http://hdl.handle.net/2117/5347 Wed, 19 Jun 2013 21:51:20 GMT 2013-06-19T21:51:20Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/19085 Title: A 3D temporal evolutionary numerical model of a masonry building in Barcelona subjected to tunnelling subsidence Authors: Camos Andreu, Carles; Molins i Borrell, Climent Abstract: The aim of this work is to deepen the knowledge of the numerical simulation used in the prediction of building dam age produced by tunnel ling subsidence. This paper analyzes the structural response of a one-storey building subjected to real ground movements experienced during the construction of the L9 Metro line tunnel in Barcelona, bored by a Earth Pressure Balance Machine (EPB) Tunnel Boring Machine (TBM). A 3D temporal evolutionary numerical model is used to predict the damage in the building resulting from tunnelling subsidence. The real structural damage presented is compared with the predictions of the numerical model. This last task can be done since the measures of real ground movements given by the monitoring instruments, such as retro -reflective prisms and total stations, are available for this research. Main model parameters have been determined by means of characterization experiments developed on the site and in the laboratory, thus giving a higher significance to the analysis. Thu, 02 May 2013 16:10:06 GMT http://hdl.handle.net/2117/19085 2013-05-02T16:10:06Z Camos Andreu, Carles; Molins i Borrell, Climent no Settlements, structural damage, sensitivity, tunnelling, numerical model, 3D analysis The aim of this work is to deepen the knowledge of the numerical simulation used in the prediction of building dam age produced by tunnel ling subsidence. This paper analyzes the structural response of a one-storey building subjected to real ground movements experienced during the construction of the L9 Metro line tunnel in Barcelona, bored by a Earth Pressure Balance Machine (EPB) Tunnel Boring Machine (TBM). A 3D temporal evolutionary numerical model is used to predict the damage in the building resulting from tunnelling subsidence. The real structural damage presented is compared with the predictions of the numerical model. This last task can be done since the measures of real ground movements given by the monitoring instruments, such as retro -reflective prisms and total stations, are available for this research. Main model parameters have been determined by means of characterization experiments developed on the site and in the laboratory, thus giving a higher significance to the analysis. http://hdl.handle.net/2117/18970 Title: Ensayo de doble punzonamiento (ensayo Barcelona) para caracterizar el comportamiento del hormigón reforzado con fibra Authors: Aire, Carlos; Aguado de Cea, Antonio; Molins i Borrell, Climent Abstract: Tradicionalmente, para caracterizar el comportamiento del hormigón reforzado con fibra se realizan ensayos de flexotracción en vigas. Sin embargo, existen otros procedimientos que debido a la complejidad y variabilidad de sus resultados no son considerados como procedimientos sistemáticos de control. Recientemente, se desarrolló un nuevo método llamado ensayo Barcelona, como una alternativa para determinar la resistencia a tracción indirecta del hormigón reforzado con fibra. Es un ensayo de fácil ejecución mediante el cual un cilindro de 150 mm de diámetro y 150 mm de altura, se someten a ensayo de doble punzonamiento. El método permite obtener la resistencia a tracción del hormigón confinado con fibra con coeficientes de variación menor a los obtenidos por otros métodos. Este artículo presenta un estudio comparativo entre los resultados de resistencia y tenacidad aplicando el ensayo Barcelona y el de Flexotracción. Tue, 23 Apr 2013 18:30:03 GMT http://hdl.handle.net/2117/18970 2013-04-23T18:30:03Z Aire, Carlos; Aguado de Cea, Antonio; Molins i Borrell, Climent no Concreto reforzado con fibra, ensayo de doble punzonamiento, tenacidad, ensayo Barcelona Tradicionalmente, para caracterizar el comportamiento del hormigón reforzado con fibra se realizan ensayos de flexotracción en vigas. Sin embargo, existen otros procedimientos que debido a la complejidad y variabilidad de sus resultados no son considerados como procedimientos sistemáticos de control. Recientemente, se desarrolló un nuevo método llamado ensayo Barcelona, como una alternativa para determinar la resistencia a tracción indirecta del hormigón reforzado con fibra. Es un ensayo de fácil ejecución mediante el cual un cilindro de 150 mm de diámetro y 150 mm de altura, se someten a ensayo de doble punzonamiento. El método permite obtener la resistencia a tracción del hormigón confinado con fibra con coeficientes de variación menor a los obtenidos por otros métodos. Este artículo presenta un estudio comparativo entre los resultados de resistencia y tenacidad aplicando el ensayo Barcelona y el de Flexotracción. http://hdl.handle.net/2117/18750 Title: Análisis numérico de la influencia de la fisuración en el comportamiento de una presa de hormigón Authors: Campos, A.; López Garello, Carlos María; Aguado de Cea, Antonio Abstract: This paper introduces a 2D simulation of a cross section of the block 13-14 of