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La sostenibilidad de los edificios y de las infraestructuras públicas es un tema de importancia reciente puesto en discusión por la comunidad de ingeniería. La necesidad de diseñar estructuras con bajos requerimientos de mantenimiento y durabilidad a largo plazo puede ser resuelta mediante la introducción de nuevos materiales de construcción o la implementación de sistemas estructurales innovadores. En este sentido, los polímeros reforzados con fibras (FRP) representan una de las soluciones en el campo de la ingeniería civil que ofrecen resultados prometedores. Para optimizar el uso de secciones de FRP los investigadores han propuesto la creación de sistemas híbridos donde se combinan materiales compuestos con materiales convencionales, tales como el hormigón. Las soluciones híbridas mejoran la rigidez, la ductilidad y la resistencia a pandeo de los elementos aislados de material compuesto. Debido a la novedad y a la variedad de soluciones híbridas, la tecnología requiere de la realización de más ensayos experimentales para valorar su viabilidad. Además, en la actualidad hay una falta de códigos prescriptores y normas que ayuden al diseño de estructuras construidas con perfiles compuestos y, por consiguiente, los elementos mixtos requieren del desarrollo de modelos predictivos fiables. Por lo tanto, la presente investigación tiene como objetivo estudiar el comportamiento estructural de vigas híbridas hechas de perfiles pultrusionados de FRP unidos a losas de hormigón, mediante la realización de una investigación experimental, analítica y numérica. Puesto que los efectos de deslizamiento en la interfaz han sido mayoritariamente ignorados en el pasado, la tesis se centra también en la influencia de la flexibilidad de la conexión sobre el comportamiento de flexión. Con respecto a la campaña experimental, se han fabricado y ensayado a flexión ocho vigas de perfiles de FRP de fibra de vidrio (GFRP) y hormigón, con conectores mecánicos en el rasante. También se ha compara, Sustainability of buildings and public infrastructure is a relatively recent topic put into discussion by the engineering community. A solution to designing structures that have long-term durability and low maintenance requirements is to introduce new construction materials or to implement new structural systems. In this regard, fiber reinforced polymers (FRP) represent one of the novel solutions in the civil engineering field that offer promising results. To optimize the use of FRP shapes, researchers have proposed to form hybrid structural systems by combining the composite materials with conventional materials, such as concrete, in order to improve on the stiffness, ductility, and buckling resistance of single FRP members. However, due to the novelty and wide variety of hybrid elements, the technology demands further experimental testing to prove its viability. In addition, because there is a current lack of mandatory codes for the design of structures built with composite profiles and consequently FRP-concrete members, reliable predictive models have to be developed. Addressing the above-mentioned issues is essential in lessening the introduction of advanced composite materials in common types of public works and constructions. The present research aimed thus to study the structural performance of hybrid beams made of FRP pultruded profiles attached to concrete slabs by carrying an experimental, analytical, and numerical investigation. Since interface slip effects had been largely overlooked in the past, the thesis focused also on the influence of the connection flexibility over bending behavior. With respect to the developed experimental campaign, eight glass FRP-concrete hybrid beams with mechanical shear connectors were fabricated and their flexural behavior was assessed against that of equivalent reinforced concrete beams and single GFRP structural profiles. The variables of the research were the type of hybrid cross-section and the concrete strength class., Postprint (published version)

A l'ETSEIAT hem realitzat uns experiments de flexió de bigues híbrides de formigó i compost. El TFG desenvoluparia un model computacional que permetés simular els experiments realitzats. Donat que els materials fissuren i no tene una compatibiliatt perfecta el TFG enfronta un seguit de reptes amb anàlisi no lineal., In recent years the use of advanced composite materials has gained wider space in the civil engineering sector, due to some favourable characteristics such as lightweight, high specific strength, resistance to corrosion and fatigue. Innovative systems that combine concrete with advanced composite materials have proved to be a viable and efficient solution compared to conventional systems. However, the absence of a normalized design code about these materials slows their evolution down. In this study, a computational model for the analysis of hybrid beams made of concrete and glass fibre reinforce polymer (GFRP) is presented. The material properties of the GFRP profile were obtained experimentally at the LITEM laboratory. Material properties of concrete were obtained both experimentally and using Eurocode 2. Properties of the shear connectors have been modelled using Eurocode 4 for the shear capacity, and a previous study (Oehlers & Coughlan 1986) has been used for the stiffness of the connection. Comparisons of numerical and experimental results show good agreement. However, the model is not focused on the behaviour of the beam during the cracking process. The model is also limited on simulating the microstructural behaviour of GFRP profile, since in this study effective properties of the profile have been used.

