Simulação numérica do comportamento de lajes: aplicação do método dos elementos finitos a problemas tridimensionais de elasticidade linear usando o freeFEM++

O presente trabalho entende a dedução das Equações de Compatibilidade, Equilíbrio, bem como as Leis Constitutivas, de modo a resolver numericamente problemas de Elasticidade Linear formulados para Lajes de Betão. A solução numérica é obtida usando o Método dos Elementos Finitos, implementado em freeFEM++, e comparada com os resultados conseguidos no SAP2000 e com os dados tabelados nas Tabelas de Barès, validando-se desta forma os modelos implementados através do freeFEM++

A methodology for the development of historical building archetypes for seismic performance assessment

The probabilistic estimation of the magnitude of historical earthquakes requires the analysis of actual building structures affected by those earthquakes. The analysis complicates because most of these buildings no longer exist or were greatly modified, present a great variety of features and the number of analysis for probabilistic assessment is high. As it is not practical to analyze all structures, an alternative is to use structural archetypes representing the affected buildings. This paper presents an approach to develop a quantitative framework for the generation of historical archetypes. The method is illustrated via the definition of a specific archetype for the study and assessment of the effects of the 1763 Komárom earthquake. The historical survey of Tata, Hungary, is assumed as representative of the region and one historical building is utilized to illustrate the archetypes evaluation process

Identidade, diferenciação e metafísica de eventos

The metaphysical discussion over causality and identity of events, in the aim of the physicalism, emerges in the context of the collapse of behaviorism. Whilst the paradigms of logical positivism dominated philosophy, the behaviorism dominated psychology. The rupture with the positivism was marked by the work of Willard V. O. Quine. The critics from the two dogmas of empiricism and the proposal of a radical translation allowed emergence of the theses of indetermination of meaning and inscrutability of reference. As alternative to empiricism, Quine recurs to ontological simplification and holism about theory, but considering the primacy of experience, he proposes a shift towards pragmatism. However, Quine’s pragmatism was founded in a behavioristic perspective on the acquisition of linguistic competences, and behaviorism didn’t stood as paradigm for the explanation of mentalist vocabulary. Quine had a great influence in the work and life of Donald Davidson. The ontological economy and the holism of theory marked Davidson’s work in his choice of events as basic entities and his approach to meaning in Truth and Meaning through a theory of truth. While in articles as Action, Reason and Causes Davidson develops an approach to the causal role of events in intention and action, stating that reasons are causes, in The Logical Form of Action Sentences and Causal Relations, he searches for the adequate logical forms of describing events and singular causal statements in order to establish an identity of events. The following metaphysical positions support, in Individuation of Events, a causal individuation criterion for events, and in Events as Particulars and Eternal vs Ephemeral Events, Davidson defends that events are spatiotemporal and unrepeatable particulars, finalizing a metaphysical discussion over of events that will enable him to approach the problem of the mind-body relation, in the anomalous monism argument. Donald Davidson’s anomalous monism presented in Mental Events proposes the thesis of monism – identity between physical events and mental events –, and anomalism of the mental – events do not fall under strict causal laws. To support these theses Davidson formulates three principles, whose conjunction gives us a non-reductionist version of token physicalism and, therefore, permits us to conciliate the mentalist vocabulary with the structure of physicalist language. In this sense, anomalous monism supports a supervenience theory of the mental. Despite the critics made to anomalous monism, as the epiphenomenalism accusation, the theory only crumbles in its initial presuppositions that is that of a priori causality and identity. Thus, the frailest aspects of the argument consist in the difficulty of tracking and identify in experience neural events with mental events, and in the formulation of strict laws. Those questions depend, respectively, on the advancement of neurosciences and physics. The present work, by the name of “Identity, Differentiation and Metaphysics of Events”, consists on an approach to metaphysics of events, in the context of the physicalism of tokens, more specifically to the Donald Davidson’s argument of the anomalous monism that argues for the identity of physical events and mental events and the causal role of mental events. It pretends, therefore, to coordinate the metaphysical discussion of events with Davidson’s anomalous monism.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESA discussão metafísica sobre a causalidade e a identidade de eventos, no âmbito do fisicalismo, surge no contexto do colapso do behaviorismo. Porquanto os paradigmas do positivismo-lógico dominaram a filosofia, o behaviorismo dominou a psicologia. A ruptura com o positivismo é marcada pela obra de Willard V. O. Quine: a crítica aos dois dogmas do empirismo e a proposta de uma tradução radical, permitiu erguer as teses da indetermi-nação do significado e inescrutabilidade da referência. Como alternativa ao empirismo, Quine recorre à simplificação ontológica e ao holismo da teoria, mas com a primazia da experiência, propondo assim uma guinada rumo ao pragmatismo. Contudo, o pragmatismo de Quine era fundamentado numa perspectiva behaviorista para a aquisição de competên-cias linguísticas, e o behaviorismo não se firmou como paradigma para a explicação da vocabulário mentalista. Quine teve grande influência no trabalho e vida de Donald Davidson. A economia ontológica e o holismo da teoria marcam a obra de Davidson através da escolha de eventos como entidades básicas e da proposta de problematização do significado, em Verdade e Significado, através de uma teoria da verdade. Enquanto que em artigos como Action, Reasons and Causes Davidson desenvolve uma abordagem ao papel causal de eventos na intenção e na ação, afirmando que razões são causas, em The Logical Form of Action Sentences e Causal Relations, ele explora as formas lógicas adequadas para descrever eventos e para declarações causais singulares e para estabelecer uma identidade de eventos. As posições metafísicas daqui decorrentes sustentam, em Individuation of Events, um critério de individuação causal de eventos e em Events as Particulars e Eternal vs Ephemeral Events, Davidson sustenta que eventos são particulares espaciotemporais irrepetíveis, finalizando uma discussão metafísica de eventos que lhe permitirá abordar o problema da relação corpo-mente, no argumento do monismo anômalo. O monismo anômalo de Davidson, apresentado em Mental Events propõe as teses do monismo – identidade entre eventos físicos e eventos mentais –, e do anomalismo do mental – eventos mentais falham em cair sob leis causais estritas. Para suportar essas teses, Davidson formula três princípios cuja conjunção nos dá uma versão não reducionista do fisicalismo de ocorrências, que, portanto, permite conciliar o vocabulário mentalista com a estrutura linguística fisicalista. Assim, o monismo anômalo suporta uma teoria da superveniência do mental. Apesar do monismo anômalo sofrer algumas críticas, como a acusação de epifenomenalismo, a teoria só sucumbe nos seus pressupostos iniciais, ou seja, a causalidade e a identidade a priori. Os aspetos mais frágeis do argumento consistem na dificuldade de rastrear e identificar, na experiência, eventos neurais com eventos mentais, e na formulação de leis estritas. Questões estas que dependem, respetivamente, do avanço das neurociências e desenvolvimento da física. O presente trabalho, pelo nome de “Identidade, Diferenciação e Metafísica de Eventos”, consiste numa abordagem à metafísica de eventos, no contexto do fisicalismo de ocorrências, mais especificamente do argumento do monismo anômalo de Davidson, que afirma a identidade entre eventos físicos e eventos mentais, assim como o papel causal de eventos mentais. Pretende, portanto, coordenar a discussão metafísica de eventos com o monismo anômalo de Davidson

