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La infraestructura, particularment els ponts, és essencial perquè el món modern funcioni sense problemes. Aquestes estructures són crucials per al transport, el comerç i les interaccions socials, i la seva gestió adequada és vital per a garantir la seva longevitat i seguretat. Per tant, és necessari aplicar sistemes de gestió com el Modelatge d'Informació d'Edificacions (BIM, per les seves sigles en anglès) i els Sistemes de Gestió d'Edificacions (BMS, per les seves sigles en anglès). Aquesta tesi té com a objectiu demostrar l'eficàcia d'un BMS basat en BIM per a la gestió de ponts. Les dades de BIM i BMS s'integren mitjançant el desenvolupament d'un esquema de dades, que serveix com a base per a crear elements estructurals detallats. El model paramètric desenvolupat amb el modelatge basat en algorismes i l'alineament en algorismes permet adequar qualsevol projecte de manera més ràpida i eficient. La metodologia desenvolupada per a aquest propòsit garanteix que la informació continguda en l'esquema de dades es tradueixi en elements estructurals precisos i exactes en el model. Aquests elements estructurals detallats s'utilitzen després per a crear el BMS, que proporciona monitoratge en temps real, control i recomanacions de manteniment per als ponts. El BMS desenvolupat en aquesta tesi s'aplica a un sistema pilot de gestió de ponts per a demostrar la seva importància i usabilitat. Els resultats mostren que el BMS pot ajudar a gestionar la infraestructura de manera més eficient, especialment en el cas dels ponts. Pot detectar problemes potencials abans que es tornin greus i permetre que es prenguin accions correctives oportunes, millorant la vida útil i la seguretat. La infraestructura, particularmente los puentes, es esencial para que el mundo moderno funcione sin problemas. Estas estructuras son cruciales para el transporte, el comercio y las interacciones sociales, y su gestión adecuada es vital para garantizar su longevidad y seguridad. Por lo tanto, es necesario aplicar sistemas de gestión como el Modelado de Información de Edificaciones (BIM, por sus siglas en inglés) y los Sistemas de Gestión de Edificaciones (BMS, por sus siglas en inglés). Esta tesis tiene como objetivo demostrar la eficacia de un BMS basado en BIM para la gestión de puentes. Los datos de BIM y BMS se integran mediante el desarrollo de un esquema de datos, que sirve como base para crear elementos estructurales detallados. El modelo paramétrico desarrollado con el modelado basado en algoritmos y el alineamiento en algoritmos permite adecuar cualquier proyecto de manera más rápida y eficiente. La metodología desarrollada para este propósito garantiza que la información contenida en el esquema de datos se traduzca en elementos estructurales precisos y exactos en el modelo. Estos elementos estructurales detallados se utilizan luego para crear el BMS, que proporciona monitoreo en tiempo real, control y recomendaciones de mantenimiento para los puentes. El BMS desarrollado en esta tesis se aplica a un sistema piloto de gestión de puentes para demostrar su importancia y usabilidad. Los resultados muestran que el BMS puede ayudar a gestionar la infraestructura de manera más eficiente, especialmente en el caso de los puentes. Puede detectar problemas potenciales antes de que se vuelvan graves y permitir que se tomen acciones correctivas oportunas, mejorando la vida útil y la seguridad. Infrastructure, particularly bridges, is essential for the modern world to function smoothly. These structures are crucial for transportation, commerce, and social interactions, and their proper management is vital to ensure their longevity and safety. Therefore, it is needed to apply management systems such as Building Information Modeling (BIM) and Building Management Systems (BMS) are needed. This thesis aims to demonstrate the effectiveness of a BMS based on BIM for managing bridges. BIM and BMS data are integrated by developing a data schema, which serves as the foundation for creating detailed structural elements. The parametric model developed with the algorithm-based modeling and the alignment-based algorithm allows adequating any project faster and more efficiently. The methodology developed for this purpose ensures that the information contained in the data schema is translated into accurate and precise structural elements on the model. These detailed structural elements are then utilized to create the BMS, which provides real-time monitoring, control, and maintenance recommendations for bridges. The BMS developed in this thesis is applied to a pilot bridge management system to demonstrate its usability. The results show that the BMS can help manage infrastructure more efficiently, particularly in the case of bridges. It can detect potential problems before they become severe and enable timely corrective actions to be taken, improving the lifespan and safety.

