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Martin Sáiz Rodrigo - One of the best experts on this subject based on the ideXlab platform.
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Diseño de anillos de compresión no circulares y distribución óptima de fuerzas en el plano
Universitat Politècnica de Catalunya, 2015Co-Authors: Martin Sáiz RodrigoAbstract:At the beginning of times, technique was used to reduce the physical stress of any work undertaken by the mankind; this was done without taking into consideration any saving of the resources used. Indeed, it was the other way around, as more energy was required to develop more ambitious projects. In addition to this, as the physical stress was not any more an issue, the amount of resources being mobilised was increased. From some time now, we have understood that the resources are not infinite, and that their consumption could cause irreversible damage to the system. For this reason, anything that can reduce the consumption of material and energy is now welcomed. In the construction industry, material resources become the final product: a building, a bridge, a dam, etc. To build means to extract, to transform and to assemble these materials on site. Energy is required to develop each one of these processes. Generally, this energy is directly related the amount of each specific material used. There are two exceptions to this rule: when the material is extracted and transformed in the same site (as it does not require transport). When the material is recycled from another site (as it implies less transformation or it does not require it at all). In addition to this, each material has different performance properties an requires different quantity of energy for its transformation. Therefore, if the aim is to save material, and therefore energy, the focus should be put on replacing the conventional construction techniques and technologies by those ones that allow building lighter Structures. The tensile Structures are the lighter structural solution currently available, with a design challenge: the internal loads balance. If this problem is properly taken into consideration and solved, then the efficiency, which is the relation between the structural performance (span and capacity) versus the resources used (material and energy), can be increased considerably. This is especially relevant on long-span roofs. By doing this, a good design can be achieved, and therefore, on the use of proper use of technology to save material and energy. On long-span and tensile roof systems it is better to provide the equilibrium of the inner loads by a self-balancing system based on rigid elements, rather than the use of external structural elements. The rigid element provides a closed loads path that converts the internally Statically Indeterminate Structure on an externally Statically determinate Structure. In the case of a spatial Structure, these elements are compression rings or polygons. The most efficient ones are those that under permanent loading conditions do not need to resist bending forces. This is because their geometry matches the funicular of the in-plane loads transferred by the cables or membranes, together with the fact that they are being restrained against buckling by the same tensile elements. Compression rings with circular shape under the reactions produced by membranes with uniform tension forces have to resist axial compression forces only. In addition to this, the membrane provides total bucking restraint (at least in-plane). On the other hand, in circular compression rings with isotensioned and equidistant spokes, the same forces diagrams and buckling conditions apply to the each of the ring sections. This research is focused on the design of non-circular compression rings and how to achieve an optimum distribution of in-plane loads, so that they can get closer, or even match, those design conditions that apply to circular compression rings. In order to do so, three general cases have been analysed: rings with uniform loads, rigid polygons and rings with punctual loads. For each case, a design method is defined, as well as the optimum or ideal distribution of the in-plane loadsAl principio la técnica servía para ahorrar esfuerzo físico en cualquier trabajo realizado por el hombre, pero no se ocupaba demasiado de ahorrar recursos, sino más bien lo contrario, cada vez consumía más porque cada vez requería más energía para desarrollar trabajos más ambiciosos. Además, como el esfuerzo físico ya no suponía un problema, la cantidad de recursos materiales movilizados fue aumentando. Pero hace tiempo que nos hemos dado cuenta de que los recursos no son inagotables y de que su consumo excesivo causa daños irreversibles. Así que, todo aquello que permita reducir el consumo de material y energía es bienvenido. En la construcción, los recursos materiales son los que configuran físicamente algo: un edificio, un puente, una presa, etc. El acto de construir implica extraer, transformar, transportar y colocar estos materiales en obra. Para cada uno de estos procesos se requiere energía. En general, esta energía es proporcional a la cantidad de un mismo material utilizado, pero hay al menos dos excepciones: si el material se extrae y se transforma en el mismo lugar de la obra, no requiere transporte; si el material