Modelo lineal de la rigidez a tracción del hormigón para elementos de hormigón estructural

Nowadays, linear expressions for the tension stiffening of concrete are widely used in structural analysis software packages. Nevertheless, more complex expressions of tension stiffening available in the literature have been used successfully in the past. The use of linear approximations is justified since the influence of the tension stiffening effect on the deformation of a structure is small but not negligible. Therefore, linear approximations are simpler and can be accurate enough. However, the linear approximation, in its present form, does not provide good results in terms of deformations of reinforced concrete beam-column elements. This paper proposes a linear expression of tension stiffening supported by the experimental formulation used to predict the flexural behavior of concrete beams. A detailed example is presented.Expresiones lineales de la rigidez a tracción del hormigón están siendo ampliamente utilizadas en paquetes de software de análisis estructural. Sin embargo, en el pasado se han utilizado con éxito expresiones más elaboradas de la rigidez a tracción del hormigón. El uso de aproximaciones lineales está justificado ya que la influencia del efecto de rigidez a tracción del hormigón en la deformación de las estructuras de hormigón es pequeña pero no despreciable. En este sentido, las aproximaciones lineales son más simples y pueden ser lo suficientemente precisas. Sin embargo, esta aproximación lineal, en su forma actual, no proporciona buenos resultados en términos de deformaciones a nivel de elementos estructurales. Esta publicación propone una expresión lineal de la rigidez a tracción apoyada por la formulación experimental utilizada para predecir el comportamiento a flexión de vigas de hormigón. Se presenta un ejemplo detallado

Detailed application of the Linear Acceleration Method for the response of an elasto-plastic SDOF system

The numeric computation procedure for the solution of the equation of motion of a single-degree-of-freedom (SDOF) system subjected to any type of ground acceleration is exhaustively presented. The followed numeric approach is the Linear Acceleration Method, i.e. Newmark’s Method with and . The approach allows considering any time of multilinear elasto-plastic behavior. It also allows computing the Complete Hysteretic Curve of the SDOF system

Report TEP 190 1-2019

Report TEP 190 1-2019The numeric computation procedure for the solution of the equation of motion of a single-degree-of-freedom (SDOF) system subjected to any type of ground acceleration is exhaustively presented. The followed numeric approach is the Linear Acceleration Method, i.e. Newmark’s Method with γ=1/2 and β=1/6. The approach allows considering any time of multilinear elasto-plastic behavior. It also allows computing the Complete Hysteretic Curve of the SDOF system

Mechanical characterization and elastic stiffness degradation of unstabilized rammed earth

Rammed earth is attracting renewed interest due to its sustainability. In this work, a mechanical characterization of unstabilized rammed earth is presented. Compressive strength, Young’s modulus, and Poisson’s ratio were determined, with the first of these being the most representative mechanical property of rammed earth. Stress – strain curves were obtained from uniaxial compression tests. Creep is of great importance in the long-term assessment of historical buildings and in the design of new ones. Samples of rammed earth were subjected to a constant load for 15 days to study their creep behavior. In order to simulate the long-term behavior of the material, different rheological models were fitted to the experimental results. The instantaneous deformation of rammed earth samples caused by a sudden additional load (maintaining a previous service load level) was also studied. This is the first time that this phenomenon, called elastic stiffness degradation, has been studied for rammed earth material.European Union Framework Programme for Research and Innovation 82105

Fragility Curves for Historical Structures with Degradation Factors Obtained from 3D Photogrammetry

The influence of the effects of the degradation of materials on the seismic fragility of Cultural Heritage buildings in Granada (Spain) is investigated. The degradation of the material, which mainly happens at the lower levels of the façades, is obtained by using 3D photogrammetry data. Fragility curves for three cultural heritage constructions in Granada are calculated by using FE nonlinear dynamic analyses for both non-deteriorated and deteriorated geometries. The Finite Elements (FE) models, based on the macro-modelling technique, are subjected to ground motions for the city of Granada, which were selected by considering Probabilistic Seismic Hazard Analysis (PSHA) methodology with their probability of occurrence. The response of each model is analyzed for different seismic Intensity Measure (IM) levels, which, in this study, correspond to average pseudoacceleration. The procedure is applied to three monuments in Granada that were built with two different constructions materials: calcarenite and rammed earth. The damage mechanisms considered are roof displacement or maximum compressive principal stress, depending on each case. The results show that the restoration works that have been carried out has prevented structural failures in the rammed earth construction studied, and that, during future seismic events, special attention must be paid to the level of compressive strengh reached in the Santa Pudia calcarenite used at the San Jerónimo monastery.European Union's Framework Programme for Research and Innovation (Horizon 2020)Spanish Government (Ministerio de Ciencia, Innovacion y Universidades) as part of the Research Projects 821054RTI2018-101841-B-C21 RTI2018-101841-B-C2

A Simple Method for Calculating the Shear Deformation of Reinforced Concrete Elements in the Elastic and Plastic Domains

This paper proposes a simple method for calculating the shear deformation and the shear capacity of reinforced and prestressed concrete elements containing shear reinforcement. This new approach considers that, for large deformations, concrete elements follow compatibility conditions based on displacements of the composite material subjected to shearing forces. The result is a beam, inspired by the Timoshenko-Ehrenfest beam theory, which considers a new hypothesis regarding shearing deformation, informed by the behavior of the shear reinforcement. The new method is compared with previous approaches, allowing us to assess the technological advances of the new proposal. The new method is easy to implement and provides information about the shearing deformation (in the elastic and plastic domains) and the shearing capacity of concrete beamcolumn elements. A detailed example is developed, in which all the components of the shear deformation are evaluated, and the simplification of the new method is analyzed in comparison with other more comprehensive methods in the elastic domainUniversidad de Granada/ CBU

Las tradiciones orales como proceso de enseñanza y de aprendizaje para el fortalecimiento de las tradiciones culturales Arhuacas.