Mequinenza Dam, which presents pronounced and uncommon remaining displacements. Joint elements have been included in to the model with a nonlinear constitutive law in order to represent the cracking of concrete. Potential cracking planes defined according with the crack pattern observed in the upstream face were incorporated. The numerical results show how the formation, evolution and opening of a series of horizontal cracks provide much of the observed displacements, thus helping to explain the uncommon behavior detected in the dam. In this study, the influence of fracture parameters such as tensile strength and fracture energy of the joints was considered. En este artículo se presenta una simulación 2D de una sección transversal del bloque 13-14 de la presa de Mequinenza que presenta unos movimientos remanentes acentuados en este bloque. Se ha incluido elementos junta con un comportamiento constitutivo no lineal para representar la fisuración. Se han incorporado en el modelo planos potenciales de fisuración, coincidiendo con algunas juntas de construcción, para lo cual se ha tenido en cuenta un levantamiento detallado de fisuras realizado en paramento aguas arriba de la presa. Los resultados numéricos obtenidos muestran cómo la formación, evolución y apertura de una serie de fisuras horizontales aportan gran parte de los desplazamientos observados en la estructura y permiten explicar de forma consistente el comportamiento diferenciado detectado en la presa. Los trabajos han incluido diversos análisis sobre la influencia de parámetros de fractura, como la resistencia a tracción y la energía de fractura de las juntas. Tue, 09 Apr 2013 18:37:57 GMT http://hdl.handle.net/2117/18750 2013-04-09T18:37:57Z Campos, A.; López Garello, Carlos María; Aguado de Cea, Antonio no Fisuración, Análisis numérico con elementos junta, Presas de hormigón This paper introduces a 2D simulation of a cross section of the block 13-14 of Mequinenza Dam, which presents pronounced and uncommon remaining displacements. Joint elements have been included in to the model with a nonlinear constitutive law in order to represent the cracking of concrete. Potential cracking planes defined according with the crack pattern observed in the upstream face were incorporated. The numerical results show how the formation, evolution and opening of a series of horizontal cracks provide much of the observed displacements, thus helping to explain the uncommon behavior detected in the dam. In this study, the influence of fracture parameters such as tensile strength and fracture energy of the joints was considered. En este artículo se presenta una simulación 2D de una sección transversal del bloque 13-14 de la presa de Mequinenza que presenta unos movimientos remanentes acentuados en este bloque. Se ha incluido elementos junta con un comportamiento constitutivo no lineal para representar la fisuración. Se han incorporado en el modelo planos potenciales de fisuración, coincidiendo con algunas juntas de construcción, para lo cual se ha tenido en cuenta un levantamiento detallado de fisuras realizado en paramento aguas arriba de la presa. Los resultados numéricos obtenidos muestran cómo la formación, evolución y apertura de una serie de fisuras horizontales aportan gran parte de los desplazamientos observados en la estructura y permiten explicar de forma consistente el comportamiento diferenciado detectado en la presa. Los trabajos han incluido diversos análisis sobre la influencia de parámetros de fractura, como la resistencia a tracción y la energía de fractura de las juntas. http://hdl.handle.net/2117/18653 Title: Numerical analysis of Mequinenza dam Authors: Buil, J.; Río, F.; Campos, A.; López Garello, Carlos María; Aguado de Cea, Antonio Abstract: Due to its historical and strategic significance, the Mequinenza dam has a vital importance within the Spanish hydrographic system. From its early stages in the 1960s, it is endowed with a complex and complete auscultation system which at one time detected some remanent displacements, the cause of which was attributed to the swelling (expansion induced by water absorption) of the dam concrete. The works carried out during the 1970s were efficient in controlling the movements, but the diagnosis given includes several questionable aspects. The diagnosis has been recently reformulated and a new proposal has been put forward, explaining the displacements produced more consistently [1]. This paper introduces a numerical analysis based on the 2D finite elements method (FEM), which includes joint elements with no thickness in order to represent the formation and growth of cracking, the results from which support the new proposal regarding the behavior of this dam. Fri, 05 Apr 2013 15:00:55 GMT http://hdl.handle.net/2117/18653 2013-04-05T15:00:55Z Buil, J.; Río, F.; Campos, A.; López Garello, Carlos María; Aguado de Cea, Antonio no Due to its historical and strategic significance, the Mequinenza dam has a vital importance within the Spanish hydrographic system. From its early stages in the 1960s, it is endowed with a complex and complete auscultation system which at one time detected some remanent displacements, the cause