[EN] Bridges, as an important component of infrastructure, are expected to meet all the requirements for a modern society. Traditionally, the primary aim in bridge design has been to achieve the lowest cost while guaranteeing the structural efficiency. However, concerns regarding building a more sustainable future have change the priorities of society. Ecological and durable structures are increasingly demanded. Under these premises, heuristic optimization methods provide an effective alternative to structural designs based on experience. The emergence of new materials, structural designs and sustainable criteria motivate the need to create a methodology for the automatic and accurate design of a real post-tensioned concrete bridge that considers all these aspects. For the first time, this thesis studies the efficient design of post-tensioned concrete box-girder road bridges from a sustainable point of view. This research integrates environmental, safety and durability criteria into the optimum design of the bridge. The methodology proposed provides multiple trade-off solutions that hardly increase the cost and achieve improved safety and durability. Likewise, this approach quantifies the sustainable criteria in economic terms, and evaluates the effect of these criteria on the best values of the variables. In this context, a multi-objective optimization is formulated to provide multiple trade-off and high-performing solutions that balance economic, ecologic and societal goals. An optimization design program selects the best geometry, concrete type, reinforcement and post-tensioning steel that meet the objectives selected. A three-span continuous box-girder road bridge located in a coastal region is selected for a case study. This approach provides vital knowledge about this type of bridge in the sustainable context. The life-cycle perspective has been included through a lifetime performance evaluation that models the bridge deterioration process due to chloride-induced corrosion. The economic, environmental and societal impacts of maintenance actions required to extend the service life are examined. Therefore, the proposed goals for an efficient design have been switch from initial stage to life-cycle consideration. Faced with the large computational time of multi-objective optimization and finite-element analysis, artificial neural networks (ANNs) are integrated in the proposed methodology. ANNs are trained to predict the structural response based on the design variables, without the need to analyze the bridge response. The multi-objective optimization problem results in a set of trade-off solutions characterized by the presence of conflicting objectives. The final selection of preferred solutions is simplified by a decision-making technique. A rational technique converts a verbal pairwise comparison between criteria with a degree of uncertainty into numerical values that guarantee the consistency of judgments. This thesis gives a guide for the sustainable design of concrete structures. The use of the proposed approach leads to designs with lower life-cycle cost and emissions compared to general design approaches. Both bridge safety and durability can be improved with a little cost increment by choosing the correct design variables. In addition, this methodology is applicable to any type of structure and material. / [ES] Los puentes, como parte importante de una infraestructura, se espera que reúnan todos los requisitos de una sociedad moderna. Tradicionalmente, el objetivo principal en el diseño de puentes ha sido lograr el menor coste mientras se garantiza la eficiencia estructural. Sin embargo, la preocupación por construir un futuro más sostenible ha provocado un cambio en las prioridades de la sociedad. Estructuras más ecológicas y duraderas son cada vez más demandadas. Bajo estas premisas, los métodos de optimización heurística proporcionan una alternativa eficaz a los diseños estructurales basados en la experiencia. La aparición de nuevos materiales, diseños estructurales y criterios sostenibles motivan la necesidad de crear una metodología para el diseño automático y preciso de un puente real de hormigón postesado que considere todos estos aspectos. Por primera vez, esta tesis estudia el diseño eficiente de puentes de hormigón postesado con sección en cajón desde un punto de vista sostenible. Esta investigación integra criterios ambientales, de seguridad estructural y durabilidad en el diseño óptimo del puente. La metodología propuesta proporciona múltiples soluciones que apenas encarecen el coste y mejoran la seguridad y durabilidad. Al mismo tiempo, se cuantifica el enfoque sostenible en términos económicos, y se evalúa el efecto que tienen dichos criterios en el valor óptimo de las variables. En este contexto, se formula una optimización multiobjetivo que proporciona soluciones eficientes y de compromiso entre los criterios económicos, ecológicos y sociales. Un programa de optimización del diseño selecciona la mejor combinación de geometría, tipo de hormigón, armadura y postesado que cumpla con los objetivos seleccionados. Se ha escogido como caso de estudio un puente continuo en cajón de tres vanos situado en la costa. Este método proporciona un mayor conocimiento sobre esta tipología de puentes desde un punto de vista sostenible. Se ha estudiado el ciclo de vida a través de la evaluación del deterioro estructural del puente debido al ataque por cloruros. Se