Search

This paper presents numerical pushover analyses on multiple bay pallet racks, aiming to quantify variations in global ductility when using different beam-to-upright connections. The connections differ in the layout of the beam-to-endplate welding, being one of them a technological novelty. They are modeled with envelopes of monotonic and cyclic moment-rotation curves obtained from component tests and presented in previous research. Moreover, the influence of the level height is studied throughout two different rack configurations. A single-column model for multiple bay racks, made with 3D beams and shells, is presented and compared with simpler 2D models to quantify the influence of 3D effects and upright perforations. Results exhibit that the novel connection improves the capacity to absorb energy, but an inappropriate rack configuration can lead to a soft-story mechanism, thus not taking full advantage of its ductility.

This thesis studies the vibration pattern synthesis in structures using the Dynamic Mode Decomposition (DMD) method. This numerical model is used for one degree of freedom, to know the axial response, according to x. Firstly the effectiveness of the DMD method is evaluated and give good results to reconstruct the signal, applying to initial conditions of the structure's vibration to extract the shape and temporal characteristics of the DMD modes, which were then used to synthesize the desired vibration pattern in the structure. Next, QR factorization is used in order to find sensor placement. Results showed that the DMD method, combined with QR factorization, can effectively synthesize the desired vibration pattern in structures. However, conditions about spacing of the sensors is necessary to optimize the interpolation. Regarding further research, it’s needed to study the method's limitations and potential application in more complex systems or when dealing with high-frequency data. Incoming

En este estudio se ha llevado a cabo la simulación de un ensayo realizado en los laboratorios de la Universidad Politécnica de Cataluña. El ensayo en cuestión consistió principalmente, en aplicar una carga cíclica a vigas reforzadas con FRCM (FabricReinforced Cementitious Matrix) de fibras vegetales (algodón y cáñamo) y estudiar su comportamiento. El entorno utilizado para realizar las simulaciones es ANSYS 2020 R2, concretamente uno de sus módulos; ANSYS Mechanical. Antes de realizar las simulaciones, se ha investigado el estado actual de la tecnología en la que se trabaja. Han sido analizados trabajos con vigas reforzadas con FRCM, cargas estáticas, o refuerzos vegetales como temas principales. Después de conocer las últimas novedades sobre el tema del proyecto, se empezaron a diseñar las primeras simulaciones. Se empezó calibrando la viga de control, y más adelante se añadieron los refuerzos y se ajustaron sus parámetros. En este trabajo, se redacta todos los comandos utilizados en el software, siendo útil como guía para otras simulaciones similares. Tras conseguir ajustar todas las variables que afectaban el comportamiento de la viga, se han conseguido muy buenos resultados, la simulación con el error mínimo es del 2 %, y la simulación menos ajustada tiene un error del 12 %. Además, se han comparados con los resultados reales obtenidos de los ensayos, cumpliendo así con los objetivos principales. Finalmente, se ha utilizado el mismo modelo para simular otras vigas con el mismo tipo de refuerzo, pero con diferente tipo de malla. Así concluyendo que este modelo es capaz de prever el comportamiento de las vigas conociendo las características de su malla. Esta validación se realizó comparando los nuevos resultados con ensayos experimentales. In this study, the simulation of a test carried out in the laboratories of the “Universidad Politécnica de Cataluña” has been carried out. The test in question consisted mainly of applying a cyclic load to beams reinforced with FRCM (Fabric-Reinforced Cementitious Matrix) of vegetable fibres (cotton and hemp) and studying their behaviour. The environment used to carry out the simulations is ANSYS 2020 R2, specifically one of its modules; ANSYS Mechanical. Before starting out the simulations, the current state of the art of the technology used has been investigated. Works with FRCM reinforced beams, static loads and plant reinforcements as main topic were analysed. After learning about the latest developments on the subject, the first simulations were designed. We started by calibrating the control beam model, and later we added the reinforcements and adjusted their parameters. In this work, all the commands used in the software are written, being useful as a guide for other similar simulations. After adjusting all the variables affecting the behaviour of the beam, very good results have been achieved, the simulation with the minimum error is 2 %, and the least adjusted simulation has an error of 12 %. Moreover, they have been compared with the real results obtained from the tests, thus fulfilling the main objectives. Finally, the same model has been used to simulate other beams with the same type of reinforcement, but with a different type of mesh. Thus, concluding that this model is able to predict the behaviour of the beams knowing the characteristics of their mesh. This validation was carried out by comparing the new results with experimental tests.

Aquest treball és un estudi de calibració d’un model simulat de biga reforçada amb malles vegetals a través de l’anàlisi modal. En el treball es crea un model de biga simulada que reflecteixi de la manera més similar possible el comportament de les bigues reals. L’objectiu de la simulació de les bigues és poder crear un model que pugui reflectir correctament els comportaments de les bigues experimentals. Gràcies a aquest model es pot reduir els costos tant econòmics com ambientals de l’experimentació amb bigues i el temps necessari que s’hauria d’invertir en la seva fabricació. L’estudi és purament simulat, ja que es la part que més ocupa i la més important del treball. Per dur a terme les simulacions es necessitaran dos programes, SolidWorks, que s’utilitzarà per generar i assemblar les diferents parts de la geometria de la biga i l’ANSYS Workbench, que s’utilitzarà per simular les bigues. Els materials principals que s’estudiaran són el formigó, morter, acer, cànem i cotó. Els paràmetres a trobar per dur a terme l’anàlisi són les freqüències naturals de les bigues, les seves formes modals corresponents i la diferència entre els resultats experimentals i els simulats que s’obtindran calibrant les propietats de densitat i mòdul de Young dels diferents materials. A partir dels resultats obtinguts es realitzaran les comparacions corresponents entre els assajos experimentals i les simulacions, si la diferència es inferior a 10% s’accepten els resultats com a bons. Es pot dir que el principal objectiu del treball s’ha pogut assolir gràcies a la diferència entre els resultats experimentals i els simulats. A través d’aquest paràmetre es pot calibrar correctament el model per aproximar-se el màxim possible a les proves experimentals. This work is a calibration study of a simulated model of a reinforced beam with plant mesh through modal analysis. This work creates a simulated beam model able reflect in the most similar way possible the behaviour of real beams. The goal of the beam simulation is to create a model that can accurately reflect the behaviour of experimental beams. Thanks to this work it’s possible to reduce both economic and environmental costs of experimenting with beams and the time needed to manufacture said beams. The study is purely simulated, as it is the biggest and most important part of the work. Two programs will be needed to perform the simulations, SolidWorks, which will be used to generate and assemble the different parts of the beam geometry, and ANSYS Workbench, which will be used to simulate the beams. The main materials to be studied are concrete, mortar steel, hemp, and cotton. The parameters needed to complete the study are the natural frequencies of the beams, their corresponding modal forms, and the difference between the experimental and simulated results that will be obtained by calibrating physical properties of the density and the Young modulus of the different materials. Based on the results obtained, the corresponding comparisons will be made between the experimental tests and the simulations, if the difference is less than 10%, the results will be accepted as satisfactory. It can be said that the main goal of the study was achieved thanks to the difference between experimental and simulated results. Through this parameter, the model can be correctly calibrated to resemble as closely as possible the experimental tests.

