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Évolution du relief le long des marges actives : étude de la déformation Plio-Quaternaire de la cordillère côtière d'Équateur / Relief evolution along the active margins : study of the Plio-Quaternary Deformation in the coastal Cordillera of EcuadorReyes, Pedro 15 April 2013 (has links)
La marge d’Équateur est caractérisée par un bassin avant-arc formé par un socle crétacé et une couverture de sédiments marins d’âge Crétacé à Quaternaire. Le relief de cette zone comprend d’une part la cordillère Côtière proprement dite et la plaine Côtière, située entre la cordillère Côtière et les Andes. Ce travail porte sur l’évolution et le soulèvement de la cordillère Côtière durant le Néogène. Dans un premier temps, nous avons réalisé une étude géologique régionale de la cordillère côtière. À partir de l’analyse stratigraphique et structurale des formations géologiques, nous avons réalisé une carte géologique de la cordillère côtière au 1/500 000 qui nous a permis d’effectuer pour la première fois des corrélations stratigraphique et un schéma structural à l’échelle complète de la cordillère. Dans un deuxième temps nous avons réalisé une étude géomorphologique de la zone. À partir de l’analyse de MNT, d’images satellites et aériennes nous avons défini les principales caractéristiques morphologiques de la zone d’étude. En particulier, le travail a porté principalement sur l’analyse de la géométrie du réseau hydrographique, la mesure de la géométrie des vallées et du profil en long des rivières à l’échelle de la cordillère Côtière. En complément nous avons mesuré le profil longitudinal des terrasses alluviales le long du rio Jama et analysé la morphologie des cônes alluviaux qui se déposent au pied des Andes sur la plaine Côtière. Les résultats ont permis de proposer une évolution du soulèvement de la cordillère Côtière. Les mesures des incisions relatives des rivières suggèrent que le soulèvement de la cordillère Côtière n’est pas homogène et que la cordillère est segmentée en plusieurs blocs dont les taux de soulèvement relatif sont variables: les blocs du Nord présentant les incisions les plus importantes. L’analyse des profils longitudinaux des terrasses alluviales du rio Jama montre une activité néotectonique le long des failles du système de Jama. Le taux de soulèvement estimé à partir de cette analyse est de 0.9 à 1.2 mm/ an pour le segment central de la cordillère Côtière. L’analyse du cône de Santo Domingo, situé aux pieds des Andes, révèle une importante interaction entre le soulèvement de la cordillère Côtière et le remplissage sédimentaire de la plaine côtière dont le résultat est la réorganisation du réseau hydrographique en deux grands bassins hydrographiques: Guayas au Sud et Esmeraldas au Nord. A plus long termes, la géologie et la stratigraphie montrent que la partie du Sud a subis une plus forte érosion (soulèvement ?) qu'au Nord. La mise en évidence de plusieurs discordances à l’échelle régionale montre que la cordillère Côtière s’est soulevée de façon hétérogène depuis le Plio-Pléistocène formant un grand antiforme segmenté et contrôlé par des failles régionales qui présentent une direction proche de la direction du mouvement vers le NE-NNE du bloc Nord-Andin. / The Ecuadorian margin is characterized by a forearc basin composed of a Cretaceous basement covered by marine sediments of the Cretaceous to Quaternary age. The topography of this area displays two main morphological domains: the Coastal cordillera in the west and the Coastal plain in the east at the foothills of Andes cordillera. This work focuses on the genesis of the Coastal cordillera during the Neogene. Firstly, we carried out a geological fieldwork throughout the Coastal cordillera. From stratigraphy and structural studies, we produced a regional geological map of the Coastal cordillera at 1:500000 scale, which have allowed for the first time to realize a regional stratigraphy correlation and determine the structural pattern across the Coastal cordillera. In a second step, we carried out a geomorphologic study of the area. From DEM analysis and satellite and aerial imagery processing, we characterized the main landforms features of the study area. In particular, we focused on the geometry of the drainage network and on the river profiles crossing the Coastal cordillera. In addition, we measured the longitudinal profile of the alluvial terrace treads along the Jama River and analyzed the morphology of alluvial fans that are deposited on the Coastal Plain at the foothills of the Andes cordillera. From the different results obtained, we proposed an evolution scheme of the uplift of the coastal cordillera. The measurements of incisions along river valleys suggest that the uplift of the Costal cordillera is heterogeneous: the cordillera is segmented into several blocks with own uplift rates. The incisions of the northern blocks are the highest. The analysis of the longitudinal profiles along the alluvial terrace treads of the Jama River indicates a recent activity along the faults of the system Jama. The uplift rates estimated from this analysis ranges from 0.9 to 1.2 mm/yr for the central segment of the Coastal cordillera. The analysis of Santo Domingo alluvial fan situated at the foothills of the Andes cordillera reveals a large interaction between the sedimentary filling of the Coastal plain and the contemporaneous uplift of the Andes and the Coastal cordilleras. This interaction results into the reorganization of two major drainage basins: Guayas in the south and Esmeraldas in the north. At long timescales, the geology and stratigraphy of the Neogene formations shows that domains in the southern Coastal cordillera were subject to intense erosion (rising?) with respect to the northern domains. The analysis of the several unconformities evidences that the Coastal cordillera was raised in a heterogeneous way since the Plio-Pleistocene as a large and elongated antiform segmented and controlled by regional faults which have a trend between NE and NNE, which is close to that of the movement to the North Andean block.
