The aim of this master thesis is to explore and describe behavior of slab in punching shear. In total four concrete slabs were experimentally tested; each being reinforced differently. Using real experiments, there was a possibility to observe different behavior of steel and FRP reinforcement, eventually even the effect of adding FRP stirrups on load-bearing capacity. For the purpose of experimental testing design, currently placed formulas used to determine punching shear capacity were adjusted for application on longitudinal and shear FRP reinforcement. Atena software was used to approximate behavior of specimens by performing a nonlinear analysis. After the results of loading tests were obtained, next step was the comparison of design approaches and comparison of behavior of nonlinear model to a real specimen. In practical part, design of locally supported slab with requirement of non-magnetic reinforcement took place.

This doctoral thesis focuses on the research of the pedestrian bridges formed by the flat arch. To understand the basic static behaviour of the flat arch it was necessary to make a study of the development of the direct flat arch as footbridge with large span and the impact of stiffness on its camber. For the mathematical modeling FEM software ANSYS were used. The calculation has shown that a design of purely concrete flat arch would demand enormous bending stiffness, which can be achieved only through a massive cross-section. The findings gained in this chapter were further used to design a unique pedestrian bridge formed by the curved in plan flat arch, where to transfer of the large bending moments a steel pipe was designed. Several variants with different span and rise of the arch in plan were tested. From the tested variants was then selected footbridge with a span of 45 m and with the rise of the arch 10 m, which seemed to be the best solution according to the calculations and it was further analyzed in detail. The studied structure is formed by curved concrete slab that is stiffened through the steel brackets on the inner side of a steel tube with a graded thickness. The external cables that are situated in the handrail pipe balance the dead load torsional moment. Designed structure and the static analysis procedure were verified on a fully functional 1:6 scale model. The thesis describes the model analogy used for the design of the model, its structural design and its implementation. Load tests on the model confirmed correctness of the design of the proposed curved in plan pedestrian bridge, its high carrying capacity and the accuracy of the developed procedure of static analysis. Results and experiences acquired from the design and the realization of model are the basis for a practical realization of studied structures. The last part of the thesis deals with the possibility of replacement of the steel components with concrete in pedestrian bridges formed

The theme of this doctoral thesis is research of footbridges curved in plan that are formed by stress ribbon. Recently, several noteworthy curved pedestrian bridges, which decks are suspended on their inner edges on suspension or stay cables, have been constructed. However, curved stress ribbon bridges have not been built so far. The goal of this study was to answer the question whether the use of curved stress ribbon structures is even possible. For this reason, in the first stage feasibility study of these structures has been prepared. Knowledge of both curved pedestrian bridges, which decks are suspended on their inner edge and straight stress ribbon has been used. For the mathematical modeling FEM software ANSYS was used. The obtained findings were further used to design a new type of a modern, aesthetic curved bridge for pedestrians. The structure is formed by slender reinforced deck, which is through the steel brackets on the inner side stiffened by steel section. Torsion of the deck, caused by curved structure and asymmetrical cross-section, is reduced by cable situated in the handrail. Footbridge span is 45 m, arc camber in plan is 10 m, free bridge width is 3 m. Described is a general structure effect, detail static and dynamic analysis was carried out. Designed structure including construction stages were experimentally verified on a fully physical functional 1:6 scale model. The thesis describes the model analogy used for the design of the model, its structural design and its implementation. The model was subjected to a series of load tests including the final ultimate strength test. Performed tests confirmed the good match of calculation with the reality, correctness of the design and high resistance of designed construction. Acquired results and experiences from design and realization of model form the basis for practical realization of studied structures.

The aim of this doctoral thesis is the research of the plan curved footbridges with the deck supported by arch. The research is preceded by the survey of present findings about arch structures with upper deck. The summary of reasons and difficulties of design of plan curved structures follows. The appropriate approach for design of plan curved structure is searched on the basis of methods for design of straight structure. The design of arch which is subjected to minimal bending moments is emphasised. At first, the structure is designed in the same way as straight structure and the limit plan curvature (for which the method is not suitable anymore) is sought. Then the approach based on method of inversion of suspended cable is examined and adapted for designing of plan curved arch geometry. The approach is thoroughly analysed through calculation model and experimentally verified on physical model in scale 1:10. The process of design, construction and testing of the physical model is described in detail. Measured deformations and stresses are compared with expected behaviour based on numerical analysis. The comparison proves good correlation between calculation and measurement, as well as high load bearing capacity of the structure.