Las estructuras son una gran parte de los proyectos arquitectónicos y nuestras decisiones en todas las fases de diseño las condicionan en gran medida. Es por esto que como arquitectos debemos conocer y saber las dimensiones aproximadas de las estructuras que proyectamos. Este trabajo se centra en la presentación de la viga atirantada o viga Fink, un sistema constructivo que ofrece ligereza, tanto material como espacial, en edificios de grandes luces como pabellones o auditorios. Este sistema busca proponer proyectos cuya estructura es más ligera y por tanto más económica y ecológica gracias a un diseño en que la estructura deja de ser un simple elemento pasivo y pasa a estar activada. Este tipo de soluciones en que la estructura pasa a estar diseñada para trabajar junto al edificio requieren de coordinación con el diseño del resto de partes del edificio, por lo que es importante que, aunque no realicemos un cálculo preciso en cada uno de los pasos del proyecto, sepamos qué dimensiones de predimensionado irán tomando en cada paso del proceso. Structures are a large part of architectural projects and our decisions in all design phases condition them to a great extent. That’s why as architects we must know the approximate dimensions of the structures we are going to build. This thesis focuses on the presentation of the strut and tie beam or Fink truss, a construction system that offers lightness, both material and spatial, in buildings with large spans such as pavilions or auditoriums. This system seeks to propose projects whose structure is lighter and therefore more economical and ecological thanks to a design in which the structure ceases to be a simple passive element and becomes activated. This type of solution in which the structure is designed to work together with the building requires coordination with the design of the rest of the building's parts. It’s important that although we do not carry out a precise calculation in each of the steps of the project, we know what approximate dimensions they will take in each step of the process.

This paper is the result of both experimental and numeric analyses on pallet rack components. Two cyclic testing protocols for beam-end connectors of adjustable racking systems are compared; such experiments are named as “code type” and “Castiglioni”. Both protocols share the same test mock-up: an assembly of a doubly-pinned upright segment with a cantilever beam specimen. These tests consist in an up-to-failure increasing push-pull process at the free beam end. In the “code type” test, the imposed displacement loops are centered around zero; conversely, in the “Castiglioni” tests, both upward and downward displacement segment runs are centered around a vertical static equilibrium situation (to take the gravitational load into account). The “code type” test is expected to result in a higher number of cycles than the “Castiglioni” one because of the two following features of the latter: (i) the gravitational load is always present, thus resulting in a higher demanding test, and (ii) the failure point is precisely predefined and usually produced before the total breakdown. This paper describes and compares experiments using both protocols. Additionally, these tests are numerically simulated.

Orientador: Armando Lopes Moreno Junior Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil Resumo: O objetivo deste trabalho é oferecer uma parcela de contribuição ao estudo do comportamento de vigas de concreto de alta resistência reforçadas externamente com mantas unidirecionais de polímero reforçado com fibras de carbono (pRFC), técnica esta que vem sendo executada desde 1980, porém, ainda pouco difundida e estudada no Brasil. Seis vigas, com resistência à compressão do concreto em tomo de 90 :MPa, e, mesma geometria e armaduras, longitudinal e transversal, foram levadas à ruptura por flexão. Uma viga foi considerada como viga padrão e outras cinco foram reforçadas à flexão, por intermédio de mantas de fibras de carbono aderidas às suas faces inferiores. Em três das vigas reforçadas um mecanismo de incremento de ancoragem, nas regiões próximas aos apoios, foi proposto. Os resultados experimentais foram comparados com valores esperados, que por sua vez foram obtidos de acordo com uma metodologia de cálculo à flexão desenvolvida com base no estudo de trabalhos já realizados por outros autores. Os valores dos momentos fletores de início de descolamento da manta, nas vigas sem os laço de ancoragem, também foram confrontados com valores previamente esperados. Foram ainda realizados ensaios de aderência e propostas duas metodologias para o dimensinamento dos mecanismos de melhoria da ancoragem. De acordo com os ensaios realizados pôde-se constatar que a ruptura prematura por descolamento total da manta pode ser evitada pelo mecanismo de ancoragem proposto, sendo que o reforço, pelo próprio arranjo sugerido, além de retardar o início do escoamento da armadura longitudial inferior, atua como alternativa de reforço ao esforço cortante. A resistência última à flexão da viga reforçada com quatro camadas e laços de ancoragem foi aumentada, em relação à viga testemunho, em 157 % Abstract: The objective of this dissertation is to offer a contribution in the study of the behaviour of high strength reinforced concrete beams with externally bonded carbon fiber reinforced plastic (CFRP) sheets, wich is a technique that has been executed since 1980. Six beams, with concrete strength around 90 :MPa, and with identics geometry and internal reinforcing bars were tested under bending until failure. One specimen was used as a control beam and the other five were strengthened, in flexure, with the use of CFRP sheets bonded to the tension face of the members. In three of the strengthened beams was proposed anchorages at the sheet ends, near the supports. The experimental results were compared with the analytical values. The bending moments registered in the begining of the debonding of the sheets, in the beams with no anchorage systems, were also compared with previously determined values. Aderence tests to verify the quality of the bonding in the interface sheet-concrete and two proposals of calculating methodologies for the anchorage systerns were also conducted. It was seen that the premature debonding of the sheet can be avoided through the use of the anchorage systems proposed, and, this anchorage, because of its design, can also improves the shear capacity of the beams. The results showed an increment in the ultimate flexural resistance of the beam strengthened with four plies, in comparison with the beam with no external reinforcing, of 157 % Mestrado Estruturas Mestre em Engenharia Civil

Na mecânica estrutural estocástica, o tratamento da incerteza é frequentemente o principal objetivo das simulações numéricas utilizadas para estimar as respostas de um sistema ou fenômeno físico. Essas previsões podem formar a base para a tomada de decisões e, portanto, uma questão relevante a ser estudada é o quão confiável elas são. As incertezas, em geral, são avaliadas sob dois aspectos: a partir da informação estatística disponível e considerando o modelo matemático que representa o problema numericamente. O modelo identifica um conjunto de relações geralmente baseadas em princípios, leis de conservação e métricas de magnitude física. No caso do problema de flexão estocástica de viga é possível associar a aleatoriedade às propriedades do material, da geometria e as cargas atuantes sobre a estrutura e, desta forma as estimativas das respostas estarão presentes no campo de deslocamento, tensão e deformação. No presente trabalho, a formulação variacional do problema estocástico de valor de contorno elíptico com coeficientes aleatórios é estudada à luz da versão estocástica do lema de Lax-Milgram e a propagação e quantificação da incerteza são investigadas a partir da recente metodologia numérica de complexidade assintótica λ-Neumann Monte Carlo. Os resultados da simulação numérica são obtidos para o problema de flexão estocástica de viga de Levinson-Bickford. Esta teoria de alta ordem apresenta a vantagem de atender à condição de cisalhamento nulo nas superfícies laterais e sua formulação pelo método dos Elementos Finitos evita o inconveniente numérico de travamento (shear locking). As soluções são apresentadas sobre um conjunto de aproximações numéricas através de estimativas de erro dos estimadores de valor esperado e variância do campo de deslocamento. São comparados diferentes métodos de quantificação, modelagem da incerteza, condições de contorno, coeficiente de variação e propriedades material e geométrica da viga. In stochastic structural mechanics, the treatment of uncertainty is often the main goal of numerical simulations used to estimate the responses of a system or physical phenomenon. These predictions can form the basis for decision making, and therefore a relevant question to be studied is how reliable they are. In general, uncertainties are evaluated from two aspects: from the available statistical information and by considering the mathematical model that represents the problem in a numerical way. The model identifies a set of relationships usually based on principles, conservation laws, and metrics of physical magnitude. In the case of the stochastic beam bending problem, it is possible to associate randomness to material properties, geometry and loads acting on the structure, and thus the response estimates will be present in the displacement, stress and strain field. In the present work, the variational formulation of the stochastic elliptic boundary value problem with random coefficients is studied in the light of the stochastic version of the Lax-Milgram lemma, and the propagation and quantification of uncertainty are investigated from the recent λ-Neumann Monte Carlo numerical methodology of asymptotic complexity. Numerical simulation results are obtained for the Levinson-Bickford stochastic beam bending problem. This high-order theory has the advantage of meeting the condition of zero shear at the lateral surfaces, and its formulation by the Finite Element method avoids the numerical drawback of shear locking. The solutions are presented over a set of numerical approximations through error estimates of the expected value and variance estimators of the displacement field. Different methods of quantification, uncertainty modeling, boundary conditions, coefficient of variation, and material and geometric properties of the beam are compared.

