Made available in DSpace on 2014-12-17T14:48:15Z (GMT). No. of bitstreams: 1 RaulOOD_DISSERT_Capa_ate_pag84.pdf: 4478808 bytes, checksum: 521324acaeff6345df14d7924098c227 (MD5) Previous issue date: 2013-06-27 / Through this research is detailed the Brazilian seismic code focused on concrete projects design related to seismic engineering. At the beginning of the research is debated the fundaments of the seismic effects, the influence factors to the development of seismic effects and also relates the main data registration happened in Brazil. The second step is study the Brazilian seismic code explaining all the concepts related to it and does a compilation to the most important international seismic code. At this research is developed the designing of a building submitted to horizontal equivalent seismic forces and the modal process based on the answer spectrum based on the brazilin seismic code. It was also developed the design of a commercial building submitted to seismic loads based on the Brazilian code answer spectrum and compared to the same building submitted to wind loads.The research also focus on projects conception and detailing of seismic engineering Project design. At the study of seismic engineering it was concluded that seismic effects require special focus on concrete structures design, proving that is the essential consider the seismic effects / Nesse trabalho s?o apresentados e discutidos diversos crit?rios da norma NBR 15421:2006 para o desenvolvimento de um projeto de estruturas de concreto, considerando a a??o s?smica. Inicialmente fez-se um levantamento dos conceitos fundamentais da engenharia s?smica, das principais ocorr?ncias, globais e regionais, abordando-se a an?lise dos efeitos geradores de sismos, seus conceitos e particularidades. Apresentou-se posteriormente o detalhamento de todos os par?metros s?smicos presentes na NBR 15421:2006 e comparou-se com diversas normas s?smicas internacionais. Foi desenvolvida uma compara??o entre edif?cios modelados atrav?s de espectro de resposta e atrav?s das for?as horizontais s?smicas equivalentes, tamb?m se desenvolveu um estudo comparativo de uma edifica??o comercial submetido ao vento e a solicita??es s?smicas. Destaca-se ainda a apresenta??o das principais recomenda??es e orienta??es t?cnicas em termos de concep??o e detalhamento estrutural que devem servir de condicionantes para projetos atuais. Demonstra-se que os efeitos s?smicos incorrem na necessidade de detalhamentos espec?ficos na estrutura, comprovando-se que a necessidade de uma abordagem diferenciada ? essencial

[pt] Esta pesquisa investiga o comportamento sísmico da barragem de terra de Breapampa, situada no Peru em zona de atividade sísmica. A previsão numérica é feita com auxílio do programa computacional FLAC 2D v.7, baseado no método das diferenças finitas. É simulada a construção incremental da barragem, a elevação gradual do nível d água do reservatório durante a etapa do primeiro enchimento do reservatório, é estabelecida a posição da linha freática em regime de fluxo permanente e são calculados os fatores de segurança estático da estabilidade dos taludes nas condições de final da construção e após o primeiro enchimento do reservatório. A simulação do comportamento sísmico da barragem é feita em seguida, discutindo-se vários e importantes aspectos que devem ser considerados para uma correta análise como a seleção do terremoto de projeto, a filtragem de altas frequências para minimizar o número de elementos da malha, a introdução de condições de contorno silenciosas, a escolha de modelos constitutivos incluindo a incorporação de amortecimento histerético, entre outros pontos. A resposta sísmica da barragem, nas condições de reservatório vazio e reservatório cheio, foi obtida em termos de deslocamentos permanentes, história de deslocamentos, amplificações da aceleração horizontal, desenvolvimento de poropressões no corpo da barragem e potencial de ruptura cíclica no material do núcleo. / [en] This research investigates the seismic behavior of the Breapampa earth dam, situated in Peru within a seismic activity zone. The numerical prediction is carried out using the computer program FLAC 2D v.7, based on the finite difference method. it is simulated the incremental construction of the dam, the gradual raise of the water level during the stage of reservoir impounding, the establishment of the phreatic line under steady state flow and the determination of safety factor for the stability of the soil slopes considering both conditions of after construction and after reservoir impounding. The modeling of the seismic behavior of the dam is then made with detailed discussion of several important aspects for a correct analysis such as the selection of the design earthquake, the filtering of high frequencies in order to minimize the number of elements in the mesh, the introduction of silent boundaries, the choice of proper constitutive soil models including the representation of hysteretic damping, among others points. The seismic response of the dam, under the conditions of full and empty reservoir, was obtained in terms of permanent displacements, displacement history, amplifications horizontal acceleration amplification, porepressure distribution and potential of cyclic failure in the saturated material of the core of the dam.