es reaprovechado de otra obra, requiere una transformación menor o incluso nula. Además, cada material tiene unas prestaciones específicas y requiere una cantidad de energía distinta para su transformación. Entonces, si se trata de ahorrar material y consecuentemente energía, se necesita substituir las técnicas y las tecnologías de la construcción convencional por aquellas que permiten construir más ligero. Las estructuras tensadas son las construcciones menos pesadas que existen hoy en día, aunque presentan siempre el problema del equilibrio de sus fuerzas internas. Si este problema se resuelve bien, la eficiencia, es decir, la relación entre prestaciones (luz y capacidad de carga) y recursos consumidos (material y energía) resulta muy elevada, especialmente en cubiertas de grandes luces. Esto implica un buen diseño, es decir, una buena técnica para ahorrar. En estas cubiertas (tensadas y de grandes dimensiones) resulta más ventajoso absorber las fuerzas internas de manera autónoma, mediante elementos rígidos equilibrantes, que utilizando elementos o recursos de fuera de la estructura. Los elementos rígidos equilibrantes forman un circuito cerrado de fuerzas y convierten la estructura (internamente hiperestática) en externamente isostática. Si la estructura es espacial, estos elementos tienen forma de anillo o polígono rígido de compresión. Los más eficientes son los que, en situación de acciones permanentes, apenas tienen que soportar esfuerzos de flexión, porque su geometría coincide con la del funicular de las fuerzas en el plano transmitidas por los cables o membranas, y además tienen impedido el pandeo por el arriostramiento que le confieren los propios elementos tensados. Los anillos de compresión de planta circular sometidos a la acción de membranas tensadas uniformemente sólo tienen que soportar un esfuerzo axil de compresión y además, al menos en su propio plano, el pandeo está totalmente impedido por el efecto de arriostramiento de la propia membrana. Los que también son circulares y están sometidos a la acción de radios isotensos y equidistantes tienen los mismos diagramas de esfuerzos y condiciones de pandeo en todos los tramos entre radios. Esta investigación trata sobre el diseño de anillos de compresión no circulares y de la distribución óptima de fuerzas en el plano, de manera que se aproximen o incluso se igualen sus condiciones de dimensionado con respecto a las que tienen los anillos circulares. Se estudian tres casos generales: anillos con fuerza distribuida, polígonos rígidos y anillos con fuerzas puntuales. En cada caso se enuncia un método para el diseño y se formula la distribución óptima o ideal de fuerzas en el plano
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Diseño de anillos de compresión no circulares y distribución óptima de fuerzas en el plano
Universitat Politècnica de Catalunya, 2015Co-Authors: Martin Sáiz RodrigoAbstract:At the beginning of times, technique was used to reduce the physical stress of any work undertaken by the mankind; this was done without taking into consideration any saving of the resources used. Indeed, it was the other way around, as more energy was required to develop more ambitious projects. In addition to this, as the physical stress was not any more an issue, the amount of resources being mobilised was increased. From some time now, we have understood that the resources are not infinite, and that their consumption could cause irreversible damage to the system. For this reason, anything that can reduce the consumption of material and energy is now welcomed. In the construction industry, material resources become the final product: a building, a bridge, a dam, etc. To build means to extract, to transform and to assemble these materials on site. Energy is required to develop each one of these processes. Generally, this energy is directly related the amount of each specific material used. There are two exceptions to this rule: when the material is extracted and transformed in the same site (as it does not require transport). When the material is recycled from another site (as it implies less transformation or it does not require it at all). In addition to this, each material has different performance properties an requires different quantity of energy for its transformation. Therefore, if the aim is to save material, and therefore energy, the focus should be put on replacing the conventional construction techniques and technologies by those ones that allow building lighter Structures. The tensile Structures are the lighter structural solution currently available, with a design challenge: the internal loads balance. If this problem is properly taken into consideration and solved, then the efficiency, which is the relation between the structural performance (span and capacity) versus the resources used (material and energy), can be increased considerably. This is especially relevant on long-span roofs. By doing this, a good design can be achieved, and therefore, on the use of proper use of technology to save material and energy. On long-span and tensile roof systems it is better to provide the equilibrium of the inner loads by a self-balancing system based on rigid elements, rather than the use of external structural elements. The rigid element provides a closed loads path that converts the internally