L’état de l’art réalisé dans le cadre de ce travail a permis d’identifier une grande variété de techniques de réalisation de micropieux avec des comportements effort-déformation difficiles à prédire. Quant aux méthodes de contrôle, du point de vue de l’intégrité il existe deux méthodes développées pour les pieux lesquelles ne sont pas toujours applicables aux cas de micropieux ; et du point de vue du contrôle du comportement mécanique, il existe un essai assez utilisé pour le contrôle de micropieux : l’essai d’arrachement. Cet essai est facile à réaliser et à interpréter, cependant il est onéreux (long temps d’essai) et difficile à mettre en place. Un autre type d’essai, utilisé dans le contrôle de fondations profondes, est l’essai de chargement dynamique. La recherche bibliographique a permis d’identifier les avantages et inconvénients de ce type d’essai adaptés et déjà validés dans le contrôle de pieux. Nous avons donc proposé une nouvelle méthodologie basée sur des essais de chargement dynamique à faible contrainte nécessitant des énergies de battage beaucoup moins importantes que dans les essais de chargement dynamique classiques. Le protocole et dispositif d’essai de la méthodologie ont été calibrés et validés à partir de simulations numériques afin notamment de justifier les choix de l’énergie d’impact, de la masse du marteau et de l’amortisseur à utiliser. Les observations numériques sont ensuite vérifiées expérimentalement sur des micropieux à échelle réelle mis en place dans un site expérimental développé dans le cadre de ce projet. La méthodologie de contrôle en place de la résistance en service de micropieux développée, c’est une méthode originale simple à réaliser, facile à mettre en oeuvre et d’interprétation immédiate. Elle a été validée aussi dans le cas de micropieux à échelle réelle en conditions maitrisées dans le site expérimental et non maitrisées dans trois chantiers réels de micropieux. Finalement, le progrès dans les recherches, a permis le développement d’une méthodologie de contrôle de la résistance limite de micropieux. Pour cela nous proposons d’utiliser un modèle analytique de prédiction du comportement effort-déformation alimenté par les résultats de l’essai de chargement dynamique à faible déformation et d’un essai complémentaire de reconnaissance des paramètres à la rupture du sol. L´objectif de ce développement est de proposer une prédiction de la résistance limite du micropieux testé sans compromettre son intégrité. L’application de la méthodologie a montré qu’elle donne des résultats très proches de ceux observés dans les essais statiques. / The review of the state-of-the-art of micropiles produced as part of this work allows to identify a wide variety of construction methodologies which have a stress-strain behavior difficult to predict. As for the testing methods, there are methods for assessing the condition of piles or shafts but they are not always applicable to the micropiles; and in terms of the control of mechanical behavior, the most used load testing micropile is the uplift static load test. The static load test is easy to perform and interpret, however the reaction system is cumbersome and slow to erect, therefore this test is time and cost consuming. Another type of test that can be used in the control of deep foundations is the dynamic load testing. The literature review helped to identify the advantages and disadvantages of this type of test that has been adapted and validated in control of pile behavior. The new methodology proposed in this work is based on low-strain dynamic test requiring a smaller impact energy than a high-strain dynamic test. The testing protocol and loading device of the methodology have been calibrated and validated by numerical simulations in order to justify the choice of the impact energy, the weight of hammer and the cushion that will be used. The numerical observations are then verified by experiences in full-scale micropiles installed in an experimental site developed as part of this project. The developed in situ control methodology of the resistance in service of micropiles is an original method, easy to carry out, simple to execute and with an immediate interpretation. This methodology has been validated on full-scale micropiles in contained conditions and also in uncontained conditions in three real projects of micropiles. Finally, the advances in the investigations have led to develop a methodology for control the micropile’s ultimate resistance. We propose to use an analytical model for predicting the stress-strain behavior, which must be supplied with the results of the low-strain dynamic micropile test and of a complementary geotechnical test in order to examine the parameter of soil failure. The goal of this development is to provide a method for predict the micropile’s ultimate resistance without compromising its integrity. The results of the application of the new method to the experimental micropiles are in close agreement with the results observed in the static load test. / La revisión del estado del arte en relación a micropilotes, realizada en este trabajo, ha permitido identificar una gran variedad de técnicas de construcción, donde la predicción de sus comportamientos mecánicos, es una tarea difícil de realizar. Con respecto a los métodos de control, desde el punto de vista de la integridad, existen actualmente métodos no siempre aplicables a los micropilotes, y desde el punto de vista del control del comportamiento mecánico, el ensayo más utilizado es el ensayo de arrancamiento. El ensayo de arrancamiento es de fácil realización e interpretación, sin embargo es oneroso, por su larga duración y la necesidad de disponer de equipos muy pesados.Otro tipo de ensayo, que es utilizado para el control de fundaciones profundas en general, es el ensayo de carga dinámica, cuyas ventajas y desventajas han sido identificadas en la investigación bibliográfica.La nueva metodología propuesta, motivo de este trabajo, está basada en los ensayos de carga dinámica a baja deformación, donde se necesita una energía de impacto mucho menos importante que en el caso de los ensayos clásicos de carga dinámica.El protocolo de la metodología y su dispositivo de ensayo han sido calibrados y validados a partir de simulaciones numéricas con el fin de, principalmente, justificar la elección de la energía de impacto, de la masa del martillo y del amortiguador a utilizar. Las observaciones numéricas han sido, luego, verificadas experimentalmente sobre micropilotes a escala real, instalados en un sitio experimental desarrollado en el marco de este proyecto.La metodología de control in situ, de la resistencia en servicio de micropilotes, desarrollada en este trabajo, es un método original, simple de realizar, con un sistema fácil de instalar y de interpretación inmediata. Ella ha sido validada, en el caso de micropilotes a escala real en condiciones controladas en el sitio experimental, y no controladas en el caso de tres proyectos reales.Además, el avance en las investigaciones, dio lugar al desarrollo de una metodología de control de la resistencia límite de micropilotes. Para ello proponemos utilizar un modelo analítico de predicción del comportamiento esfuerzo-deformación alimentado por resultados del ensayo de carga dinámica a baja deformación y de un ensayo complementario de reconocimiento de los parámetros de ruptura del suelo. El objetivo de este desarrollo es de proponer un método de predicción de la resistencia límite de micropilotes sin comprometer su integridad. La aplicación de la metodología ha mostrado que los resultados son muy cercanos a los observados en los ensayos de carga estática.

