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Imagen de apoyo de  Active Confinement of RC Columns with External Post-tensioned Clamps = Confinamiento Activo de Columnas de Concreto Reforzado con Abrazaderas Presforzadas

Active Confinement of RC Columns with External Post-tensioned Clamps = Confinamiento Activo de Columnas de Concreto Reforzado con Abrazaderas Presforzadas

Por: Julián David; Skillen Rincón Gil | Fecha: 2023

Abstract: There are too many reinforced concrete (RC) columns built before mid-1970s without sufficient transverse reinforcement. By now, we understand quite well the importance of transverse reinforcement in allowing a column to maintain its integrity under large displacement reversals in the nonlinear range of response. Poorly confined RC columns undergo a fast decay in resistance due to formation of criss-crossing inclined cracks, which can cause an abrupt failure or more gradual disintegration and trigger collapse of the structure. Those columns need to be strengthened to increase their drift capacity. Although there are several alternatives to retrofit RC columns, they often require specialized workmanship and equipment, and involved installation procedures. An easy-todesign and easyto-implement retrofit technique is examined here. It consists of external posttensioned clamps fastened around the column. Results of tests on full-scale RC columns furnished with the proposed clamps suggest the clamps can be effective in increasing column shear strength and drift capacity. Resumen: Muchas columnas de concreto reforzado construidas antes de mediados de la década de 1970 tienen insuficiente refuerzo transversal. Hace solo un par de décadas que se entendió la importancia del refuerzo transversal para permitir que una columna mantenga su integridad bajo grandes desplazamientos en el rango de respuesta no lineal. Las columnas de concreto reforzado mal confinadas sufren una rápida disminución de la resistencia debido a la formación de grietas, que pueden causar una falla abrupta o una desintegración más gradual y desencadenar el colapso de la estructura. Es necesario reforzar dichas columnas para aumentar su capacidad de deriva. Aunque existen varias alternativas para reforzar columnas de concreto reforzado, a menudo requieren mano de obra y equipo especializados, además de procedimientos de instalación complicados. Aquí se examina una técnica de reforzamiento fácil de diseñar e implementar. La técnica consta de abrazaderas presforzadas externas fijadas alrededor de la columna. Los resultados de laboratorio de las columnas de concreto reforzado a gran escala equipadas con las abrazaderas propuestas sugieren que las abrazaderas pueden ser efectivas para aumentar la resistencia al corte y la capacidad de deriva de la columna.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Active Confinement of RC Columns with External Post-tensioned Clamps = Confinamiento Activo de Columnas de Concreto Reforzado con Abrazaderas Presforzadas

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Imagen de apoyo de  Improving International Cooperation Projects: How to match real-world problems with solutions in Bangladesh/  Mejora de los proyectos de cooperación internacional: cómo hacer coincidir los problemas del mundo real con las soluciones en Bangladesh

Improving International Cooperation Projects: How to match real-world problems with solutions in Bangladesh/ Mejora de los proyectos de cooperación internacional: cómo hacer coincidir los problemas del mundo real con las soluciones en Bangladesh