Statically Indeterminate Structure on an externally Statically determinate Structure. In the case of a spatial Structure, these elements are compression rings or polygons. The most efficient ones are those that under permanent loading conditions do not need to resist bending forces. This is because their geometry matches the funicular of the in-plane loads transferred by the cables or membranes, together with the fact that they are being restrained against buckling by the same tensile elements. Compression rings with circular shape under the reactions produced by membranes with uniform tension forces have to resist axial compression forces only. In addition to this, the membrane provides total bucking restraint (at least in-plane). On the other hand, in circular compression rings with isotensioned and equidistant spokes, the same forces diagrams and buckling conditions apply to the each of the ring sections. This research is focused on the design of non-circular compression rings and how to achieve an optimum distribution of in-plane loads, so that they can get closer, or even match, those design conditions that apply to circular compression rings. In order to do so, three general cases have been analysed: rings with uniform loads, rigid polygons and rings with punctual loads. For each case, a design method is defined, as well as the optimum or ideal distribution of the in-plane loadsAl principio la técnica servía para ahorrar esfuerzo físico en cualquier trabajo realizado por el hombre, pero no se ocupaba demasiado de ahorrar recursos, sino más bien lo contrario, cada vez consumía más porque cada vez requería más energía para desarrollar trabajos más ambiciosos. Además, como el esfuerzo físico ya no suponía un problema, la cantidad de recursos materiales movilizados fue aumentando. Pero hace tiempo que nos hemos dado cuenta de que los recursos no son inagotables y de que su consumo excesivo causa daños irreversibles. Así que, todo aquello que permita reducir el consumo de material y energía es bienvenido. En la construcción, los recursos materiales son los que configuran físicamente algo: un edificio, un puente, una presa, etc. El acto de construir implica extraer, transformar, transportar y colocar estos materiales en obra. Para cada uno de estos procesos se requiere energía. En general, esta energía es proporcional a la cantidad de un mismo material utilizado, pero hay al menos dos excepciones: si el material se extrae y se transforma en el mismo lugar de la obra, no requiere transporte; si el material es reaprovechado de otra obra, requiere una transformación menor o incluso nula. Además, cada material tiene unas prestaciones específicas y requiere una cantidad de energía distinta para su transformación. Entonces, si se trata de ahorrar material y consecuentemente energía, se necesita substituir las técnicas y las tecnologías de la construcción convencional por aquellas que permiten construir más ligero. Las estructuras tensadas son las construcciones menos pesadas que existen hoy en día, aunque presentan siempre el problema del equilibrio de sus fuerzas internas. Si este problema se resuelve bien, la eficiencia, es decir, la relación entre prestaciones (luz y capacidad de carga) y recursos consumidos (material y energía) resulta muy elevada, especialmente en cubiertas de grandes luces. Esto implica un buen diseño, es decir, una buena técnica para ahorrar. En estas cubiertas (tensadas y de grandes dimensiones) resulta más ventajoso absorber las fuerzas internas de manera autónoma, mediante elementos rígidos equilibrantes, que utilizando elementos o recursos de fuera de la estructura. Los elementos rígidos equilibrantes forman un circuito cerrado de fuerzas y convierten la estructura (internamente hiperestática) en externamente isostática. Si la estructura es espacial, estos elementos tienen forma de anillo o polígono rígido de compresión. Los más eficientes son los que, en situación de acciones permanentes, apenas tienen que soportar esfuerzos de flexión, porque su geometría coincide con la del funicular de las fuerzas en el plano transmitidas por los cables o membranas, y además tienen impedido el pandeo por el arriostramiento que le confieren los propios elementos tensados. Los anillos de compresión de planta circular sometidos a la acción de membranas tensadas uniformemente sólo tienen que soportar un esfuerzo axil de compresión y además, al menos en su propio plano, el pandeo está totalmente impedido por el efecto de arriostramiento de la propia membrana. Los que también son circulares y están sometidos a la acción de radios isotensos y equidistantes tienen los mismos diagramas de esfuerzos y condiciones de pandeo en todos los tramos entre radios. Esta investigación trata sobre el diseño de anillos de compresión no circulares y de la distribución óptima de fuerzas en el plano, de manera que se aproximen o incluso se igualen sus condiciones de dimensionado con respecto a las que tienen los anillos circulares. Se estudian tres casos generales: anillos con fuerza distribuida, polígonos rígidos y anillos con fuerzas puntuales. En cada caso se enuncia un método para el diseño y se formula la distribución óptima o ideal de fuerzas en el plano.Postprint (published version
Mancini Giuseppe - One of the best experts on this subject based on the ideXlab platform.