To meet the economic, social and infrastructure needs of the community for safe and efficient transportation systems, long span bridges have been built throughout the world. Long span bridges are one of the most challenging kinds of structures in civil engineering. The cable-stayed bridges are of great interest mainly as an alternative and a more economic solution than the one of suspension bridges. In addition, the fiber reinforced polymer (FRP) composites are, nowadays, successfully used for constructing modern bridges, where the significant weight saving provides additional benefits. Because of the great flexibility, modern long-span cable-stayed bridges are usually very susceptible to dynamic loads especially to the earthquake and strong winds. Therefore, the earthquake-resistant and wind-resistant designs become one of key issues for successful construction of bridges. The objective of the present research is to develop a very efficient spline finite strip technique, for modelling and analysis of both conventional and hybrid FRP cable-stayed bridges. The study falls into the categories of bending, free vibration, seismic, and aerodynamic flutter analysis. The spline finite strip method (SFSM) is one of the most efficient numerical methods for structural analysis of bridges, reducing the time required for estimating the structural response without affecting the degree of accuracy. In the finite strip method, the degrees of freedom could be significantly reduced due to the semi-analytical nature of this method. However, the previous versions of SFSM are not able to model the entire bridge system. For that reason, the structural interactions between different structural components of the bridge could not be handled. In addition, the vibrations and displacements of the towers and cables could not be investigated. In the present formulation, all these obstacles have been eliminated. Moreover, the proposed finite strip technique is very efficient and accurate due to the drastic reduction in the formulation time, simplicity of data preparation, rapid rate convergence of the results, and the semi-analytical nature. Last but not least, and for the first time, a fully finite strip solution is extended to the area of wind engineering. Using the spline finite strip discretization, the aerodynamic stiffness and mass properties of the long-span cable-stayed bridge are derived. The aerodynamic properties along with the structural properties of long-span plates and bridges are formulated in the aerodynamic equation of motion and are used to analyze the flutter problem. The accuracy and efficiency of the proposed advanced finite strip method is verified against the finite element and field measurement results. The results demonstrate that this methodology and the associated computer code can accurately predict the dynamic and aerodynamic responses of the conventional and FRP long-span cable-stayed bridge systems. The outcome of the present research will lead to a comprehensive structural analysis of bridges in the framework of the proposed discretization which is more efficient and straightforward than the finite element analysis.