A butterfly web girder is a box girder that has discretely distributed side-surface openings. Due to these openings, butterfly web girders show better aerodynamic performance than conventional box girders. This study aims to investigate the effects of side-surface openings on the aerodynamic instability of a box girder when it is placed in tandem with another girder. In addition, this study aims to investigate whether the aerodynamic instability of one girder is affected by the side-surface openings of an adjacent girder. A series of wind tunnel tests will be carried out on a butterfly web girder and conventional box girder, with another rigidly supported butterfly web girder or conventional box girder, respectively, at its upstream or downstream side. The fixed downstream girder increased the galloping instability of the upstream girder, and the fixed upstream girder amplified the vortex-induced vibration of the downstream girder. The side-surface openings of the upstream girder stabilized its galloping and vortex-induced vibration, irrespective of the type of girder downstream. The side-surface openings of the downstream girder stabilized its vortex-induced vibration independent of the type of girder upstream.

La tècnica de correlació d’imatges digitals, Digital Image Correlation en anglès, i d’ara endavant DIC, és un mètode que permet mesurar desplaçaments i deformacions a partir de la correlació d’imatges, tal com indica el seu nom. En aquest treball es requereix dissenyar, fabricar i analitzar una biga d’eix curvilini, en forma de “U”, que pugui aguantar els esforços generats en una estructura de suport existent. El disseny ha de permetre simular el comportament del material mitjançant eines computacionals, així com el seu assaig a través de tècniques extensomètriques clàssiques i avançades. L’objectiu del treball és, en primer lloc, dissenyar tres models de peça de diferents dimensions mitjançant mètodes analítics i numèrics (elements finits) i analitzar el seu estat de tensions i deformacions quan se sotmeten a diferents càrregues verticals, tenint en compte que sempre es treballarà per sota del límit elàstic del material de la peça i de l’estructura de suport. Les deformacions s’avaluaran en els punts extrems de la secció central de la peça a través de galgues extensomètriques i de la tècnica DIC. Per últim, es compararan els resultats experimentals i numèrics amb els resultats analítics The Digital Image Correlation Technique, Digital Image Correlation in English, and now forward DIC, is a method that allows to measure displacements and deformations from of the image correlation, as its name suggests. This work requires the design, manufacture and analysis of a curvilinear beam, U-shaped, which can withstand the stresses generated in a support structure existing. The design must allow to simulate the behavior of the material by means of computer tools, as well as their testing through extensometric techniques classic and advanced. The goal of this work is to first design three different part models dimensions using analytical and numerical methods (finite elements) and analyze their state of stresses and strains when subjected to different vertical loads, bearing note that work will always be done below the elastic limit of the material of the piece and of the support structure. Deformities will be assessed at the endpoints of the section central part of the piece through extensometric gauges and the DIC technique. Finally, the experimental and numerical results will be compared with the analytical results

The general characteristics of earthquake-resistant structures of running tunnels and shallow underground stations of the Tashkent subway developed and implemented in the design and construction of the first Chilanzar, the second Uzbekistan and the third Yunusabad lines of the Tashkent subway are given. The results of the experimental research carried out by the theoretician are described. The necessity of creating new lines is substantiated. The features of constructive solutions of overhead lines are described.

La present tesi, s'ha centrat en el desenvolupament d'un model de resistència a tallant de bigues pretensades amb armadures preteses de FRP, vàlid per a seccions rectangulars, T o I, amb o sense armadures transversals de FRP. Es tracta de l'adaptació d'un model desenvolupat a la UPC (Barcelona) i a la UIB (Mallorca) per esforç tallant en bigues, anomenat "Multi-action Shear Model (MASM)", que posteriorment va ser estès a bigues de formigó pretensat amb armadures d'acer i a bigues armades amb FRP. En aquesta tesi s'ha reformulat i verificat experimentalment el model per a bigues pretensades amb armadures d'acer, i s'ha adaptat al cas de pretesat amb armadures actives de FRP, tenint en compte els efectes de les seves propietats a la resistència a tallant. S'ha observat que l'adherència entre l’armadura de FRP i el formigó juga un paper determinant en la resistència a tallant. Això ha propiciat la realització d’una formulació per a identificar la ruptura deguda a una longitud d'ancoratge insuficient. Aquesta formulació s'ha verificat amb una sèrie d'assajos experimentals mencionats a la bibliografia, havent obtingut bona concordança en la tipologia de trencament i una bona precisió en les prediccions de la resistència, tot i les incerteses existents en aquest camp. D’altra banda, el model s’ha utilitzat per dur a terme una predicció dels assajos a tallant que es realitzaran en l'àmbit del projecte Straduravius. La presente tesis se ha centrado en el desarrollo de un modelo de resistencia a cortante de vigas pretensadas con armaduras pretesas con armaduras activas de FRP. Se trata de la adaptación de un modelo desarrollado en la UPC (Barcelona) y en la UIB (Mallorca) para cortante en vigas, llamado “Multi-action Shear Model (MASM)”, que posteriormente fue extendido a vigas de hormigón pretensado con armaduras de acero y a vigas armadas con FRP. En esta tesis se ha reformulado y verificado experimentalmente el modelo para piezas pretensadas con armaduras de acero y se ha adaptado a vigas pretensadas con barras de FRP como armadura activa, incluyendo los efectos de sus propiedades en la resistencia a cortante. Se ha observado que la adherencia entre el FRP y el hormigón juega un papel fundamental en la resistencia a cortante, lo cual ha dado lugar al desarrollo de una forma de identificar la rotura por insuficiente anclaje. Ello ha sido verificado con una serie de ensayos disponibles en la bibliografía, en los que se ha obtenido una buena concordancia en la forma de rotura y una buena precisión en las predicciones de la resistencia, a pesar de las incertidumbres en este campo. Por otra parte, el modelo ha sido utilizado para hacer una predicción de los ensayos que se realizarán en el ámbito del proyecto Straduravius, el Laboratorio de tecnología de estructuras y materiales de la UPC. The present Master’s thesis has focused on the development of a mathematical model of shear strength on prestressed pre-tensioned concrete beams, with FRP prestressing reinforcements, valid for rectangular, T and I sections, with or without transversal FRP reinforcements. This model is based on a previous one developed in the UPC and at the University of Balearic Islands (UIB), for the shear strength of steel reinforced concrete beams, named “Multi-action Shear Model (MASM)”, which was later extended to prestressed concrete beams with steel reinforcements and to RC beams using FRP as passive reinforcement. In this thesis, first the model has been reformulated and experimentally verified for prestressed concrete beams with steel reinforcement and, subsequently, has been adapted to beams with FRP active reinforcement, accounting for the effects of FRP’s properties on their shear strength. Moreover, it has been observed, that bond between FRP and concrete plays a relevant role in determining the shear strength. Therefore, a mathematical model to identify when such type of failure takes place, has been developed in this thesis. The model has been verified using the shear tests available in the literature, obtaining a good concordance on the failure mode and good precision on the strength predictions, even within the uncertainties of the field. In addition, the model has been used to predict the results of the shear tests to be performed within the scope of Straduravius project.

Wooden multi-span beams with steel reinforcement were studied experimentally on a stationary stand using an eight-point loading scheme that simulated a load uniformly distributed over the beam span. The studies were carried out on beams with a span of 4.8 m with a cross-sectional area of 40 mm × 80 mm, reinforced in the stretched zones of the cross-section with rods made of hot-rolled steel reinforcement of A400 class. The rational zones for the location of reinforcements in the tensioned and compressed zones of the beams were determined. The rational placements of reinforcement in the support and span zones was based on the numerical simulation of the volumetric stress state calculated using the finite element method. It was experimentally confirmed that the failure of wood composite beams had a plastic nature and occurred only along normal sections. This excluded the possibility of brittle fracture from shear stresses and ensured the operational reliability of structures as a whole. It was shown that the proposed rational reinforcement of wooden beams increased their bearing capacity by 175% and reduced bearing deformability by 85%. The results obtained indicated high efficiency of the application of the developed method of reinforcement in beams of roofs and floors of buildings.

