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Study of the fresh state of steel fiber reinforced self compacting concrete
No full textLa implementación de fibras de acero en concretos auto-compactantes es un tema objeto de investigación en la actualidad debido a las ventajas que proporciona este material en términos estructurales, económicos y ambientales. Este proyecto pretende evaluar las propiedades en estado fresco del concreto auto-compactante reforzado con fibras de acero, a partir de un análisis de estadística descriptiva y un estudio de sensibilidad estadístico. En esta investigación se determinó la incidencia de utilizar proporciones de fibra del 0.0% - 2.0% (con respecto al volumen total de la mezcla) y relaciones agua cemento entre 0.4-0.6, en las propiedades reológicas del concreto auto-compactante. Para lograr el objetivo se utilizó un diseño estadístico de experimentos multi-variable del tipo central compuesto desde puntos axiales basado en un factorial 2k con puntos al centro, en conjunto con la metodología de superficie de respuesta y el análisis de varianza (ANOVA). Se evaluó la incidencia de los factores estudiados sobre la viscosidad plástica y el esfuerzo de fluencia calculados con base en el modelo lineal de Bingham. Los resultados obtenidos evidencian una disminución en la trabajabilidad del concreto auto-compactante al añadir fibras de acero. Además, las superficies de respuesta cemento en la viscosidad plástica, el esfuerzo de fluencia y la resistencia a la compresión; mientras que la incorporación de fibras de acero solo resultóPregradoIngeniero CivilThe implementation of steel fibers in self-compacting concrete is subject of research nowadays due to the advantages the material provides in structural, economic and environmental terms. This project aims to evaluate the fresh state properties of self-compacting concrete reinforced with steel fibers, based on a descriptive statistics analysis and a statistical sensitivity study. In this research the incidence of using fiber proportion between 0.0%-2.0% (regarding the total volume of the mixture) and water-binder ratios between 0.4-0.6 was determined in rheological properties of the self-compacting concrete. To achieve the objectives, a statistical design of multi-variable experiments of the type central composed from axial points based on a 2k factorial with central points was used, along with the response surface methodology and analysis of variance (ANOVA).The influence of the factors studied on the plastic viscosity and yield stress calculated based on the Bingham linear model, was evaluated. The obtained results evidenced a decrease in the workability of the self-compacting concrete when adding steel fibers. In addition, the results obtained suggest a statistically significant (=0.10) incidence of the water binder ratio on the plastic viscosity, static yield stress and compressive strength; whereas the addition of steel fibers only was statistically significant (=0.10) on the static yield stress
Alysis for a building incorporating soilstructure interaction *
No full textEl estudio del comportamiento sísmico de las edificaciones ha demostrado que su capacidad, medida en términos del coeficiente modificación de respuesta sísmica R, se ve considerablemente afectada por la interacción suelo-estructura (ISE). Sin embargo, hay poca información sobre el efecto de este fenómeno en el coeficiente R para edificaciones que involucran muros estructurales, debido al alto costo computacional que demandan estos modelos. Por lo tanto, este proyecto de investigación estudia el efecto de la ISE sobre R, mediante un caso de estudio de una edificación irregular con muros estructurales y un sistema de cimentación de zapatas aisladas cargadas excéntricamente a través de un modelo de análisis no lineal estático de plasticidad concentrada computacionalmente eficiente, en el software SAP-2000. Se estudiaron los efectos de un suelo con velocidades de onda de corte (Vs) entre 360 (m/s) y 180 (m/s), modelados como resortes discretos e independientes contemplando la plasticidad del suelo y el levantamiento de los cimientos. Se determinaron las curvas de capacidad y los valores de R en la dirección no simétrica Y en sentido negativo (-Y) y positivo (+Y) y en la dirección X, para 39 modelos con pandeo; i) 1 modelo restringido en la base, ii) 19 modelos con comportamiento lineal del suelo, iii) y 19 modelos con comportamiento no lineal del suelo. Se compararon los resultados obtenidos de R respecto al modelo restringido en la base encontrando que los valores de R aumentaron al incluir los efectos de ISE siendo más notorio este cambio en la dirección X donde la fuerza sísmica afectó a los muros fuera del plano, presentándose valores de R promedio con respecto al modelo restringido en la base en las direcciones X, +Y y -Y para suelo lineal de 103%, 12.7% y 2% y para suelo no lineal de 104%, 12.7% y 2.2%, respectivamente.PregradoIngeniero CivilThe study of seismic behavior on buildings has demonstrated that its capacity measured in terms of response reduction factor R is considerably affected by soil-structure interaction (ISE, by its acronym in Spanish). Although, there is few information about the effect of this phenomena in the R coefficient for buildings with structural walls due to the high computational cost demanded by the models. Therefore, this research project studies the effect of ISE on R through a case of study of an irregular building with structural walls and an isolated footings foundation system loaded eccentrically by means of a nonlinear static analysis model of concentrated plasticity computationally efficient using the software SAP-2000. Capacity curves and R coefficients were determined in the non-symmetric direction Y for positive axis (+Y) and negative axis (-Y) and in X direction, for 39 models with buckling: i) 1 model fixed at base ii) 19 models with linear soil behavior iii) and 19 models with nonlinear soil behavior. The R coefficients results obtained were compared respect the fixed model finding that R coefficient increase due to the ISE effects being more noticeable this change in X direction where the seismic force affected the walls out of plane, presenting average values of R coefficient respect the fixed model in X, +Y and -Y directions to the lineal soil of 103%, 12.7% y 2% and to the nonlinear soil of 104%, 12.7% and 2.2%, respectively