La propuesta busca fortalecer la identidad cultural del pueblo indígena arhuaco, para integrar los saberes propios a las diferentes áreas de saber escolar, la estrategia se fundamenta en la oralidad como recurso comunicativo y pedagógico, utilizado de forma ancestral por la comunidad indígena donde hace presencia la Institución Educativa. La sociedad occidental perdió el atributo de la comunicación oral, como mecanismo para transmitir los conocimientos y una muestra tangible de esto, es el uso del cuaderno y los libros que se utilizan en forma regular en la escuela, como herramientas para la enseñanza y aprendizaje, sin embargo la necesidad del pueblo arhuaco de preservar su identidad cultural requiere, que el educador desde una perspectiva educativa de contexto, diseñe y motive alternativas educativas que conserven el modelo tradicional de enseñanza y aprendizaje. Desde la óptica de utilizar un mecanismo tradicional de enseñanza, la escuela participa en el rescate de la identidad cultural de la etnia arhuaca, más aún si la Institución Dionisia Alfaro está en la construcción de un proyecto educativo comunitario (PEC) que responda a la necesidad de rescatar la educación y conocimientos propios del pueblo étnico Iku. La comunicación verbal, alma de la tradición oral, incluye a los ancianos portadores de la sabiduría ancestral dentro de la sociedad indígena, que vino con su Ley de Origen, esas consideraciones, por supuesto y, en general, a los pueblos ancestrales, que han demostrado, hasta la saciedad, que pueden vivir plenamente y enseñar, aunque no sepan leer y escribir, es un argumento que soporta esta investigación.The proposal seeks to strengthen the cultural identity of the Arhuaco indigenous people, to integrate their own knowledge into the different areas of school knowledge, the strategy is based on orality as a communicative and pedagogical resource, used ancestrally by the indigenous community where the Educational institution. Western society lost the attribute of oral communication, as a mechanism to transmit knowledge and a tangible sample of this, is the use of notebooks and books that are used regularly in school, as tools for teaching and learning, However, the need of the Arhuaco people to preserve their cultural identity requires that the educator, from an educational perspective of context, design and motivate educational alternatives that preserve the traditional model of teaching and learning. From the perspective of using a traditional teaching mechanism, the school participates in the rescue of the cultural identity of the Arhuaca ethnic group, even more if the Institution Dionisia Alfaro is in the construction of a community educational project (PEC) that responds to the need to rescue the education and knowledge of the Iku ethnic people. Verbal communication, soul of the oral tradition, includes the old bearers of the ancestral wisdom within the indigenous society, which came with its Law of Origin, those considerations, of course and, in general, to the ancestral peoples, who have demonstrated, ad nauseam, that they can live fully and teach, although they can not read and write, is an argument that supports this research

Upper bound to the effective area of concrete in tension

Congreso celebrado en la Escuela de Arquitectura de la Universidad de Sevilla desde el 24 hasta el 26 de junio de 2015.The effective tension area of concrete is a well known parameter in structural concrete. It is involved in several phenomena that affect the design of structural concrete elements, such as cracking, shear deformation or flexural deformation. In this work, the authors put forward a necessary change in the definition of the effective tension area of concrete provided by some groups of Standards

Designing compression structures by topological mapping

Congreso celebrado en la Escuela de Arquitectura de la Universidad de Sevilla desde el 24 hasta el 26 de junio de 2015.The Force Density Method has been traditionally employed to seek the equilibrium shape of tension structures. Recently, the use of a process based on topology has been introduced to provide a first network in which the Force Density Method can be applied. Compression-only structures such as vaults and domes can also be modelled by means of the former approach if this is modified to get a design process similar to the Gaudí’s one based on hanging models. The conjunction of Topological Mapping and the Forced Density Method is first explained in the form-finding process of tension structures and, later on, the modifications to that approach are introduced so that an iterative procedure is obtained to get equilibrium shapes of compression-only structures. The versatility of this novel approach is presented by means of the analysis of some representative examples

El mercado venezolano en las exportaciones colombianas: Dependencia de los exportadores en 2006

En este documento analizamos el comportamiento reciente de las exportaciones a Venezuela, y a nivel de firma, la dependencia de los ingresos frente a las ventas realizadas al vecino país en 2006. Para esto se utilizó la base de comercio exterior del Departamento Administrativo Nacional de Estadística (DANE), y los balances de la Supersociedades. Esta revisión muestra que las ventas a Venezuela han crecido de manera importante en el último año, y representan una porción significativa del total de exportaciones del país. A nivel de firma, se observa que la mayoría de las empresas concentraron en Venezuela una porción significativa de sus ventas al exterior, pero éstas no fueron la principal fuente de sus ingresos operacionales. No obstante, un número reducido de firmas, que efectuaron una parte importante de las exportaciones a dicho país, registraron una alta dependencia de sus ingresos operacionales. Se encontró también que los exportadores a Venezuela tienden a especializarse en unos pocos mercados, en lugar de diversificar destinos. Ésta tendencia se ha reforzado durante el auge de los últimos años, pues una proporción alta de exportadores a Venezuela abandonó los demás destinos a los que vendía para atender únicamente éste mercado.Exportaciones, Venezuela, dependencia, ingresos operacionales, empresas. Classification JEL: F14; F19; D23; D29.