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Reinforced concrete slabs can be subjected simultaneously to transverse loads and in-plane tensile forces, as it occurs in top slabs of continuous box girder bridges at intermediate supports, or in flat slabs supported on columns, subjected to horizontal loads. To study the effects of in-plane forces in the slab punching-shear strength, an experimental and theoretical investigation was carried out, which is described in this paper. Five square slabs of 1650 mm (42”) side and 120 mm (4.7”) thickness were tested under a centered transverse point load and different degrees of uniaxial in-plane tensile force. Numerical predictions using non-linear finite element analyses were performed to help in the experiments design. Furthermore, the punching-shear mechanical model, Compression Chord Capacity Model (CCCM), was extended to incorporate the effects of in-plane tensile forces. The experimental results showed that the punching strength linearly decreases with the level of applied tensile force and, if cracking in the slabs is produced by the tensile force, yielding of the reinforcement and further reduction may take place. Excellent agreement was found between theoretical predictions and tests results. Furthermore, the CCCM was verified with available results of punching tests with uniaxial and biaxial tensile forces, obtaining very good results. This work has been carried out within the framework of research projects BIA-2015-64672-C4-1-R, and BIA2015- 64672-C4-3-R financed by the Ministry of Economy and Competitiveness (MINECO) of Spain, and also with the financial support of the Government of Catalonia through the contract for research and innovation in infrastructures E1-INF-18500. The authors want to deeply thank also the personnel of the Structural Technology Laboratory of the Universitat Politècnica de Catalunya.

The new version of Eurocode 2 will include for the first time an informative annex, Annex R “Embedded FRP reinforcement”, to design reinforced concrete structures with fibre reinforced polymer (FRP) reinforcement. FRP embedded reinforcement has some advantages such as their low susceptibility to corrosion, high-strength, and low life-cycle cost. FRP rebars can be used as longitudinal or transverse reinforcement in a similar way than conventional steel rebars. However, in the design of FRP reinforced concrete structures, some particular aspects related to the reinforcement properties must be taken into account, among which it is worth highlighting their linear elastic behaviour until failure, their relatively low modulus of elasticity or their behaviour under sustained stresses. Since, the content of Annex R is new, a summary and background related to all aspects required for designing with FRP reinforcement are given in this paper. The authors acknowledge the support provided by Spanish Ministry of Science and Innovation (MCIN/ AEI) and by the European Funds for Regional Development in the following projects during their collaboration in the TN140/SC2 and in the CEN/TC250/SC2/WG1/TG1 (Eva Oller): BIA2015‐64672‐C4‐1‐R, RTI2018‐097314‐B‐C21, and PID2020‐119015GB‐C22.

To evaluate how the size effect affects the stresses developed along the compression chord in a beams subjected to shear forces, a simplified experimental program was developed on 50 prismatic specimens subjected to a splitting test. The studied parameters were: dimensions, slenderness, concrete compressive strength, and maximum aggregate size. To capture the post-peak behavior of the concrete, the load was introduced as a function of the crack width, through appropriate control algorithms. Digital Image Correlation (DIC) in a 2D configuration has also been used to accurately capture the formation, width and propagation of cracks to corroborate the experimental measurements. The financial support provided by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Funds for Regional Development (FEDER), through the Research projects: BIA2015-64672-C4-1-R and BIA2017-84975-C2-2-P and through the Excellence network BIA2015-71484-REDT.