of which was attributed to the swelling (expansion induced by water absorption) of the dam concrete. The works carried out during the 1970s were efficient in controlling the movements, but the diagnosis given includes several questionable aspects. The diagnosis has been recently reformulated and a new proposal has been put forward, explaining the displacements produced more consistently [1]. This paper introduces a numerical analysis based on the 2D finite elements method (FEM), which includes joint elements with no thickness in order to represent the formation and growth of cracking, the results from which support the new proposal regarding the behavior of this dam. http://hdl.handle.net/2117/18652 Title: Use of double punching test (Barcelona test) for quality control of fiber reinforced concretes Authors: Carmona Malatesta, Sergio Alejandro; Aguado de Cea, Antonio; Molins i Borrell, Climent Abstract: Traditionally, flexural testing is used to characterize the strength and post–peak behavior of fiber–reinforced concretes (FRC). Nevertheless, these tests results exhibit a high dispersion, and therefore invalidate their use as tests for the systematic control of FRCs in works. Also, they have the disadvantage of being complex tests, which require heavy specimens and highly qualified staff. With the aim to solve these problems, an indirect tensile test based on double punching test set up, called the Barcelona test, has been proposed to control tensile behavior of FRC. This test requires smaller specimens, with a high specific surface of fracture, allowing obtain values representative of strength and toughness of materials, with considerably less dispersion than other experimental methodologies, and was recently standardized in Spain. This paper presents the results of an experimental program, which validate the use of Barcelona test as a suitable methodology to systematic characterization FRC in works. Fri, 05 Apr 2013 14:51:45 GMT http://hdl.handle.net/2117/18652 2013-04-05T14:51:45Z Carmona Malatesta, Sergio Alejandro; Aguado de Cea, Antonio; Molins i Borrell, Climent no Fiber reinforced concrete, toughness, Barcelona test Traditionally, flexural testing is used to characterize the strength and post–peak behavior of fiber–reinforced concretes (FRC). Nevertheless, these tests results exhibit a high dispersion, and therefore invalidate their use as tests for the systematic control of FRCs in works. Also, they have the disadvantage of being complex tests, which require heavy specimens and highly qualified staff. With the aim to solve these problems, an indirect tensile test based on double punching test set up, called the Barcelona test, has been proposed to control tensile behavior of FRC. This test requires smaller specimens, with a high specific surface of fracture, allowing obtain values representative of strength and toughness of materials, with considerably less dispersion than other experimental methodologies, and was recently standardized in Spain. This paper presents the results of an experimental program, which validate the use of Barcelona test as a suitable methodology to systematic characterization FRC in works. http://hdl.handle.net/2117/18322 Title: Fiabilidad de las estructuras patrimoniales Authors: Roca Fabregat, Pedro Abstract: Las estructuras de las construcciones históricas plantean retos específicos al analista debido a la necesidad de conjugar las exigencias de naturaleza resistente con la preservación de sus caracteres históricos y culturales. Modernamente, se reconoce que el fin último de la conservación de todo tipo de patrimonio cultural estriba en la preservación de su autenticidad en términos tanto materiales como intangibles. La estructura que sustenta una construcción histórica constituye asimismo una parte importante del patrimonio y debe ser tratada desde esta misma óptica. Ello conlleva que toda intervención de mantenimiento, reparación o refuerzo deba respetar y hasta potenciar los distintos valores culturales ligados a la propia estructura. En la práctica, estos conceptos llevan a preferir intervenciones muy respetuosas y de carácter mínimo. No obstante, y con el fin de reducir a límites aceptables los riegos para las personas y para el posible contenido cultural inamovible del edificio, es necesario conciliar el carácter mínimo de la intervención con la satisfacción de un nivel adecuado de fiabilidad estructural. Estas ideas se desarrollan a continuación a partir de la consideración algunos documentos internacionales, entre los que cabe destacar el Documento de Nara sobre Autenticidad (1994), y las recomendaciones del comité ISCARSAH. Se presentan asimismo algunas ideas consideradas en la elaboración del Anejo sobre Estructuras Patrimoniales de la nueva versión de la norma ISO 13822 sobre Verificación de Estructuras Existentes, en cuya elaboración ha colaborado el autor. Thu, 14 Mar 2013 19:27:58 GMT http://hdl.handle.net/2117/18322 2013-03-14T19:27:58Z Roca Fabregat, Pedro no Las estructuras de las construcciones históricas plantean retos específicos al analista debido a la necesidad de conjugar las exigencias de naturaleza resistente con la preservación de sus caracteres