http://hdl.handle.net/2117/3555 2013-05-24T20:39:43Z 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. 2013-04-09T18:37:57Z 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. 2013-04-05T15:00:55Z http://hdl.handle.net/2117/16647 Title: Influence of foundation compressibility on reinforcement loads in geosynthetic reinforced soil walls Authors: Bathurst, Richard; Puig Damians, Ivan; Ezzein, F.; Josa Garcia-Tornel, Alejandro; Lloret Morancho, Antonio Abstract: A numerical FLAC model was used to investigate the influence of vertical stiffness of the foundation on the performance of an idealized 6-m high reinforced soil modular block retaining wall. Three different Winkler linear spring values were used to simulate a rigid foundation and two compliant foundation cases. For each foundation condition, the influence of reinforcement material stiffness was also investigated. One material matched the properties of a relatively extensible polymeric geogrid product and the other a relatively inextensible welded wire mesh material with much higher stiffness but the same strength. The results of simulations show that as foundation stiffness decreases, reinforcement loads increase. However, for the two reinforcement materials in this study, the influence of axial stiffness of the reinforcement had a greater effect on wall performance than the foundation stiffness for walls subjected to operational (working stress) conditions at end of construction. 2012-10-04T13:15:34Z http://hdl.handle.net/2117/15905 Title: Avaliação dos impactos ao meio ambiente causados pelos materiais e produtos da construção civil Authors: Cardim, A; Josa Garcia-Tornel, Alejandro; Aguado de Cea, Antonio; Gettu, Ravindra Abstract: Este artigo apresenta a necessidade de minimizaçao do impacto meioambiental, de todo tipo de atuaçao, pela necessidade de obtermos um desenvolvimento sustentável. Faz-se uma breve sintese da situaçao atual, no caso especifico de produtos da constru9ao civil, já que a construçao indiscriminada, e sem nenhuma consciencia do tipo meioambiental, tem contribuido significativamente para uma imagem negativa do setor, que, inclusive, tem levado a que muitas vezes a populaçao se oponha a construçao de novas infraestruturas. Se expoem qualitativamente os beneficios dos produtos da construçao civil ao meio ambiente, nos funbitos da saúde, segurança e desenvolvimento, pois frequentemente sao esquecidos de considerar nos seus impactos. E com o objetivo de quantificar este último, se introduz brevemente o conceito e a metodología de análise do ciclo de vida - ACV - de processos e produtos. 2012-05-21T16:10:36Z http://hdl.handle.net/2117/15430 Title: LCM of rainwater harvesting systems in emerging neighborhoods in Colombia Authors: Morales-Pinzón, Tito; Angrill, S.; Rieradevall, J.; Gabarrell, Xavier; Gasol, C.; Josa Garcia-Tornel, Alejandro Abstract: Potential environmental impacts of water harvesting systems for rain to emerging neighbourhoods in Colombia were studied. Two tools were integrated into a simulation model (life cycle analysis and system dynamics). This was performed as an application case study in two urban areas of Colombia (Bogota and Pereira). We modelled a standard neighbourhood with 10 residential 5-storey buildings of 24 apartments. The results show that it is possible to avoid in every neighbourhood 150,729 kg CO2e and 44,857 kg CO2e, respectively. 2012-02-29T19:48:36Z http://hdl.handle.net/2117/15339 Title: Análisis numérico de los esfuerzos verticales en el paramento de un muro de tierra reforzada en suelo diabásico Authors: Puig Damians, Ivan; Josa Garcia-Tornel, Alejandro; Albuquerque, P.J.R.; Lloret Morancho, Antonio; Ledesma Villalba, Alberto; de Santos, C. Abstract: The paper presents a numerical analysis of the service behaviour of a reinforced soil wall constructed in a diabasic soil. A 2D model developed through the Finite Element Method (FEM) using the commercial computer software PLAXIS has been developed for this purpose. This model has been applied to the case of a 6 meters high wall constructed on a diabasic, lateritic and porous underlying soil, common to the region of Campinas (São Paulo, Brazil). The geotechnical properties of this soil have been quantified for different compaction levels. In particular the vertical stresses in the front structure of the wall have been analyzed. The results show that variations in the soil stiffness and of the structure elements