Examinando por Materia "ONDAS SÍSMICAS"

Mostrando 1 - 13 de 13
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    Aproximación general al comportamiento del campo de onda sísmico en un medio homogéneo aplicando el método de los elementos finitos
    (Universidad EAFIT, 2018) Cano Uribe, Leonardo; Mosquera Ampudia, Santhier Stiwar; Villegas Gutiérrez, Jairo Alberto; Castaño Bedoya, Jorge Iván
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    Building monitoring during the partial implosion stage
    (Universidad EAFIT, 2015) Garcés Lengua, Julio; Botero, J.C.; Muriá Vila, David
    The partial collapse of a building in Colombia caused severe damage to its structural components -- An implosion was realized to induce the collapse of 50% of the deteriorated building -- To evaluate the influence of the implosion on the remaining structure, a monitoring survey was realized using triaxial accelerometers -- Time signals associated with ambient, seismic and forced vibration were obtained -- A study of the records in the time and the frequency domain was made -- The analysis of the information allowed determining some structural properties that were useful to calibrate the analytical model of the structure
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    Diseño de parámetros de adquisición sísmica 3D orientado a la detección de fracturas asistido por modelado sísmico anisótropo
    (Universidad EAFIT, 2013) Vega Delgado, Juan Carlos; Checa Jiménez, Jaime; Mora Bohórquez, Andrés Roberto
    The improving of seismic images with low illumination is possible a trough the new seismic acquisitions planned using seismic modeling and specific objectives to illuminate in areas where it has “low illumination” -- This work is focused to development a theory to improve the illumination of the subsurface, based in the ray tracing and it having into account the anisotropy effect that both, overburden and geological unit can to print to seismic wave registered -- In the first chapters, we try to rebuild the anisotropic effect increasingly complex analysis to have a geological model representative of a prospective field, which is affected by intense fracturing and this affects the quality of the currently acquired seismic, so we have created a seismic model with HTI anisotropy to evaluate the possibility of improving the quality of a new seismic design that can be added to the existing seismic through a processing flow -- Results show that to use a ray tracer methodology in “ghost zones”, is possible to find a new geometry in surface that really adds the illumination in Problem areas with interest in fracture reservoirs
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    Efectos locales un caso de aplicación a la ciudad de Medellín
    (Universidad EAFIT, 2014) Murillo Salazar, Juan Sebastián; Jaramillo Fernández, Juan Diego
    Tomando como punto de partida el modelo unidimensional de onda de corte, se estiman los 4 parámetros dinámicos que caracterizan la respuesta dinámica de un perfil de suelo (velocidad de propagación ondas de corte, altura del perfil de suelo, amortiguamiento, impedancia) -- Para este caso en particular, el proceso de estimación implementa el heurístico de Recocido Simulado ( Simulated Annealig ); el cual fue desarrollado en el software MATLAB -- El proceso se efectúa estrictamente en el dominio de la frecuencia; para 6 estaciones acelerográficas pertenecientes a la RAM (Red Acelerográfica de Medellín) con código EET, SEM, UEA, SOL, CSJ, FMI -- A pesar de la incertidumbre asociada a los parámetros, la complejidad del problema; tanto desde el aspecto geofísico y computacional; se logra obtener de forma satisfactoria buenas soluciones en un tiempo de cómputo razonable
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    Effects of topography on 3D seismic ground motion simulation with an application to the Valley of Aburrá in Antioquia, Colombia
    (Universidad EAFIT, 2013) Restrepo Sánchez, Doriam Leidin; Jaramillo Fernández, Juan Diego
    This dissertation presents a numerical scheme based upon the finite element framework for the numerical modeling of earthquake-induced ground motion in the presence of realistic topographic variations of the Earth’s crust -- We show that by adopting a non-conforming meshing scheme for the numerical representation of the surficial topography we can obtain very accurate representations of earthquake induced ground motion in mountainous regions -- From the computational point of view, our methodology proves to be accurate, efficient, and more importantly, it allows us to preserve the salient features of multi-resolution cubic finite elements -- We implemented the non-conforming scheme for the treatment of realistic topographies into Hercules, the octree-based finite-element earthquake simulator developed by the Quake Group at Carnegie Mellon University -- We tested the benefits of the strategy by benchmarking its results against reference examples, and by means of convergence analyses -- Our qualitative and quantitative comparisons showed an excellent agreement between results -- Moreover, this agreement was obtained using the same mesh refinement as in traditional flat-free simulations -- Our approach was tested under realistic conditions by conducting a comprehensive set of deterministic 3D ground motion numerical simulations in an earthquake-prone region exhibiting moderate-to-strong surficial irregularities known as the Aburr´a Valley in Antioquia-Colombia -- We proposed a 50 50 25 km3 volume to perform our simulations, and four Mw = 5 rupture scenarios along a segment of the Romeral fault; a significant source of seismic activity of Colombia -- We created and used the Initial Velocity Model of the Aburr´a Valley region (IVM-AbV) which takes geology as a proxy for shear-wave velocity -- Each earthquake model was simulated using three different models: (i) realistic 3D structure with realistic topography; (ii) realistic 3D structure without topography; and (iii) homogeneous half space with realistic topography. Our results show how topographic irregularities greatly modify the ground response -- In particular, they highlight the importance of the combined interaction between source-effects, focusing, soft-soil conditions, and 3D topography -- We provide quantitative evidence of this interaction and show that topographic amplification factors at some locations can be as high as 500 percent, while some other areas experience reductions -- These are smaller than the amplifications, on the order of up to 100 percent
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    Engineering estimation of topographic effects in site response analysis
    (Universidad EAFIT, 2021) Vergara Gallego, Juan Carlos; Gómez Cataño, Juan David
    Despite the irrefutable amount of theoretical and field evidence of the impact of topographic effects on the local response at a site the engineering community still lacks practical methods for its consideration in a standard routinely basis. The incorporation of topographic effects into site response analysis has been a major challenge to engineers as it involves coupling between mechanical and geometric modifications to the incident seismic waves, which at the same time demands for field data that is rarely available to the practicing engineer. On the other hand, it has been observed that the main signature of topographic effects, besides the expected change in frequency con tent, is its spatial variation. These complexities combined to the field data required to build fully coupled mechanical-geometrical models have resulted in complete under consideration of these effects. In this work we follow a rational approach to study the effect of surface topography on the response at local sites after formulating the problem following a diffraction perspective. Since this work is framed in an engineering context our main result is a method to incorporate the effect of surface topography in ground response analysis. Although the method requires numerical simulations we show that if the analyst brings into the problem the dynamic properties of the structure for which the analysis is conducted in the first place very moderate models may be required. These idea leads to the concept of size conditioned response spectra which uses a target structural response spectra to fix the size of the computational model. The resulting numerical domain turns out to be of manageable size thus it can be handled with standard computing resources. Although our proposed approach is limited to surface topography the combination of the theory of diffracted waves and the consideration of the structural response creates new venues to advance in understanding the problem of topographic effects.