históricos y culturales. Modernamente, se reconoce que el fin último de la conservación de todo tipo de patrimonio cultural estriba en la preservación de su autenticidad en términos tanto materiales como intangibles. La estructura que sustenta una construcción histórica constituye asimismo una parte importante del patrimonio y debe ser tratada desde esta misma óptica. Ello conlleva que toda intervención de mantenimiento, reparación o refuerzo deba respetar y hasta potenciar los distintos valores culturales ligados a la propia estructura. En la práctica, estos conceptos llevan a preferir intervenciones muy respetuosas y de carácter mínimo. No obstante, y con el fin de reducir a límites aceptables los riegos para las personas y para el posible contenido cultural inamovible del edificio, es necesario conciliar el carácter mínimo de la intervención con la satisfacción de un nivel adecuado de fiabilidad estructural. Estas ideas se desarrollan a continuación a partir de la consideración algunos documentos internacionales, entre los que cabe destacar el Documento de Nara sobre Autenticidad (1994), y las recomendaciones del comité ISCARSAH. Se presentan asimismo algunas ideas consideradas en la elaboración del Anejo sobre Estructuras Patrimoniales de la nueva versión de la norma ISO 13822 sobre Verificación de Estructuras Existentes, en cuya elaboración ha colaborado el autor. http://hdl.handle.net/2117/18138 Title: On the design of a survey to measure effective communication in building Authors: Serrat Piè, Carles; Rodriguez, Sonia; Forcada Matheu, Núria Abstract: Although effective communication is identified as a key indicator of project performan ce, communication aspects on contractors’ evaluation are not yet included. This paper aims to review the most relevant contributions on the specific literature in order to design a survey to test for the parameters that affect effective communication among Construction Agents (CA), i.e. PM’s, builder, designer and other professionals participants, during the construction process of the project. The survey will be based on the experience and perceptions of the corresponding professionals in Spain. The availa bility of these par ameters is crucial and it represents basic information for developing procedures and tools for the evaluation and selection management of CAs. Thu, 07 Mar 2013 14:44:23 GMT http://hdl.handle.net/2117/18138 2013-03-07T14:44:23Z Serrat Piè, Carles; Rodriguez, Sonia; Forcada Matheu, Núria no Although effective communication is identified as a key indicator of project performan ce, communication aspects on contractors’ evaluation are not yet included. This paper aims to review the most relevant contributions on the specific literature in order to design a survey to test for the parameters that affect effective communication among Construction Agents (CA), i.e. PM’s, builder, designer and other professionals participants, during the construction process of the project. The survey will be based on the experience and perceptions of the corresponding professionals in Spain. The availa bility of these par ameters is crucial and it represents basic information for developing procedures and tools for the evaluation and selection management of CAs. http://hdl.handle.net/2117/17975 Title: Assessment of the expected seismic damage in the aggregated masonry buildings of the late XIX century of Barcelona, Spain Authors: Moreno González, Rosángel; Bairán García, Jesús Miguel Abstract: This paper aims at the evaluation of expected seismic damage of aggregated masonry buildings system, formed by a line of buildings along of the street; real buildings were studied of whom structural drawings were available. Each structure was individually built without any gaps between them, producing interaction among the buildings under lateral loads. Numerical model consists of 7 buildings: 5 in-row with rectangular shape and 2 corners (in the intersection of two streets) with a pentagonal shape. Damage probability matrices were obtained from pushover analysis using the capacity and fragility curves. Seismic hazard is considered for the acceleration of Barcelona. Four damage states were considered: slight, moderate, extensive and complete (collapse). The results showed that aggregated system analysed presents slight damage in a hard soil while very extensive damage occur in soft soil, furthermore, the expected seismic damage is high considering the low seismic action of Barcelona. Tue, 26 Feb 2013 12:09:56 GMT http://hdl.handle.net/2117/17975 2013-02-26T12:09:56Z Moreno González, Rosángel; Bairán García, Jesús Miguel no This paper aims at the evaluation of expected seismic damage of aggregated masonry buildings system, formed by a line of buildings along of the street; real buildings were studied of whom structural drawings were available. Each structure was individually built without any gaps between them, producing interaction among the buildings under lateral loads. Numerical model consists of 7 buildings: 5 in-row with rectangular shape and 2 corners (in the intersection of two streets) with a pentagonal shape. Damage probability matrices were obtained from pushover analysis using