geometry cause significant variations of the stress-strain state and the forces that are generated. Mediante el desarrollo de un modelo numérico 2D por el método de los elementos finitos (M.E.F.) con el programa comercial de ordenador PLAXIS se ha modelado el comportamiento en servicio de muros de tierra reforzada. Este modelo se ha aplicado al caso de un muro de 6 metros de altura ejecutado en suelo del diabásico, laterítico y poroso, común en la región de Campinas (São Paulo, Brasil), con propiedades resistentes variables que se han cuantificado según diferentes niveles de compactación. Utilizando este modelo se ha estudiado, en particular, el estado tensional en el paramento del muro. Los resultados más relevantes de dicho análisis, presentados en este documento, muestran que variaciones tanto en la rigidez del terreno como en la geometría de los elementos constructivos provocan cambios significativos en el estado tenso-deformacional y en de los esfuerzos que se generan. 2012-02-23T14:56:35Z http://hdl.handle.net/2117/14017 Title: LCM in urban planning for diminishing GHG: case study on concrete sidewalks Authors: Oliver-Solà, Jordi; Josa Garcia-Tornel, Alejandro; Gabarrell, Xavier; Rieradevall, J. Abstract: The Kyoto protocol, signed by 160 countries, pledges greenhouse gas (GHG) emissions reductions of at least 5% relative to 1990 levels [1]. Besides the global concern and action to mitigate GHG emissions, national-level policies are increasingly being supplemented with city-scale actions to mitigate climate change [2]. Marshall [3] makes us notice that although much attention on mitigating climate change has focused on alternative fuels, energy consumption in vehicles, and electricity generation, better urban design represents an important yet undervalued opportunity. The built environment is responsible for huge amounts of pollution and waste generation [4] at millions of different locations worldwide. And one of the major construction materials is concrete. 2011-11-22T17:32:44Z http://hdl.handle.net/2117/12189 Title: Influence of cracking in the desiccation process of clay soils Authors: Levatti, Hector Ulises; Prat Catalán, Pere; Ledesma Villalba, Alberto Abstract: It is well known that clayey soils undergoing desiccation tend to shrink and eventually crack. Analysis of the behaviour and influence of cracks in these types of soils is very important in several engineering fields such as mine tailing dams, long-term radioactive waste storage, impervious core of earth dams, and in any situation where clay is used as a barrier to fluid flow. Loss of humidity and cracking changes the permeability of such barriers that may no longer work properly and pose potentially high risks to property and lives. This paper presents an analysis of cracking during drying of soils using a computer code de-veloped within the framework of the finite element and finite differences methods. A study of the influence of crack initiation and propagation in the desiccation process is also undertaken, with a comparative analysis of the phenomenon both with and without crack generation that allows some preliminary conclusions about the desiccation problem. The computer code has been implemented within the MatLab environment. The formulation is based on the principles of the unsaturated soil mechanics and the mechanics of a continuum medium. The partial differential equations that govern the problem are solved using the finite element (Galerkin) method in space and the finite differences method, using the Crank-Nicholson scheme, in time. Further developments of the code will include fracture mechanics principles to simulate crack propagation. 2011-03-31T14:10:14Z http://hdl.handle.net/2117/9704 Title: MIVES: modelo integrado de valor para evaluaciones de sostenibilidad Authors: Viñolas Prat, Bernat; Cortés, F.; Marques, A.; Josa Garcia-Tornel, Alejandro; Aguado de Cea, Antonio Abstract: La valoración y agregación cuantitativa de los distintos requisitos que constituyen los tres pilares básicos de la sostenibilidad es importante para poder comparar de forma objetiva la incidencia relativa de alternativas de materiales o procesos e introducir mejoras. La mayoría de estos requisitos tienen unidades de medida diferentes. Por ello, para valorar el grado de sostenibilidad, es importante basarse en metodologías multicriterio de valoración que permitan valorar y ponderar todos estos requisitos de diferente