Due to the complex deformational behavior of cracked RC members, an effective way to ensure the fulfilment of the SLS is to limit the slenderness ratio l/d of the element. In this study, the deformation slenderness limit concept is generalized to incorporate crack width limitations. The proposed slenderness limits are compared with those derived from non-linear time-dependent analysis and also with those obtained using the EC2 method of deflections interpolation. Very good approximation and low scatter has been obtained showing that the proposed slenderness limits are a useful tool for performance-based design of RC structures. The financial support provided by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Funds for Regional Development (FEDER), through the Research projects: BIA2015-64672-C4-1-R and BIA2017-84975-C2-2-P and through the Excellence network BIA2015-71484-REDT

Los procedimientos actuales de dimensionamiento a flexión de elementos de hormigón armado, basados en la comprobación de estado límite último (ELU), proporcionan suficiente resistencia para soportar las cargas de diseño con un canto reducido. Sin embargo, las dimensiones estrictas de la sección transversal y la cantidad de armadura calculada para satisfacer el ELU pueden ser insuficientes para evitar deformaciones excesivas que pueden producir daños en los elementos no estructurales, o para garantizar el control de la fisuración y satisfacer así, los requisitos de durabilidad, funcionalidad o estética.Debido a la complejidad asociada a un cálculo riguroso de las deformaciones y el ancho de fisura en elementos de hormigón armado a lo largo de su vida útil, una forma efectiva de garantizar la satisfacción del estado límite de servicio es mediante la limitación de la relación de esbeltez l/d del elemento. En el presente estudio, el concepto de esbeltez límite, utilizado anteriormente para el control de la deformación, se generaliza para incorporar las limitaciones de la abertura de fisura, en el marco del diseño estructural basado en prestaciones. Por ello, se derivan las ecuaciones para la esbeltez límite que incorporan los parámetros principales que influyen en el comportamiento de servicio de los elementos de hormigón armado, que son válidos para secciones transversales rectangulares en forma de I o T y para elementos simplemente apoyados o continuos. La fisuración y los efectos a largo plazo se explican a través de coeficientes simplificados derivados de la mecánica estructural y las observaciones experimentales.Las esbelteces límite propuestas, tanto para una carga aplicada constante como para una deformación en la armadura constante, se comparan con las obtenidos utilizando el procedimiento EC2 para el cálculo de deformaciones, basado en la integración de curvaturas. Se han obtenido buenos resultados en términos de errores y dispersión, lo que demuestra que las esbelteces límite propuestas son una herramienta útil para el diseño basado en prestaciones de estructuras de hormigón armado. El carácter mecánico de la formulación facilita su modificación para situaciones diferentes a las utilizadas en su deducción, por ejemplo, diferentes tipos de carga, vigas parcialmente pretensadas o elementos de hormigón armado con FRP, entre otros. The financial support provided by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Funds for Regional Development (FEDER), through the Research projects: BIA2015-64672-C4-1-R and BIA2017-84975-C2-2-P and through the Excellence network BIA2015-71484-REDT.

RC slabs can be subjected to transverse loads and in-plane tensile forces simultaneously, as it occurs in top slabs of continuous box girder bridges at intermediate supports, or in floor slabs supported on columns and subjected to horizontal forces, due to skew in-plane compressions. Tensile forces can reduce the punching capacity of the slabs, aspect not studied yet. An experi-mental, numerical and theoretical investigation has been carried out, in which 5 1.65x1.65x0.12 m slabs have been tested under a point load and different degrees of unidirectional tensile force. Numerical predictions were made with FEA software ABAQUS and, from the theoretical point of view, the Compression Chord Capacity Model (CCCM) was extended to take into account the effect of in-plane tensile forces in the punching strength of the slabs. The experimental results showed that the ultimate punching load decreases linearly with the applied tensile force, and if that tensile force cracks the slabs, such reduction is higher. Results obtained with FEA and CCCM are in agreement with the observations made at the laboratory This work has been carried out within the framework of research project BIA-2015-64672-C4-1-R, financed by the Ministry of Economy and Competitiveness (MINECO) of Spain. The authors want o deeply thank the personnel of the Structural Technology Laboratory of the Polytechnic University of Catalonia and Master student Laura Beltrán who collaborated in the execution of the tests.

