Alfonso Mariano Ramos

Alfonso Mariano Ramos
Pontificia Universidad Javeriana · Department of Civil Engineering

Doctor of Engineering

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74
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389
Citations

Publications

Publications (74)
Article
Full-text available
Contexto: La variabilidad natural (incertidumbre) espacial y la temporal de los insumos que intervienen en la modelación hidrodinámica, para la evaluación de la amenaza y la delimitación de las zonas potencialmente inundables, se propagan en las variables de salida de los modelos. En la práctica, suele considerarse la variabilidad natural temporal...
Article
Full-text available
Se presenta la metodología utilizada para la determinación de umbrales asociados a avenidas torrenciales en el municipio de Mocoa – Putumayo (Colombia). Estos se proponen en términos de precipitación, cota de nivel del agua (msnm) y caudal; y se obtuvieron con soporte en la modelación basada en la física de un escenario de avenida torrencial y su a...
Article
Full-text available
Undrained instability is a failure mode that has been observed in many sandy slopes. However, the highly anisotropic stress states caused by the geometry of the slope have not been duly considered from the experimental point of view. This article studies the influence of the initial stress anisotropy of laboratory samples on the static undrained in...
Conference Paper
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Esta investigación presenta los resultados de un programa conjunto de pruebas tipo Round Robin Test (RRT), centrado en la caracterización física de la arena del Guamo. La arena del Guamo es un suelo transportado aluvial colombiano ampliamente utilizado con fines de investigación e ingeniería en el país. Las pruebas cooperativas fueron realizadas po...
Article
Debris flows are among the most catastrophic natural phenomena, attracting the interest of researchers, engineers and government agencies. The complexity of the physical process has led to the development of numerous mathematical models to simulate and deeper understand the propagation of debris flows. Nevertheless, the intrinsic characteristics of...
Book
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En el capítulo 1 se describe el marco conceptual en el que se fundamenta la metodología. Este contempla los conceptos utilizados a lo largo del documento y el alcance del marco normativo que rige la evaluación de amenaza por avenidas torrenciales. El capítulo 2 aborda la delimitación del área de estudio, las escalas de trabajo, los modelos de eleva...
Book
Guía metodológica para zonificación de amenaza por avenidas torrenciales
Article
Full-text available
This work proposes a criterion for the detection of undrained instability under multiaxial stress conditions at elemental level. To do so, it develops the application of the proposed criterion to the implicit implementation of a multiaxial elastoplastic constitutive model, which considers the effect of inherent anisotropy for the simulation of mono...
Conference Paper
Full-text available
Mocoa, capital city of the department of Putumayo -Colombia-, was devastated the night of 31 March of 2017 after a series of landslides triggered a large debris flow along the Taruca, Taruquita creek basins. The emergency event was triggered by a 4-day rainfall accumulation and high rainfall intensities on the night of the event. These led to 629 m...
Article
Debris flows have been widely researched during the last decades since they are catastrophic events with significant infrastructure and environmental impacts. Typically, they are composed of various materials which interactions are worth for studying, to improve the prediction of some variables, such as velocities, forces and affected areas. Consti...
Article
La caracterización mecánica de depósitos de materiales heterogéneos (BIMrocks/BIMsoil – Block in Matrix) requiere del conocimiento de la cantidad de bloques inmersos en una matriz débil (Proporción Volumétrica de Bloques, PVB). La aleatoriedad en el proceso de formación de dichos depósitos impide obtener información unívoca mediante estudios geotéc...
Article
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This work presents a high-order element-based numerical simulation of an experimental granular avalanche, in order to assess the potential of these spectral techniques to handle geophysical conservation laws. The spatial discretization of these equations was developed via the spectral multidomain penalty method (SMPM). The temporal terms were discr...
Article
Full-text available
On the night of March 31, 2017, a series of mass movements took place in the Mocoa Basin and devastated the northwestern part of its urban area. The mass movements were triggered by a 4-day rainfall accumulation and high rainfall intensities on the night of the event. After the trigger, about 420 mass movements transported material as landslides, d...