Por: Juan David Patiño Guerra | Fecha: 2018

Tackling climate change effects worldwide brings the interest of many donor countries with expertise to (co)develop solutions into beneficiary countries through international cooperation. The solutions proposed can be either too solution-driven, understood as a donor country selling its knowledge / products, or on the other hand, too locally problem-driven, which is desirable in theory, but facing practical limitations such as time or scale constraints when closing to outside influences. A methodology that tries to join both (apparently opposing) sides, with their advantages and disadvantages of problem and solution driven hasn’t been explored yet.For exploring how this can be done, in this research 2 case studies are analyzed: the Bangladesh Delta Plan 2100 (BDP2100), a nation-wide long term holistic plan on the Bangladeshi Delta, and a group of Coastal Water Management initiatives, a set of continuous efforts to adopt livelihoods to the dynamic situation in the coastal regions of Bangladesh. These cases are analyzed through interviews and desk research to determine to what extent are they problem and solution driven compared to proposed frameworks and pointing how can they be improved. From these analyses, a combined framework is proposed where problem and solution driven approaches are joined taking the best from each perspective. The result is meant to be a first guiding tool for decision-makers in donor and beneficiary countries that face the dilemma between taking local and foreign elements for developing solutions. Resumen Hacer frente a los efectos del cambio climático en todo el mundo atrae el interés de muchos países donantes con experiencia para (co) desarrollar soluciones en los países beneficiarios, a través de la cooperación internacional. Las soluciones propuestas pueden ser demasiado orientadas a la solución, entendidas como un país donante que vende sus conocimientos / productos o, por otro lado, demasiado localmente orientadas a los problemas, lo que es deseable en teoría, pero enfrentan limitaciones prácticas como limitaciones de tiempo o escala cuando se cierran a influencias externas. Aún no se ha explorado una metodología que intente unir a ambas partes (aparentemente opuestas), con las ventajas y desventajas de soluciones basadas en desarrollo netamente de problemas y desarrollo netamente de soluciones. Para explorar cómo se puede combinar esto, en esta investigación se analizan 2 casos de estudio: el Bangladesh Delta Plan 2100 (BDP2100), un plan holístico a largo plazo a nivel nacional en el delta de Bangladesh, y un grupo de iniciativas de gestión costera del agua, un conjunto de esfuerzos continuos para adoptar medios de vida a la situación dinámica en las regiones costeras de Bangladesh. Estos casos se analizan a través de entrevistas e investigaciones teóricas para determinar en qué medida están orientados a los problemas y soluciones en comparación con los marcos propuestos, y señalan cómo pueden mejorarse. A partir de estos análisis, se propone un marco combinado donde se unen los enfoques impulsados por problemas y soluciones, tomando lo mejor de cada perspectiva. El resultado pretende ser una primera herramienta de guía para los tomadores de decisiones en los países donantes y beneficiarios que enfrentan el dilema entre tomar elementos locales y extranjeros para desarrollar soluciones.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
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Improving International Cooperation Projects: How to match real-world problems with solutions in Bangladesh/ Mejora de los proyectos de cooperación internacional: cómo hacer coincidir los problemas del mundo real con las soluciones en Bangladesh

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Imagen de apoyo de  Geothermal Conceptual and Numerical Modelling of a Gas-Condensate Field in the Eastern Llanos Basin, Colombia = Modelación geotérmica conceptual y numérica de un campo de gas condensado en la cuenca de los Llanos Orientales, Colombia

Geothermal Conceptual and Numerical Modelling of a Gas-Condensate Field in the Eastern Llanos Basin, Colombia = Modelación geotérmica conceptual y numérica de un campo de gas condensado en la cuenca de los Llanos Orientales, Colombia

Por: Andrés Felipe Laverde Martínez | Fecha: 2022

Abstract: This project presents three-dimensional conceptual and numerical flow models of a gascondensate field in the foothills region of the Eastern Llanos Basin in Colombia. The Eastern Llanos Basin has been the subject of diverse studies for hydrocarbon exploitation. Over the past decade, this region has been assessed for its geothermal potential in currently exploited oil & gas fields. A gas-condensate field located in the foothills of the basin represents a promising opportunity to produce geothermal energy. The conceptual and numerical models integrate geological, geophysical, geochemical and well data to enhance the understanding of the geothermal system in a sedimentary environment. The Leapfrog Geothermal model shows that the gas-condensate field presents a structurally complex architecture, where hydrocarbons and water accumulate in an relatively permeable reservoir. Well data exhibit a constant geothermal gradient, indicating conductive heat transfer. Based on geochemical data and hydrological analyses, it is identified that meteoric recharge occurs in the Andean orogenic belt and fluid flows from NW to SE. TOUGH2 numerical simulations are developed to generate a natural state model and geothermal production scenarios, which give an estimation of water extraction in the field. The thermal and hydraulic parameters were extracted from published experimental and well data. In order to simplify this first geotermal model, and reduce the number of parameters, it is assumed that the field is completely saturated with water. The natural state model temperature field is concordant with measured well data and simulated mass flow direction confirm expected patterns. Production scenarios demonstrate that it is possible to extract water at more than 90 °C without termal breakthrough during the 30 years simulation. Thermal power calculations yield two optimistic scenarios with more than 30 MWth of heat production, and a conservative scenario with approximately 6 MWth. The conservative scenario provides a better approach to reality with current water production. Thus, this project presents the basis for further studies on geothermal development in actively exploited hydrocarbon fields.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
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Geothermal Conceptual and Numerical Modelling of a Gas-Condensate Field in the Eastern Llanos Basin, Colombia = Modelación geotérmica conceptual y numérica de un campo de gas condensado en la cuenca de los Llanos Orientales, Colombia