The objective is to familiarize students with real civil engineering problems as posed by social agents (e.g. a city council, a neighbourhood association, etc.) and to foster social responsibility, active and cooperative learning, teamwork and sustainability. A multidisciplinary team accompanies students in finding solutions to problems affecting a region, with the goal of training them in how to sensitively deal with complex urban realities and understand the possible impacts and conflicts of their projects for their region and society. Methodologically, this training strategy is based on active teamwork and cooperation applied to a real case. It is also influenced by service learning in that local stakeholders explain their problems to the students and ask for solutions. This initiative is not part of any study plan but is a complementary teaching activity organized by the Civil Engineering School of Barcelona and worth 3 ECTS for participating students. In 2016-2017, the workshop —covering problems related to harbour design, water quality, pedestrian bridges and retaining walls— as conducted in Marina d’Empuriabrava on the Costa Brava, proving to be a very satisfactory experience for students, teachers and local stakeholders in terms of learning and proposals. In 2017-2018 the workshop has been held in El Vendrell (Tarragona). In the next, editions, it is planned to make ongoing improvements in terms of time organization and teamwork evaluation.

A punching shear strength mechanical model for RC slabs with and w/o punching reinforcement, based on a previous shear model developed by the authors, is presented. The identified differences between shear and punching resisting mechanisms have been incorporated into the governing equations and failure mode. The model provides consistent explanations to the experimentally observed behavior, such as the position of the critical perimeter, the influence of the moment transferred to the slab or the efficiency of the shear reinforcement. Good agreement has been obtained between the model results and those of an available large database of punching tests.

This paper presents a comparative analysis of the performance of some the existing formulations to evaluate the FRP contribution to the total shear strength of reinforced concrete beams strengthened in shear by externally bonded FRP sheets. This analysis has been performe through the use of a wide database of 275 experimental tests of rectangular RC beams distinguishing those cases with and without internal steel transverse reinforcement and the different FRP strengthening configurations.

The punching-shear strength of slabs reinforced with FRP bars without transverse reinforcement is a complex phenomenon. The main difference with the conventional reinforced concrete is that the passive reinforcement has a linear elastic behaviour up to failure. In this paper, a comparative analysis of the reliability of the existing formulations to evaluate the punching strength of FRP RC slabs without transverse reinforcement is performed through an assembled database of 88 existing tests. In addition, a preliminary proposal based on the multiaction shear capacity model has been made and its reliability has also been evaluated by means of the assembled database.

In this paper a non-linear and time dependent evolutive analysis model, previously developed by the authors, is applied to the prediction of the response of reinforced concrete structures strengthened in flexure by FRP prestressed laminates throughout the elastic, cracked and ultimate ranges. The model considers the structural effects of changes in geometry, structural scheme, material properties and applied loads that may occur along the structure service life, including those due to strengthening.