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Reinforced Concrete Frame Structures
The Author(s). Published by Elsevier Ltd., 2016Co-Authors: Bertagnoli Gabriele, Giordano Luca, La Mazza Dario, Mancini GiuseppeAbstract:AbstractAccording to Comitè Europèen de Normalisation, robustness is the ability of a Structure to withstand events like fire, explosions, impact or the consequences of human error, without being damaged to an extent disproportionate to the original cause. Avoiding the progressive collapse of a building in presence of accidental loading conditions is one of the challenges for the designers. The tie-force method is actually one of the most used design techniques for resisting progressive collapse, whereby a Statically Indeterminate Structure is designed with reference to local simplified models determined in accordance to the failure mode considered. In this work a computational study of a reinforced concrete frame is presented. The Structure studied is a beam-column assembly which represents a portion of the structural framing system of a ten-story reinforced concrete frame building and is subjected to distributed loads and to monotonically increasing vertical displacement of the centre column to simulate a column removal scenario
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Use of different numerical models to evaluate the robustness of reinforced concrete frame Structures
2016Co-Authors: Bertagnoli Gabriele, Giordano Luca, La Mazza Dario, Mancini GiuseppeAbstract:According to Comitè Europèen de Normalisation, robustness is the ability of a Structure to withstand events like fire, explosions, impact or the consequences of human error, without being damaged to an extent disproportionate to the original cause. Avoiding the progressive collapse of a building in presence of accidental loading conditions is one of the challenges for the designers. The tie-force method is actually one of the most used design techniques for resisting progressive collapse, whereby a Statically Indeterminate Structure is designed with reference to local simplified models determined in accordance to the failure mode considered. In this work a computational study of a reinforced concrete frame is presented. The Structure studied is a beam-column assembly which represents a portion of the structural framing system of a ten-story reinforced concrete frame building and is subjected to distributed loads and to monotonically increasing vertical displacement of the centre column to simulate a column removal scenari
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Robustness of reinforced concrete framed buildings: A comparison between different numerical models
'Trans Tech Publications Ltd.', 2016Co-Authors: Bertagnoli Gabriele, Giordano Luca, La Mazza Dario, Gino Diego, Mancini GiuseppeAbstract:According to Eurocode, robustness is the ability of a Structure to withstand events like fire, explosions, impact or the consequences of human error, without being damaged to an extent disproportionate to the original cause. Avoiding the progressive collapse of a building in presence of accidental loading conditions is one of the challenges for the designers. The tie-force method is actually one of the most used design techniques for resisting progressive collapse, whereby a Statically Indeterminate Structure is designed with reference to local simplified models determined in accordance to the failure mode considered. In this work a computational study of a reinforced concrete frame is presented. The beam-column assembly represents a portion of the structural framing system of a ten-story reinforced concrete frame building and is subjected to monotonically increasing vertical displacement of the center column to simulate a column removal scenario. Two different finite element models, with distinct levels of modeling, are used in order to compare the numerical results with the experimental ones coming from a full-scale test, and evaluate the ability of the models to simulate the structural behavior of the frame
Man Yuan - One of the best experts on this subject based on the ideXlab platform.