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Efeito da instalação de estacas helicoidais em solo tropical / Effects of installation of helical piles in tropical soilsSantos Filho, João Manoel Sampaio Mathias dos 31 March 2014 (has links)
Neste trabalho e avaliado o comportamento de estacas helicoidais instaladas em solo residual tropical, submetidas a esforços de tração. Para este fim, foram ensaiadas estacas helicoidais em dois campos experimentais distintos, um em Itirapina (SP), e outro em Betim (MG). No primeiro terreno, as hélices das estacas ficaram instaladas em solo residual não saturado, e no segundo terreno em solo residual saturado. Neste tipo de fundação, o efeito da instalação da estaca no solo acima das hélices e um dos fatores que afetam significantemente a capacidade de carga a tração da estaca. Portanto, considerando-se a modificação que ocorre na estrutura de solos residuais tropicais após serem penetrados pelas hélices da estaca durante a sua instalação no terreno, a presente pesquisa foi desenvolvida com o intuito de compreender o efeito desta desestruturação do solo no comportamento da estaca a tração. Para esta avaliação, foi realizado um programa experimental com provas de carga em estacas helicoidais (instrumentadas e não-instrumentadas) e ensaios de laboratório em amostras indeformadas do solo coletado ao redor de uma estaca instalada no terreno de Itirapina. Os resultados mostram o efeito significante da instalação na capacidade de carga a tração deste tipo de estaca, principalmente no caso de solo poroso e não saturado. Alem disso, por meio dos ensaios em estacas instrumentadas, foi verificado que este efeito e mais acentuado no solo acima das hélices superiores, que foi penetrado mais vezes durante a instalação. / In this work, it was evaluated the behavior of helical piles installed in tropical residual soil under tensile loads. For this purpose, helical piles of different configuration were tested in two different experimental sites, one in Itirapina (SP), and another in Betim (MG). In Itirapina, the pile helices were installed in unsaturated residual soil, and in Betim in saturated residual soil. For this type of foundation, the effect of pile installation on the soil above the helices is one of the factors that significantly affect the pile uplift capacity. Therefore, considering the changes that occur in the structure of tropical residual soils after being penetrated by the helices during pile installation, this research was conducted in order to understand the effect of this soil alteration on the uplift behavior of helical piles installed in this type of soil. For this evaluation, pile load tests were carried out on instrumented and non-instrumented helical piles. Also, laboratory tests were performed on undisturbed soil samples collected around a pile installed in the site of Itirapina. The results show the significant effect of pile installation on the uplift capacity of the tested helical piles, especially in the case of porous and unsaturated soil. In addition, through the tests on the instrumented piles, it has been found that this effect is more pronounced in the soil above the upper helices, which were penetrated more times during pile installation.