[pt] Apresenta-se um estudo de avaliação dos critérios e métodos que são empregados atualmente na análise e projeto dos sistemas de tubulação nas usinas nucleares assim como a verificação da aplicação de alguns dos novos critérios apresentados pela comunidade técnico-científica internacional, dentro do método de análise modal-espectral. Estudam-se os tópicos da interação entre o sistema de tubulação e a estrutura que o suporta mediante o uso de espectros acoplados, a consideração do efeito do deslocamento relativo dos apoios da tubulação, usando-se espectros que o consideram ou uma excitação espectral múltipla, a introdução da combinação dos máximos modais dependendo da posição relativa das suas freqüências e a inclusão da resposta espectral correspondente aos modos de alta freqüência ou modos rígidos. A ferramenta básica de análise é constituída pelo programa computacional ANSYS. A avaliação é feita sobre parâmetros de esforços internos em trechos de um modelo de um sistema real de tubulações da usina nuclear brasileira, Angra 3. Os padrões são obtidos por análises no tempo de cada modelo sob o acelerograma de projeto. Conclusões são apresentadas sobre as atitudes mais convenientes para a atual conjuntura brasileira de projeto. / [en] The main concern of this work is with the application of the modal spectral seismic analysis to secondary structural systems of nuclear power plants, with the large amount of conservatism which is included in them, and, of course, with the consequences to the particular case of the plants under construction in Brazil. One considers the design analysis methods which have been used so far in Brazil, as well as the most recent developments in the area, in USA and in Europe, to conclude about the adequacy of those procedures and recommend eventual changes to them. One then studies the subjects of the coupling effect between the primary and secondary system responses, the influence of the piping support relative displacements, the contribution of the cross-correlation among response modal components and the participation in the overall response of the so-called rigid modes. The main computer program aid is taken from an ANSYS-2 version and one uses a reduced model of a piping system as the secondary system and a 3-D beam element model of a reactor building as the primary system. The spectral analysis results are compared to time domain solutions using the same structural models excited by a design accelerogram. Conclusions and recommendations are oriented to the present design practice in Brazil. / [es] En esta tesis se presenta un estudio de evaluación de los criterios y métodos que se emplean actualmente en el análisis y proyecto de los sistemas de tubulación en las plantas nucleares así como la verificación de la aplicación de algunos de los nuevos criterios presentados por la comunidad técnico-científica internacional, dentro del método de análisis modal-espectral. Se estudian los tópicos de la interacción entre el sistema de tubulación y la extructura que él soporta mediante el uso de espectros acoplados; la consideración del efecto de deslocamiento relativo de los apoyos de la tubulación, utilizando espectros que lo consideran o una excitación espectral múltipla; la introdución de la combinación de los máximos modales dependiendo de la posición relativa de las sus frecuencias y la inclusión de la respuesta espectral correspondiente a los modos de alta frecuencia o modos rígidos. La herramienta básica de análisis es el programa computacional ANSYS. La evaluación se realiza sobre parámetros de esfuerzos internos en trechos de un modelo de un sistema real de tuberías de la planta nuclear brasilera, Angra 3. Los padrones se obtienen por análisis en el tiempo de cada modelo bajo el acelerograma de proyecto. Se presentan conclusiones sobre las actitudes más convenientes para la actual conyuntura brasilera.

Le geyser d'Old Faithful dans le Parc National de Yellowstone, aux États-Unis, est l'undes geysers les plus connus au monde. La cyclicité de ses éruptions est étudiée depuis lesannées 60 a_n de comprendre sa dynamique. En e_et, le caractère bimodal de la fréquencede ses éruptions intriguent les scienti_ques qui cherchent à en connaître les causes.Les enregistrements sismiques réalisés à la surface du geyser démontrent des signauximpulsionnels dont l'origine fut identi_ée par Sharon Kedar. Ainsi, en 1992, S. Kedar etses collègues ont déployé plusieurs capteurs sismiques dans le but d'étudier la source dessignaux sismiques de type tremor enregistrés à la surface du dôme. Ils ont ainsi identi_éla source du signal sismique enregistré à la surface du geyser comme étant des signauxde cavitation de bulles. La cavitation se produisant à la surface du niveau de l'eau dansle conduit, les localisations des sources sismiques réalisées à partir des enregistrements desurface peuvent être reliées au niveau de l'eau dans le conduit.Dans un premier temps nous avons proposé de localiser les sources sismiques desenregistrements à partir de la méthode du Matched Field Processing (MFP) provenantde l'acoustique sous-marine. Plusieurs algorithmes du MFP ont été testés pour pouvoirlocaliser au