El proyecto de investigación Straduravius, financiado por el Ministerio de Ciencia e Innovación de España, estudia la aplicación de materiales de construcción avanzados en estructuras de hormigón de altas prestaciones. Las barras de fibras reforzadas con polímeros (FRP) ofrecen una alternativa prometedora a los tendones de acero en hormigón pretensado. Sus ventajas son, una alta durabilidad y resistencia a la tracción, manteniendo un módulo de elasticidad comparablemente alto. La adherencia entre armadura y hormigón, en hormigón pretensado depende considerablemente del fenómeno llamado efecto Hoyer. Esto se debe a la expansión lateral del material cuando se somete a carga, produciendo que el diámetro de los tendones pretensados aumente y las propiedades de unión mejoren. Por el contrario esto limita el diseño, por lo tanto una comprensión fundamental del sistema de adherencia es vital para un diseño seguro. Esta tesis se fundamenta en una revisión bibliográfica exhaustiva, donde se resumen los hallazgos y fórmulas para calcular la longitud de anclaje de los tendones de FRP. Sigue la directriz de la normativa 440.4R-04 del American Concrete Institute (ACI) para pruebas de materiales FRP, mediante ensayos de tracción y extracción de la barra. Se determinaron las características del material y se definió un comportamiento sobre la adherencia. Esto con base en la prueba del prisma ECADA, que cuantifica la transferencia y la longitud de la unión por flexión de los tendones de FRP. El estudio experimental se ejecuta con barras de alta resistencia CFRP Carbopree®, barras GFRP Glasspree® FL E46 y un nuevo tipo de barra de fibra de vidrio con una resina termoplástica (TGFRP). El comportamiento elástico-lineal del material y su falla frágil se verificó por los ensayos de tracción. El módulo de elasticidad medido es superior a los definidos por el fabricante. Las demás características del material no pudieron verificarse, pero todas excedían el valor de diseño del 60 % del valor final. Se concluyó que el comportamiento de adherencia de las barras de fibra es mejor comparado con los tendones de acero, ya que la tensión de adherencia media permanece casi constante después de alcanzar su valor máximo. Se observaron fallas de anclaje debido a una presión lateral insuficiente que provocaron el deslizamiento de la barra. Cabe mencionar, que debido a una presión lateral excesiva, se produjo un fallo por fragilidad ligado a la ruptura de la fibra. En consecuencia, se deben determinar los estándares de prueba y mejorar el desarrollo del dispositivo de anclaje provisto para cada tipo de barra. La barra TGFRP no es aplicable como refuerzo porque se observó picos de tensión en la prueba de adherencia, producido por las muescas en espiral y en la prueba ECADA la barra deslizó en el anclaje por su acabado liso superficial. Sin embargo el CFRP y el GFRP son alternativas adecuadas para sustituir a los tendones de acero pretensado. The Straduravius research project, funded by the Spanish Ministry of Science and Innovation, studies the application of advanced construction materials in high- performance concrete structures. Fibre-reinforced polymer (FRP) bars offer a promising alternative to steel tendons in prestressed concrete. Their advantages lie in a high durability and high tensile strength while maintaining a comparably high modulus of elasticity. In prestressed concrete the bond between the reinforcement and the concrete differs from the bond in conventional reinforced concrete. Due to the lateral expansion of a material when subjected to load, the diameter of pre-tensioned tendons increases towards the end of a prestressed member. This so-called Hoyer effect increases the bond properties, but also elicits design limitations. The fundamental understanding of the bond is therefore important for a safe design. This thesis is based on a well-founded literature review, that summarizes the most important findings and formulas to calculate the anchorage length of FRP prestress tendons. Following the American Concrete Institute (ACI) 440.4R-04 guideline for FRP material testing, tensile and Pull-Out Tests are performed. The material characteristics are determined and statements about the bond performance are formulated. Based on the ECADA prism test, the transfer and flexural bond length of the FRP tendons are quantified. The experimental study is carried out with CFRP Carbopree® High Strength Rods, GFRP Glasspree® FL E46 Round Bars, and a new type of glass fibre bar with a thermoplastic resin (TGFRP). The conducted tensile tests can verify the linear-elastic material behaviour with a brittle failure. The measured modulus of elasticity is on the safe side, exceeding the expected values. The other material characteristics could not be verified but were all within the design value of 60 % of the ultimate value. The bond behaviour is found to be preferable to steel tendons because the mean bond stress stays close to constant after the maximum value is reached. Anchorage failures due to insufficient lateral pressure and therefore slip-out, but also due to too large lateral pressure and therefore brittle failure as a consequence of fibre rupture are observed. Accordingly, it is recommended to determine testing standards and further develop the provided anchoring device. The TGFRP bar observed bond stress peaks at the spiral indentations and it slipped out of the anchorage as a result of the smooth surface finishing. It is therefore not applicable as FRP reinforcement. However, the CFRP and GFRP are considered to be a suitable alternatives to steel prestress tendons. Incoming