Conference Paper
Full-text available
Introducción El Municipio de Mocoa está ubicado en la parte norte del Departamento del Putumayo, Colombia y su población actual aproximada es de 43.731 habitantes (DANE, 2005). Su territorio se ubica en una zona de piedemonte y es atravesado por dos ríos: el Mulato y el Sangoyaco, el cual es alimentado por las quebradas Taruca y la Taruquita. Las f...
Conference Paper
Complex geotechnical processes such as debris or tailings flows, rain-induced landslides, foundation instability, and soil-structure interaction require advanced laboratory techniques, including remote-sensing technology. The purpose of this paper is to describe the implementation of a laboratory-scale LIDAR-type system installed on an environmenta...
Article
Full-text available
Este trabajo aborda la falta de certeza en la estimación de las propiedades del suelo con las cuales se diseñan estructuras geotécnicas. Se propone un procedimiento para incorporar la incertidumbre aleatoria puntual de las propiedades del suelo en los procesos geoestadísticos que se utilizan para estimar valores de variables geotécnicas en localiza...
Article
Full-text available
Los depósitos coluviales son materiales sueltos y heterogéneosde suelos o fragmentos de roca depositados en la base o parte media de las laderas. Para denominar a estos materiales, se deriva el término Bimsoil para definir bloques de roca embebidos en una matriz de suelo, en el que la relación de resistencia y rigidez entre los bloques y la matriz...
Article
The colluvial deposits are loose and heterogeneous materials composed of soils or rock fragments deposited on the slopes. The Bimsoil term is used for denominate blocks of rock embedded in soil matrix and the strength and stiffness ratio is higher to 2. Frequently, the geotechnical engineer considers the strength of weak matrix in design, which cou...
Article
Los resultados del ensayo de corte directo tanto a nivel experimental como en simulaciones con elementos discretos se ven afectados por la escala, es decir los resultados dependen del tamaño de las partículas y de la caja de corte. El geotecnista tiene que utilizar los resultados de los ensayos de laboratorio a escala pequeña en problemas a escala...
Article
Full-text available
A method to estimate liquefaction is the one proposed by Seed et al. (1985). This method depends on the cyclic resistance ratio CRR and the cyclic shear stress ratio CSR to calculate the safety margin. Frequently, this measure of safety is assumed deterministic and it is not contemplated the uncertainty of the seismic loads and soils resistance pro...
Article
Full-text available
Landslide occurrence is associated with some conditioning factors and triggering landslide processes. This research contributes to quantify the influence of geomorphology as a conditioning factor in slope stability, via analysis based on a finite element method with an elastoplastic constitutive model. The analysis performs through a numerical simu...
Article
Full-text available
El flujo de detritos es un proceso de naturaleza granular que ha sido abordado ampliamente bajo metodologías basadas en el medio continuo. Sin embargo, estas aproximaciones simplifican la realidad granular del suelo. Como material granular, la granulometría puede gobernar el comportamiento de este movimiento desagregado de masa. Es posible estudiar...
Article
Full-text available
Context: Shear wave velocity tests (Vs) are commonly used to estimate the increase in resistance of explosive densified soils. In some historical cases, Vs tests performed after the soil improvement process do not show a significant increase in soil resistance, even though the soil surface sits more than 0.50 m. It is believed that this response is...
Article
A vulnerability assessment frame is necessary from a holistic perspective that integrates the factors that affect a territory along with socio-cultural elements and timescales subsequent to the disasters. Such a frame has the potential to assess a territory's particular characteristics and generate local knowledge for prevention, mitigation, and re...
Article
Full-text available
Debris flow is a process of granular nature that has been widely analysed with methodologies based upon continuum mechanics. However, those approaches do not take into account the real granular condition of the soil. Grain size distribution exerts an important control on the movement of debris flows. This behaviour can be studied by analyzing three...
Article
Full-text available
A smooth cold joint of concrete is an untreated weak plane caused by an interruption of the casting process, which can significantly affect the performance of a structural system. In this paper, the problem of the generation of cold joints is approached from two complementary perspectives. a) The loss of resistance due to the occurrence of cold joi...