mieux les sources sismiques. La bonne concordance des résultats obtenus avecchacun des algorithmes a permis d'obtenir un grand nombre de localisations des sourcesau cours du cycle. Les positions déterminées avec les di_érents algorithmes du MFP ontpermis de mettre en évidence deux zones d'activité hydrothermale du geyser associéesà di_érentes périodes du cycle éruptif, telles que le remplissage du conduit avant leséruptions et l'alimentation du geyser en eau une fois la vidange du conduit e_ectuée.Dans un second temps, l'analyse des variations de vitesse des signaux sismiques estproposée pour suivre des changements des propriétés du dôme du geyser, comme des variationsde pression avant l'éruption. Pour cela, une nouvelle méthode basée sur les mesuresde phases instantanées est suggérée. Les résultats obtenus montrent des faibles changementsde vitesse, pouvant être associés à la mise en pression du dôme ou à l'augmentationde la température du milieu avant l'éruption en surface. / The geyser of Old Faithful in the National Park of Yellowstone, in USA, is one of themost famous geysers in the world. The cyclic behavior of the geyser is studied since the60's with the aim to understand its dynamics. In fact, the bimodal nature of the frequencyof the eruptions raises questions and scientists want to know the causes of this behavior.The seismic signals recorded at the surface of the geyser present pulses whose origin wasidenti_ed by Sharon Kedar. Thus, in 1992, S. Kedar and his colleagues deployed severalseismic sensors in order to study the source of the seismic signals, which are tremor-like,recorded at the surface of the edi_ce. They identi_ed the source of the seismic signalrecorded at the surface of the geyser that they related to bubbles collapse. The bubblescollapse takes place at the surface of the water level in the conduit, thus the localizationsof the seismic sources determined with the records made at the surface would be relatedto the water level in the conduit.In a _rst time we proposed to locate the seismic sources of the records using theMatched Field Processing (MFP), a method used in ocean acoustics. Several algorithmsof the MFP were tested to better localize the seismic sources. The good agreement ofthe di_erent results obtained with each technique allowed to obtain a big number oflocalizations of the sources through the cycle. The locations determined with di_erentalgorithms of MFP allowed to highlight two areas of hydrothermal activities of the geyserlinked to di_erent periods of the eruption's cycle, as the _lling-up of the conduit beforeeruptions and the feeding of the geyser with water once the discharge of the conduitaccomplished.In a second time, the analysis of velocity's changes of the seismic records is proposedto follow changes in the properties of the edi_ce of the geyser, and pressure changes beforean eruption for example. To do that, a new technique based on the measurement of theinstantaneous phases is suggested. The results obtained show weak changes of velocity,that can be related to the pressure buildup of the edi_ce or to the increase of temperaturein the medium before an eruption.

Las edificaciones construidas sobre suelo costero, ubicados sobre el cinturón del fuego presentan un alto riesgo sísmico, ya que sobre estas existen condiciones de suelo desfavorables y en otros casos subducción de placas. Esto ha conllevado a que los países ubicados en estas zonas desarrollen normativas sísmicas que permitan el diseño adecuado de obras de ingeniería; sin embargo, diversos reglamentos presentan distintas consideraciones para el diseño como la utilización de los parámetros que permiten estandarizar el diseño que muchas veces no presentan las mismas respuestas sísmicas del comportamiento dinámico real del suelo. Por ello, la presente investigación propone evaluar la respuesta sísmica de dos edificaciones, una esencial y otra común, con un análisis utilizando espectros de sitio, un análisis dinámico modal espectral y adicionalmente un análisis tiempo-historia teniendo consideraciones de tipos de suelo y utilización de distintos parámetros sísmicos de normas sudamericanas. El principal resultado es que la respuesta sísmica por análisis con espectros de sitio (ES) es mayor en comparación con el análisis dinámico modal espectral según la magnitud de los sismos y la tipología de suelos. / The buildings built on coastal soil, located on the fire belt present a high seismic risk, since there are unfavorable soil conditions and in other cases plate subduction. This has led to countries located in these areas developing seismic regulations that allow the proper design of engineering works; however, various regulations present different considerations for the design, such as the use of parameters that allow standardizing the design that often does not present the same seismic responses of the real dynamic behavior of the soil. Therefore, the present research proposes to evaluate the seismic response of two buildings, one essential and the other common, with an analysis using site spectra, a dynamic spectral modal analysis and additionally a time-history analysis taking into account soil types and use of different seismic parameters of South American standards. The main result is that the seismic response by analysis with site spectra (ES) is greater compared to the dynamic spectral modal analysis according to the magnitude of the earthquakes and the type of soil / Tesis