A través de los años se ha estudiado que el comportamiento del hormigón armado sometido a esfuerzos transversales se ve muy influido por el estado multi-axial de tensiones en el hormigón y el comportamiento anisótropo a que da lugar, después de la fisuración, debido a la distinta resistencia a tracción y compresión. Este mismo comportamiento depende de la capacidad de las fisuras de una viga de hormigón para transmitir tensiones, según su abertura e interacción con la región de la viga que permanece sin fisurar. Por lo tanto, podemos observar que el comportamiento a cortante tras la fisuración del hormigón es complejo y ha sido tradicionalmente abordando con modelos empíricos, que desprecian algunos efectos o que han sido calibrados hace décadas y para situaciones específicas. Por ello, tales modelos y expresiones, en general, no son directamente aplicables a casos diferentes a aquellos para los que fueron derivados. Debido a estas limitaciones se han desarrollado modelos teóricos que tratan de cuantificar las distintas componentes de la contribución del hormigón. Entre ellos el modelo, “Compresion Chord Capacity Model” (CCCM), derivado a partir de uno más general (Multi-action shear model, MASM) previamente desarrollado por los mismos autores, incorpora las contribuciones de la cabeza de compresión del hormigón, el alma fisurada, el efecto pasador de las armaduras y el refuerzo de corte en una expresión compacta. El carácter mecánico del modelo proporciona información valiosa sobre la física del problema e incorpora los parámetros más relevantes que rigen la resistencia al corte de los elementos de hormigón estructural. El objetivo de este trabajo final de master es estudiar, mediante verificaciones experimentales sistemáticas, la precisión de la formulación del modelo CCCM y contribuir a su mejora. Para ello, en primer lugar, se ha tratado de identificar experimentalmente los valores de dos parámetros del modelo, la posición de inicio y la inclinación de la fisura crítica y compararlos con los valores supuestos en el modelo. Esta identificación experimental está justificada por la enorme dificultad en deducir teóricamente la posición e inclinación de la fisura crítica, dado que depende de las deformaciones normales y tangentes en cada punto. Para ello, en este trabajo se recopilaron ensayos disponibles en la bibliografía, como son los incluidos en la base de datos de (Reineck et al., 2013), para vigas de hormigón con refuerzo transversal y 5 sin refuerzo transversal. En dicha base de datos se observa que en muchas de las vigas ensayadas no se da información sobre la posición o la inclinación de la fisura, que son los parámetros que se estudian en esta tesis. Por ello, se recopilaron datos de algunas campañas experimentales adicionales, de los que se dispone de imágenes de los ensayos a cortante y se puede realizar la medición de estos parámetros mediante “Autocad”. Los valores de la posición e inclinación de la fisura, identificados experimentalmente, se compararon con los supuestos en el modelo, extrayendo conclusiones al respecto. Por otra parte, a partir de los valores identificados experimentalmente se han reformulado las ecuaciones del modelo y se ha hecho un estudio de sensibilidad de cómo dichos parámetros influyen realmente en la resistencia a cortante. En concreto se ha estudiado la influencia que tiene la cot $ sobre el cortante resistido por el hormigón, &' , y por el refuerzo transversal &(, y la influencia de la posición de la fisura critica Xcr sobre el cortante resistido por el hormigón, &'. Por último se han comparado las predicciones, realizadas con el modelo reformulado, de la resistencia a cortante de las vigas incluidas en la base de datos habiendo obtenido una ligera mejora en los valores estadísticos (media y coeficiente de variación) respecto del modelo original.

The first, and probably the most determining, decision that engineering teams need to make when facing the structural design of any infrastructure is the choice of both an appropriate material and the suitable structural typology for its components. Each component is required to satisfy technical and functional aspects imposed by standards and stakeholder. Currently, the aspects that are most frequently considered in decision-making processes are economic. Nevertheless, environmental and social criteria are also required if one aims at making sustainability-based decisions. In this regard, to the best of the authors’ knowledge, very few tools or studies exist that can support decision-makers. The few that do exist, are rather limited, either because they fail to incorporate many relevant factors in the sustainability assessment of a project or because they only evaluate environmental and social impacts of a project as a whole. Although a global assessment is useful to gain a holistic understanding of impacts of a project and to compare them to other projects, it does not necessarily help engineering teams understand the impact of fundamental decisions made when designing individual structural components. Therefore, the aim of the present research paper is to develop a new method for the sustainability analysis of building structural components which has been specifically oriented to beams and girders. This is done by means of the Integrated Value Model for the Evaluation of Sustainability method, which is known by its Spanish acronym, MIVES (Modelo Integrado de Valor para una Evaluacion Sostenible). This method draws on multi-attribute utility theory and that allows building an integrated value model as an approach for multi-criteria decision-making. The developed model has been applied to assess the sustainability of different alternatives of beams and trusts to support the non-accessible roof of a sports hall in Vila-seca, Spain. Different material types and structural typologies are analysed. The findings show that the most sustainable alternatives are timber and reinforced concrete trusses, which are actually two options that are seldom used in practice.

Ultrahigh-performance concrete (UHPC) offers significant potential to address a variety of needs in bridge design, construction, and performance enhancement. Bridge owners have shown willingness to embrace novel solutions that could address specific challenges related to the cost, speed of construction, durability, and service life of their projects. There are hundreds of bridges worldwide that, largely in the past decade, have utilized UHPC. These applications range from minor field-cast closures to precast segments for long-span bridges to kilometer-long bridge deck overlays on a signature structure. The objective of this paper is to promote the application of this class of cementitious material in bridge engineering by presenting the progress that has been made in different regions of the world in the past two decades. Today, UHPC is being widely used in Malaysia to design and construct many bridges of different types and spans as they build out their roadway network. In South Korea, the unique characteristics of UHPC are being utilized to advance the state-of-the-art in long-span bridges. The French were early adopters and pioneers in building a strong foundation for using UHPC in a variety of bridge applications. In Switzerland, UHPC is employed to address major bridge rehabilitation needs. The United States bridge sector has embraced UHPC for a variety of field-cast connections. Current research and development efforts are promoting the use of UHPC in major rehabilitation projects and construction of primary bridge components. The adoption of UHPC solutions into the bridge sector is progressing rapidly because of the unique opportunities provided by the strength and durability of the material. It is expected that additional innovations and refinements of solutions will occur as knowledge of the material proliferates. (C) 2020 American Society of Civil Engineers.

El present treball té com a objectiu trobar una sol·lució, realitzable des del punt de vista teòric, i raonable des del punt de vista econòmic i tecnològic, per a poder reforçar provisionalment ponts de fins a uns 50 m de llum, la qual cosa significaría doblar la capacitat actual que hi ha usant bigues saltadores. La solució proposada, mitjançant bigues saltadores amb pretensat extradosat, és el resultat de combinar els conceptes i filosofia de bigues saltadores, pretensat exterior i pretensat extradosat.

Este trabajo pretende estudiar el comportamiento a cortante de vigas de vigas en T reforzadas con polímeros reforzados en forma de U. Para ello se realizará una modelización numérica de unos ensayos realizados en el laboratorio de tecnología de estructuras y se compararán los resultados numéricos con los obtenidos de la instrumentación empleada en los ensayos.

In the late 19th century, Belgian engineer Jules Arthur Vierendeel registered the patent for a new type of beam. This would be later on better known as the Vierendeel truss. It is characterized by the frame’s lack of diagonal members, something which would appear to contradict conditions of steadiness and balance, along with its notable deformation and difficult calculation, caused technicians in his time to be skeptical about its applicability. Nevertheless, its application surged in popularity during the 20th century, being used both in civil engineering and architecture. What are the advantages of the Vierendeel truss as compared to other types, such as diagonal trusses? In this article, the Vierendeel typology will be introduced along with its main features, its calculation as well as its implementation in civil engineering and architectural works.