Influence of Prior Distributions and Fragility assessment methods in the estimation of the Magnitude of a Historical Seismic Event

The production of fragility functions describing the probable behaviour and damage on historical buildings is a key step in a method for the estimation of the magnitude of historical seismic events that uses a Bayes'. The fragilities are estimated by integrating the structural capacity with the seismic demand using either static methods, as the Capacity Spectrum Method (CSM), or dynamic methods, as Incremental Dynamic (IDA) and Multiple Stripes Analysis (MSA). Uncertainties in both resistance, demand, and distance and magnitude models propagate to the posterior magnitude distribution. The present paper studies the effect of uncertainties related both to the production of fragility functions and prior distributions, in the estimation of the magnitude of the 1763 Komárom earthquake (in historical Hungary). In the XVIII century most of the structures in the region were built of earth, adobe, clay or stone masonry, which is complex to model. While micro or detailed macro-modelling strategies are computationally costly, simplified macro-approaches are often more efficient, but require a pre-identification of the failure mode(s) and the determination of the backbone curve. For this study, a simplified macro-model of a Hungarian peasant house archetype is calibrated for CSM and IDA. The physical and geometrical uncertainties are incorporated in the fragilities using Monte-Carlo simulation. Prior magnitude and distance distributions are studied. The final magnitude estimates are presented and discussed

Influence of Prior Distributions and Fragility assessment methods in the estimation of the Magnitude of a Historical Seismic Event

The production of fragility functions describing the probable behaviour and damage on historical buildings is a key step in a method for the estimation of the magnitude of historical seismic events that uses a Bayes'. The fragilities are estimated by integrating the structural capacity with the seismic demand using either static methods, as the Capacity Spectrum Method (CSM), or dynamic methods, as Incremental Dynamic (IDA) and Multiple Stripes Analysis (MSA). Uncertainties in both resistance, demand, and distance and magnitude models propagate to the posterior magnitude distribution. The present paper studies the effect of uncertainties related both to the production of fragility functions and prior distributions, in the estimation of the magnitude of the 1763 Komárom earthquake (in historical Hungary). In the XVIII century most of the structures in the region were built of earth, adobe, clay or stone masonry, which is complex to model. While micro or detailed macro-modelling strategies are computationally costly, simplified macro-approaches are often more efficient, but require a pre-identification of the failure mode(s) and the determination of the backbone curve. For this study, a simplified macro-model of a Hungarian peasant house archetype is calibrated for CSM and IDA. The physical and geometrical uncertainties are incorporated in the fragilities using Monte-Carlo simulation. Prior magnitude and distance distributions are studied. The final magnitude estimates are presented and discussed