Reinforced concrete members, especially when subjected to concentrated loads, can fail in shear. This is an undesirable and brittle failure mode preventing the structure from deforming and reaching higher load levels. It is therefore important to investigate and understand the nature of shear failures in RC beams and slabs, which are typically not provided with shear reinforcement. Despite the exhaustive research work carried out since the beginning of the XXth century, the shear behavior of reinforced concrete elements is still not fully clear. The complex kinematics and the different contribution of the widely accepted shear resisting actions, which depend, among other parameters, on the load level and the geometry of the specimens, are part of those uncertainties that have provoked the lack of consensus that currently exist around the shear problem in structural engineering. In this context, this thesis focuses on the shear behavior of reinforced concrete slabs without shear reinforcement subjected to point loads. On the one hand, part of the work carried out during this investigation deals with shear in one way slabs supported on linear supports. Thanks to the experimental work conducted in the last two decades, a significant database of test results is now available, which has allowed to develop and verify a new mechanical model to predict the shear strength of RC one-way slabs without shear reinforcement. It takes into account a significant number of variables involved in the phenomenon and is applicable to is applicable to simply supported slabs, cantilever slabs and situations with partial restraint to the rotation. The model is divided into two sub-models. One for loads applied close to supports, where the direct transmission of the load to the support plays an important role in the shear strength and a second one for loads applied away from supports where the possibility of a shear failure is assumed to coexist with the possibility of a local punching failure. On the other hand, the second part of the investigation deals with the shear behavior of reinforced concrete slabs subjected to the simultaneous action of in plane tensile stresses and out-of-plane point loads. This load case has not been exhaustively studied throughout the years, and in order to contribute to gain insight into this aspects of shear design, the mechanical model recently developed at UPC for the prediction of the punching-shear strength of two-way slabs has been extended to the case of simultaneous in-plane tensile forces. A set of experimental test for the validation of the model for the particular case of uniaxial in-plane tension is also presented. In addition to that, the particular case of one-way simply supported slabs subjected to transverse tensile stresses has also been experimentally studied. This is a seldom studied load case and the conducted set of test will help to understand the overall behavior of these elements under this particular loading condition. Los elementos de hormigón armado, especialmente cuando están sometidos a la acción de cargas puntuales, pueden alcanzar su resistencia última a esfuerzo cortante, lo cual limita su capacidad para deformarse y resistir valores de carga mayores. Este es un modo de fallo frágil y repentino, por lo que debe ser evitado. Así pues, es importante seguir investigando y comprender la naturaleza de la respuesta de vigas y losas de hormigón armado ante solicitaciones de este tipo, sobre todo cuando no están provistas de armadura de cortante. A pesar de la gran cantidad de campañas experimentales llevadas a cabo desde principios del siglo XX, el comportamiento a cortante y punzonamiento de los elementos estructurales de hormigón armado no está todavía del todo claro. La compleja cinemática y la diferente contribución de los mecanismos resistentes ampliamente aceptados, la cual depende, entre otros factores, del nivel de carga y de la geometría de los especímenes, son parte de esas incertidumbres que han provocado la falta de consenso que existe actualmente dentro del campo de la ingeniería estructural. En este contexto, esta tesis se centra en el comportamiento a cortante de losas de hormigón armado sin armadura de cortante sometidas a la acción de cargas puntuales. Por un lado, parte del trabajo realizado durante esta investigación está orientado al cortante en losas unidireccionales apoyadas sobre apoyos lineales. Gracias a todas las campañas experimentales realizadas en las últimas dos décadas, una significativa base de datos de resultados experimentales se encuentra disponible en la literatura, lo que ha permitido desarrollar y verificar un nuevo modelo mecánico para predecir la resistencia última a cortante de este tipo de elementos. Dicho modelo tiene en cuenta un número importante de variables involucradas en el fenómeno y es aplicable a losas simplemente apoyadas, en ménsula, y apoyadas en apoyos con restricción parcial al giro. El modelo se ha dividido en dos sub-modelos para facilitar su desarrollo. Uno para cargas aplicadas cerca de los apoyos, donde la transmisión directa de la carga al apoyo juega un papel importante, y un segundo para cargas aplicadas lejos de los apoyos, en donde se asume que la posibilidad del fallo por cortante coexiste con la posibilidad de un fallo local por punzonamiento. Por otro lado, la segunda parte de la investigación está focalizada en el comportamiento a cortante de losas de hormigón armado sometidas simultáneamente a la acción de cargas puntuales y tracciones en su plano. Este caso de carga no ha sido demasiado investigado a lo largo de las últimas décadas, y con la intención de contribuir a comprender esta compleja interacción, el modelo mecánico recientemente desarrollado en la UPC, para la predicción de la resistencia a punzonamiento en losas bidireccionales, ha sido extendido a este caso particular de cargas y validado con los resultados de campañas experimentales disponibles en la literatura y el conjunto de ensayos realizados como parte de esta investigación para el caso particular de tracciones unidireccionales. Adicionalmente, el efecto de las tracciones transversales en el plano en la resistencia a cortante de losas unidireccionales también ha sido estudiado experimentalmente. Esta combinación de cargas no ha sido apenas investigada y un nuevo grupo de ensayos experimentales puede contribuir a comprender el comportamiento global de este tipo de elementos ante este caso particular de carga. Enginyeria de la construcció