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Imagen de apoyo de  Optimization of the design and scheduling of a biomethane plant integrated with a reversible Solid Oxide Cell and a PV solar field

Optimization of the design and scheduling of a biomethane plant integrated with a reversible Solid Oxide Cell and a PV solar field

Por: Fabrizio Llinás Biava | Fecha: 2020

Abstract: This thesis addresses the numerical optimization of the design and scheduling of a biomethane plant integrated with a reversible solid oxide cell, amongst other technologies, that allow the processing of biogas coming from OFMSW anaerobic digestion as to maximize profitability on a yearly basis under different circumstances. The optimization model is carried out through a mixed integer linear program as to obtain the adequate sizes of the different technologies that compose the integrated energy plant whilst taking advantage of the energy and material stream interactions to reach optimal financial feasibility. The inclusion of a reversible oxide fuel cell allows the system to work in different modes as in Power-to-gas and Gas-to-power, generating interest on to the different services that the system can provide to the gas and electricity grids and most importantly to a future decarbonized energy scenario. Furthermore, inclusion of linear models for an amine scrubbing section for biomethane upgrading, a photovoltaic solar field, gas and heat storage units, a battery energy storage system and a biogas boiler into the MILP is carried out as they are part of the technologies in study for the integrated energy plant. The seasonal variability for gas and electricity prices, part load performances, size effects, weather related data, and technological modelling of components are all part of the challenges to be tackled as to obtain a MILP able to compute accurate, adequate and optimal solutions for the design and scheduling problem whilst subjected to technological, environmental and operational constraints. Resumen: Esta tesis se centra en la optimización numérica del diseño y operación de una planta de biometano integrada con una celda de hidrogeno reversible, entre otras tecnologías, que permiten el procesamiento de biogás proveniente de la digestión anaeróbica de material orgánico con el objetivo de maximizar las ganancias en temporalidad anual ante diferentes circunstancias. El modelo de optimización se lleva a cabo con un algoritmo de programación lineal de entornos mixtos para obtener los tamaños de diseño adecuados de las diferentes tecnologías que componen a la planta integrada de energía mientras se toma ventaja de las interacciones entre cada flujo de energía y/o materia para obtener la mas óptima viabilidad económica. La inclusión de una celda reversible de hidrógeno permite al sistema trabajar en diferentes modos como electricidad a gas o gas a electricidad, generando interés en los distintos servicios que el sistema puede proveer a las redes de gas y electricidad y aun más importante a un futuro escenario mundial de energético descarbonizado. Mas aún, la inclusión de modelos lineales como un sistema de mejora de la calidad del biometano mediante absorción con aminas, un campo de energía solar fotovoltaica, unidades de almacenamiento de gas y calor, un sistema de almacenamiento de energías mediante baterías y una caldera de biogás en el modelo de programación lineal es llevado a cabo pues son parte de las tecnologías en estudio para la planta energética integrada. La variación estacional por los precios de gas y electricidad, desempeño a cargas parciales, efectos de tamaños, data ambiental, y el modelado tecnológico de los componentes son parte de los retos a ser resueltos para poder obtener un MILP capaz de computar precisas, adecuadas y optimas soluciones para el problema de diseño y operación mientras se encuentra sujeto a restricciones tecnológicas, ambientales y operacionales.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
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Optimization of the design and scheduling of a biomethane plant integrated with a reversible Solid Oxide Cell and a PV solar field

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Imagen de apoyo de  Playing With Uncertainty: Facilitating Community-Based Resilience Building = Jugando con la incertidumbre: Facilitación de la construcción de resiliencia basada en la comunidad