the capacity and fragility curves. Seismic hazard is considered for the acceleration of Barcelona. Four damage states were considered: slight, moderate, extensive and complete (collapse). The results showed that aggregated system analysed presents slight damage in a hard soil while very extensive damage occur in soft soil, furthermore, the expected seismic damage is high considering the low seismic action of Barcelona. http://hdl.handle.net/2117/17690 Title: Influence of fibre orientation on the performance of steel fibre-reinforced concrete Authors: Grünewald, Steffen; Laranjeira de Oliveira, Filipe; Walraven, Joost; Aguado de Cea, Antonio; Molins i Borrell, Climent Abstract: The performance of fibre-reinforced materials in the hardened state depends on the material behaviour, the production method and influences related to the structure. The position and the orientation of fibres in a structure can differ from the homogenous distribution and the random orientation in a mixer. Due to the flow of the concrete, fibres are able to orient which makes the prediction of the structural behaviour of fibre-reinforced concrete more complex, but it also offers the potential for an improved structural performance. Synergetic effects were observed with regard to flowable concrete related to the fibre efficiency. This paper discusses two studies on the effect of fibre orientation on the performance of steel fibre- reinforced concrete. The first study discusses the relation between fibre orientation and the distribution of fibre orientation. The analysis indicates that the variation of fibre orientation follows a Gaussian law and the distribution of fibre orientation can be predicted from the average fibre orientation. The second study on tunnel segments discusses the influence of production on the fibre orientation and how this affects the splitting tensile strength. The fibre orientation affects the fibre efficiency and the structural performance of steel fibre-reinforced concrete. Tue, 12 Feb 2013 18:25:08 GMT http://hdl.handle.net/2117/17690 2013-02-12T18:25:08Z Grünewald, Steffen; Laranjeira de Oliveira, Filipe; Walraven, Joost; Aguado de Cea, Antonio; Molins i Borrell, Climent no Fibre orientation, tensile behaviour, image analysis, X-ray photograph, production influence, tunnel segments The performance of fibre-reinforced materials in the hardened state depends on the material behaviour, the production method and influences related to the structure. The position and the orientation of fibres in a structure can differ from the homogenous distribution and the random orientation in a mixer. Due to the flow of the concrete, fibres are able to orient which makes the prediction of the structural behaviour of fibre-reinforced concrete more complex, but it also offers the potential for an improved structural performance. Synergetic effects were observed with regard to flowable concrete related to the fibre efficiency. This paper discusses two studies on the effect of fibre orientation on the performance of steel fibre- reinforced concrete. The first study discusses the relation between fibre orientation and the distribution of fibre orientation. The analysis indicates that the variation of fibre orientation follows a Gaussian law and the distribution of fibre orientation can be predicted from the average fibre orientation. The second study on tunnel segments discusses the influence of production on the fibre orientation and how this affects the splitting tensile strength. The fibre orientation affects the fibre efficiency and the structural performance of steel fibre-reinforced concrete. http://hdl.handle.net/2117/17689 Title: Numerical tool for modeling steel fiber reinforced concrete Authors: Molins i Borrell, Climent; Pros Parés, Alba; Díez, Pedro Abstract: Steel Fiber Reinforced Concrete (SFRC) allows overcoming brittleness and weakness in tension, the main drawbacks of plain concrete. The goal of the present presentation is to present an ad-hoc numerical strategy to account for the contribution of the fibers in the simulation of the mechanical response of SFRC. In the model presented, the individual fibers immersed in the concrete bulk are accounted for in their actual location and orientation. The selected approach is based on the ideas introduced in the Immersed Boundary (IB) methods. These methods were developed to account for 1D (or 2D) solids immersed in 2D (or 3D) fluids. Here, the concrete bulk is playing the role of the fluid and the cloud of steel fibers is acting as the immerse boundary (that is a 1D structure in a 2D or 3D continuous). Thus, the philosophy of the IB methodology is used to couple the behavior of the two systems, the concrete bulk and the fiber cloud, precluding the need of matching finite element meshes. In the proposed approach, the meshes of the concrete bulk and fiber cloud are independent and the models are coupled imposing displacement compatibility and equilibrium of the two systems. The concrete bulk is modeled using any nonlinear model. The constitutive model for the fibers is designed to account for the complex interaction between fibers and concrete. The fiber models are based on previous investigations describing the concrete-fiber interaction and its dependence on the factors identified to be relevant: shape of the fiber (straight or hooked) and angle between the fiber and the crack plane. 