examina el impacto económico, ambiental y social que produce el mantenimiento necesario para extender la vida útil del puente. Por lo tanto, los objetivos propuestos para un diseño eficiente han sido trasladados desde la etapa inicial hasta la consideración del ciclo de vida. Para solucionar el problema del elevado tiempo de cálculo debido a la optimización multiobjetivo y el análisis por elementos finitos, se han integrado redes neuronales en la metodología propuesta. Las redes neuronales son entrenadas para predecir la respuesta estructural a partir de las variables de diseño, sin la necesidad de analizar el puente. El problema de optimización multiobjetivo se traduce en un conjunto de soluciones de compromiso que representan objetivos contrapuestos. La selección final de las soluciones preferidas se simplifica mediante una técnica de toma de decisiones. Una técnica estructurada convierte los juicios basados en comparaciones por pares de elementos con un grado de incertidumbre en valores numéricos que garantizan la consistencia de dichos juicios. Esta tesis proporciona una guía que extiende y mejora las recomendaciones sobre el diseño de estructuras de hormigón dentro del contexto de desarrollo sostenible. El uso de la metodología propuesta lleva a diseños con menor coste y emisiones del ciclo de vida, comparado con diseños que siguen metodologías generales. Los resultados demuestran que mediante una correcta elección del valor de las variables se puede mejorar la seguridad y durabilidad del puente con un pequeño incremento del coste. Además, esta metodología es aplicable a cualquier tipo de estructura y material. / [CA] Els ponts, com a part important d'una infraestructura, s'espera que reunisquen tots els requisits d'una societat moderna. Tradicionalment, l'objectiu principal en el disseny de ponts ha sigut aconseguir el menor cost mentres es garantix l'eficiència estructural. No obstant això, la preocupació per construir un futur més sostenible ha provocat un canvi en les prioritats de la societat. Estructures més ecològiques i durables són cada vegada més demandades. Davall estes premisses, els mètodes d'optimització heurística proporcionen una alternativa eficaç als dissenys estructurals basats en l'experiència. L'aparició de nous materials, dissenys estructurals i criteris sostenibles motiven la necessitat de crear una metodologia per al disseny automàtic i precís d'un pont real de formigó posttesat que considere tots estos aspectos. Per primera vegada, esta tesi estudia el disseny eficient de ponts de formigó posttesat amb secció en calaix des d'un punt de vista sostenible. Esta investigació integra criteris ambientals, de seguretat estructural i durabilitat en el disseny òptim del pont. La metodologia proposada proporciona múltiples solucions que a penes encarixen el cost i milloren la seguretat i durabilitat. Al mateix temps, es quantifica l'enfocament sostenible en termes econòmics, i s'avalua l'efecte que tenen els dits criteris en el valor òptim de les variables. En este context, es formula una optimització multiobjetivo que proporciona solucions eficients i de compromís entre els criteris econòmics, ecològics i socials. Un programa d'optimització del disseny selecciona la millor geometria, tipus de formigó, armadura i posttesat que complisquen amb els objectius seleccionats. S'ha triat com a cas d'estudi un pont continu en calaix de tres vans situat en la costa. Este mètode proporciona un major coneixement sobre esta tipologia de ponts des d'un punt de vista sostenible. S'ha estudiat el cicle de vida a través de l'avaluació del deteriorament estructural del pont a causa de l'atac per clorurs. S'examina l'impacte econòmic, ambiental i social que produïx el manteniment necessari per a estendre la vida útil del pont. Per tant, els objectius proposats per a un disseny eficient han sigut traslladats des de l'etapa inicial fins a la consideració del cicle de vida. Per a solucionar el problema de l'elevat temps de càlcul degut a l'optimització multiobjetivo i l'anàlisi per elements finits, s'han integrat xarxes neuronals en la metodologia proposada. Les xarxes neuronals són entrenades per a predir la resposta estructural a partir de les variables de disseny, sense la necessitat d'analitzar el pont. El problema d'optimització multiobjetivo es traduïx en un conjunt de solucions de compromís que representen objectius contraposats. La selecció final de les solucions preferides se simplifica per mitjà d'una tècnica de presa de decisions. Una tècnica estructurada convertix els juís basats en comparacions per parells d'elements amb un grau d'incertesa en valors numèrics que garantixen la consistència dels dits juís. Esta tesi proporciona una guia que estén i millora les recomanacions sobre el disseny d'estructures de formigó dins del context de desenrotllament sostenible. L'ús de la metodologia proposada porta a dissenys amb menor cost i emissions del cicle de vida, comparat amb dissenys que seguixen metodologies generals. Els resultats demostren que per mitjà d'una correcta elecció del valor de les variables es pot millorar la seguretat i durabilitat del pont amb un xicotet increment del cost. A més, esta metodologia és aplicable a qualsevol tipus d'estructura i material. / García Segura, T. (2016). Efficient design of post-tensioned concrete box-girder road bridges based on sustainable multi-objective criteria [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/73147