В статье приведены результаты статических и конструктивных расчетов прогонов шатра покрытия здания со стальным каркасом при нормальных условиях эксплуатации и при учете недопущения прогрессирующего обрушения. В статических и конструктивных расчетах учтено изменение расчетной схемы прогонов при отказе одной из стропильных ферм покрытия. Помимо этого, рассмотрены и проанализированы варианты конструирования узлов опирания прогонов на стропильные фермы на обычных и высокопрочных болтах, а также на монтажной сварке., This article presents the results of static and constructive calculations of beam of a tent of a covering of the building with a steel framework as a result of the action of design loads and with the progressive collapse. In static and constructive calculations considers change of the scheme of a beam at refusal of one of rafter farms of a covering is considered. Options of designing of knots of connection of beams on rafter farms on usual and high-strength bolts, and also on assembly welding are considered and analyzed., №4(39) (2019)

Formulae for determining the full cross-section elastic local buckling stress of structural steel profiles under a comprehensive range of loading conditions, accounting for the interaction between the individual plate elements, are presented. Element interaction, characterised by the development of rotational restraint along the longitudinal edges of adjoined plates, is shown to occur in cross-sections comprising individual plates with different local buckling stresses, but also in cross-sections where the isolated plates have the same local buckling stress but different local buckling half-wavelengths. The developed expressions account for element interaction through an interaction coefficient ζ that ranges between 0 and 1 and are bound by the theoretical limits of the local buckling stress of the isolated critical plates with simply-supported and fixed boundary conditions along the adjoined edges. A range of standard European and American hot-rolled structural steel profiles, including I-sections, square and rectangular hollow sections, channel sections, tee sections and angle sections, as well as additional welded profiles, are considered. The analytical formulae are calibrated against results derived numerically using the finite strip method. For the range of analysed sections, the elastic local buckling stress is typically predicted to within 5% of the numerical value, whereas when element interaction is ignored and the plates are considered in isolation with simply-supported boundary conditions along the adjoined edges, as is customary in current structural design specifications, the local buckling stress of common structural profiles may be under-estimated by as much as 50%. The derived formulae may be adopted as a convenient alternative to numerical methods in advanced structural design calculations (e.g. using the direct strength method or continuous strength method) and although the focus of the study is on structural steel sections, the functions are also applicable to cross-sections of other isotropic materials.

Consideration of moment redistribution (MR) in the design of continuous reinforced concrete (RC) beams results in an efficient and economical design. Adding fibre-reinforced polymer (FRP) materials to RC structures to enhance flexural capacity leads to a reduction in ductility such that design standards severely limit the exploitation of MR in the design of FRP strengthening systems. This has forced engineers to use elastic analyses for the strengthening design which leads to waste of FRP materials under many circumstances. To overcome this, complicated or empirical solutions have been applied to solve the problem of MR in FRP-strengthened RC members, with limited success. This paper presents a novel theoretical strategy for quantifying and tracking MR in such members by employing basic structural mechanics without any need for estimating rotation capacity or ductility. Fully non-linear flexural behaviour of continuous FRP-strengthened members can be predicted, and any geometry, loading arrangement and strengthening technique or configuration can be considered. The numerical model is validated against existing experimental data from the literature. Good agreement is shown between the experimental and numerical data, with the significance of this work being that, potentially, for the first time MR could credibly and confidently be incorporated into design guides for FRP strengthening of RC structures.

Metal gates of hydraulic structures are supplied with load bearing girders. Girders, crossbeams and gates require much steel when being manufactured. Girders of hydraulic gates rational design leads to considerable cost savings. The paper describes steel hydraulic girders optimal design. Steel hydraulic girders optimal design is based on the strength theory introduced by M. Huber, R. Mises, H. Hencky and on the theory of mirror functions. With the help of out-form volume we can either calculate the optimal form for a girder with variable cross-section or the optimal height for a girder of uniform cross-section. The paper introduces hydraulic girders calculations according to the authors’ methodology.

The National Bridge Inventory (NBI) of the United States includes more than 600,000 highway bridges. Approximately 25 % of the nation’s inventory is structurally deficient or functionally obsolete. Currently, the Federal Highway Administration (FHWA) is investigating different alternatives to build new bridge with longer life-span, lower maintenance, and repair needs. Currently, the FHWA is successfully using accelerated bridge construction (ABC) techniques to expedite the construction of new bridges, and minimize material, labor, and equipment cost. In this research, the ABC of new bridges using prefabricated bridge elements and systems (PBES) is discussed, including the fabrication of precast/prestressed elements using an economic high performance concrete (HPC) mix, developed using local construction materials. The successful use of HPC in fabricating PBES used in ABC techniques allows the FHWA to construct new bridges under current budget restraints. This improves the overall rating of the bridge network within the United States.

This article describes an experimental program developed to study the influence of longitudinal prestress on the behaviour of high-strength concrete hollow beams under pure torsion. The pre-cracking, the post-cracking and the ultimate behaviour are analysed. Three tests were carried out on large hollow high-strength concrete beams with similar concrete strength. The variable studied was the level of longitudinal uniform prestress. Some important conclusions on different aspects of the beams&rsquo, behaviour are presented. These conclusions, considered important for the design of box bridges, include the influence of the level of prestress in the cracking and ultimate behaviour.

En este trabajo se modeliza mediante la combinación del metodo de elementos finitos (FEM) y el método del elemento discreto (DEM) los ensayos realizados en el Laboratorio de Tecnología de estructuras Luis Agulló sobre elementos prismáticos sometidos a tracción indirecta para estudiar el efecto tamaño en la zona de compresión de elementos sometidos a esfuerzo cortante.

En el presente trabajo de fin de grado se desarrolla un software para calcular las torsiones a las que se ve sometida una viga continua. Es decir, se resuelve el problema de una viga continua sometida a torsión en su caso general y, por tanto, incluyendo la torsión uniforme y de alabeo. El desarrollo del software se basa en la aplicación del método directo de la rigidez siendo necesaria la obtención de la matriz de rigidez de un elemento de viga sometida a torsión general. La obtención de las leyes de esfuerzos, en este caso, torsor uniforme, torsor de alabeo, torsor total y bimomento, necesitan de las correspondientes expresiones derivadas de la solución de la ecuación diferencial de la torsión. El método se implementa mediante Visual Basic con una interfaz en Excel, para la entrada de datos y la salida de resultados. Una vez desarrollado, se ha verificado dicho programa mediante dos pruebas diferentes. La primera verificación se basa en la creación de cuatro casos particulares para los cuales se ha hallado su solución exacta (analítica) para, posteriormente, comparar dicha solución a los resultados del software. La segunda verificación se desarrolla a partir de un determinado ejercicio resuelto, obtenido de la literatura, con unas características de viga concretas, las cuales se introducirán en el software para comparar que los resultados de este se corresponden a los resultados del ejercicio resuelto. En el CD se incluye el software implementado en Microsoft Excel para los alumnos de la EEBE que estén interesados en las vigas continuas sometidas a torsión.

[EN] Writing project for repair and structural reinforcement of the floors of a residential building . These floors were made with ceramic beams , widely used in the 40s this project is intended to define the necessary measures to strengthen the stability of the building repairing damaged beams and reinforcing that are located in wetlands works. current legislation is studied in the project report regarding restricting the use of steel in construction and type of joist detailed work ., [ES] Redacción de proyecto para reparación y refuerzo estructural de los forjados de un edificio de viviendas. Estos forjados se realizaron con viguetas cerámicas, muy utilizadas en los años 40. Se pretende con este proyecto definir las obras necesarias para consolidar la estabilidad del edificio reparando las viguetas deterioradas y reforzando las que se encuentran ubicadas en zonas húmedas. Se estudia en la memoria del proyecto la normativa vigente en cuanto a restricción del uso de acero en edificación y se detalla el tipo de vigueta de la obra.