Playing With Uncertainty: Facilitating Community-Based Resilience Building = Jugando con la incertidumbre: Facilitación de la construcción de resiliencia basada en la comunidad

Por: Bryann E.; Lukosch Avendano Uribe | Fecha: 2022

Abstract: Resilience has become a fundamental paradigm for communities to deal with disaster planning. Formal methods are used to prioritise and decide about investments for resilience. Strategies and behaviour need to be developed that cannot be based on formal modelling only because the human element needs to be incorporated to build community resilience. Participatory modelling and gaming are methodological approaches that are based on realistic data and address human behaviour. These approaches enable stakeholders to develop, adjust, and learn from interactive models and use this experience to inform their decision?making. In our contribution, we explore which physical and digital elements from serious games can be used to design a participatory approach in community engagement and decision?making. Our ongoing research aims to bring multiple stakeholders together to understand, model, and decide on the trade?offs and tensions between social and infrastructure investments toward community resilience building. Initial observations allow us as researchers to systematically document the benefits and pitfalls of a gamebased approach. We will continue to develop a participatory modelling exercise for resilience planning with university graduate students and resilience experts within academia in Christchurch, New Zealand. Resumen: La resiliencia se ha convertido en un paradigma fundamental para que las comunidades afronten la planificación de las catástrofes. Se utilizan métodos formales para priorizar y decidir sobre las inversiones en resiliencia. Es necesario desarrollar estrategias y comportamientos que no pueden que no pueden basarse únicamente en modelos formales, ya que es necesario incorporar el elemento humano para aumentar la resiliencia de la comunidad. La modelización participativa y los juegos son enfoques metodológicos que se basan en datos realistas y abordan el comportamiento humano. Estos enfoques permiten que las partes interesadas desarrollen, ajusten y aprendan de los modelos interactivos y utilicen esta experiencia para informar su toma de decisiones. En nuestra contribución, exploramos qué elementos físicos y digitales de los juegos seriados pueden utilizarse para diseñar un enfoque participativo en el compromiso y la toma de decisiones de la comunidad. Nuestra investigación en curso pretende reunir a múltiples partes interesadas para comprender, modelar y decidir sobre las compensaciones y tensiones entre las inversiones sociales y las de infraestructura para el desarrollo de la resiliencia de la comunidad. Las observaciones iniciales nos permiten, como documentar sistemáticamente las ventajas y los inconvenientes de un enfoque basado en el juego. Seguiremos desarrollando un ejercicio de modelización participativa para la planificación de la resiliencia con estudiantes universitarios y expertos en resiliencia dentro de universitarios y expertos en resiliencia de Christchurch (Nueva Zelanda).
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Playing With Uncertainty: Facilitating Community-Based Resilience Building = Jugando con la incertidumbre: Facilitación de la construcción de resiliencia basada en la comunidad

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Imagen de apoyo de  Evaluation of sampling frequency impact on the accuracy of water quality status as determined considering different water quality monitoring objectives

Evaluation of sampling frequency impact on the accuracy of water quality status as determined considering different water quality monitoring objectives

