New mechanism for continuous and bidirectional displacement of heavy structures: Design and analysis

The aim of this paper is to design and study a new mechanism for moving heavy structures using the force of friction. The mechanism designed is called DCACLM and was patented in 2011. This new device is based on an inverted crawler which is able to displace heavy structures such as large span bridges in a continuous and bidirectional way. Furthermore, the DCACLM design has taken into account other important aspects such as safety and sustainability in order to develop new construction methods. Nonlinear numerical models using the Finite Element Method have been developed to study the complex structural behavior of this new mechanism. The main conclusions provide acceptable results in terms of stresses and strains for the main elements of DCACLM.the authors wish to acknowledge the financial support provided by the Spanish Ministry of Science and Innovation with funds from ALCANZA Research Project number IPT-380000-2010-12. This project has been co-financed with FEDER funds, “A Way of Making Europe”

Patch loading in slender and high depth steel panels: FEM–DOE analyses and bridge launching application

This paper studies the optimum way to design both type and position of the stiffeners when a steel bridge is assembled by means of the new protect-patented launching method based on a self-supporting deck system. This procedure is able to launch bridge up to a span of 150 m, in an economical and sustainable way. The main objective of this research paper is to numerically analyze the best stiffener combination and distribution along the length of bridge, both longitudinally and transversally, in order to avoid the patch-loading phenomenon in the slender webs. An optimum design of a triangular cell along the lower plate is also presented. Thus the best stiffener distribution along the deck can be achieved to solve the two most important factors during the launching of a steel bridge: the huge forces on the support section – higher than the serviceability limit state – and buckling instability due to the point loads on the bearings. In this way, a three dimensional finite element model (FEM) is built and the design of experiments technique (DOE) is applied to obtain the best stiffener configuration. The numerical simulation allows the exact definition of the response of the structure to be achieved, covering the gaps and limits which are common in some national and international codes. Very good results have been obtained, in terms of deflection, patch loading resistance and vertical load distribution on the support section. Finally, the most important conclusions of this work are given.The authors wish to acknowledge the financial support provided by the Spanish Ministry of Science and Innovation with funds from ALCANZA Research Project number IPT-380000-2010-12 and BIA-2012-31609

Bridge–structure interaction analysis of a new bidirectional and continuous launching bridge mechanism

This paper presents a numerical study of the structural interaction between a bridge and a new continuous device for launching heavy structures using the force of friction. In this way, it provides a great contribution for the civil engineering field focused on a new method for launching bridges by a continuous and bidirectional mechanism. A non-linear finite element model using contact elements studies the structural interaction between the bridge and the new device. Bridge and device interaction are studied using linear and non-linear contact behavior. The substructuring technique is used for the bridge modeling in order to reduce the overall degrees of freedom. This technique allows the selection of the best arrangement for two mechanism models placed under the webs of the bridge: two parallel arrangements where external device is opposite or behind the internal one, and other arrangement with devices in series. Furthermore, the non-uniform load distribution over the mechanism was studied during the launching process. With this methodology, it is possible to study the structural behavior of the mechanism taking into account the real load distribution applied for the bridge during the launching process.This work was partially financed with FEDER funds by the Spanish Ministry of Science and Innovation through the Research Project BIA2012-31609 and the Gijon City Council through the SV-13-GIJON-1.7 project. We would also like to thank Swanson Analysis Inc. for the use of the ANSYS University research program and Workbench simulation environment. Finally, we would like to acknowledge the help of the Spanish Ministry of Economics and Competitiveness through the Research Project ALCANZA, IPT-380000-2010-012 INNPACTO program

Improvement of a functional method to determine the design thermal transmittance of building façades. Implementation in southern Spain