O presente trabalho apresenta uma modelagem estocástica de uma viga Euler- Bernoulli e, para isso, foi utilizado a técnica conhecida como Elementos Finitos Estocásticos, essa técnica tem sido bastante utilizada nos últimos anos devido à grande evolução da capacidade dos processadores, já que a mesma tem um grande custo computacional. Dentre as variáveis de projeto, os possíveis parâmetros incertos são o módulo de elasticidade, massa específica e os coeficientes de amortecimento proporcional, α e β. Pela análise de sensibilidade, foi possível verificar qual parâmetro tem maior influência na resposta do sistema. Foi utilizado, também, técnicas de otimização para identificar os parâmetros incertos. As incertezas foram modeladas como campos estocásticos gaussianos homogêneos e discretizadas de acordo com o método espectral utilizando a expansão de Karhunen-Loève. Já o método de Simulação de Monte Carlo combinado com a amostragem do Hipercubo Latino é utilizado como solucionador estocástico. E, por fim, foi realizado um experimento com uma viga na vertical, para obter os parâmetros por meio do problema inverso, sendo utilizadas técnicas de otimização neste processo de identificação, e assim, utilizá-los para obter o envelope e verificar o quanto o resultado experimental está dentro desse envelope. This paper presents a stochastic modeling of the Euler-Bernoulli beam and, here, it was used a technique known as Stochastic Finite Elements, this technique has been widely used in the last years due to large evolution of the capacity of the processors since it has a high computational cost. Among the design variables, the possible uncertain parameters are the modulus of elasticity, specific mass and the proportional damping coefficients, α and β. By the sensibility analysis, it was possible to verify which parameter has the biggest influence on the system response. Optimization techniques were also used to identify the uncertain parameters. The uncertainties are modeled as homogeneous Gaussian stochastic fields and discretized according to the spectral method by using Karhunen-Loève expansions. The Monte Carlo Simulation method combined with the Latin Hypercube Sampling is used as stochastic solver. Finally, an experiment was performed with a vertical beam, to obtain the parameters by means of the inverse problem, using optimization techniques in this identification process, and then, to use them to obtain the envelope and check how much the experimental result is inside it.

U ovom diplomskom radu izvršeno je modelsko i numeričko ispitivanje montažnog stropnog nosača Zgrade 3F. Model je odabran na temelju pravila koja vrijede u modelskoj analizi. Prototip nosača je izveden od montažnih armirano-betonskih elemenata, a model je načinjen od medijapana. Proveden je numerički proračun modela i prototipa te su dobiveni rezultati uspoređeni. Izrađeni model je ispitan u laboratoriju, a izmjereni pomaci na polovici raspona su uspoređeni s pomacima koji su izmjereni na prototipu., In this thesis, model and numerical testing of prefabricated ceiling girder of the Building 3F in Split was performed. Model was selected by the rules that apply in the model analysis. The prototype girders were made of prefabricated reinforced concrete elements and model was made of MDF (Medium Density Fibreboard). Numerical calculation was performed for model and prototype and obtained results were compared. Model was tested in the laboratory, and measured deflections in the middle of the span were compared with deflections that were measured on a prototype.

[ES] El objetivo de este Trabajo Fin de Grado es la de caracterizar una estructura híbrida de hormigón de ultra altas prestaciones (UHPC) y barras de polímero reforzado con fibra de vidrio (GFRP), para después estudiar cómo se comporta frente a esfuerzos de sismo. Para ello se caracterizarán los materiales UHPC y GFRP, para después realizar en laboratorio la estructura viga-pilar, así como los encofrados, la ferralla, su cálculo y construcción, y procesos de puesta en obra, para finalmente ensayarla hasta la rotura, en entorno controlado., [EN] The problem addressed in this Final Degree Project paper is the behavior of hybrid structures made of Ultra High Performance Concrete and Glass Fiber Reinforced Polymer bars against earthquake strains. The following procedure has been followed. First, UHPC and GFRP materials were characterized. Then the pillar-beam structure as well as formworks and the appropiate calculations and construction were made in order to carry out a burst test, in a controlled environment.

El trabajo final de máster consiste en el prototipado, análisis y desarrollo experimental y numérico de herramientas de bajo coste y acceso libre que permitan controlar los procesos de lanzamiento de puentes por empujes sucesivos en estructuras metálicas. Se utilizan tanto hardware como software libre y se utilizan herramientas de impresión 3D como soporte. Actualmente hay una gran variedad de procesos constructivos para la construcción de puentes. Uno muy utilizado tanto por sus ventajas económicas como logísticas es el método por empuje. La superestructura es construida por tramos en un parque de prefabricación donde se ejecutan los tramos del tablero. Se empuja el tramo para construir un nuevo segmento y se va repitiendo el ciclo hasta completar el tablero. El peso que se genera al lanzar estas vigas es importante y hay que estudiarlo con detalle por si el proceso constructivo actúa como condicionante en el diseño de las vigas. Durante el proceso de lanzamiento, todas las secciones transversales pasan por las pilas del puente, por lo que se pueden ver sometidas a cargas concentradas en dirección vertical de un gran calibre. No solo se utilizan las vigas rectas, sino que el uso de vigas armadas con curvatura horizontal cada vez se utiliza más en el mundo de la construcción y la ingeniería civil. Las vigas curvas se utilizan a menudo cuando las condiciones del sitio o las alineaciones de carretera no permiten utilizar el uso de vigas rectas. En la actualidad existe una formulación definida por la norma EN 1993-1-5, para calcular la resistencia de vigas rectas sujetas bajo este tipo de solicitaciones y no especifica si estas fórmulas son aplicables a vigas con curvatura horizontal. Las vigas con curvatura horizontal no han sido muy estudiadas, especialmente si tienen rigidización longitudinal. En este estudio se realiza un estudio paramétrico con 180 modelos de vigas donde se utilizan distintos radios de curvatura y distintas posiciones del rigidizador longitudinal para ver la influencia de estos en el comportamiento estructural de las vigas. El estudio de las vigas curvas rigidizadas se realiza con el software Abaqus CAE.

U ovom diplomskom radu izvršeno je modelsko i numeričko ispitivanje montažnog stropnog nosača Zgrade 3F. Model je odabran na temelju pravila koja vrijede u modelskoj analizi. Prototip nosača je izveden od montažnih armirano-betonskih elemenata, a model je načinjen od medijapana. Proveden je numerički proračun modela i prototipa te su dobiveni rezultati uspoređeni. Izrađeni model je ispitan u laboratoriju, a izmjereni pomaci na polovici raspona su uspoređeni s pomacima koji su izmjereni na prototipu. In this thesis, model and numerical testing of prefabricated ceiling girder of the Building 3F in Split was performed. Model was selected by the rules that apply in the model analysis. The prototype girders were made of prefabricated reinforced concrete elements and model was made of MDF (Medium Density Fibreboard). Numerical calculation was performed for model and prototype and obtained results were compared. Model was tested in the laboratory, and measured deflections in the middle of the span were compared with deflections that were measured on a prototype.

Proračun rešetkastog krovišta kao okvirnog sustava od 11 paralelnih nosača, statička analiza na stalno i promjenjivo opterećenje (vjetar i snijeg) te dimenzioniranje poprečnih presjeka elemenata konstrukcije., Calculation of a roof with 11 parallel girders, static analysis for heavy and live load (wind, snow) and sizing the elements of structure.

We will study the effect of flexoelectricity in the electromechanical response of nanobeams under torsion.