This master thesis is focused for design, respectively for creating counterproposal of existing structure of Motorway Bridge located at D1 motorway between Jánovce and Jablonov in district Levoča in Slovakia. This bridge is over a local road. The main aim of this thesis is design, analysis and assessment of bearing elements of bridge deck. For purposes of this thesis was created three variants of bridge deck. Detailed analysis was performed on bearing construction from post-tensioned precast beam with monolithing concrete slab. Two mathematic models were used for analysis of chosen variant. First model was spatial 3D shell construction. The purpose of this model was determinate cross spreading line of other constant load and live load. Second, flat 2D model, was for determination creep and shrinkage appeared from long-term load. These effects were observed in at advanced defined time nodes. Outcomes from upper mentioned model were used from design and assessment of bearing elements of bridge deck, design prestressed reinforcement cables and concrete reinforcement rods.

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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.

Diploma thesis deals with reconstruction of old beam bridge in town Ledeč nad Sázavou. Three variants of reconsttruction were done. Detailed structural design report was done to one of them, streithening with post-tensioning. Calculation of load effect was solved with finite elemet method via software on grillage model. Construction was checked on ultimate limit state and serviceability limit state. Necessary drawings were elaborated to chosen method.

The final thesis is focused on design of valley bridging on I/38 road at the Havlickuv Brod bypass. The thesis contains study of the bridging area. For detailed assessment was chosen, from three variants, a two-beam cross-section girder of 4 spans. Load-bearing structure is designed as cast-in-place, post-tensioned, concreted at fixed falsework without phased construction. The serviceability limit state and the ultimate limit state were assessed. The thesis contains, apart from structural design, drawings and visualizations of the bridge.

The diploma thesis is focused on solving road bridge situated between Roudno and Razová village over the water basin Slezská Harta. Before the design itself 3 studies were created and compared together. The selected variant is a continuous box girder with inclined walls, post-tensioned by bonded cables. The girder of a total lenght 148,0 m and width 13,6 m is divided into three spans. Height of the girder is 3,3 m. A detailed structural design, including construction limit state assessment, prestress design and time dependent analysis verification is processed. The design and the assessments of temporary and permanent situations are made according to valid standarts and regulations. Drawings and vizualizations are parts of the diploma thesis.

This diploma thesis is about designing the structure of roof of swimming stadium. Three solutions are created - concrete arc with tie, steel truss slab and concrete pretensioned membrane. One choosed solution - concrete pretensioned membrane - is afterwards developed. In the beginning there are several designs of geometry fulfilling the requirements for given type of structure being created. In part of static calculation, the parametrical mathematical model in form of macro in APDL language for Ansys software has been created. Afterwards all the parameters (initial state of cables, level of pretension, dimensions of membrane and peripheral frame, etc.) has been optimized in order to the membrane be fulfilling criterias for ultimate limit state and serviceability limit state. Afterwards other selected parts of structure has been checked. On basis of designed geometry and design checks in static calculation the drawings of conctruction and designed parts has been created. In the end, the 3D model of the structure has been created in graphical software Rhinoceros. Then visualizations of structure in concstruction stages and after completion has been rendered.