Article
Full-text available
A smooth cold joint of concrete is an untreated weak plane caused by an interruption of the casting process, which can significantly affect the performance of a structural system. In this paper, the problem of the generation of cold joints is approached from two complementary perspectives. a) The loss of resistance due to the occurrence of cold joi...
Article
Full-text available
Context: Experimental results show that the stress-strain behavior of granular materials depends upon the scale analysis. However, due to the intrinsic assumptions of the mechanics of a continuum medium, the analysis of finite elements based on the Boltzmann´s continuum does not allow to consider characteristic lengths in its formulation to reflect...
Conference Paper
In the process of characterization and modeling of the mechanical behavior of geomaterials assumptions are adopted related to the theory of continuous medium, such as homogeneity and isotropy condition derived from the stress-strain response. Thus the development of element tests on undisturbed samples or reconstituted in laboratory the actual eval...
Article
Full-text available
This work summarises results of the evaluation of the physical earthquake vulnerability for the structural system of an essential building by using reliability methods. The research was based on the compilation of drawings and design memories, pathology studies, a structural surveying, and the assessment of the local earthquake hazard. In order to...
Article
Full-text available
This paper presents a methodology to quantify the amount of blast densification or number of passes required for a given project to prevent liquefaction and flow in saturated, loose sandy soils. The proposed methodology is based on the concepts of the critical state soil mechanics, and the number of passes is chosen so that the final state of stres...
Conference Paper
The soil tends to be evaluated as a homogeneous material and rocks as solid or continuous media. However, there has always been a great uncertainty when evaluating materials with a high degree of heterogeneity; such materials are referred as bimrocks. In this paper the implementation of multiscale numerical modeling is shown for the study of materi...
Article
Full-text available
p>El trabajo contribuye al entendimiento del efecto de la geoforma en la estabilidad de taludes en un análisis tridimensional por medio de nueve modelos conformados por la combinación en planta y perfil de la forma recta, convexa y cóncava. El análisis se basa en el cálculo de indicadores potenciales de falla que representan de manera unificada un...
Article
Full-text available
InvestIgacIón RESUMEN Contexto: Los resultados experimentales en materia-les granulares muestran que el comportamiento es-fuerzo deformación tiene dependencia con la escala de análisis, sin embargo, debido a las supocisiones intrínsecas que tiene la mecánica del medio conti-nuo, los análisis de elementos finitos basados en el continuo de Boltzmann...
Article
Full-text available
InvestIgacIón Resumen Contexto: Los ensayos de velocidad de onda de cor-te (Vs), son comúnmente utilizados para estimar el incremento en resistencia de suelos densificados con explosivos. En algunos casos históricos los en-sayos de Vs realizados después del proceso de me-joramiento de suelo no muestran un incremento significativo en la resistencia...
Article
Full-text available
En el mundo se han propuesto múltiples relaciones lluvia-deslizamientos para sistemas de alerta temprana. Este trabajo presenta una base de datos que sintetiza el estado del arte de umbrales de lluvia que generan movimientos en masa en todo el mundo. Las relaciones más comunes lluvia-deslizamiento se procesan con el fin de analizar los datos en fun...
Article
Full-text available
In order to understand the processes that trigger landslides and the factors that may influence their generation such as geomorphology and climatology, this paper presents a new database of landslide processes compiledfor Bogotá, constructedfrom technical reports elaborated by the Instituto Distrital de Gestión del Riesgo y Cambio Climático IDIGER...
Article
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This paper shows the results obtained for the variation of the mechanical properties of adobe units subjected to simulated environmental factors of radiation and condensation. For doing this, adobes over three hundred years old,taken from the chapel doctrinera de Tausa, and new laboratory-built adobes were studied. Both kinds of adobe blocks were s...
Conference Paper
There is no agreement between experimental researchers whether the point where a granular material responds with a large change of stresses, strains or excess pore water pressure given a prescribed small input of some of the same variables defines a straight line or a curve in the stress space. This line, known as the instability line, may also var...