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Les mouvements verticaux de Madagascar (90 - 0 Ma) : une analyse couplée des formes du relief et de l'enregistrement sédimentaire des marges ouest malgaches / Vertical movements of Madagascar (90 - 0 Ma) : a coupled analysis of relief morphology and sedimentary record of western Madagascar margins.Delaunay, Antoine 16 March 2018 (has links)
Madagascar est un lambeau de croûte continentale archéenne à néoproterozoïque entouré de marges transformantes, obliques et divergentes : la marge oblique du bassin de Morondava à l’Ouest, bornée par la ride de Davie, et au Nord, la marge divergente du bassin de Majunga connectée au bassin de Somalie. Cette île de 1600 kilomètres de long est composée d’un plateau axial archéen-protérozoïque entre 1200 et 1800m d’altitude, bordé de tous côtés par des bassins sédimentaires. Le sommet du plateau correspond à des surfaces d’aplanissement altérées, délimitées par des escarpements plus ou moins marqués. L'altitude des hauts plateaux traduit l'existence de processus mantelliques, mais la cinétique et l'origine du relief malgache est mal comprise. Peu d'études ont étudié les domaines non orogéniques dans leur intégralité terre-mer, depuis le bassin versant en érosion jusqu'aux marges en sédimentation, et aucune d'entre elles ne porte sur Madagascar. Ce travail de thèse repose donc sur une double approche: une analyse géomorphologique des formes du relief (surfaces d'aplanissement) à terre, basée sur leur (i) cartographie, (ii) chronologie relative, (iii) relation avec les profils d'altération et (iv) datation au moyen des placages sédimentaires et du volcanisme daté qui les scellent; une analyse stratigraphique de l'intervalle post-rift des marges, basée sur l'interprétation de données de sub-surface (puits et lignes sismiques), lesquelles ont été réévaluées en âge (biostratigraphie), pour (i) identifier, dater et mesurer les déformations des marges et de leur relief en amont, (ii) mesurer les flux silicoclastiques, produits de l'érosion continentale. Un calendrier et une cartographie des déformations ont été obtenus sur les marges et mis en relation avec les différentes générations de surfaces d'aplanissement étagées caractérisant le relief malgache. Au Crétacé supérieur, une flexuration de l'île est initiée au sud, à grande longueur d'onde, autour de ~94 Ma. Cette déformation est scellée par la mise en place d'une surface d'aplanissement non déformée mise en place entre 80 et 66 Ma. Durant le Paléocène jusqu’à l'Eocène supérieur (66 à 20 Ma), Madagascar est une île relativement plate, de faible altitude, entourée de larges plateformes carbonatées. Ce relief est largement altéré avec la croissance de nombreux profils latéritiques et les influx silico-clastique dans les bassins sont alors relativement faibles. Le Miocène moyen à supérieur correspond au paroxysme de la surrection et de la déformation avec (1), le basculement de la marge ouest (Morondava), (2) une augmentation du flux de sédimentation silicoclastique depuis le Miocène moyen et (3) la mise en place d’une succession de quatre surfaces d’aplanissement correspondant à des pics d'intensité de la déformation. Le résultat de cette surrection est la morphologie en dôme de l’île de Madagascar (avec un plateau central) marquée par la forme concave de la surface crétacé supérieure altérée à l’Eocène. Le mécanisme de la surrection doit prendre en compte une déformation de très grande longueur d’onde (x 1000 km), forcément liée à la dynamique mantellique. Les relations avec les dômes d’Afrique de l’Est (Ethiopie, Afrique du Sud) sont discutées. / Madagascar is an Archean to Neoproterozoic continental crust surrounded by transform, oblique and divergent margins: the transform Morondava basin to the west, pounded by the Davie Fracture Zone, and to the north, the divergent Mahajanga Basin connected to the Somali Oceanic Basin. This 1600 km long island is a high axial plateau with elevations from 1200 to 1800m. The top of the plateau corresponds to weathered planation surfaces (etchplains), bounded by more or less high scarps. Such elevation of the high axial plateau imply mantle processes, but the age and cinetic of the uplift is still poorly known. Few studies dealt with anorogenic domains in their entirety from the catchment area, the source, to the downstream depositional system, the sink, none of which is about Madagascar. This work lies on a double approach : it is onshore based on the analysis of the macroforms (planation surfaces, etchplains, pediments) throughout their (i) mapping, (ii) relative dating, (iii) relationships with weathering profiles and (iv) dating by their intersection with preserved sediments and volcanism (lava flow and intrusions). offshore, it is based on the interpretation of a dataset of seismic lines and industrial wells, coupled with refreshed biostratigraphy, in order to (i) identify, date and measure vertical movements of the margins and upstream reliefs. Chronology and mapping of vertical movements were defined on the Morondava margin and compared with the onset of the stepped planation surfaces typical of Madagascar topography. During Upper Cretaceous, the southern part of the island is uplifted, at ~94 Ma. This deformation is sealed by the onset of an undeformed planation surface between 80 and 66 ma. From Paleocene to Upper Eocene (66 to 20 Ma), Madagascar is a flat, low elevated island, surrounded by wide carbonate platforms. The relief is highly weathered with growth of lateritic profiles and silico-clastic influx within the basin is low. During Middle to Upper Miocene is the uplift and doming paroxysm with (1), tilt of the western margin (Morondava), (2) increase of silico-clastic influx from Middle Miocene and (3 the onset of four planation surfaces associated to deformation paroxysms. The end result of this uplift is a convex up shape pattern for the end Cretaceous surface weathered during Eocene times, creating the present-day dome morphology (with a central plateau) of Madagascar. The mechanism of this uplift has to explain a very long wavelength deformation (x1000 km) necessary due to mantle dynamics. The relationships with the other East African domes (Ethiopia, East Africa, South Africa) are discussed.