The use of externally bonded fibre reinforced polymers, FRP, for strengthening reinforced concrete (RC) beams or columns is an alternative to other traditional strengthening techniques due to its high strength-to-weight ratio, stiffness-to-weight ratio, and improved durability in comparison to steel. The use of FRP for shear strengthening is not as widespread as flexural strengthening or column confinement. One of the main reasons is that the shear resisting mechanisms of FRP strengthened elements are more complex. In addition, there is still no universally accepted model to evaluate the contribution of the FRP to the shear strength of the reinforced element, because this contribution is strongly related to the stress level of the external reinforcement, which is linear elastic up to failure and does not yield as conventional steel. The total shear strength of an structural element is given by several components: concrete, longitudinal and transverse steel reinforcement and external FRP reinforcement. The contribution of each part is difficult to evaluate, since there is an interaction between them. This coupling effect is not taken into account in the major part of the current models, which are additive without considering the possible modification of the shear component resisted by the concrete, Vc, and by the steel, Vs, due to the existence of the FRP, VFRP. The present thesis aims to identify and quantify the contribution of each component that contributes to resist the shear force of RC elements externally strengthened in shear by FRP, as well as the interaction between them. For this purpose, 20 shear tests of RC beams with a T-section, externally strengthened by FRP sheets have been performed. The influence on the shear strength of different FRP reinforcement ratios in a U-shaped configuration and the influence of two longitudinal steel reinforcement ratios have been analysed. The thickness of the FRP laminate has been kept constant, as well as the spacing between the sheets which is the same as the stirrups spacing. The different FRP reinforcement ratios correspond to different widths of the sheets applied to the beams (discontinuous of 50 or 100 mm wide, or continuous). In the control beams, upon a certain load level, a critical shear crack appears in the web with a certain inclination. Failure occurred when this critical shear crack propagated through the flanges with less inclination up to the load application point. In the tests with U-shaped FRP sheets, a premature debonding of the reinforcement was observed once the critical shear crack opened. Failure occurred in a similar manner when the critical shear crack propagated through the beam flanges to the load application point. In some tests, especially those with a greater longitudinal reinforcement ratio, the ultimate load was similar to that of the control beam. In order to avoid premature debonding of the reinforcement, two types of anchorage were designed and applied in some of the tests. The anchors held the transverse FRP sheets once the critical shear crack opened and propagated, delaying debonding. Failure occurred in a similar manner but for a higher ultimate load in compariston to the unanchored beams. In order to quantify the different contributions of concrete, transverse steel and FRP reinforcement to the shear strength, the beams were instrumented with strain gauges and displacement transducers. The analysis of the information provided by the instrumentation has allowed to estimate the contribution to the shear strength of the concrete web, concrete flanges, the longitudinal and transverse steel reinforcement and the FRP sheets., El refuerzo de vigas o