Recent developments in the design of advanced composite materials for construction have led researchers to create novel high-performance structural elements that combine fiber-reinforced polymer (FRP) shapes with traditional materials. The current study analyzes the experimental structural response of eight hybrid beams made of pultruded glass FRP (GFRP) profiles mechanically connected to reinforced concrete (RC) slabs, suitable for building floors as well as footbridge and marine pier superstructures. The influence of partial interaction is studied by considering a low degree of shear connection and an analytical assessment of the whole response is carried out using previous formulations, highlighting a good accuracy. The behavior of the hybrid beams is further evaluated against that of equivalent reinforced concrete beams and single GFRP profiles, thus proving the feasibility of the solution., Peer Reviewed, Postprint (author's final draft)

Hybrid beams made of pultruded fiber-reinforced polymer (PFRP) shapes connected to reinforced concrete (RC) slabs are regarded as novel cost-effective and structurally-efficient elements. The current study addresses the need for a robust analytical procedure for the design of such members considering the structural implications of shear interaction effects. The discussed analytical procedure is based on the Timoshenko beam theory and on the elastic interlayer slip model extended from steel-concrete and timber-concrete composite beams, and presents the necessary mathematical tools for evaluating deflections, flexural capacities and stress distributions of hybrid beams. Partial interaction effects are quantified by using a proposed dimensionless parameter that depends mainly on the connection's stiffness. The analytical equations were validated successfully against available experimental data and conclusions indicate that the simplified model for partial interaction is viable and should be used even for specimens with full interlayer shear capacity, Peer Reviewed, Postprint (author's final draft)

Una viga compuesta es aquella en que la sección está formada por la combinación de dos o más materiales. En el presente proyecto los materiales son hormigón y polímeros reforzados con fibra de vidrio que forman un perfil. Es habitual en ingeniería de la construcción encontrar este tipo de vigas para aprovechar las características de ambos materiales en un solo componente. En este proyecto final de carrera se pretende estudiar el comportamiento transversal de vigas compuestas de hormigón y GFRP (polímeros reforzados con fibra de vidrio). Para ello se utilizará un software de cálculo por el método de elementos finitos. Los resultados obtenidos se compararán con los resultados que anteriormente se habrán conseguido en el laboratorio y se discutirán y estudiarán para comprobar que la simulación ha sido correcta. El software elegido para llevar a cabo el trabajo ha sido ANSYS, en su variante Workbench. Lo que nos permite modelar la viga, introducir las características de las materiales, aplicar las cargas correspondientes a los ensayos realizados en el laboratorio y poder medir con precisión en los mismos puntos para poder conseguir finalmente los resultados más realistas posibles. En la primera etapa del proyecto se han modelado y calibrado los perfiles mediante la repetición de los distintos ensayos variando algunos parámetros hasta dar con la solución adecuada. En la segunda etapa, se han estudiado los resultados computacionales y se han comparado con los experimentales

The current paper presents various analytical models suitable for the evaluation of hybrid beam deflections, ranging from simple to complex expressions, which can be applied in common design practice. The formulations are based primarily on the Euler-Bernoulli composite beam theory and on the Stüssi–Granholm–Newmark–Pleshkov interlayer slip model, completed by shear deflection contributions based on the Timoshenko beam th eory. The analytical expressions rely on the degree of shear interaction and connection stiffness, and can be independent of the loading and supporting conditions. The theoretical models were validated successfully against experimental data found in literature. Conclusions are drawn concerning the recommended formulations for use in practice., Postprint (published version)