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Pioneer Settlement in the Mesolithic of Northern SwedenOlofsson, Anders January 2003 (has links)
<p>The aim of the thesis is to cast light on the earliest settlement of northern Sweden. The starting point is lithic artifacts, which have been studied from a technological as well as a more conventional typological perspective (Papers I, II, and IV). Paper III deals primarily with geological and palaeoecological methods and my contribution is mainly confined to the lithic artifacts. The main research objectives are concerned with early postglacial colonization and cultural affiliation mirrored through technological traditions. Another “main thread” is a source-critical discussion regarding dating problems, and the chronological integrity of find contexts. The chronological position of artifact types in the North Swedish Mesolithic is another related problem being discussed.</p><p>The geographical area under investigation comprises northern Sweden sensu largo: Norrland plus the provinces of Värmland and Dalarna. The time period studied is the Mesolithic, with an emphasis on the earliest part, ca. 8500–7500 BP.</p><p>Paper I discusses the Mesolithic in the province of Värmland. There are traits indicating both an affiliation with the Lihult/Nøstvet sphere (for example, Lihult axes and saws/knives of sandstone) as well as other features more common in an eastern/northern context (quartz use, bipolar reduction, and, at least for the final Mesolithic and Neolithic, slate artifacts).</p><p>Paper II aims at elucidating microblade technology in northern Sweden as regards chronological position and cultural context. It was found that microblade production from handle cores (also called wedge-shaped cores) was introduced at about the same time in northern Sweden as in other areas of Scandinavia where these artifacts occur, ca. 8000–7500 BP. The handle core tradition continued until ca. 5500/5000 BP.</p><p>Paper III deals with lake-tilting caused by non-uniform glacio-isostatic uplift. This phenomenon has been used to identify potential areas of Mesolithic occupation in the Arjeplog area, Lapland. Surveys and excavations within the research project "Man, Fire, and Landscape", have significantly increased the number of Mesolithic sites in the area. The investigations have resulted in the discovery of the oldest firmly dated archaeological site in northern Sweden, Dumpokjauratj, in Arjeplog parish, Lapland, with a maximum date of 8630 ± 85 BP.</p><p>Paper IV discusses the pioneering phase of occupation in northern Sweden, in the light of the above-mentioned site of Dumpokjauratj and a site at Garaselet in northern Västerbotten. These are further compared with contemporary sites in surrounding areas of Fennoscandia. The majority of the assemblages are dominated by platform reduction, even if bipolar reduction also occurs at the earliest sites. Slate artifacts found at Dumpokjauratj suggest connections with the Finnish Mesolithic, which is the only cultural context in our region with documented slate use at this early point in time. But there are also traits that do not specifically point towards Finland, e.g. frequent use of fine-grained flint-like materials and porphyry, and (at Dumpokjauratj) a lanceolate microlith made of a microblade of this fine-grained igneous rock. The latter suggests associations with the Scandinavian Mesolithic in general.</p><p>In any event, the early dates from Dumpokjauratj show that interior Lapland was occupied soon after deglaciation, probably within a few hundred years.</p>
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Pioneer Settlement in the Mesolithic of Northern SwedenOlofsson, Anders January 2003 (has links)
The aim of the thesis is to cast light on the earliest settlement of northern Sweden. The starting point is lithic artifacts, which have been studied from a technological as well as a more conventional typological perspective (Papers I, II, and IV). Paper III deals primarily with geological and palaeoecological methods and my contribution is mainly confined to the lithic artifacts. The main research objectives are concerned with early postglacial colonization and cultural affiliation mirrored through technological traditions. Another “main thread” is a source-critical discussion regarding dating problems, and the chronological integrity of find contexts. The chronological position of artifact types in the North Swedish Mesolithic is another related problem being discussed. The geographical area under investigation comprises northern Sweden sensu largo: Norrland plus the provinces of Värmland and Dalarna. The time period studied is the Mesolithic, with an emphasis on the earliest part, ca. 8500–7500 BP. Paper I discusses the Mesolithic in the province of Värmland. There are traits indicating both an affiliation with the Lihult/Nøstvet sphere (for example, Lihult axes and saws/knives of sandstone) as well as other features more common in an eastern/northern context (quartz use, bipolar reduction, and, at least for the final Mesolithic and Neolithic, slate artifacts). Paper II aims at elucidating microblade technology in northern Sweden as regards chronological position and cultural context. It was found that microblade production from handle cores (also called wedge-shaped cores) was introduced at about the same time in northern Sweden as in other areas of Scandinavia where these artifacts occur, ca. 8000–7500 BP. The handle core tradition continued until ca. 5500/5000 BP. Paper III deals with lake-tilting caused by non-uniform glacio-isostatic uplift. This phenomenon has been used to identify potential areas of Mesolithic occupation in the Arjeplog area, Lapland. Surveys and excavations within the research project "Man, Fire, and Landscape", have significantly increased the number of Mesolithic sites in the area. The investigations have resulted in the discovery of the oldest firmly dated archaeological site in northern Sweden, Dumpokjauratj, in Arjeplog parish, Lapland, with a maximum date of 8630 ± 85 BP. Paper IV discusses the pioneering phase of occupation in northern Sweden, in the light of the above-mentioned site of Dumpokjauratj and a site at Garaselet in northern Västerbotten. These are further compared with contemporary sites in surrounding areas of Fennoscandia. The majority of the assemblages are dominated by platform reduction, even if bipolar reduction also occurs at the earliest sites. Slate artifacts found at Dumpokjauratj suggest connections with the Finnish Mesolithic, which is the only cultural context in our region with documented slate use at this early point in time. But there are also traits that do not specifically point towards Finland, e.g. frequent use of fine-grained flint-like materials and porphyry, and (at Dumpokjauratj) a lanceolate microlith made of a microblade of this fine-grained igneous rock. The latter suggests associations with the Scandinavian Mesolithic in general. In any event, the early dates from Dumpokjauratj show that interior Lapland was occupied soon after deglaciation, probably within a few hundred years.
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Tectonic evolution of continental rifts. Inference from numerical modelling and fission track thermochronologyvan der Beek, Pieter 24 May 1995 (has links) (PDF)
pas de résumé
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Inkrementell responsanalys : Vilka kunder bör väljas vid riktad marknadsföring? / Incremental response analysis : Which customers should be selected in direct marketing?Karlsson, Jonas, Karlsson, Roger January 2013 (has links)
If customers respond differently to a campaign, it is worthwhile to find those customers who respond most positively and direct the campaign towards them. This can be done by using so called incremental response analysis where respondents from a campaign are compared with respondents from a control group. Customers with the highest increased response from the campaign will be selected and thus may increase the company’s return. Incremental response analysis is applied to the mobile operator Tres historical data. The thesis intends to investigate which method that best explain the incremental response, namely to find those customers who give the highest incremental response of Tres customers, and what characteristics that are important.The analysis is based on various classification methods such as logistic regression, Lassoregression and decision trees. RMSE which is the root mean square error of the deviation between observed and predicted incremental response, is used to measure the incremental response prediction error. The classification methods are evaluated by Hosmer-Lemeshow test and AUC (Area Under the Curve). Bayesian logistic regression is also used to examine the uncertainty in the parameter estimates.The Lasso regression performs best compared to the decision tree, the ordinary logistic regression and the Bayesian logistic regression seen to the predicted incremental response. Variables that significantly affect the incremental response according to Lasso regression are age and how long the customer had their subscription.