Por: Camilo; Gitau Torres Pardo | Fecha: 2022

Abstract: Water quality sampling is a key element in tracking water quality monitoring objectives. However, frequencies adapted by different agencies might not be sufficient to provide an accurate indication of water quality status. In this study, data from low- and high-resolution water quality datasets were analyzed to determine the extent to which monitoring objectives could be achieved with different sampling frequencies, with a view to providing recommendations and best practices for water quality monitoring frequency in places with limited resources with which to implement a high-frequency monitoring plan. Water quality data from two watersheds (Maumee River and Raisin River) located in the Western Lake Erie Basin (WLEB) were used since these watersheds have consistent records over substantial periods of time, and the water quality data available have a high resolution (at least daily). The water quality constituents analyzed included suspended solids (SS), total phosphorus (TP), soluble reactive phosphorus (SRP), and nitrate + nitrite (NO2+3). Sources of pollutants for watersheds located in the WLEB include contributions from point sources like discharges from sewage treatment plants and non-point sources such as agricultural and urban storm runoff. Weekly, bi-weekly, monthly, and seasonal datasets were created from the original datasets, following different sampling rules based on the day of the week, week of the month, and month of the year. The resulting datasets were then compared to the original dataset to determine how the sampling frequency would affect the results obtained in a water quality assessment when different monitoring objectives are considered. Results indicated that constituents easily transported by water (such as sediments and nutrients) require more than 50 samples/year to provide a small error (< 10%) with a confidence interval of 95%. Monthly and seasonal sampling were found appropriate to report a stream’s prevailing water quality status and statistical properties. However, these resolutions might not be sufficient to capture longterm trends, in which case bi-weekly samples would be preferable. Limitations of lowresolution sampling frequency could be overcome by including rainfall events and random sampling during specific time windows as part of the monitoring plan.
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Evaluation of sampling frequency impact on the accuracy of water quality status as determined considering different water quality monitoring objectives

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Imagen de apoyo de  Evaluation of sampling frequency impact on the accuracy of water quality status as determined considering different water quality monitoring objectives

Evaluation of sampling frequency impact on the accuracy of water quality status as determined considering different water quality monitoring objectives

Por: Camilo; Gitau Torres Pardo | Fecha: 2022

Abstract: Water quality sampling is a key element in tracking water quality monitoring objectives. However, frequencies adapted by different agencies might not be sufficient to provide an accurate indication of water quality status. In this study, data from low- and high-resolution water quality datasets were analyzed to determine the extent to which monitoring objectives could be achieved with different sampling frequencies, with a view to providing recommendations and best practices for water quality monitoring frequency in places with limited resources with which to implement a high-frequency monitoring plan. Water quality data from two watersheds (Maumee River and Raisin River) located in the Western Lake Erie Basin (WLEB) were used since these watersheds have consistent records over substantial periods of time, and the water quality data available have a high resolution (at least daily). The water quality constituents analyzed included suspended solids (SS), total phosphorus (TP), soluble reactive phosphorus (SRP), and nitrate + nitrite (NO2+3). Sources of pollutants for watersheds located in the WLEB include contributions from point sources like discharges from sewage treatment plants and non-point sources such as agricultural and urban storm runoff. Weekly, bi-weekly, monthly, and seasonal datasets were created from the original datasets, following different sampling rules based on the day of the week, week of the month, and month of the year. The resulting datasets were then compared to the original dataset to determine how the sampling frequency would affect the results obtained in a water quality assessment when different monitoring objectives are considered. Results indicated that constituents easily transported by water (such as sediments and nutrients) require more than 50 samples/year to provide a small error (< 10%) with a confidence interval of 95%. Monthly and seasonal sampling were found appropriate to report a stream’s prevailing water quality status and statistical properties. However, these resolutions might not be sufficient to capture longterm trends, in which case bi-weekly samples would be preferable. Limitations of lowresolution sampling frequency could be overcome by including rainfall events and random sampling during specific time windows as part of the monitoring plan.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Evaluation of sampling frequency impact on the accuracy of water quality status as determined considering different water quality monitoring objectives

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Imagen de apoyo de  Bio-inspired Topologies to Enhance the Mechanical Strength of Co-cured Ti-CFRP Hybrid Joints

Bio-inspired Topologies to Enhance the Mechanical Strength of Co-cured Ti-CFRP Hybrid Joints

