Les travaux présentés dans cette thèse contribuent au développement du contrôle non destructif des conduits de précontrainte extérieure dans les ouvrages d'art. Une sonde capacitive a été développée pour ausculter ces conduits. L'objectif est d'en améliorer le diagnostic.Dans un premier temps, une cellule de mesure en transmission coaxiale a été développée pour caractériser les matériaux présents dans le conduit sur la bande de fréquence 50 MHz - 1 GHz. Le ciment, les produits de la ségrégation du ciment et la cire d'injection ont été étudiés.La deuxième partie du travail exploite ces résultats dans une modélisation directe du problème global. Une étude paramétrique nous a permis de proposer une méthode d'estimation de l'épaisseur de vide à l'intérieur du conduit à partir des signaux délivrés par la sonde, qui a pu être validée sur une maquette de conduit. A partir de ces résultats sont proposées plusieurs améliorations du dispositif visant à l'obtention de signaux plus riches issus des capteurs, afin de pouvoir estimer un plus grand nombre de paramètres. / The work presented in this report contributes to the development of Non Destructive Evaluation of the external post-tensioned ducts in bridges. A capacitive probe has been developed for bridge monitoring applications. The aim of this work is to improve its diagnostic.In a first step, a coaxial transmission line was developed to characterize the materials involved in the duct over the frequency range 50 MHz - 1 GHz. The cement grout, segregation products of the cement grout and the injection wax were studied.In the second part of this work the previous results are used in the modelling of the devices. A parametrical study has shown the ability to get from the signals an estimate of the thickness of the void in the duct. This estimation method has been validated using a laboratory duct. Further, several improvements of the probes are proposed to get signals containing more information in order to get a better estimation of the target parameters.

A failure associated with steel corrosion was identified in early 2011 in a bridge external post-tensioned tendon, approximately eight years after construction. Large voids in the grout and pockets of non-homogeneous material were identified. The non-homogeneous grout was characterized by high moisture content, and in most cases, the chloride content was lower than conservative threshold values. The non-homogeneous grout also had high pH and high content of sulfates (approximately in the range of 10,000-ppm). As a result, there was an interest in the study of possible corrosion development in repaired systems in which the affected tendons have been re-grouted with dissimilar grouts. The presence of two distinct grouting materials, manifested by the existing/simulated base grout and a newly introduced repair grout, provided the dissimilar grout condition studied. Corrosion activity was monitored in un-stressed mock up assemblies, in sections retrieved from the failed tendon, and in samples immersed in simulated pore solution. Corrosion activity was monitored through macrocell current, linear polarization resistance, open circuit potential, potentiodynamic scans, and electrochemical impedance spectroscopy. Samples in simulated pore solutions were studied at various pH levels and constituent concentrations. All samples were repaired or built with commercially available grouts. After analysis, no evidence of corrosion development was found when both existing and repair grout were free of material deficiencies. Corrosion activity was noted in the presence of nonhomogeneous grout and an increase in rate was observed due to macrocell coupling with sections containing normal grout. Results suggest that early exposure to sulfate to hydroxyl ion ratio as low 0.35 may prevent steel passivation and result in early high corrosion rates. Otherwise, sulfate to hydroxyl ratios as high as three may not be sufficient to initiate corrosion after formation of passive layer.

The main aim of the diploma thesis is a design of two bridges on D1 highway (Říkovice – Přerov). Structural system of these two bridges is a seven spans continuous beam. The bridges span the rail track and road I/35. The structural system of these two bridges is identical. The preliminary design is processed in two options. The first one considers the use of post-tensioned pre-casted beams PETRA with cast-in place cross beams and composite bridge deck. The second draft considers the use of two slab-beam with the cross beams. Effects of loads were calculated in SCIA Engineer program. The build-up phases were assessed by TDA method. The assessment of the structure was made according to EC.