En la práctica profesional de la ingeniería civil, generalmente, se consideran los componentes del movimiento del suelo de forma independiente y desestimando la componente vertical en los análisis sísmicos. Sin embargo, ya existen estudios que invalidan dichos supuestos, y, es por tal, que el análisis sísmico debería considerar el efecto de todas las componentes del sismo a fin de estimar cualquier respuesta en la estructura. En este estudio se propondrán factores de amplificación para los espectros generados por los análisis uni-direcconales, con el fin de extenuar el efecto tri-direccional del sismo. Dichos factores se realizarán por medio del análisis de 54 estructuras caracterizadas por distintos parámetros dinámicos. Y, además, utilizando ángulos de incidencia cada 10° y 11 registros sísmicos para el ATH. Las respuestas máximas se compararán con las del espectro propuesto por la Norma E0.30 [1], obteniendo así reglas lineales para los factores de amplificación. / In the professional practice of civil engineering, generally, the components of the ground movement are considered independently and disregarding the vertical component in seismic analyzes. However, there are already studies that invalidate these assumptions, and, therefore, the seismic analysis should consider the effect of all the components of the earthquake in order to estimate any response in the structure. In this study, amplification factors will be proposed for the spectra generated by the uni-directional analyzes, in order to exhaust the tri-directional effect of the earthquake. Said factors will be carried out through the analysis of 54 structures characterized by different dynamic parameters. And, in addition, using incidence angles every 10 ° and 11 seismic records for the ATH. The maximum responses will be compared with those of the spectrum proposed by Standard E0.30, thus obtaining linear rules for the amplification factors. / Trabajo de investigación

Throughout the years earthquakes are a huge concern for structures; causing losses of peoples’ lives, damages and collapse of homes. Usually, most of the buildings that collapse or have serious damages are mostly old buildings that do not fulfil any longer the updated regulations and building codes concerning seismic design. The purpose of this Master’s thesis is to analyse and strengthen an existing building given by the company Sweco, by using proper and innovative retrofitting techniques; considering Eurocode 8 and collected data from previous studies. The selected building is a seven-storey structure in Stockholm; consists of prefabricated concrete and steel elements and is tested under seismic loading to investigate the global behaviour of the structure using the software MIDAS GEN. Two analyses are performed; assessment analysis which includes modelling of the given structure where the structural capacities are studied. The second analysis is the seismic analysis which includes two secondary analyses; before seismic retrofitting and after seismic retrofitting respectively. In the seismic analysis before the seismic retrofitting is applied, the main scope is to identify the most critical positions of the building where it behaves abnormally and the displacements are high enough in order to modify the structure to decrease displacements. Moreover, the frequencies were obtained and examined. The second seismic analysis includes the modified structure; where it was tested with different alternative methods of seismic retrofitting in order to identify which technique is the most proper one to optimise the strength and the structural performance of the given building. Finally, it appeared that a combination of seismic retrofitting methodologies was the most suitable selection. The selected combination consists of steel bracings and prefabricated reinforced concrete walls (shear walls). After performing the seismic retrofitting analysis, results of the frequencies and displacements of the structure were acquired and compared with the un-retrofitted analysis. The obtained results displayed that using this structural modification improved by increasing the frequency in the transverse direction (y) by 57.2%, in the longitudinal direction (x) by 27.6% and rotational along the z-axis by 12.9%; lastly, by decreasing the displacements in the x- and y-direction remarkably. Consequently, a combination of innovative seismic retrofitting methods appeared to be more effective, achieving a more resistant building under seismic hazards, by improving the stability and ductility of the structure. This gives rise to further researches and investigations for future solutions regarding seismic retrofitting applications and methodologies. / Jordbävningar är skakningar i marken som orsakar förluster av människors liv och leder till skador och kollaps av byggnader. Vanligtvis är de flesta byggnader som har allvarligt