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Effects Of Vertical Excitation On Seismic Performance Of Highway Bridges And Hold-down Device RequirementsDomanic, Arman Kemal 01 February 2008 (has links) (PDF)
ABSTRACT EFFECTS OF VERTICAL EXCITATION ON SEISMIC PERFORMANCE OF HIGHWAY BRIDGES AND HOLD-DOWN DEVICE REQUIREMENT
Domaniç / , Kemal Arman
M.S., Department of Civil Engineering Supervisor: Assist. Prof. Dr. Alp Caner
February 2008, 152 pages
Most bridge specifications ignore the contribution of vertical motion in earthquake analyses. However, vertical excitation can develop significant damage, especially at bearing locations as indeed was the case in the recent 1999 izmit Earthquake. These observations, combined with recent developments in the same direction, supplied the motivation to investigate the effects of vertical component of strong ground motion on standard highway bridges in this study. Reliability checks of hold-down device requirements per AASHTO Bridge Specifications have been conducted in this context. Six spectrum compatible accelerograms were generated and time history analyses were performed to observe the uplift at bearings. Selected case studies included precast pre-stressed I-girders with concrete slab, composite steel I-girders, post-tensioned concrete box section, and composite double steel box section. According to AASHTO specifications, hold-down devices were required in two cases, for which actual forces obtained from time history analyses have been compared with those suggested per AASHTO. The only non-linearity introduced to the analyses was at the bearing level. A discussion of effects on substructure response as well as compressive bearing forces resulting from vertical excitation is also included. The results of the study confirmed that the provisions of AASHTO governing hold-down devices are essential and reasonably accurate. On the other hand, they might be interpreted as well to be suggesting that vertical ground motion components could also be included in the load combinations supplied by AASHTO, especially to be able to estimate pier axial forces and cap beam moments accurately under combined vertical and horizontal excitations.
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An Assessment Of Winkler Model For Simulation Of Shallow Foundation UpliftTaymus, Refik Burak 01 August 2008 (has links) (PDF)
Foundation uplift is the partial separation of a shallow foundation from soil due
to excessive load eccentricity. Foundation uplift can significantly change the
seismic response of slender structures, and frames as well. In literature, different
support models for foundations are employed in order to simulate foundation
uplift in seismic analysis of structures. One of the most widely used models is the
Winkler model which assumes distributed tensionless springs beneath a shallow
foundation. In this study, two simple algorithms are developed in order to
compute static and dynamic response of foundations on tensionless supports. Any
formula given in literature for calculation of foundation impedance coefficients
can be easily introduced in these algorithms. Hence, the use of Winkler model is
critically evaluated through comparisons with the response of a foundation on
elastic halfspace. For that purpose, available impedance formulas given for a
shallow rectangular foundation on elastic halfspace are used. It is concluded that,
the coupling between vertical displacement and rocking of foundation is very
significant during uplift. Therefore, the accuracy of Winkler model in uplift
v
simulation is limited, since the model cannot simulate vertical and rocking
response of a shallow foundation concurrently with a single spring coefficient.
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An Investigation Of The Inertial Interaction Of Building Structures On Shallow Foundations With Simplified Soil-structure Interaction Analysis MethodsEyce, Bora 01 September 2009 (has links) (PDF)
Seismic response of a structure is influenced by the inertial interaction between structure and deformable medium, on which the structure rests, due to flexibility and energy dissipation capability of the surrounding soil. The inertial interaction analyses can be performed by utilizing simplified soil-structure interaction (SSI) analyses methods. In literature, it is noted that varying soil conditions and
foundation types can be modeled by using these SSI approaches with springdashpot couples having certain stiffness and damping.
In this study, the seismic response of superstructure obtained by using simplified SSI methods is compared with those of the fixed base systems. For this purpose,
single and multi degree of freedom structural systems are modeled with both spring&ndash / dashpot couple and fixed base models. Each system is analyzed for varying structural and soil stiffness conditions under the excitation of three
different seismic records. Next, the total base shear acting on the structural system and internal forces of load bearing members are investigated to observe
the inertial interaction and foundation uplift effects on the superstructure. It is also aimed to examine the compatibility of the simplified SSI approaches utilized
in the analyses.
It is concluded that the structural and soil stiffness parameters are the most influential parameters that affect seismic structural response. Structures becomemore sensitive to varying soil properties as the structural stiffness increases. On the other hand, decreasing soil stiffness also increases the sensitivity of the structure to the seismic excitation. Calculated values of total base shear and
internal member forces revealed that the inertial interaction might be detrimental for the superstructure. Contrary to general belief, the fixed base
approach does not always yield to the results, which are on the safe side. Considering the analysis results, it is concluded that SSI analysis is very useful for more precise and economical design for the seismic behavior.
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