La presente investigación tiene como propósito comparar la capacidad última de conectores de cortante tipo espigo con cabeza (stud) con los conectores de cortante tipo perno, en losa de concreto vaciado sobre tablero metálico, los cuales junto con la viga de acero conforman sección compuesta -- Dicha comparación se realizó a partir de los resultados obtenidos de las pruebas de corte directo, push out, realizadas a probetas -- Estas consistieron en dos placas de concreto vaciado sobre tablero metálico, unidas mediante un perfil de acero, logrando una probeta simétrica -- Para realizar la fijación de los elementos indicados se utilizaron conectores de cortante, soldados al eje del ala del perfil -- Todos en posición débil -- Se utilizaron tres probetas con conector tipo espigo con cabeza y tres probetas con conector tipo perno -- Se elaboraron gráficas de carga versus desplazamiento -- Se determinó la capacidad promedio por cada grupo de tipo de conector -- Se obtiene el cociente entre la capacidad promedio del conector tipo espigo sobre la capacidad promedio del conector tipo perno, dando como resultado una variación del 4 %, por lo que se concluye que es equivalente usar el uno o el otro

This work gives a semi-analytical approach for the dynamic analysis of beams and plates rest-ing on an elastic half-space with inertial properties. Such calculations have been associated with significant mathematical challenges, often leading to unrealizable computing processes. Therefore, this paper presents a detailed analysis of Green’s function defining surface displacements of such a space in the contact zone with structures, which allows determination of reactive forces and other physical responses. The obtained solutions can be applied to (i) study dynamic interaction between soil and structures, (ii) determine transient wave fields caused by a seismic source, and (iii) assess numerical computations with different numerical methods programs. Natural frequencies, natural shapes, and the dynamic response of a beam due to external harmonic excitation are determined. Eigenfrequencies and Eigenshapes are presented. Validation with a Boussinesq problem illustrates the inertia effect on the results of the dynamic analysis. Not applicable au, ti, ke - kpw25/11/11

[ES] El presente proyecto se realiza el estudio del sistema constructivo de una nave industrial sin uso, ejecutada con estructura prefabricada de hormigón y cubierta tipo sándwich. El objetivo de este trabajo ha sido profundizar en la construcción de la tipología de edificación industrial, basándonos en un caso práctico real y en el seguimiento del mismo realizado en obra. Esto ha permitido dar soluciones a los distintos problemas que han ido surgiendo, sirviendo de aprendizaje en la profesión. En este TFG se desarrollan los sistemas constructivos utilizados, desde el replanteo, movimiento de tierras, cimentación, estructura, cerramientos y sistema de sustentación de la cubierta, haciendo un análisis de todos los puntos singulares, tales como encuentros con los paneles de fachada, ménsulas de apoyo, apoyos de vigas, anclajes de pilares a cimentación, etc. Posteriormente se realiza un análisis de las fases de obra y se confecciona un guion del seguimiento de la misma, dando como resultado la visión completa de la ejecución de la nave y sus detalles constructivos, incluyendo las partidas, su ordenación y tiempos de ejecución., [EN] This project embodies the study of the construction system of a warehouse unused, executed with prefabricated concrete deck sandwich structure. The aim of this study was to investigate the construction of the typology of industrial buildings, based on a real case study and monitoring conducted in the same work. This has led to solutions to the various problems that have arisen, serving learning in the profession. This construction is implemented following the actual steps taken. The building methods used from the stakeout, earthwork, foundation, structure, enclosures and support system will be developed cover, with analysis of all singular, such as meetings with panels face, bearing brackets, braces points beams, pillars foundation anchors, etc. Then we will proceed to an analysis of the phases of work and a script for monitoring the same shall be drawn, resulting in the complete picture of the operation of the ship and its construction details, including headings, their management and execution times.

Patch loading is a predominant load case at incremental bridge launching. Bridge girder webs are frequently provided with longitudinal stiffeners to increase in-service shear and bending strength, and its effect has been included in design codes. However, no straightforward rules are given to account for the influence of such stiffeners on improving the patch loading resistance. This paper presents a review of some available formulae found in the literature to estimate the girder ultimate strength including the provisions of the European, American and Colombian design codes. Additionally, a nonlinear finite element analysis is conducted on three case studies related to actual launched bridges. The case studies are also used to study the influence of the longitudinal stiffener and girder depth on the girder capacity. Different load-displacement responses are observed depending on the girder depth. Finally, the finite element analysis shows to what extent the longitudinal stiffeners can increase the patch loading capacity of bridge girder webs during launching. Cargas concentradas son normalmente la condición de carga predominante durante el lanzamiento de puentes por empujes sucesivos, por lo cual, las almas de las vigas del puente son frecuentemente rigidizadas con placas longitudinales para incrementar la resistencia de servicio a cortante y flexión. Este efecto benéfico del rigidizador longitudinal es tomado en cuenta por varios códigos de diseño. Sin embargo, no hay normas claras que indiquen como tener en cuenta la influencia de tales rigidizadores en el incremento de la resistencia bajo cargas concentradas. Este artículo, presenta una revisión de algunas de las formulaciones disponibles en la literatura técnica para el cálculo de cargas últimas de pandeo en vigas bajo cargas concentradas incluyendo los lineamientos de los códigos de diseño Europeo, Americano y Colombiano. Adicionalmente, se presenta un análisis no lineal por elementos finitos de tres casos de estudio concernientes con el lanzamiento de puentes. Los casos de estudio son también utilizados para estudiar la influencia del rigidizador y de la profundidad de la viga en la carga última. Se observaron diferentes respuestas carga-deformación dependiendo de la profundidad de la viga y se muestra hasta qué punto los rigidizadores longitudinales pueden incrementar la capacidad de carga de vigas de puente durante su lanzamiento.

A presente dissertação propõe a resolução do problema de flexão estocástica em uma viga Euler-Bernoulli, sobre uma fundação do tipo Pasternak, através de um método computacional baseado na simulação de Monte Carlo. A incerteza está presente nos coeficientes elásticos da viga e da fundação. Primeiramente, é estabelecida a formulação matemática do problema que é oriunda, de um modelo físico de deslocamento da viga, que leva em consideração a influência da fundação sobre a resposta do problema. Portanto foi realizado um estudo a cerca dos modelos mais usuais de fundação, que são: o modelo do tipo Winkler, e modelo de Pasternak. Logo a seguir foi provado que o problema variacional abstrato, derivado da formulação forte do problema, apresenta solução e esta é única. Para a obtenção da solução do problema, foi realizada uma fundamentação matemática, dos seguintes assuntos: representação da incerteza, método de Galerkin, série de Neumann, e por fim das cotas inferiores e superiores. Finalmente, o desempenho das cotas inferiores e superiores, em relação à simulação de Monte Carlo direto, foram avaliadas através de vários casos, nos quais a incerteza repousa sobre os diversos coeficientes que compõe a equação de flexão na forma de um problema variacional. A metodologia mostrou-se eficiente, tanto no aspecto da convergência da resposta quanto no que se refere ao custo computacional. This work proposes the resolution of stochastic bending problem in a Euler- Bernoulli beam, on a foundation type Pasternak, through a computational method based on Monte Carlo simulation. Uncertainty is present in the elastic coefficients of the beam and foundation. First, it is established the mathematical formulation of the problem which is derived from a physical model displacement of the beam, that takes into account the influence of the foundation on the problem of response. This requires an approach that is made up on the most common models of foundation, which are: the model Winkler type and model of Pasternak.In sequence we study the existence and uniqueness of the variational problem. To obtain the solution of the problem, a mathematical reasoning is carried out, to the following matters: representation of uncertainty, Galerkin method, serial Neumann, and finally the lower and upper bounds. Finally, the performance of lower and upper bounds, derived from direct simulation of Monte Carlo were evaluated through various cases where the uncertainty lies in the different coefficients composing the equation bending as a variational problem. The method proved to be efficient, both in the response of the convergence point as regards the computational cost.