skadats eller kollapsat, äldre byggnader som inte längre uppfyller de uppdaterade byggreglerna för seismisk design. Syftet med detta examensarbete är att analysera och stärka en befintlig byggnad som har distribuerats av konsult företaget Sweco; lämpliga och innovativa seismisk eftermonteringsmetoder har använts för att förbättra byggnadens tillstånd med hjälp av insamlat vetenskapliga artiklar, tidskrifter och tidigare examensarbete samt svensk standard (Eurokod 8 - för dimensionering av bärverk med avseende på jordbävning). Den utdelade byggnaden är sju våningar hög och ligger i Stockholm. Den består av prefabricerade betong- och stålelement. Byggnaden kommer att testas under seismisk belastning med hjälp av programvaran MIDAS GEN, för att sedan examinera byggnadens globala beteende. Två analyser har utförts; en bedömningsanalys som innefattar granskning av den givna byggnadens kapacitet. Den andra analysen är den seismiska analysen som omfattar två sekundära analyser; en ’före applikation av seismisk eftermonteringsmetod’ och en ’efter applikation av seismisk eftermonteringsmetod’. I den första seismiska analysen, identifieras de mest kritiska positionerna där byggnadens beteende är avvikande med höga förskjutningar och låga frekvenser; således, är behovet av att modifiera och förbättra byggnadens prestanda betydande. Den andra seismiska analysen innefattar den modifierade byggnaden, som har testats med olika alternativa seismiska eftermonteringsmetoder för att identifiera vilken teknik som är mest passande för att optimera byggnadens hållfasthet, elasticitet och prestanda. Efter många experimentella försök, framgick det att en kombination av varierande seismiska eftermonteringsmetoder var det mest lämpliga urvalet. Den valda kombinationen består av stålfackverk och skjuvväggar. Efter genomförandet av den seismiska eftermonteringsanalysen erhölls resultat av frekvensen och förskjutningarna av byggnaden som sedan jämfördes med den första seismiska analysen, innan en eftermonteringsmetod var tillämpad. De erhållna resultaten visade att valet av denna modifikation har förbättrat byggnadens prestanda genom att öka frekvensen i tvärriktningen (y) med 57,2%, i längdriktningen (x) med 27.6% och rotationsfrekvensen längs z-axeln med 12.9%; slutligen, genom att minska förskjutningarna i x- och y-riktningen anmärkningsvärt. Följaktligen, verkade en kombination av varierande seismiska eftermonteringsmetoder vara effektiv, vilket resulterade i en seismisk resistent byggnad med avsevärt god hållfasthet, elasticitet och stabilitet. Denna forskning ger upphov till ytterligare efterforskningar och undersökningar för framtida lösningar avseende seismiska eftermonteringsapplikationer och metoder.

A key consideration in seismic design of buildings is to ensure that the lateral load resisting system has an appropriate combination of strength, stiffness and energy dissipation capacity. Hybrid coupled wall systems, in which steel beams are used to couple two or more reinforced concrete shear walls in series, can be designed to have these attributes and therefore have the potential to deliver good performance under severe seismic loading. This research presents an investigation of the seismic behavior of this type of structural system. System response of 12- and 18-story high prototypes is studied using transient finite element analyses that accounts for the most important aspects of material nonlinear behavior including concrete cracking, tension stiffening, and compressive behavior for both confined and unconfined concrete as well as steel yielding. The developed finite element models are calibrated using more detailed models developed in previous research and are validated through numerous comparisons with test results of reinforced concrete walls and wall-beam subassemblages. Suites of transient inelastic analyses are conducted to investigate pertinent parameters including hazard level, earthquake record scaling, dynamic base shear magnification, interstory drift, shear distortion, coupling beam plastic rotation, and wall rotation. Different performance measures are proposed to judge and compare the behavior of the various systems. The analyses show that, in general, hybrid coupled walls are particularly well suited for use in regions of high seismic risk. The results of the dynamic analyses are used to judge the validity of and to refine a previously proposed design method based on the capacity design concept and the assumption of behavior dominated by the first vibration mode. The adequacy of design based on the pushover analysis procedure as promoted in FEMA-356 (2000) is also investigated using the dynamic analysis results. Substantial discrepancies between both methods are observed, especially in the case of the 18-story system. A critical assessment of dynamic base shear magnification is also conducted, and a new method for estimating its effects is suggested. The method is based on a modal combination procedure that accounts for presence of a plastic hinge at the wall base. Finally, the validity of limitations in FEMA-368 (2000) on building height, particularly for hybrid coupled wall systems, is discussed.