Fragility Estimation and Comparison Using IDA and Simplified Macro-Modeling of In-Plane Shear in Old Masonry Walls

The estimation of fragility functions associated with dynamic structural analysis provides the probability of a certain damage state given an intensity measure. The presented paper discusses this technique regarding its application to a method to estimate the magnitude of historical seismic events relying on the behavior and damage in real historical structures. A bin of 50 seismic records is selected matching the Komárom hazard spectrum and applied with Incremental Dynamic Analysis to generate the damage state points of a 2D one-story frame numerical model developed using Opensees code and calibrated to simulate the in-plane shear behavior of historical old clay and adobe masonry infilled walls. A scaling technique is applied and a damage type identification strategy adapted to the material model are developed to perform Incremental Dynamic Analysis and efficient fragility function fitting in MATLAB. Results highlight considerable uncertainties regarding the calibration of the numerical model, material and geometric nonlinearities and seismic record selection in this procedure. Despite efficiency, the methodology application and overview suggest that a full probabilistic approach fragility function fitting using the background of seismic hazard analysis and reliability theory, providing a concomitant sensitivity analysis, is important to proceed with variables weight evaluation and account for uncertainties

Implementation and validation of an approach for the estimation of the magnitude of historical earthquakes in Azores Islands

In many regions of the globe, the seismic data associated with higher magnitude seismic events usable in the characterization of the seismic hazard is scarce. Therefore, seismologists have been estimating the magnitude and probable epicentral location of historical earthquakes using the historical records and intensity scales to map the observed damage. Another method, employed by earthquake engineers, uses fragility functions, a ground motion model and the Bayes’ theorem to estimate the probable magnitude of historical seismic events. Nevertheless, this method requires assembling an approach consistent with the local seismicity and building stock of the period of reference. This paper implements and validates an approach for the estimation of the magnitude of historical seismic events in Azores Islands, Portugal, that uses fragility functions. In order to carry out this study, data from the damage surveys, a vulnerability distribution and approximate epicentral positions of the 1998 Faial earthquake Mw = 6.0–6.2, as well as a specific attenuation model, are utilized in a calibration phase. The vulnerability index methodology is employed to derive fragility functions from a detailed vulnerability assessment. Afterwards, the approach is validated using analogous data corresponding to the 1980 Terceira earthquake Mw = 6.8–7.2. The different assumptions and results are discussed and compared. The results show that this approach can model expected magnitude values with accuracy: Mw = 6.01–5.76 for the 1998 Faial and Mw = 6.90–6.55 for the 1980 Terceira earthquakes. Additionally, the real PGAs may have been in several locations lower than those predicted by the selected ground motion equation.info:eu-repo/semantics/publishedVersio

An approach for the estimation of the magnitude of historical earthquakes: a sensitivity study of the 1980 and 1998 earthquakes in Azores

In regions with low-to-moderate seismicity, the return-period of seismic events with large magnitudes is relatively high. Nevertheless, historical seismic events are relevant for the evaluation of seismic hazard in those regions. Thus, seismologists study the records of the effects of historical earthquakes to map the distribution intensity points, using an Intensity Scale. Afterwards, the maximum intensity point is identified as well as the probable epicentral location and magnitude. Another method, introduced by earthquake engineers, incorporates the knowledge of the behaviour of structures into posterior distributions of magnitude using fragility functions and the damage reported in historical documents. The method uses the total probability theorem to combine the uncertainty in the structural behaviour, ground motion intensity, site-to-source distance. Then, the Bayes’s theorem is employed to update a prior magnitude model into a posterior magnitude distribution. Thus, the reduction of the uncertainty in the final estimates requires the preliminary application of the method to instrumental events in order to validate the appropriate framework to address historical seismicity, namely ground motion and structural response. This paper investigates the earthquakes of January 1st 1980 with Mw=6.8-7.2 and of July 9th 1998 with Mw=5.9-6.2 in Azores Islands (Portugal) as study cases to test the sensitivity to different attenuation models Ambraseys et al. (2005) and Akkar et al. (2014). A single set of fragility functions, derived from a detailed vulnerability assessment in Faial, is assumed to model the structural response in both events. The results show that, for both events, the attenuation model from Akkar et al. (2014) and the fault source model presented results closer to those of detailed methods. Discrepancies can also be explained by differences in the prior distance model resulting from source models assumptions. The intervals Mw=5.96±0.53 and Mw=6.91±0.42 have been estimated for the 1998 and the 1980 earthquake, respectively.info:eu-repo/semantics/publishedVersio