índole. La metodología multicriterio y programa informático aquí presentado, “MIVES1: Modelo integrado de valor para evaluaciones de sosteniblidad”, permite obtener un único índice de valor que mide el grado de sostenibilidad del material o proceso evaluado. En las primeras fases de la metodología MIVES se realiza un modelo de valoración. En éste, se establecen las condiciones de contorno y los límites del sistema, se estructuran todos los aspectos que serán estudiados, se decide qué funciones de valor se utilizarán para valorar cada uno de los aspectos y por último se determina la importancia de cada uno de ellos. En estas primeras fases es donde realmente se toma la decisión, es decir, se definen los aspectos que serán estudiados y la forma de valorarlos sin estar condicionado por las valoraciones de las alternativas. Posteriormente, se seleccionan y valoran las alternativas. Las aplicaciones de la metodología MIVES son numerosas. Cabe destacar el Anejo 13 de la Instruccuón del hormigón2, que sirve para medir el grado de sostenibilidad de las estructuras de hormigón. La metodología desarrollada representa un avance en términos de valoración, ya que se dota de objetividad y claridad en los procedimientos. A la vez, permite que cualquier persona pueda estudiar la sostenibilidad de otras alternativas a partir del modelo de valoración creado. 2010-10-14T18:48:15Z http://hdl.handle.net/2117/9700 Title: Com mesurar la sostenibilitat de les nostres estructures? Authors: Viñolas Prat, Bernat; Aguado de Cea, Antonio; Josa Garcia-Tornel, Alejandro Abstract: En aquesta comunicació, a part d'una reflexió general, es presenta una experiència pionera a nivell internacional com és la quantificació de la sostenibilitat en la nova versió de la Instrucció de l'EHE al denominat Índex de contribució de les estructures a la sostenibilitat (ICES). Aquesta experiència innovadora ha estat fortament impulsada des de la Secretaria Tècnica del Ministeri de Foment, posant de manifest l'existència de voluntat política. La metodologia emprada ha sigut el Model Integrat de Valor per Avaluacions Sostenibles - MIVES. Es tracta d'una metodologia que utilitza l'anàlisi de valor com a suport a la decisió mitjançant la valoració de diferents alternatives, amb l'objectiu, en particular, de valorar quantitativament la sostenibilitat. 2010-10-14T17:28:27Z http://hdl.handle.net/2117/7933 Title: Computational modeling of external sulfate attack in concrete at the meso-level Authors: Idiart Castellano, Andrés Enrique; Carol, Ignacio; López Garello, Carlos María; Murcia Vela, Juan Abstract: This paper presents recent work by the authors along the domain of coupled chemo-mechanical problems in concrete. External sulfate attack is analyzed from a mesoscale point of view, in which the main heterogeneities of the material are explicitly introduced. Zero-thickness interface elements are introduced a priori in order to consider cracking phenomena. The distribution of sulfate ions and ettringite are obtained from a non-linear diffusion-reaction analysis. The results include the analysis of the influence of coupling on the crack patterns and on the sulfate ions and ettringite distribution of within the cracked material. 2010-06-30T17:48:08Z http://hdl.handle.net/2117/7932 Title: Meso-mechanical analysis of the fracture of concrete specimens in mixed mode Authors: Rodríguez, Mariana; López Garello, Carlos María; Carol, Ignacio; Caner, Ferhun Cem Abstract: This paper describes recent numerical simulation results of some experiments carried out by Nooru-Mohamed to study mixed mode fracture of concrete. The numerical simulation is based on a meso-mechanical model developed in the group of Mechanics of Materials UPC, which represents the largest aggregate particles explicitly, and represent cracks in a discrete manner by inserting zero-tickness interface elements in all potential crack trajectories a priori of the analysis. 