pilares de hormigón armado mediante polímeros reforzados con fibras (FRP, de las siglas en inglés) constituye una alternativa a otras técnicas de refuerzo tradicionales, por su elevada relación resistencia-peso, rigidez-peso, así como por su mejor durabilidad en relación al acero. En refuerzos a cortante, esta técnica no se encuentra tan extendida como en refuerzos a flexión o confinamiento de pilares, entre otras razones porque los mecanismos resistentes son en sí mismos más complejos, y porque todavía no existe un modelo universalmente aceptado para evaluar la contribución del FRP a la resistencia a cortante del elemento reforzado, puesto que ésta depende del nivel de tensión o deformación en el refuerzo, que no plastifica a diferencia del acero. La resistencia a esfuerzo cortante procede de las aportaciones del hormigón, de la armadura longitudinal y transversal de acero y del refuerzo externo de FRP. La contribución de cada una de las partes es difícil de evaluar puesto que existe una interacción entre ellas. Este efecto de acoplamiento no se tiene en cuenta en gran parte de los modelos actuales, que son aditivos sin considerar la posible modificación de las componentes de cortante resistido por el hormigón Vc y por la armadura Vs debido al refuerzo de FRP, VFRP. La presente tesis doctoral pretende identificar y cuantificar la contribución de cada una de las componentes que contribuyen a resistir el esfuerzo cortante de elementos reforzados externamente a cortante con FRP. Para ello se ha realizado una serie de 20 ensayos a cortante de vigas de hormigón armado de sección en T, bajo carga puntual creciente hasta rotura. Se ha estudiado la influencia de diferentes cuantías de refuerzo a cortante con FRP en forma de U y de dos cuantías de armadura longitudinal de acero. El espesor del laminado FRP se ha mantenido constante, así como la separación longitudinal entre refuerzos externos que coincide con la separación de los cercos. Las diferentes cuantías estudiadas corresponden con distintos anchos de laminado (discontinuos de 50 o 100 mm de ancho, o continuos). En las vigas de control, bajo un cierto estado de carga se produjo la formación de una fisura crítica de cortante con una cierta inclinación en el alma. La rotura se produjo cuando esta fisura se propagó a través del ala con una menor inclinación. En los ensayos con refuerzo FRP en forma de U, se observó el desprendimiento prematuro del refuerzo cuando se abrió la fisura crítica de cortante en el alma. Una vez se fueron desprendiendo los laminados atravesados por la fisura crítica, la rotura se produjo cuando la fisura se propagó a través del ala de la viga hasta el punto de aplicación de la carga. En algunos ensayos, especialmente los que disponían de una mayor cuantía de refuerzo transversal la carga última obtenida fue similar a la de la viga de control. Para evitar el desprendimiento prematuro del refuerzo, se diseñaron dos tipos de anclaje que se aplicaron en algunos de los ensayos realizados para la presente tesis. Los anclajes sostuvieron al refuerzo transversal al abrirse la fisura crítica de cortante, y retardaron la rotura, que se produjo de forma similar pero para una carga última superior a la de las vigas sin anclaje. A fin de cuantificar las distintas contribuciones del hormigón, del acero transversal y del refuerzo FRP, las vigas se instrumentaron con galgas extensométricas y con transductores de desplazamiento. El análisis de la información proporcionada por la instrumentación ha permitido estimar la contribución a la resistencia a cortante del alma de hormigón, del ala de la sección transversal, de la armadura longitudinal, de la armadura transversal y del FRP.