Article
Full-text available
Se presenta un estudio del comportamiento de materiales granulares sometidos a procesos de inestabilidad en un tambor rotador. Mediante un procedimiento novedoso se evalúa la aplicabilidad de la energía cinética como parámetro de medición de procesos de inestabilidad y su relación con las granulometrías de los materiales y las velocidades de rotaci...
Article
Full-text available
Bogotá is located in the central Andean region of Colombia, which is frequently affected by landslide processes. These processes are mostly triggered during the rainy season in the city. This fact remarks the importance of determining what rainderived parameters (e.g. intensity, antecedent rain, daily rain) are better related with the occurrence of...
Article
Results of the direct shear test performed both experimentally and numerical simulations using the discrete element method are affected by the scale, i.e. results depend on both, the particle size and the size of the shear box. The geotechnical engineer must use the results of tests on small-scale laboratory in solve real scale problems. This work...
Article
Full-text available
A numerical study on the onset of static liquefaction in slopes under undrained conditions of loading was developed based on a general liquefaction flow instability criterion for elastoplastic soils based on the concept of loss of controllability. The criterion is applied to the case of axisymmetric loading to detect the onset of static liquefactio...
Article
Full-text available
Los modelos desarrollados a partir de herramientas de inteligencia artificial han sido utilizados de manera activa en los últimos años, siempre buscando capturar el conocimiento experto y/o información de mapas para reproducirlo en diferentes disciplinas y actividades. En este estudio se toma la información relacionada con la geología, geotecnia y...
Article
Full-text available
The study of seismic intensity attenuation plays an important role in the analysis of menace that includes historical events. Mapping the intensity attenuation is usually done by regressing the intensity versus distance. Nowadays there are different ways to examine the characteristics of a seismic event using instrumental means, however, the expert...
Article
Full-text available
Modelling based upon the discrete element method has opened the possibility of simulating different processes, which under the paradigm of traditional continuum mechanics, had not been duly modelled due to their granular nature. Many fields have benefited from the headway made in recent years in the modelling of granular materials with discrete ele...
Article
This study describes a general liquefaction flow instability criterion for elastoplastic soils based on the concept of loss of uniqueness. We apply the criterion to the general case of axisymmetric loading and invoke the concepts of effective stresses and loss of controllability to arrive at a general criterion for the onset of liquefaction flow. T...
Article
Full-text available
The standard practice of foundation engineering calculates the capacity of the pile regardless that the construction process can affect the geometric component of the bearing capacity. In this paper, we present a method for incorporating the method of construction in reliability based design of piles by mean of the random finite element method, whi...
Article
Full-text available
Como una forma alternativa a los métodos convencionales para realizar análisis de estabilidad de taludes, este artículo presenta una revisión bibliográfica de algunos procedimientos para modelar los flujos de material desagregado que parten desde la mecánica de medios continuos (perspectiva Euleriana), conservación de masa y momentum, de las que se...
Article
Full-text available
Como una forma alternativa a los métodos convencionales para analizar la estabilidad de taludes, este artículo implementa un procedimiento para modelar los flujos de material desagregado que parten de la mecánica de medios continuos (perspectiva Euleriana), propuesta por Iverson y Delinger [1]. Esta metodología supone el comportamiento de una mezcl...
Article
As an option against typical methods for slope stability analysis, this paper implements a procedure to model material flows from continuum mechanics (Eulerian approach), proposed by Iverson and Denlinger [1]. This methodology involves the behavior of a Newtonian fluid-and-solid mixture whose friction interaction is denoted by the Coulomb law. The...
Article
This paper presents a criterion for detecting diffuse (homogeneous) instabilities in granular soils sheared under fully drained conditions. The criterion is based on bifurcation theory and applied to elasto-plasticity by allowing multiple incremental solutions in elasto-plastic soils, physically losing controllability of stress boundary conditions....
Article
Full-text available
IIn the normal practice of foundation engineering the bearing capacity of micropiles is calculated without taking into account that the construction processes may affect the problem geometry. This work quantifies the influence of both, construction processes and the inherent variability of soil properties in the bearing capacity of a selfbored and...