The doctoral thesis deal with the interaction between the foundation plate and deep foundation in the form of bored piles in the case of skeleton construction. The issue of tension redistribution from the column between the plate and the pile is investigated on specific object – „Shopping and entertainment center Fórum Nová Karolina”. On this object were selected columns monitored and load tests of the piles was executed. Values of the axial loading of the piles and the actual deformation of the construction have been derived from measurements and tests. They were compared with the results of structural behavior by numerical modeling.

This thesis is focused on creation of mobilization curves, based on data, obtained from standard and detailed monitoring of the load test. The load test was performed on the 9 meters long ductile micropile. The first part of the thesis explains the methods and principles, which was used to construct the mobilization curves. Next there is description of the technologies of ductile micropiles and the load test. In the next part of the thesis is generally explained process, which was applied to the evaluated data. For evaluation was used spreadsheet Microsoft Excel and programming language Matlab, with Kernel Smoothing extension. In the last chapter of the thesis there are interpreted the load transfer function together with skin friction and micropile displacement.

The master thesis consists of a theoretical part and a practical part. In the theoretical part jet-grouting technology is described briefly. Mechanical properties of jet-grouted piles were characterized. Various estimation methods of ultimate pile bearing capacity are described in this thesis – analytical calculation of ultimate bearing capacity for bored piles and estimation of ultimate pile bearing capacity by analysis of load-displacement curve defined by CHIN (1970; 1972). Load transfer method for piles and hyperbolic load-transfer curve are introduced. As a part of the load-trasfer method analysis, a method of estimating ultimate pile shaft friction called beta method is defined. In the practical part were evaluated several static load tests of jet-grouted piles and were constructed their load-displacemnt curves. Then reverse analysis of the results from static load tests was performed using load-transfer method. Then ultimate pile bearing capacity was estimated using analytical calculation of pile bearing capacity for bored piles and using analysis of load-displacement curve with method by CHIN (1970; 1972). By evaluation of load transfer method and beta method ultimate shaft resistence for each pile was estimated. Results and load-displacement curves were compared.

Since their inception, building materials are constantly improving. New ways to explore and improve the material's properties are constantly investigated (especially to improve the mechanical and deformation characteristics of the materials). This thesis is focused on identifying and comparing values of the modulus of elasticity of fine-grained composites. These features are compared with respect to water cement ratio, ageing and compressive strength of the investigated materials. Afterwards, the values of the modulus of elasticity are studied in the relation to the tested materials.

Design and manufacture of reinforced concrete beams for laboratory testing. Implementation of selected tests of mechanical properties for selected elements. Experimental analysis of reinforced concrete beams in the laboratory. Creating a numerical model in the software ATENA 2D. Graphic processing of numerical and experimental analysis and comparison.