2010-06-30T17:35:35Z http://hdl.handle.net/2117/7640 Title: Análisis meso-mecánico del hormigón bajo la acción de procesos expansivos internos. Authors: Campos, A.; López Garello, Carlos María; Aguado de Cea, Antonio Abstract: Es conocido que la existencia de procesos expansivos en el hormigón inducidos por reacciones químicas, puede provocar una considerable degradación de sus propiedades mecánicas. Este comportamiento puede ser la respuesta a diferentes causas como la reacción álcali-árido, las reacciones de oxidación de sulfuros, el ataque sulfático (externo o interno), etc. Los procesos reactivos, en general, provocan cambios de volumen diferencial en la estructura interna del material, aspecto que viene a acentuar la importancia de realizar análisis mediante modelos mesomecánicos, en los que se representa explícitamente la estructura interna de primer nivel (meso-estructura). En este trabajo se presentan resultados de simulaciones numéricas meso-mecánicas de un hormigón sometido a acciones expansivas internas. Se han obtenido curvas de la degradación del módulo de elasticidad y de la resistencia a tracción en función del grado de expansión, que se comparan con resultados experimentales [1]. También se muestran aspectos de la fisuración y de la energía disipada, que se correlacionan con el nivel de expansión y la evolución de los parámetros mecánicos. ABSTRACT It is known that the existence of expansive processes in concrete induced by chemical reactions can cause considerable degradation of its mechanical proprieties. This phenomenon may have several causes such as alkali-aggregate reaction, sulphides oxidation reaction, the sulfate attack (internal or external), among others. The reactive processes, in general, cause differential volume changes in the internal structure of the material, aspect that accentuates the importance of analysis by meso-mechanical models that take into account the explicit representation of the first level internal structure (meso-structure). This paper presents results of meso-mechanical simulations of a concrete subjected to internal expansion actions. Curves have been obtained for the degradation of the elastic modulus and tensile strength in function of the degree of expansion and compared with experimental results [1]. Furthermore, this work shows aspects of the evolution of cracking and energy dissipation, both of which can be correlated with the degree of expansion and the variation of the mechanical parameters 2010-06-14T11:10:42Z http://hdl.handle.net/2117/7636 Title: Análisis del hormigón en modo mixto de fractura utilizando un modelo meso-estructural con elementos junta. Authors: López Garello, Carlos María; Carol, Ignacio; Carol, Ignacio Abstract: En este trabajo se presentan resultados de la simulación numérica de algunos ensayos experimentales sobre muestras de hormigón sometidas a carga biaxial que combina tracción y corte [1]. Para ello se emplea una modelización en la que se representan explícitamente los principales componentes de la estructura interna del hormigón a nivel mesoescala. Los ensayos experimentales se realizaron mayoritariamente en muestras de 200 mm de lado, si bien en algunos casos de carga también se emplearon muestras de 100 y 50 mm. En un trabajo anterior presentado en el Congreso del Grupo Español de Fractura del año 2009 se ha estudiado una muestra de 200 mm con tamaño máximo de árido de 16 mm. En este artículo se analiza ahora la muestra de 50 mm de lado con un tamaño máximo de árido similar al de las probetas empleadas en los experimentos (2mm). Los resultados obtenidos en uno de los estados de carga han permitido reproducir satisfactoriamente el comportamiento carga-desplazamiento (tensión-desplazamiento), así como la formación y evolución de la tendencia de fisuración detectada en los ensayos llevados a cabo en [1] y similares en [2].-----------------------------------------ABSTRACT This paper presents the results of the numerical simulation of some of the experimental tests on concrete samples subjected to different biaxial loading paths combining tension and shear [1]. The study uses a meso-structural model which explicitly represents the main components of the internal structure of concrete at meso-scale level. The experimental tests were conducted mostly in samples of 200 mm side, although in some load cases were also used samples of 100 and 50mm side. In a previous work presented in the Congress of the Spanish Group of Fracture (2009) a sample of 200 mm side with maximum aggregate size 16mm has been studied. This paper now examines the sample of 50 mm side with a maximum aggregate size similar to the used in the experimental test (2mm). The numerical results obtained in one of the loading conditions have allowed satisfactorily reproduce the load-displacement behaviour (tension-displacements) and the cracking patterns detected in the experimental tests conducted in [1] and similarly in [2]. 2010-06-14T10:45:46Z