Por: Breyner Andrés Castro Castillo | Fecha: 2022

Abstract: The main aim of this study is to investigate utilising root improve the interfacial strength of pin-like integrated hybrid composite architectures to metal structures. Joints are critical elements in aircraft structures and require special consideration due to their vital role in the structural integrity of airframes. Although bonded and bolted systems are used commonly in engineering applications, pinning technologies have shown tremendous potential for hybrid joints. Nonetheless, exploring complex pin geometries has been challenging when considering associated manufacturing techniques. Using pre-preg constrains the topography of the pin, while vacuum resin infusion offers more possibilities to manufacture complex hybrid joints. This study develops an experimental methodology to fabricate hybrid joints with arbitrary pin geometry using Selective Laser Melting (SLM) and resin infusion techniques. First, titanium parts with four inclination angles of 0°, 20°, 45° and 80° were fabricated using the SLM method, and their surface roughness was examined using a profilometer. Then, dry unidirectional carbon fabrics were stacked into pins in a hand layup process followed by epoxy infusion in a vacuum chamber. The cross-section of the fabricated joints was inspected employing an optical microscope, SEM and ?CT-scanner. The pin angle shape of the resin and fibre alignment impacted the geometry and rich area in the insertion region. Manufacturing defects such as pores were present in the composite with a high density closer to the titanium composite bondline. Despite those setbacks, resin-infused composites were integrated into highly tilted pins such as 45° or 80°. This precedent demonstrated that root like pins could also be co-cured with composites. The effect of pin angle on the mechanical performance of hybrid joints was experiment ally investigated. The load-displacement response of various specimens was recorded while joints were subjected to pull-off tensile loading. Experimental results showed how the pin angle affects the stiffness, strength and strain energy of joints. Damage initiation and propagation in the hybrid joints were also investigated by examining the fracture surfaces and the relationship between damage mechanisms and pin angles. Significant matrix crushing was realised in joints with 45° and 80° inclined pins with p in rupture only observed in the latter. Furthermore, a numerical study was conducted to explore the response of multiple root-like pin geometries. A 2D model was developed and validated for parametric study based on the experimentally measured interfacial strength. This bidimensional model accurately captured the experimental load-displacement curves for joints under tensile load. After calibration, the model was used to study the effect of three branches geometrical features of a rootlike pin on the mechanical behaviour of the hybrid joint. It was demonstrated that the diameter, length and location of side branches play a vital role in the failure behaviour of joints by affecting the stress distribution in composite adherend. Based on the findings from this study, it can be concluded that the integration of complex pin shapes and composite are likely using resin infusion techniques. Moreover, root like pins with optimised topology can be incorporated into hybrid joints to enhance bonding strength and failure behaviour.
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Bio-inspired Topologies to Enhance the Mechanical Strength of Co-cured Ti-CFRP Hybrid Joints

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Imagen de apoyo de  Determinación de la huella hídrica y modelación de la producción de biomasa de cultivos forrajeros a partir del agua en la sabana de Bogotá (Colombia)

Determinación de la huella hídrica y modelación de la producción de biomasa de cultivos forrajeros a partir del agua en la sabana de Bogotá (Colombia)