My thesis is focused on a design and comparism of the highway bridge across Dolansky creek. The bridge is built by balanced cantilever method. The common span length is 110metres. The bridge is post-tensioned concrete structure.The static model is made of beams.The static analysis during lifespan of bridge is made by Time discretization analysis . The design of reinforcement is made for longitudinal section and cross section.

The topic of the thesis is the design and assessment of roadway bridge structure, which is curved in the horizontal plan with a very small radius. Bridges is part of the flyover crossing in Brno. There are designed two variations of which are further developed the variant of the two-chamber cross-section. Calculations and assessments are conducted in according to the valid European standards (Eurocodes). The static calculation is supplemented with a clear technical drawings and visualizations.

The subject of Diploma’s thesis is the design of a road bridge on the R1 expressway, at km 1,293 above the road III/51311. The main content is static calculation of supporting structure consisting of four spans. Four studies were processed and the first variant of double-girder monolithic structure was chosen. The range of spans is ranging from 25 m - 30 m. Double-girder consists of two post-tensioned concrete beams and reinforced concrete slab. Static models and load effects are solved in Scia Engineer. Bridge is located in the horizontal curvature, however, compromise was elected (because of small curvature), assessing the upright design. Calculation is made without effects of temperature, wind loads and horizontal forces causing by traffic.

The final thesis is focused on design a bridge construction. across the valley near Dobruška. The existing bridge is convenient and it will be replaced by a new bridge construction. The bridge is situated on motorway I/14 and it is used to transfer across the valley and Brtevsky brook.The bridge construction is designed in three alternatives. The chosen variant is a post-tensioned two-beam concrete construction with a lenght of 88,5 metres and a width of 14,0 metres. The calculation of load is solved in Scia Engineer 2014. The construction is designed in accordance with valid standards and it is made a drawing documentation.

The aim of the diploma thesis is the proposal of a bridge structure in the direction of Přerov – Lipník in the cadastral territory of the Osek nad Bečvou. A bridge is used to overcome the road III/43612 in km 93,550, the stream Lubeň and a field trip. From tree alternatives is selected a post-tensioned two-beam concrete struction and assessed according to the limit states including an impact of phased construction according to the European standards. Also it is prepared a drawing documentation, an accompanying report and a visualization of the beam.

Thesis involves designing and analysis of horizontally curved bridge contruction with chamber-shaped profile and oblique side walls. The object is a part of fly-over crossig at VMO Brno. Calculations are according to actually valid standards ( Eurocodes ). Thesis gives a basic look at the problematics of horizontaly curved bridge construction, including solution of prestressing cables´ 3D-tracking with usage of common software.

Objective condition assessment is essential to make better decisions for safety and serviceability of existing civil infrastructure systems. This study explores the condition of an existing transit guideway system that has been in service for thirty-five years. The structural system is composed of six-span continuous prestressed concrete bridge segments. The overall transit system incorporates a number of continuous bridges which share common design details, geometries, and loading conditions. The original analysis is based on certain simplifying assumptions such as rigid behavior over supports and simplified tendon/concrete/steel plate interaction. The current objective is to conduct a representative study for a more accurate understanding of the structural system and its behavior. The scope of the study is to generate finite element models (FEMs) to be used in static and dynamic parameter sensitivity studies, as well load rating and reliability analysis of the structure. The FEMs are used for eigenvalue analysis and simulations. Parameter sensitivity studies consider the effect of changing critical parameters, including material properties, prestress loss, and boundary and continuity conditions, on the static and dynamic structural response. Load ratings are developed using an American Association for State Highway Transportation Officials Load and Resistance Factor Rating (AASHTO LRFR) approach. The reliability of the structural system is evaluated based on the data obtained from various finite element models. Recommendations for experimental validation of the FEM are presented. This study is expected to provide information to make better decisions for operations, maintenance and safety requirements; to be a benchmark for future studies, to establish a procedure and methodology for structural condition assessment, and to contribute to the general research body of knowledge in condition assessment and structural health monitoring.