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    Geometric analysis of trapezoidal hills subject to vertically incident SH waves
    (Universidad EAFIT, 2014) Vélez Zuluaga, Susana; Gómez Cataño, Juan David
    Topographic effects have been shown to play a significant role on the local ground response during earthquakes -- However, due to the large number of involved parameters the problem is rarely considered in seismic design regulations -- Recently, there has been a tremendous development by the engineering community, regarding methods and computational infrastructure to address the problem via numerical simulations -- Although numerically based models may give accurate results when fed with appropriate field data, the obtained solutions are still very limited and strongly dependent on unknown factors like the input excitation -- Therefore, there is a clear need to develop strong conceptual understanding allowing practising engineers to arrive at first order approximations, useful to validate complex numerical solutions -- In this work we explore the use of purely geometrical methods in the determination of the dynamic response of trapezoidal geometries to vertically incident horizontally polarized shear waves -- The geometries may be considered representative of hills or earth embankments, depending on its characteristic dimensions -- The hill response is first found with a frequency domain based boundary element code and the results are later analysed using a geometric approach, where the solution is partitioned into incident and reflected rays, forming the incoming or optical field, and the diffraction contribution -- This last term is obtained with a technique available from the literature -- The analysis corresponding to the optical field, reveals that there are only 5 possible scenarios or different solutions and that any given hill can be classified into one of these five possible cases -- Depending upon the dimensionless frequency of the problem (relating incident wavelength to the hill characteristic dimension), the solution is found to be governed by the optical solution or by the contribution from the diffraction terms -- The results are first presented in terms of frequency amplitude functions since that description facilitates the analysis by geometric methods, however for completeness, the resulting transfer functions are later used to obtain results in the time domain representative of typical numerical solutions as the ones derived with commercial computational software
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    Interacción suelo estructura considerando pilas
    (Universidad EAFIT, 2020) Portilla Cubillos, Carlos Augusto; Botero Palacio, Juan Carlos
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    Respuesta dinámica de depósitos de suelos considerando propagación vertical de ondas SH y variación lineal de la velocidad de onda de corte
    (Universidad EAFIT, 2017) Carvajal Gutiérrez, Dora Lucía; Jaramillo Fernández, Juan Diego
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    Simulador de ondas P utilizando el paquete Seismic Un *X
    (Universidad EAFIT, 2009) Gutarra Vélez, Eduardo; Lorduy Gómez, Roberto
    La carrera de ingeniería de sistemas tiene la capacidad de interactuar con otras disciplinas poniendo a su disposición tecnologías que simplifiquen, agilicen o mejoren tareas que le son afines -- La educación, propiamente dicha, es una de las disciplinas que se puede beneficiar de la ingeniería de sistemas para ayudar a explicar temas por medio de la visualización y la simulación en donde el estudiante pueda poner en práctica lo que está aprendiendo -- El proyecto que se va a introducir cumple su propósito en este ámbito, pues la aplicación que se va a realizar apoyará en la enseñanza del comportamiento de las ondas sísmicas P -- La contribución que se hizo en este trabajo consiste en la implementación de una interfaz gráfica de usuario que coordina el funcionamiento de un conjunto de programas que provienen de un paquete llamado Seismic Un*X el cual es utilizado por geólogos, geofísicos, ingenieros de petróleo y civiles entre otros, para estudiar el fenómeno de propagación de ondas sísmicas al interior de la tierra
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    The Spectral Cell Method in Nonlinear Earthquake Modeling
    (Universidad EAFIT, 2016) Giraldo Cuartas, Daniel; Restrepo Sánchez, Doriam Leidin
    In this study we focus at examining an efficient high order finite element strategy to compute the dynamic response of heterogeneous basins under nonlinear soil behavior subjected to point-source earthquake events -- The numerical technique known as the Spectral Cell Method (SCM) combines Fictitious-Domains concepts with the Spectral-version of the finite element method to accurately solve the wave equations in heterogeneous geophysical domains -- We tested the SCM in physically and computationally challenging domains namely, (i) a semi-elliptical basin, and (ii) an undulated basin embedded in a half-space with several irregular geological structures with different material discontinuities -- Nonlinear behavior is considered by implementing a Mohr-Coulomb, and a Drucker- Prager yielding criteria -- We benchmark our simulations with results obtained using MIDAS GTS NX, a finite element tool for geotechnical applications based upon traditional boundary-fitted meshing techniques