The thermo-hygrometric conditions to which construction materials are subjected cause their thermal performance to vary by location. These variations must be characterised in order to design building envelopes adjusted to the requirements of each situation, thus contributing to improve their energy efficiency under actual operating conditions. To this end, a functional calculation procedure that corrects the standardised thermal conductivity values of façade materials (¿-value) has been recently proposed; which considers the climatic characteristics of each location. This work proposes and validates improvements that, while preserving its functionality, overcome some limitations of the original procedure. To calculate more accurate corrections, the façade configuration and the climatic zones established by the building codes are also considered, allowing a more reliable characterisation of the design thermal transmittance of each building façade. By using climatic records gathered from 316 weather stations, a detailed isopleth map is also developed to present the applicable corrections for more than 250, 000 km2 of southern Spain. The largest ¿-value corrections are identified on the southeast coast and reach up to +6% in the summer months (with average annual corrections above +4%). This improved procedure can be extrapolated to any national building code that establishes constant values of thermal conductivity for façade materials and that defines thermal design requirements based on climatic zones

Estudio comparativo experimental del comportamiento de uniones de cumbrera en cubiertas de madera laminada encolada con placas interiores de acero o tablero contrachapado de abedul

El presente trabajo tiene por objeto llevar a cabo un análisis experimental del comportamiento mecánico de ciertos sistemas planos de unión para elementos estructurales de madera laminada empleados en la construcción de cubiertas El estudio incluye los ensayos a escala real de seis din-teles a dos aguas de madera laminada, de 6 m de luz, 1 m de altura y una sección de 100 mm x 180 mm, sometidos a flexión en cuatro puntos. En tres dinteles el elemento de unión es una pieza de tablero contra-chapado de abedul, mientras que en los otros tres se ha utilizado un herraje de acero. La finalidad es valorar la posibilidad de sustituir los elementos de unión, realizados mediante herrajes, por otros constituidos por piezas de tablero contrachapado de abedul. Este objetivo se logra comparando el comportamiento resistente mostrado por ambos dispositivos de unión, y las deformaciones en cada caso de las estructuras completas. Los resultados resultaron muy satisfactorios tanto en la capacidad portante como en la rigidez de los dintele

Método de diseño de sistemas flexibles anclados al terreno

Un método de diseño de un sistema flexible anclado al terreno para la estabilización de un talud, donde dicho sistema flexible comprende al menos una membrana flexible y una pluralidad de bulones para anclar dicha membrana flexible al terreno, y donde dicho talud comprende una masa estable y una masa inestable. El método comprende las etapas de: calcular la forma y las dimensiones de una masa inestable de un talud, siendo dicha masa inestable el círculo de rotura en el caso de un talud de suelo y la cuña en el caso de un talud de roca; introducir al menos los siguientes componentes geométricos: la masa inestable del talud calculada en la etapa anterior, la masa estable del talud, la membrana flexible y la ubicación de las cabezas de dicha pluralidad de bulones; asignar una formulación numérica a cada componente geométrico anterior; introducir las propiedades de los materiales de al menos los siguientes componentes geométricos anteriores: masa inestable del talud, masa estable del talud y membrana flexible; definir las siguientes interacciones o contactos entre componentes geométricos: masa inestable del talud y masa estable del talud, masa inestable del talud y membrana flexible, y masa estable del talud y membrana flexible; simular numéricamente de forma dinámica la caída de dicha masa inestable de talud como consecuencia de la fuerza de la gravedad, obteniendo los valores instantáneos en el tiempo de la fuerza a tracción en al menos dicha membrana flexible.Solicitud: 201100456 (19.04.2011)Nº Pub. de Solicitud: ES2363587A1 (09.08.2011)Nº de Patente: ES2363587B1 (19.06.2012

Modelos de selección y promoción. El caso de la Universidad de Oviedo

La paralización en la dotación de plazas de cuerpos docentes y el incremento en el número de docentes acreditados a las figuras de profesorado funcionario han llevado a las universidades públicas a una situación que las obliga a establecer mecanismos de promoción y estabilización, que permitan corregir las deficiencias estructurales y de plantilla. El presente artículo quiere mostrar el procedimiento desarrollado en la Universidad de Oviedo