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In the current report are analyzed the experimental results of several tensile tests of Basalt FRP (BFRP) rebars provided by VSL, anchored with steel wedges with aluminum sleeves. The investigation was conducted in the laboratory of CER LITEM from the Department of Strength of Materials and Structural Engineering of Universitat Politècnica de Catalunya – BarcelonaTech. Objective of the study: to determine the failure modes and ultimate tensile stresses of 6 mm and 8 mm Basalt FRP rebars, anchored with steel wedge systems with aluminum sleeves., Preprint

In the current report are analyzed the experimental results of several tensile tests of Basalt FRP (BFRP) rebars provided by VSL, anchored with steel wedges. The investigation was conducted in the laboratory of CER LITEM Objectives of the study: to determine the failure modes and ultimate tensile stresses of 6 mm and 8 mm Basalt FRP rebars anchored with two different steel wedge systems; and to compare the anchoring efficiency of the wedge systems., Preprint

In the current report are analyzed the experimental results of initial tensile tests of Basalt FRP (BFRP) rebars provided by VSL. The investigation was conducted on the 19th of February 2013, in the laboratory of CER LITEM. Objectives of the study: to determine the tensile strengths of 6 mm and 8 mm basalt FRP rebars, and to determine what type of test setup and anchorage system is best suited for future tensile tests of BFRP bars., Preprint

In the current report are analyzed the experimental results of initial tensile tests of Basalt FRP (BFRP) rebars provided by VSL. The investigation was conducted in the laboratory of CER LITEM. Objectives of the study: to determine the tensile strengths of 6 mm and 8 mm basalt FRP rebars, and to determine what type of test setup and anchorage system is best suited for future tensile tests of BFRP bars., Preprint

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The current report presents the experimental results regarding the flexural bahavior of GFRP-concrete hybrid beam M1-HB3., Preprint

The current report presents the experimental results regarding the flexural behavior of reinforced concrete beam M1-HB1., Preprint

The current report presents the experimental results regarding the flexural bahavior of concrete hybrid beam M0-RC2., Preprint

The current report presents the experimental results regarding the flexural bahavior of GFRP-concrete hybrid beam M2-HB3., Preprint

The current report presents the experimental results regarding the flexural behavior of reinforced concrete beam M2-HB1., Preprint

The current report presents the experimental results regarding the flexural bahavior of GFRP-concrete hybrid beam M2-HB2., Preprint

The current report presents the experimental results regarding the flexural behavior of reinforced concrete beam M1-HB2., Preprint

The current report presents the experimental results regarding the flexural bahavior of GFRP-concrete hybrid beam M2-HB4., Preprint

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The current report presents the experimental results regarding the flexural behavior of reinforced concrete beam M0-RC1., Preprint

The current report presents the experimental results regarding the flexural bahavior of GFRP-concrete hybrid beam M1-HB4., Preprint

In the present report are being discussed the results of an experimental test regarding the compressive properties of sample concrete specimens. The investigation has been conducted in the laboratory of CER LITEM – Department of RMEE of UPC. 2. Objectives To determine the ultimate compressive strength of the concrete specimens. To determine the elastic modulus of the concrete and to compare it with theoretical values obtained from various code prescriptions., Preprint

The thesis starts from the need to identify methods, materials and techniques that can contribute to the stregthening of the reinforced concrete structures. Fiber reinforced polymer (FRP) application is a very effective way to repair and strengthen structures that have become structurally inefficient over their life span. CFRP laminates are new carbon-based composite materials that attach externally to concrete beams. These hight strenght materials improve the bending behavior of beams. The main objective of the research, described in this thesis, is the analysis of the response behavior of retrofitted reinforced concrete beams with CFRP laminates. This implied an experimental study, with took place in the Laboratory for Technical Innovation in Structures and Materials (LITEM) of the Department of Strenght of Materials and Structural Engineering of the Polytechnic University of Catalonia. During the experiments, the following aspects were evaluated and recorded regarding the response of the tested beams: load-displacement analysis, deformation behavior, stress distribution, displacement profiles, failure modes and crack patterns. In order to attain these goals, we used five reinforced concrete beams, differently preparated for the test (one control beam, two beams with one CFRP laminate attached and another two beams with a pair of the same laminates). Final observations have confirmed the efficiency of the composite strengthening system. Also we noticed that the results were close to the theoretical values, in most of the aspects.