Pedagogical practice in the subject design of reinforced concrete i
No full textEl desarrollo de la sociedad está ligado a la formación de personas innovadoras y competentes en materia de su profesión, siendo la universidad una etapa donde el aprendizaje ético, cognitivo y social se enfoca hacia cierta área del conocimiento, sin pasar por alto la formación integral y teniendo en cuenta que actualmente es imperativo el buen manejo de herramientas tecnológicas. Aspectos muy importantes del conocimiento técnico y la responsabilidad de los profesionales en ingeniería civil formados por la Universidad Industrial de Santander, los cuales están relacionados con el curso Diseño de Hormigón Armado I, debido a que este es el primer curso de pregrado donde los conceptos se aplican directamente a la industria del diseño estructural y la construcción. Este proyecto se enfocó en integrar actividades al curso desarrollado durante el primer semestre del año 2016, cuya función fue servir como fundamento, guía e inspiración al futuro profesional. Las actividades desarrolladas se seleccionaron con base en las propuestas del ABET (Accreditation Board for Engineering and Technology) junto a las recomendaciones de los estudiantes y profesores. Dichas actividades, implementadas por primera vez en la historia del curso, buscaron acortar la brecha entre la academia y la industria de la construcción, desarrollar las habilidades en manejo de software especializado, contribuir a la realización del perfil profesional, utilizar normativa nacional e internacional para el cálculo de edificaciones y enfatizar en la aplicación de los conceptos a la práctica del diseño estructural.PregradoIngeniero CivilSociety development is related to the formation of innovative and competent people in matter of their profession, being the university a stage where the ethic, cognitive and social learning focusses into a specific area of knowledge, without overlooking integral formation and taking on account nowadays it is imperative the good use of technological tools. Very important aspects about technical knowledge and the responsibility of the professionals at Civil Engineering formed at Industrial University of Santander are related to the subject Design of Reinforced Concrete. This is the first subject on the undergraduate program where concepts are directly applied to the structural design and construction industry. This project focused on integrating activities to the course which were developed on the first semester of 2016, whose role was serving as basis, guide and inspiration to the future professional. The proposed activities were selected based on the ABET (Accreditation Board for Engineering and Technology) along the student and teachers recommendations. shorten the gap between the academy and the construction industry, to develop skills on specialized software use, to contribute on the realization of the professional profile, to use national and international building codes and to emphasize in the application of the theoretical concepts to the structural design practice
Test protocol for the systematic evaluation of the response to loads and deformations of a beam-column connection reinforced with fique fiber mesh with graphite oxide
No full textEste artículo presenta un protocolo de prueba diseñado para comparar la respuesta estructural de conexiones viga-columna en condiciones óptimas y deterioradas. El enfoque principal se centra en la determinación de la respuesta estructural de la conexión viga-columna, el desarrollo de un método de reparación externo y la implementación de un procedimiento de laboratorio que permite evaluar la deformación completa en el nodo y la curvatura de la viga bajo un protocolo de carga específico. El método de reparación externo propuesto utiliza malla de fibra de fique impregnada con óxido de grafito para rehabilitar conexiones viga-columna afectadas. Este protocolo busca proporcionar una evaluación exhaustiva del desempeño estructural, resaltando las mejoras resultantes del refuerzo externo con materiales específicos mediante diagramas de momento-curvatura.PregradoIngeniero CivilThis article presents a testing protocol designed to compare the structural response of beam-column connections under optimal and deteriorated conditions. The main focus is on determining the structural response of the beam-column connection, developing an external repair method, and implementing a laboratory procedure to evaluate the complete deformation at the node and the curvature of the beam under a specific loading protocol. The proposed external repair method uses a jute fiber mesh impregnated with graphite oxide to rehabilitate affected beam-column connections. This protocol aims to provide a comprehensive assessment of structural performance, highlighting the improvements resulting from external reinforcement with specific materials through a moment-curvature diagram.https://orcid.org/0009-0006-4071-253
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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