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analysis of stress increment of reinforcing frame beams by outside prestressed technology
Concrete, 2008Co-Authors: Man YuanAbstract:External prestressing is an important branch of post-tensioning system,which has widely adopted in bridge engineering and building Structure as well as Structure strengthening.Stress increment and second-order effect are the two critical factors in design of concrete beams with external prestressing.The study on concrete beams with external prestressing,domesticaly and overseas,mainly deal with simple-supported beams and rarely deal with Statically Indeterminate beams.So it is necessary to do an in-depth study on Statically Indeterminate concrete beam with external prestressing.The up-to-date state of stress increment of external tendon was given firstly and an relationship between the tendon stress increments and deflection of the concrete beams was found,by the analysis of experiments' data and the test result,drew some beneficial trial conclusions on stress increment of reinforcing frame beams by outside prestressed technology.The simplified calculate formula using in caculating Statically Indeterminate Structure is proposed,it will provide a certain help about design and reinforce with Statically Indeterminate Structures,also have extensive applied foreground in structural construction at port,dam,bridge etc.
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analysis of stress increment of reinforcing frame beams by outside prestressed technology
Concrete, 2008Co-Authors: Man YuanAbstract:External prestressing is an important branch of post-tensioning system,which has widely adopted in bridge engineering and building Structure as well as Structure strengthening.Stress increment and second-order effect are the two critical factors in design of concrete beams with external prestressing.The study on concrete beams with external prestressing,domesticaly and overseas,mainly deal with simple-supported beams and rarely deal with Statically Indeterminate beams.So it is necessary to do an in-depth study on Statically Indeterminate concrete beam with external prestressing.The up-to-date state of stress increment of external tendon was given firstly and an relationship between the tendon stress increments and deflection of the concrete beams was found,by the analysis of experiments' data and the test result,drew some beneficial trial conclusions on stress increment of reinforcing frame beams by outside prestressed technology.The simplified calculate formula using in caculating Statically Indeterminate Structure is proposed,it will provide a certain help about design and reinforce with Statically Indeterminate Structures,also have extensive applied foreground in structural construction at port,dam,bridge etc.
Bertagnoli Gabriele - One of the best experts on this subject based on the ideXlab platform.
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Reinforced Concrete Frame Structures
The Author(s). Published by Elsevier Ltd., 2016Co-Authors: Bertagnoli Gabriele, Giordano Luca, La Mazza Dario, Mancini GiuseppeAbstract:AbstractAccording to Comitè Europèen de Normalisation, robustness is the ability of a Structure to withstand events like fire, explosions, impact or the consequences of human error, without being damaged to an extent disproportionate to the original cause. Avoiding the progressive collapse of a building in presence of accidental loading conditions is one of the challenges for the designers. The tie-force method is actually one of the most used design techniques for resisting progressive collapse, whereby a Statically Indeterminate Structure is designed with reference to local simplified models determined in accordance to the failure mode considered. In this work a computational study of a reinforced concrete frame is presented. The Structure studied is a beam-column assembly which represents a portion of the structural framing system of a ten-story reinforced concrete frame building and is subjected to distributed loads and to monotonically increasing vertical displacement of the centre column to simulate a column removal scenario
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Use of different numerical models to evaluate the robustness of reinforced concrete frame Structures
2016Co-Authors: Bertagnoli Gabriele, Giordano Luca, La Mazza Dario, Mancini GiuseppeAbstract:According to Comitè Europèen de Normalisation, robustness is the ability of a Structure to withstand events like fire, explosions, impact or the consequences of human error, without being damaged to an extent disproportionate to the original cause. Avoiding the progressive collapse of a building in presence of accidental loading conditions is one of the challenges for the designers. The tie-force method is actually one of the most used design techniques for resisting progressive collapse, whereby a Statically Indeterminate Structure is designed with reference to local simplified models determined in accordance to the failure mode considered. In this work a computational study of a reinforced concrete frame is presented. The Structure studied is a beam-column assembly which represents a portion of the structural framing system of a ten-story reinforced concrete frame building and is subjected to distributed loads and to monotonically increasing vertical displacement of the centre column to simulate a column removal scenari