[pt] Enfoca-se a análise sísmica de usinas termonucleares sob metodologia no domínio da frequência utilizando-se como modelo, o do prédio do reator da usina Angra 3 e como principal ferramenta o programa de análise de problemas com interação solo-estrutura, SASSI. São avaliadas alternativas para três fases distintas do projeto: geração de sismos artificiais, análise do sistema principal e desenvolvimento de espectros para análise do sistema secundário. Na geração de sismos artificiais, a introdução de critérios de compatibilização complementares ao do espectro de resposta é avaliada considerando-se as consequências sobre as respostas em um ponto da estrutura. No sistema principal, sujeito a excitações sísmicas nas direções horizontal e vertical, comparam-se soluções no domínio do tempo e da freqüência e se reconhece a metodologia na frequência como uma alternativa conveniente à análise no tempo para cálculo de respostas em termos de acelerações , deslocamentos e tensões máximas e de espectros de acelerações. São ainda, desenvolvidos espectros de resposta acoplados para a análise de sistemas secundários segundo sistemática já proposta, para cálculo no domínio do tempo, que comparados com estes, alcançam amplitudes da mesma ordem, porém com tempo de processamento inferior. A metodologia de análise no domínio da frequência apresenta- se como um recurso mais preciso, pois permite a consideração de parâmetros do solo não constantes com a frequência; no que diz respeito ao programa utilizado, mostra-se flexível e acessível. / [en] The seismic analysis of nuclear power plant structures and components is considered to evaluate the convenience to update the brazilian design routine through the use of frequency domain techniques provided by codes such as SASSI. For this purpose one uses a FEM model of a reactor building which has been already analyzed by current techniques in time domain, and comparisons are made with results obtained in the frequency domain, with special attention to the following points: - analysis of the main structures using foundation impedance functions variable with the excitation frequency; - generation of coupled floor response spectra and their application to the analysis of secondary systems; - consideration of complementary criteria based on a minimum seismic spectral density function to generate artificial ground motion accelerograms compatible with a prescribed design response spectrum. As a first step, an exploratory work on the usage of SASSI program is made running a couple of simple examples. In the continuation of the work, a series of runs is made using the above-mentioned structural model under currently prescribed ground motions in the design of brazilian NPP structures. The results are compared with those from previous analyses using different methodologies and some interesting conclusions are brought up. / [es] En el presente trabajo se enfoca el análisis sísmico de plantas termonucleares bajo la metodología en el dominio de la frecuencia utilizando como modelo, el del edificio del reactor de la planta Angra 3 y como principal herramienta el programa de análisis de problemas con interacción suelo-extructura, SASI. Son evaluadas alternativas para tres fases distintas del proyecto: generación de sismos artificiales, análisis del sistema principal y desarrollo de espectros para análisis del sistema secundario. En la generación de sismos artificiales, se evalúa la introducción de criterios de compatibilización complementares al del espectro de respuesta. En el sistema principal, sujeto a excitaciones sísmicas en las direcciones horizontal y vertical, se compararon soluciones en el dominio del tiempo y de la frecuencia. Se reconoce la metodología en la frecuencia como una alternativa conveniente para cálculo de respuestas en términos de aceleraciones, deslocamientos y tensiones máximas y de espectros de aceleraciones. Se desarrollan, además, espectros de respuesta acoplados para el análisis de sistemas secundarios según sistemática ya propuesta, para cálculo en el dominio del tiempo, que comparados con éstes, alcanzan amplitudes de la misma orden, pero con tiempo de procesamiento inferior. La metodología de análisis en el dominio de la frecuencia se presenta como un recurso más preciso, pués permite la consideración de parámetros del suelo no constantes con la frequencia; con respecto al programa utilizado, éste se muestra flexible y accesible.