3D examples with fibers distributed and oriented randomly are reproduced using the proposed approach. Tue, 12 Feb 2013 18:16:39 GMT http://hdl.handle.net/2117/17689 2013-02-12T18:16:39Z Molins i Borrell, Climent; Pros Parés, Alba; Díez, Pedro no Plain concrete, Steel Fiber Reinforced Concrete, Numerical Model, Immersed Boundary methods, Pullout test, Model Validation, Direct Tension Test, Three Point Bending Test Steel Fiber Reinforced Concrete (SFRC) allows overcoming brittleness and weakness in tension, the main drawbacks of plain concrete. The goal of the present presentation is to present an ad-hoc numerical strategy to account for the contribution of the fibers in the simulation of the mechanical response of SFRC. In the model presented, the individual fibers immersed in the concrete bulk are accounted for in their actual location and orientation. The selected approach is based on the ideas introduced in the Immersed Boundary (IB) methods. These methods were developed to account for 1D (or 2D) solids immersed in 2D (or 3D) fluids. Here, the concrete bulk is playing the role of the fluid and the cloud of steel fibers is acting as the immerse boundary (that is a 1D structure in a 2D or 3D continuous). Thus, the philosophy of the IB methodology is used to couple the behavior of the two systems, the concrete bulk and the fiber cloud, precluding the need of matching finite element meshes. In the proposed approach, the meshes of the concrete bulk and fiber cloud are independent and the models are coupled imposing displacement compatibility and equilibrium of the two systems. The concrete bulk is modeled using any nonlinear model. The constitutive model for the fibers is designed to account for the complex interaction between fibers and concrete. The fiber models are based on previous investigations describing the concrete-fiber interaction and its dependence on the factors identified to be relevant: shape of the fiber (straight or hooked) and angle between the fiber and the crack plane. 3D examples with fibers distributed and oriented randomly are reproduced using the proposed approach. http://hdl.handle.net/2117/17687 Title: An attempt to the determination of the partial safety factor for SFRC members subjected to bending forces Authors: Camos Andreu, Carles; Casas Rius, Joan Ramon; Molins i Borrell, Climent Abstract: In the last few years, research on techniques that permit the reduction or even the complete elimination of structural bar reinforcements has been intensified. The addition of steel fibres to the concrete matrix is proven to be an effective way of covering the deficiencies in this material when subjected to tensile stress. However, there still exists uncertainty surrounding some of the basis of design of structural members in ultimate condition. A clear example is the partial safety factor applied to the tensile strength. In this paper, a reliability-based analysis is carried out through the study of a particular application, such as the tunnel lining concrete segments built in an experimental section of the L9 Metro tunnel in Barcelona, solely reinforced with steel fibres. Specimens were extracted from three different segments and tested in tension by using the Barcelona test. Such a representative sample of tensile strength results made possible an assessment of the degree of the existing safety in this particular case by applying the reliability method FORM. The reliability analysis suggested a partial factor equal to 1.77. This would represent a first step to obtain the general material safety factor, which may involve a calibration in a wide range of tunnel segments and afterwards, other structural members and applications of SFRC. Tue, 12 Feb 2013 18:03:45 GMT http://hdl.handle.net/2117/17687 2013-02-12T18:03:45Z Camos Andreu, Carles; Casas Rius, Joan Ramon; Molins i Borrell, Climent no safety, factor, residual strength, segment, reliability, FORM In the last few years, research on techniques that permit the reduction or even the complete elimination of structural bar reinforcements has been intensified. The addition of steel fibres to the concrete matrix is proven to be an effective way of covering the deficiencies in this material when subjected to tensile stress. However, there still exists uncertainty surrounding some of the basis of design of structural members in ultimate condition. A clear example is the partial safety factor applied to the tensile strength. In this paper, a reliability-based analysis is carried out through the study of a particular application, such as the tunnel lining concrete segments built in an experimental section of the L9 Metro tunnel in Barcelona, solely reinforced with steel fibres. Specimens were extracted from three different segments and tested in tension by using the Barcelona test. Such a representative sample of tensile strength results made possible an assessment of the degree of the existing safety in this particular case by applying the