Article
Full-text available
This work presents a numerical study of the instability line that relies on balance laws of physics rather than phenomenology. The instability line defines the onset of static liquefaction for loose sandy materials in the p-q space of effective stresses under undrained loading conditions. The onset of static liquefaction is predicted by means of a...
Article
This paper presents a database of isoseismal maps and referenced/processed (isoseismal contour areas and equivalent radii) data for Colombia and neighboring regions based on earthquakes occurring between 1766 and 2004. The database is used to develop a model for the conditional exceedence probability of a level of seismic intensity, given distance...
Article
Full-text available
The daily practice of designing civil engineering projects focuses its efforts on quantifying the factor of safety to ascertain whether a structure is safe or not. However, the factor of safety in itself does not reflect the probability offailure of the designed structure. This practice is deeply rooted within the geotechnical engineering field. Th...
Article
En los análisis geomecánicos convencionales realizados con el Método de Elementos Finitos, las características de la banda de corte son dependientes, entre otros factores, de la orientación de los elementos. Para eludir la dependencia de los resultados con el enmallado se han empleado medios continuos no convencionales. Sin embargo no se encuentra...
Article
Full-text available
In conventional geomechanical analysis performed with the Finite Element Method, the orientation of the failure surface or shear band depends on the orientation of the elements. To avoid this undesirable dependence, the analysis in finite elements has been developed based on non conventional continuum media. However, there is not available geomecha...
Article
Full-text available
This document presents the analysis of seismic vulnerability and load capacity for Cesar Gaviria Trujilo Viaduct, by means of structural reliability techniques based on instrumentation works. Such study includes: geophysical trial tests, trials tests on material mechanical properties, environmental vibrations, measurements on the effects of traffic...
Conference Paper
Many authors have analyzed bifurcation with hypoplasticity, but they have not studied the influence of the hypoplastic parameters on strain localization analysis. The focus of this work is twofold: 1. To analyze the influence of the hypoplastic parameters, which control the strain-softening behavior, on the onset of bifurcation. 2. To study the inf...
Article
This document presents the analysis of seismic vulnerability and load capacity for Cesar Gaviria Trujilo Viaduct, by means of structural reliability techniques based on instrumentation works. Such study includes: geophysical trial tests, trials tests on material mechanical properties, environmental vibrations, measurements on the effects of traffic...
Article
Full-text available
In this document, seismic vulnerability and load carrying capacity analyses are presented for a bridge in Colombia after monitoring by means of reliability of structures. Results of this work are part of a new methodology to evaluate existing bridges carried out though a partnership among University – Private Companies – and Goverment. This study h...
Article
In this document, seismic vulnerability and load carrying capacity analyses are presented for a bridge in Colombia after monitoring by means of reliability of structures. Results of this work are part of a new methodology to evaluate existing bridges carried out though a partnership among University - Private Companies - and Goverment. This study h...
Article
This work summarises results of the evaluation of the physical earthquake vulnerability for the structural system of an essential building by using reliability methods. The research was based on the compilation of drawings and design memories, pathology studies, a structural surveying, and the assessment of the local earthquake hazard. In order to...
Article
Soil conditions modify the level of Hazard on Soil Surface and affect risk mitigation cost analysis. Traditional loss estimation methodologies like HAZUS allow for local site effects by using deterministic amplification factors ignoring the inherent uncertainty in dynamic soil properties. This paper attempts to highlight the variability of expected...
Technical Report
Full-text available
El territorio de la ciudad de Ibagué está ubicado en la zona andina donde los mayores rasgos morfotectónicos son las cordilleras Central y Oriental y el valle del río Magdalena, accidentes relacionados con posibles fenómenos distensivos en el Jurásico y compresivos en el Cenozoico, a los que se asocia el levantamiento de las cordilleras y la depres...
Technical Report
Full-text available
Debido a la ubicación geográfica de Neiva, esta zona ha sido afectada por los diferentes tipos de esfuerzos geotectónicos compresionales debido a la evolución del Valle Medio del Magdalena, como consecuencia de la interacción de las diferentes placas tectónicas, así la capital del departamento del Huila tiene latente la amenaza sísmica reflejada en...

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