings in the L'Aquila (Italy) and Lorca (Spain) earthquakes a large number of buildings that suffered severe damage or collapse had their poor performance associated with the influence of the infill panels. The masonry infill walls are considered non-structural elements but, their contribution should be considered in the structural response analysis of existing buildings, for which the understanding out-ofplane non-linear behaviour of infill walls is of full importance in order to develop efficient strengthening solutions to prevent and improve their performance in future earthquakes, and consequently reduce their seismic vulnerability. The main objective of the present paper was to obtain further knowledge concerning to the out-of-plane response of masonry infill walls panels. For this an experimental testing campaign on full scale infill walls was carried out in three experimental (cyclic and monotonic) out-of-plane tests with and without previous in-plane damage. The experimental campaign, material characterization and the test setup will be described along the manuscript as well as the main experimental tests results will be presented and discussed.

Monumentos. Revista Semestral de Edifícios e Monumentos, 2003

The seismic vulnerability and risk assessment of old city centre areas is truly essential in urba... more The seismic vulnerability and risk assessment of old city centre areas is truly essential in urban rehabilitation programs and should not be focused exclusively over recognized historical and patrimonial valuable buildings but also in relation to current old masonry buildings that are highly valued in urban context. In addition, due to their geographical, demographic or historical features some old city centres are particularly interesting and critical, in respect to seismic risk mitigation. An excellent example of this reality is the old city of Faro, Capital of the Algarve, Portugal, which is one of the most popular summer touristic destination in Europe in a prone seismic region. This fact explains the high seasonal flux of population, which together with the moderate to high seismic hazard of the Algarve region and a vulnerable building stock increases both the seismic and tsunami risk in this area. From the exposed, this paper approaches the seismic vulnerability assessment of ...

In Aveiro, Portugal, adobe can be found with abundance in rural and urban buildings. Many of thes... more In Aveiro, Portugal, adobe can be found with abundance in rural and urban buildings. Many of these buildings present, however, an important level of structural damage. To face the lack of information concerning the mechanical properties and structural behaviour of adobe masonry, it was developed an experimental campaign at University of Aveiro. The mechanical behaviour of adobe units, mortars and small wallets was studied. Laboratory and in situ tests on full-scale walls were performed. Test results reveal the behaviour and structural fragilities of adobe elements, and will help in the assessment of existing constructions, and in the strengthening strategy definition.

The latest transposition into Portuguese legislation of the European Directive on the energy perf... more The latest transposition into Portuguese legislation of the European Directive on the energy performance of buildings (EPBD) has considerably increased the requirements for both new buildings and rehabilitation. In old buildings, architectural and existing materials features condition the available solutions. The most effective energetic refurbishment solution often involves identifying and combining strategies that lead to a cost-optimal solution. To identify the best options within the possible lines of action (at the scale of the envelope, passive strategies, equipment, renewable energy systems), in order to optimize the intervention and improve thermal performance and comfort conditions, it is necessary to perceive the real performance of this type of buildings. Therefore, this paper presents the preliminary results of the study on thermal performance and comfort of a set of case studies located in Ovar. Monitoring included the measurement of hygrothermal parameters and surveys ...

Conservar Património, 2018

A sustentabilidade de valores culturais de centros históricos depende em grande parte do equilíbr... more A sustentabilidade de valores culturais de centros históricos depende em grande parte do equilíbrio alcançado entre a manutenção da população residente, a prevenção do abandono do edificado e a compatibilização das novas funções instaladas nesses centros. Atualmente, o turismo é visto como solução para reativar centros históricos, sacrificando muitas vezes a permanência da população residente original. O presente estudo analisa dois exemplos de reabilitação urbana em centros históricos, um em Portugal e outro no Brasil, respetivamente, o Porto e Salvador da Bahia, com classificações pela UNESCO em 1996 e em 1985, respetivamente. O presente estudo analisa a interação entre a evolução do edificado, o arrendamento e o turismo, focando aspetos que resultam em ações positivas e negativas para a preservação do património edificado desses centros, da sua identidade e a exclusão de residentes tradicionais. Palavras-chave Património edificado Centro histórico Classificação UNESCO Identidade do lugar Conservação integrada Compromisso social

Journal of Architectural Engineering, 2018