reliability method FORM. The reliability analysis suggested a partial factor equal to 1.77. This would represent a first step to obtain the general material safety factor, which may involve a calibration in a wide range of tunnel segments and afterwards, other structural members and applications of SFRC. http://hdl.handle.net/2117/17684 Title: Numerical simulation of the structural behaviour of buildings under tunnelling settlements: a case study in the L9 metro line (Barcelona) Authors: Camos Andreu, Carles; Molins i Borrell, Climent; Arnau Delgado, Oriol; Gálvez, Javier Tue, 12 Feb 2013 17:32:55 GMT http://hdl.handle.net/2117/17684 2013-02-12T17:32:55Z Camos Andreu, Carles; Molins i Borrell, Climent; Arnau Delgado, Oriol; Gálvez, Javier no http://hdl.handle.net/2117/17483 Title: Dalla raccolta dei dati all'analisi del modello nella valutazione della sicurezza sismica Authors: Benedetti, Andrea; Pelà, Luca Abstract: Nella nota si presentano considerazioni e valutazioni utili a istituire un procedimento logico per la traduzione del ventaglio dei dati raccolti nello studio preliminare di una costruzione, in un modello numerico sufficientemente accurato nella determinazione del grado di sicurezza, delle sezioni critiche, e dell’effetto degli eventuali interventi di consolidamento. In particolare, la raccolta dei dati storici della costruzione, della consistenza materica rilevata dalla prove in sito e di laboratorio, della geometria degli elementi strutturali, necessita di una fase di rielaborazione per tradurre i dati in geometria di una discretizzazione in elementi finiti e in parametri meccanici dei materiali costituenti. La necessità di valutare la variabilità della soluzione in funzione di eventuali errori sui dati richiede la messa a punto di un procedimento per il confronto di differenti ipotesi e di differenti modelli numerici di rappresentazione. Nel caso di strutture in muratura la soluzione non può essere espressa da un solo modello omnicomprensivo, ma sono necessarie analisi globali a differenti livelli di complessità e analisi locali capaci di definire il comportamento di singoli elementi strutturali enucleati dal complesso strutturale Tue, 22 Jan 2013 18:43:19 GMT http://hdl.handle.net/2117/17483 2013-01-22T18:43:19Z Benedetti, Andrea; Pelà, Luca no Nella nota si presentano considerazioni e valutazioni utili a istituire un procedimento logico per la traduzione del ventaglio dei dati raccolti nello studio preliminare di una costruzione, in un modello numerico sufficientemente accurato nella determinazione del grado di sicurezza, delle sezioni critiche, e dell’effetto degli eventuali interventi di consolidamento. In particolare, la raccolta dei dati storici della costruzione, della consistenza materica rilevata dalla prove in sito e di laboratorio, della geometria degli elementi strutturali, necessita di una fase di rielaborazione per tradurre i dati in geometria di una discretizzazione in elementi finiti e in parametri meccanici dei materiali costituenti. La necessità di valutare la variabilità della soluzione in funzione di eventuali errori sui dati richiede la messa a punto di un procedimento per il confronto di differenti ipotesi e di differenti modelli numerici di rappresentazione. Nel caso di strutture in muratura la soluzione non può essere espressa da un solo modello omnicomprensivo, ma sono necessarie analisi globali a differenti livelli di complessità e analisi locali capaci di definire il comportamento di singoli elementi strutturali enucleati dal complesso strutturale http://hdl.handle.net/2117/16986 Title: Nanotecnología para la calefacción de componentes de automóvil Authors: Carod de Arriba, Xavier; Ferreté Aymerich, Eduard; Casanova Hormaechea, Ignasi; González Benítez, María Margarita; Mendoza Gómez, Ernesto Abstract: Desde hace ya unos años, el sector de la automoción centra sus esfuerzos en fabricar productos cada vez más eficientes y respetuosos con el medio ambiente. El creciente interés en desarrollar modelos eléctricos, ha desencadenado un gran trabajo de desarrollo de nuevos materiales y tecnologías más eficientes. La reducción de peso y la disminución del consumo eléctrico se han convertido en factores clave para conceder cada vez más autonomía a este tipo de vehículos. En este trabajo se presenta el desarrollo de un prototipo de calefactor para retrovisores mediante la aplicación de un recubrimiento a base de nanotubos de carbono, que actúa como resistencia eléctrica y produce calor por efecto Joule aplicando muy poca potencia. Además del desarrollo conceptual de esta nanotecnología, también se demuestra la viabilidad tecnológica de su aplicación al haberse testado la estabilidad térmica y estructural del material calefactor. Se ha determinado que la composición de nanotubos de carbono, la forma geométrica de la superficie recubierta y la disposición de los contactos son aspectos cruciales para obtener las propiedades deseadas. La versatilidad que ofrece esta tecnología es muy amplia, ya que es fácilmente reproducible en otras piezas calefactables del interior de un vehículo Tue, 20 Nov 2012 19:46:43 GMT http://hdl.handle.net/2117/16986 2012-11-20T19:46:43Z Carod de