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Robustness of reinforced concrete framed buildings: A comparison between different numerical models
'Trans Tech Publications Ltd.', 2016Co-Authors: Bertagnoli Gabriele, Giordano Luca, La Mazza Dario, Gino Diego, Mancini GiuseppeAbstract:According to Eurocode, robustness is the ability of a Structure to withstand events like fire, explosions, impact or the consequences of human error, without being damaged to an extent disproportionate to the original cause. Avoiding the progressive collapse of a building in presence of accidental loading conditions is one of the challenges for the designers. The tie-force method is actually one of the most used design techniques for resisting progressive collapse, whereby a Statically Indeterminate Structure is designed with reference to local simplified models determined in accordance to the failure mode considered. In this work a computational study of a reinforced concrete frame is presented. The beam-column assembly represents a portion of the structural framing system of a ten-story reinforced concrete frame building and is subjected to monotonically increasing vertical displacement of the center column to simulate a column removal scenario. Two different finite element models, with distinct levels of modeling, are used in order to compare the numerical results with the experimental ones coming from a full-scale test, and evaluate the ability of the models to simulate the structural behavior of the frame
Lieping Ye - One of the best experts on this subject based on the ideXlab platform.
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an improved tie force method for progressive collapse resistance design of reinforced concrete frame Structures
Engineering Structures, 2011Co-Authors: Yi Li, Hong Guan, Xinzheng Lu, Lieping YeAbstract:Abstract Progressive collapse of Structures refers to local damage due to occasional and abnormal loads, which in turn leads to the development of a chain reaction mechanism and progressive and catastrophic failure. The tie force (TF) method is one of the major design techniques for resisting progressive collapse, whereby a Statically Indeterminate Structure is designed through a locally simplified determinate Structure by assumed failure mode. The method is also adopted by the BS8110-1:1997, Eurocode 1, and DoD 2005. Due to the overly simplified analytical model used in the current practical codes, it is necessary to further investigate the reliability of the code predictions. In this research, a numerical study on two reinforced concrete (RC) frame Structures demonstrates that the current TF method is inadequate in increasing the progressive collapse resistance. In view of this, the fundamental principles inherent in the current TF method are examined in some detail. It is found that the current method fails to consider such important factors as load redistribution in three dimensions, dynamic effect, and internal force correction. As such, an improved TF method is proposed in this study. The applicability and reliability of the proposed method is verified through numerical design examples.
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improved tie force method for progressive collapse resistance design of rc frame Structures
2011Co-Authors: Yi Li, Hong Guan, Xinzheng Lu, Lieping YeAbstract:Progressive collapse of Structures refers to a local damage due to occasional and abnormal loads which in turn leads to the development of a chain reaction mechanism and progressive and catastrophic failure. The tie force (TF) method is one of the major design techniques for resisting progressive collapse, whereby a Statically Indeterminate Structure is designed through a locally simplified determinate Structure by assumed failure mode. The method is also adopted by the BS8110-1:1997, Eurocode 1 and DoD 2005. Due to the overly simplified analytical model used in the current practical codes, it is necessary to further investigate the reliability of the code predictions. In this research, a numerical study on two reinforced concrete frame Structures demonstrates that the current TF method is inadequate in increasing the progressive collapse resistance. In view of this, the fundamental principles inherent in the current TF method are examined in some detail. It is found that the current method fails to consider such important factors as load redistribution in three dimensions, dynamic effect, and internal force correction. As such, an improved TF method is proposed in this study. The applicability and reliability of the proposed method is verified through the numerical design examples.