This paper is aimed at studying the elastoplastic behavior of longitudinally stiffened girder webs subjected to patch loading and bending. The investigation is carried out by means of nonlinear finite element analysis to study the structural behavior of the girder components (flanges, web and stiffener) at ultimate limit state. Initial geometrical imperfections, plastic material behavior and large deflection effects are considered in the model. For the numerical model validation, the computer results from the simulations are compared with experimental results taken from the literature. A parametric study was carried out in order to investigate the influence of the applied bending moment and the relative location of the stiffener on the ultimate strength to patch loading. Este artículo está enfocado en estudiar el comportamiento elastoplástico de vigas rigidizadas longitudinalmente en el alma y sujetas a combinaciones de carga concentrada y momento flector. La investigación se realiza mediante un análisis de elementos finitos no lineal para estudiar el comportamiento estructural de los diferentes componentes de la viga (aletas, alma y rigidizador) bajo el estado límite de carga. El modelo considera los efectos de imperfecciones geométricas iniciales, comportamiento plástico del material y grandes deflexiones. La validación del modelo numérico se hace mediante comparación directa de los resultados numéricos con valores experimentales disponibles en la literatura técnica. Finalmente, se realiza un estudio paramétrico con el objeto de investigar la influencia del momento flector y la localización del rigidizador en la resistencia última de la viga bajo cargas concentradas.

Patch loading is a predominant load case at incremental bridge launching. Bridge girder webs are frequently provided with longitudinal stiffeners to increase in-service shear and bending strength, and its effect has been included in design codes. However, no straightforward rules are given to account for the influence of such stiffeners on improving the patch loading resistance. This paper presents a review of some available formulae found in the literature to estimate the girder ultimate strength including the provisions of the European, American and Colombian design codes. Additionally, a nonlinear finite element analysis is conducted on three case studies related to actual launched bridges. The case studies are also used to study the influence of the longitudinal stiffener and girder depth on the girder capacity. Different load-displacement responses are observed depending on the girder depth. Finally, the finite element analysis shows to what extent the longitudinal stiffeners can increase the patch loading capacity of bridge girder webs during launching. Cargas concentradas son normalmente la condición de carga predominante durante el lanzamiento de puentes por empujes suce-sivos, por lo cual, las almas de las vigas del puente son frecuentemente rigidizadas con placas longitudinales para incrementar la resistencia de servicio a cortante y flexión. Este efecto benéfico del rigidizador longitudinal es tomado en cuenta por varios códigos de diseño. Sin embargo, no hay normas claras que indiquen como tener en cuenta la influencia de tales rigidizadores en el incre-mento de la resistencia bajo cargas concentradas. Este artículo, presenta una revisión de algunas de las formulaciones disponibles en la literatura técnica para el cálculo de cargas últimas de pandeo en vigas bajo cargas concentradas incluyendo los lineamientos de los códigos de diseño Europeo, Americano y Colombiano. Adicionalmente, se presenta un análisis no lineal por elementos finitos de tres casos de estudio concernientes con el lanzamiento de puentes. Los casos de estudio son también utilizados para estudiar la influencia del rigidizador y de la profundidad de la viga en la carga última. Se observaron diferentes respuestas carga-deformación dependiendo de la profundidad de la viga y se muestra hasta qué punto los rigidizadores longitudinales pueden incrementar la capacidad de carga de vigas de puente durante su lanzamiento.

[EN] In this document the designing of a structure has been carried out. This structure is located along the road CV-190 passing by Figueroles and spanning the Lucena river as well as the ravine previous to this one. In order to do that an extensive outcome assessment considering many different types of bridges has been performed. Some of these types were cable-stayed bridge, arch bridge, precast concrete I girder and concrete box girder. After a thorough reflection over all the alternatives a precast concrete I-girder alternative was decided over the other ones. This one was selected because of its quick construction, its economical savings and simplicity of its construction. Additionally the bridge has been designed in a way that intrudes the least with the environment placing piles and abutments in strategic points where their presence is the least invasive possible. Next an structural analysis has been carried out making use of the finite element method program CSiBridge. First the geometry of the bridge is defined basing ourselves on the common practice of bridge construction and then we consider all forces the bridge has to bear. Finally, once the analysis results are gotten we proceed to the designing of the main structural elements such as girders, piles and abutments., [CA] En el document a continuación s'ha llevat a capel dimensionament de la estructura ubicada dentre de la variant CV-190 al seu pas per Figueroles que salva el riu Lucena así com el barranc previ a aquest. Per aixó s¡ha relizat un extens estudi de solucions on s'han considerat distintes tipologies de ponts, com el pont atirantat, pont en arc, pont de vigues prefabricades, pont encaixonat. Tras una reflexió exhaustiva de totes les alternatives, s'ha decidit fer un pont de vigues prefabricades , degut a que aquesta tipologia presenta els advantajes de d'una rapida construcció, estalviament economic y sencillesa constructiva. També s'ha disenyat de forma que afecte el mínim a l'entorn ubicant les piles i els estrius en punts estrategics on la seua presencia sea lo minim invasiva posible. A continución s'ha realitzat un analisis estructural usant el programa de cálcul de element finits CSiBridge definint la geometria del pont d'acord a la práctica comú en construcción de ponts y considerant les accions que el pont va a suportar. Finalment, obtenint els resultats de l'analisis es procedeix a la comprobació i dimensionament dels principals elements estructuralscom les vigues, les piles y els estrius., [ES] En el documento a continuación se ha llevado a cabo el dimensionamiento de la estructura ubicada dentro de la variante CV-190 a su paso por Figueroles que salva el rio Lucena así como el barranco previo a este. Para ello se realizado un extenso estudio de soluciones donde se han considerado distintas tipologías de puentes, como puente atirantado, puente en arco ,puente de vigas prefabricadas en doble T o puente en cajón. Tras una reflexión exhaustiva de todas las alternativas, se ha decidido por una solución de vigas prefabricadas, ya que esta tipología presenta las grandes ventajas de una veloz construcción, ahorro económico y sencillez constructiva. También se ha diseñado de forma que afecte lo más mínimo al entorno ubicando las pilas y estribos en puntos estratégicos donde su presencia sea lo menos invasiva posible. A continuación se ha realiza un análisis estructural usando el programa de cálculo de elementos finitos CSiBridge definiendo la geometría del puente acorde a la práctica común de construcción de puentes y considerando las acciones que el puente va soportar. Finalmente, obtenido los resultados del análisis se procede a la comprobación y dimensionamiento de los principales elementos estructurales como las vigas, las pilas y los estribos.

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2015, Includes bibliographical references (leaves: 33-35), Text in English; Abstract: Turkish and English, x, 36 leaves, In this study, time response of a planar curved beam with variable curvatures under in-plane impact load is analyzed by two numerical methods which are Finite Difference and Finite Element Methods. The solution procedures in both methods are based on solution of eigenvalue and time response problems. Catenary form is selected as the axis of curved beam. A computer program is developed in Mathematica for the solution with Finite Difference Method. Moreover, a computer code is written for the geometric and finite element models of curved beam with variable curvature in ANSYS by using APDL (ANSYS Parametric Design Language). Solutions of the two methods are compared in each other and then good agreement is observed. The effects of impuls and damping properties on the time response are investigated., Bu çalışmada, düzlem içi darbe yükü altındaki değişken eğrilikli düzlemsel eğri çubukların zaman cevabı sayılsal yöntemler olan Sonlu Farklar ve Sonlu Elemenlar Yöntemleri ile incelenmiştir. Her iki metoddaki çözüm usulü özdeğer ve zaman cevabı problemlerine dayalıdır. Eğri çubuğun ekseni olarak Katenary biçimi seçilmiştir. Sonlu Farklar Yöntemi ile çözüm için Mathematica’da bir program geliştirilmiştir. Ayrıca, değişken eğrilikli eğri çubuğun geometrik ve sonlu eleman modelleri için ANSYS de APDL (ANSYS Parametrik Tasarım Dili) ile bir bilgisayar kodu yazılmıştır. İki metodun çözümleri birbirleri ile karşılaştırılmış ve iyi bir uyum gözlenmiştir. İmpuls ve sönüm özelliklerinin zaman cavabına etkileri araştırılmıştır.