Arriba, Xavier; Ferreté Aymerich, Eduard; Casanova Hormaechea, Ignasi; González Benítez, María Margarita; Mendoza Gómez, Ernesto no Desde hace ya unos años, el sector de la automoción centra sus esfuerzos en fabricar productos cada vez más eficientes y respetuosos con el medio ambiente. El creciente interés en desarrollar modelos eléctricos, ha desencadenado un gran trabajo de desarrollo de nuevos materiales y tecnologías más eficientes. La reducción de peso y la disminución del consumo eléctrico se han convertido en factores clave para conceder cada vez más autonomía a este tipo de vehículos. En este trabajo se presenta el desarrollo de un prototipo de calefactor para retrovisores mediante la aplicación de un recubrimiento a base de nanotubos de carbono, que actúa como resistencia eléctrica y produce calor por efecto Joule aplicando muy poca potencia. Además del desarrollo conceptual de esta nanotecnología, también se demuestra la viabilidad tecnológica de su aplicación al haberse testado la estabilidad térmica y estructural del material calefactor. Se ha determinado que la composición de nanotubos de carbono, la forma geométrica de la superficie recubierta y la disposición de los contactos son aspectos cruciales para obtener las propiedades deseadas. La versatilidad que ofrece esta tecnología es muy amplia, ya que es fácilmente reproducible en otras piezas calefactables del interior de un vehículo http://hdl.handle.net/2117/16949 Title: Energy and sensitivity analysis of Spanish dwelling stock Authors: Hernández Sánchez, Juan Manuel; Roca Ramon, Xavier Abstract: The main aim of this paper is to know how household and dwelling related independent variables affect dependent variables: energy consumption and expenditure on energy. It is also an aim to know how energy prices and income levels affect energy consumption. Therefore, sensitivity analyses of both variables have been performed. Finally, energy price sensitivity is used to predict energy consumption for the Spanish dwelling stock in 2030. Data are extracted from the household budget survey for the period 2006 to 2010, with a sample size of around 24 000 households per year. The independent variables which have a greater effect size on the dependent variables are: energy source for heating, type of household, useful floor area, size of municipality, type of residential area, type of tenure and monthly level of net household income. Energy consumption is sensitive to energy prices, and each energy source has a different degree of sensitivity. If the price per kWh were raised one euro cent, this would result in an increase of 6.9% in electricity and decreases of 6.5% in natural gas, 5.5% in liquefied gas and 15.5% in other liquid fuels. The significant increase in electricity consumption in recent years masks its real sensitivity to its price. Reduction of income would result in a reduction of energy consumption. If income were reduced by 10%, energy consumption would fall by 3.5%. Based on predicted energy prices by 2030 and on energy price sensitivity, electricity consumption will increase by 26% and natural gas, liquefied gas and other liquid fuels consumptions will reduce by 38.4%, 23.4% and 59.8%, respectively Mon, 19 Nov 2012 14:50:46 GMT http://hdl.handle.net/2117/16949 2012-11-19T14:50:46Z Hernández Sánchez, Juan Manuel; Roca Ramon, Xavier no Degree of sensitivity, Dependent variables, Effect size, Electricity-consumption, Energy prices, Energy source, Floor areas, Household income, Income levels, Independent variables, Residential areas, Sample sizes The main aim of this paper is to know how household and dwelling related independent variables affect dependent variables: energy consumption and expenditure on energy. It is also an aim to know how energy prices and income levels affect energy consumption. Therefore, sensitivity analyses of both variables have been performed. Finally, energy price sensitivity is used to predict energy consumption for the Spanish dwelling stock in 2030. Data are extracted from the household budget survey for the period 2006 to 2010, with a sample size of around 24 000 households per year. The independent variables which have a greater effect size on the dependent variables are: energy source for heating, type of household, useful floor area, size of municipality, type of residential area, type of tenure and monthly level of net household income. Energy consumption is sensitive to energy prices, and each energy source has a different degree of sensitivity. If the price per kWh were raised one euro cent, this would result in an increase of 6.9% in electricity and decreases of 6.5% in natural gas, 5.5% in liquefied gas and 15.5% in other liquid fuels. The significant increase in electricity consumption in recent years masks its real sensitivity to its price. Reduction of income would result in a reduction of energy consumption. If income were reduced by 10%, energy consumption would fall by 3.5%. Based on predicted energy prices by 2030 and on energy price sensitivity, electricity consumption will increase by 26% and natural gas, liquefied gas and other liquid fuels consumptions will reduce by 38.4%, 23.4% and 59.8%, respectively