Por: César Augusto Terán Chaves | Fecha: 2015

Abstract: Summary The main objective was aimed at determining the biomass production from water based on water relations, levels of water consumption of the species, and climate variables that affect the formation of biomass and soil present and specifically it focused on two forage crops which were Forage Oats (Avena sativa L.) and ryegrass (Lolium perenne). The solution to the problem is based on AquaCrop model (FAO) Steduto et al, (2009) which was recently proposed for the determination of both biomass and agricultural production from water transpired by herbaceous species, this is gather scientific and technological advances on the effect of water in the estimation of crop production has been achieved in recent years. In the present research we have identified key variables AquaCrop model input for the two species mentioned, through field research conducted using the methodology gradient Hanks et al., (1980), and a new methodology proposal for determining water stress. A total of 18 major experiments were developed to generate the levels of biomass production of forage oats and ryegrass, determining 32 variables or parameters for each crop that requires the model to estimate the biomass produced by the forage and pasture. Furthermore, the engine for determining crop production handling model is the concept of crop water productivity (WP) which is a conservative parameter resulting in greater strength, besides water productivity is normalized in two ways: (1) the climate are represented by the reference evapotranspiration (ET0) and (2) the content of CO2 in the atmosphere. These normalization allow abstract both climate and CO2 content over time, whereby, the engine model turns out to be an essential tool to estimate both the biomass and production, even considering the effects of global climate change. The experiments were conducted mainly during the years 2008-2013 in “Centro de Investigación Tibaitatá (AGROSAVIA)” located in the savannah of Bogota (Colombia). For forage oats were developed five cycles and ryegrass crops three complete cycles, with seven, four and two cuts were made respectively. Based on the information provided in the field, forage oats and ryegrass crops were calibrated and validated for AquaCrop model reaching adjustments R2=0.92, RMSE=1,86t.ha-1, NRMSE=17.67%, EF=0.91, d=0.97 for forage oat and R2=0.97, RMSE=0,47t.ha-1, NRMSE=13.6%, EF=0.88, d=0.98 for ryegrass. Two synthetic crops were determined one for each specie, which are "prototypes" for estimating biomass by the water use in different conditions of crops. The total biomass was determined to forage oats at 22.2 t.ha-1 on average with peaks that can reach up to 27 t.ha-1 in the production environment of the savannah of Bogota. For ryegrass total biomass reached levels of up to 9 t.ha-1 on average with peaks that can reach up to 9,9 t.ha-1 for the period from planting to first cut, and 6 t.ha-1 for others cuts. The intrinsic water footprint for fodder oats was determined in 175 L.kg-1 and 442 ryegrass L.kg-1 and 431 L.Kg-1. This research is novel because implemented scientific and technological advances of AquaCrop in forage crops, for the determination of the biomass by the water, because until this had not been calibrated and validated for the model, special biophysical considerations forage crops driving differently elements like crop production and harvest index. In addition to the large expanses of areas that exist today in the world of forages and pastures, which can be incorporated into local, regional or global studies biomass production, efficient water use, water consumption and determination of requirements, carbon sequestration, and determining the effects of changes in the coverage of pasture and forage in the global climate change. Resumen: El objetivo principal estuvo orientado a la determinación de la producción de biomasa a partir del agua con base en las relaciones hídricas, los niveles de consumo de agua de las especies, y las variables del clima que inciden en la formación de biomasa y el suelo presentes y se centró específicamente en dos cultivos forrajeros: Avena Forrajera (Avena sativa, L.) y Raigrás (Lolium perenne). La solución al problema se basa en el modelo AquaCrop (FAO) Steduto et al, (2009) el cual fue propuesto para la determinación tanto de la biomasa como del rendimiento a partir del agua transpirada por las especies herbáceas, en este se reúnen los avances científicos y tecnológicos que sobre el efecto del agua en la estimación de la producción de cultivos se ha logrado en los últimos años. En el presente trabajo de investigación se han parametrizado las variables de entrada al modelo AquaCrop, para las dos especies mencionadas, por medio de investigación de campo realizada con la metodología del gradiente de Hanks et al, (1980), y con una nueva metodología propuesta para la determinación del estrés hídrico. Se desarrollaron un total de 18 experimentos principales generando los niveles de producción de biomasa de avena forrajera y raigrás, determinando 32 parámetros para cada uno de los cultivos que requiere el modelo para la estimación de la biomasa producida por las especies forrajeras y pastos. El modelo AquaCrop implementa varios avances sobre el conocimiento del desarrollo de cultivos, como la separación de la evapotranspiración en evaporación del suelo y la transpiración del cultivo, la consideración independiente de la producción del cultivo en biomasa y el índice de cosecha. Para la determinación del desarrollo del cultivo se maneja el porcentaje de cobertura del dosel en vez del índice de área foliar (IAF). Además, el motor para la determinación de la producción del cultivo que maneja el modelo es el concepto de la productividad hídrica del cultivo (WP) la cual es un parámetro conservativo que redunda en mayor robustez, la productividad hídrica además se normaliza bajo dos aspectos que son el clima representado por la evapotranspiración de referencia (ET0) y el contenido del CO2 en la atmósfera. Con base en la información establecida en campo se calibraron y validaron los cultivos de avena forrajera y raigrás para el modelo AquaCrop alcanzando ajustes de R2=0,92, RMSE=1,86t.ha-1, NRMSE=17,67%, EF=0,91, y d=0,97 para avena forrajera y de R2=0,97, RMSE=0,47t.ha-1, NRMSE=13,6%, EF=0,88, y d=0,98 para raigrás. Se determinaron dos cultivos sintéticos uno para cada especie, los cuales constituyen los “prototipos” que son el punto de partida para la estimación de la biomasa a partir del uso del agua en diferentes condiciones de los cultivos mencionados. La biomasa total para avena forrajera fue determinada en 22,2t.ha-1 en promedio con valores máximos que pueden llegar a alcanzar hasta 27t.ha-1 en el entorno productivo de la sabana de Bogotá. Para raigrás la biomasa total alcanzó niveles de hasta 9t.ha-1, para el período de siembra a primer corte, y de 6t.ha-1 para los cortes posteriores al primero. La huella hídrica intrínseca para avena forrajera fue determinada en 175L.kg-1 y para raigrás en 442L.kg-1 y 431L.Kg-1. El presente trabajo es novedoso por la implementación de los avances científicos y tecnológicos de AquaCrop en cultivos forrajeros, para la determinación de la biomasa a partir del agua, pues hasta la presente no habían sido calibrados y validados para el modelo, las consideraciones biofísicas especiales de los cultivos forrajeros que manejan de forma diferente elementos como la producción de cosecha y el índice de cosecha. Además por las grandes extensiones de áreas que existen hoy en el mundo de cultivos forrajeros y pastos, las cuales pueden ser incorporadas en estudios locales, regionales o globales de producción de biomasa, eficiencia en el uso del agua, consumos y determinación de requerimientos hídricos, captura de carbono, y determinación de los efectos de las variaciones de las coberturas de pastos y forrajes en el cambio climático global.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
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Determinación de la huella hídrica y modelación de la producción de biomasa de cultivos forrajeros a partir del agua en la sabana de Bogotá (Colombia)

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Imagen de apoyo de  In-Plane Fragility and Parametric Analyses of Masonry Arch Bridges Exposed to Flood Hazard Using Surrogate Modeling Techniques

In-Plane Fragility and Parametric Analyses of Masonry Arch Bridges Exposed to Flood Hazard Using Surrogate Modeling Techniques

Por: Carlos Andrés; Santamaría Mendoza Cabanzo | Fecha: 2022

Abstract: Natural disasters are unavoidable and can cause serious damage to bridges, which maylead to catastrophic losses, both human and economic. Therefore, the assessment of bridges exposedto these events is of paramount importance to identify possible mitigation needs. The objective ofthe present work is to present consistent tools that may allow us to obtain the failure probability of amasonry arch bridge under a flood event, leading to local scour. Surrogate models were implementedto ease the computational cost of the probabilistic analysis. Moreover, a stochastic parametric analysisbased on the geotechnical properties of the soil components of masonry arch bridges located inPortugal was performed. The results show the failure mechanism of the masonry arch bridges whensubjected to scour-induced settlements and the influence of soil density on the failure probabilityobtained for different flow discharge values and angles of attack. The presented methodology andderived fragility curves can be used to assess bridge performance under a flood event, thus providinguseful information for bridge management and monitoring. Resumen: Los desastres naturales son inevitables y pueden causar graves daños a los puentes, lo que puede provocar pérdidas catastróficas, tanto humanas como económicas. Por lo tanto, la evaluación de los puentes expuestos a estos eventos es de suma importancia para identificar las posibles necesidades de mitigación. El objetivo del presente trabajo es presentar herramientas consistentes que nos permitan obtener la probabilidad de falla de un puente de arco de mampostería bajo un evento de inundación, conduciendo a una socavación local. Se implementaron metamodelos para reducir el costo computacional del análisis probabilístico. Además, se realizó un análisis paramétrico estocástico basado en las propiedades geotécnicas de los componentes del suelo de los puentes de arco de mampostería ubicados en Portugal. Los resultados muestran el mecanismo de falla de los puentes de arco de mampostería cuando se someten a asentamientos inducidos por socavación y la influencia de la densidad del suelo en la probabilidad de falla obtenida para diferentes valores de caudal y ángulos de ataque. La metodología presentada y las curvas de fragilidad derivadas se pueden usar para evaluar el desempeño del puente bajo un evento de inundación, proporcionando así información útil para la gestión y el monitoreo del puente.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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In-Plane Fragility and Parametric Analyses of Masonry Arch Bridges Exposed to Flood Hazard Using Surrogate Modeling Techniques

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