A hybrid girder bridge adopts a steel segment at the mid-span of the main span of a continuous concrete girder bridge. The critical point of the hybrid solution is the transition zone, connecting the steel and concrete segments of the beam. Although many girder tests revealing the structural behavior of hybrid girders have been conducted by previous studies, few specimens took the full section of a steel–concrete joint due to the large size of prototype hybrid bridges. In this study, a static load test on a composite segment to bridge the joint between the concrete and steel parts of a hybrid bridge with full section was conducted. A finite element model replicating the tested specimen results was established through Abaqus, while parametric studies were also conducted. The test and numerical results revealed that the concrete filling in the composite solution prevented the steel flange from extensive buckling, which significantly improved the load-carrying capacity of the steel–concrete joint. Meanwhile, strengthening the interaction between the steel and concrete helps to prevent the interlayer slip and simultaneously contributes to a higher flexural stiffness. These results are an important basis for establishing a rational design scheme for the steel–concrete joint of hybrid girder bridges. This research was funded by Spanish Ministry of Science and Innovation (grant number PID2021-126405OB-C31), Shanghai Science and Technology Commission (grant number 20XD1432400) and Guangdong Yejian Construction Drawing Review Center Co., Ltd. (grant number GDYJ-RD-17).

This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers. This material may be found at https://ascelibrary.org/doi/abs/10.1061/JBENF2.BEENG-5955. A partial connection–prestressing (PCP) method is proposed in this paper to decrease the prestress that was transferred to steel girders in the negative moment region of steel–concrete composite bridges. The partial connection is achieved by the application of rubber-sleeved studs (RSS) in the prestressed concrete slab in the negative moment region. Since there is no experimental research on the PCP method in continuous composite girders, to the best of the authors’ knowledge, two continuous composite girders were tested under a four-point static load to evaluate their mechanical performance. The test results showed that without decreasing the ultimate strength and overall stiffness of the steel–concrete composite girders, the PCP method enhanced the cracking load (Pcr) 3.1 times. In addition, 12.5% of the prestressing force was transferred into the steel girder at the internal support section with the PCP method, and the girder without the PCP reached 25.9%. Then, to elucidate the partial interaction effect and prestressing effect on continuous girders’ mechanical behavior, numerical models were developed and calibrated with the test results. From the numerical analysis, compared with normal composite girders, the application of RSS or prestressing could improve Pcr by 11.8% and 157.0%, respectively, and the value increases to 234.3% when RSS and prestressing are applied at the same time. The results indicate that the application of RSS in the negative moment region could effectively increase the prestressing efficiency in the concrete slab and enhance the bridge's durability. This research is sponsored by the National Natural Science Foun-dation of China (No. 51978501) and the Major Research and De-velopment Project of Jiangxi Province (No. 20165ABC2800).

Pre-stressed concrete with post-tensioned (PT) cables historically represented an attractive alternative to ordinary reinforced concrete (RC). A wide portion of the world-wide existing concrete bridges was PT. As the nominal service life of those structures expires, several collapses occurred, highlighting the problem of the inspection. The main issue is that PT cables may be affected by relevant corrosion phenomena related to the presence of air or water inside the duets: such 'hidden' defects need to be determined through reliable testing methodologies. This paper presents the in-progress research aiming to quantify the influence of the damage of the single cable on the entire structure. The case study is an ltalian viaduct composed of simply supported beams connected by an upper slab. An extensive investigation campaign was carried out to locate and quantify the damage. Starting from the data collected on-site a series of damage conditions of cables can be simulated.

Nowadays, researchers are paying close attention to using inclinometers for Structural Health Monitoring (SHM) applications. Moreover, the applications based on using inclinometers can detect the magnitude and location of bridge pathologies. However, as these applications are based on expensive commercial inclinometers, their use is typically exclusive to the SHM of structures with a high monitoring budget. There is a gap in the literature with the development and validation of low-cost accurate angular-meters for decreasing the monitoring cost of inclinometer-based damage detection applications. This work aims to develop low-cost IoT-based inclinometers for detecting damage in bridge structures. The Low-cost Adaptable Reliable Angle-meter (LARA) is a novel inclinometer that accurately measures an induced inclination by combining the measurements of five gyroscopes and five accelerometers. The accuracy, resolution, Allan variance, and standard deviation of LARA are examined through laboratory experiments and are compared with those obtained by numerical slope calculations and a commercial inclinometer (HI-INC). For further experimental validation, a robotic vehicle model is designed and developed to simulate a moving load over a bridge model. The vehicle model integrates IoT technology and can be utilized in different damage detection experiments. The outcomes of a load test experiment using a simple beam model demonstrate the high accuracy (0.003 degrees) of LARA measurements. LARA may be used for structural damage identification and location in bridges utilizing inclinometers because of its low cost and high accuracy.

Les aplicacions de monitorització de la salut estructural (SHM) estan rebent cada vegada més atenció, això és perquè mitjançant la seva aplicació es pot aconseguir la detecció i caracterització dels danys en una fase de prevenció. A més, SHM és un procés dissenyat per proporcionar informació precisa i exacta relacionada amb l'estat i rendiment d'una estructura al llarg del temps. Cal destacar que aquest monitoratge també pot ajudar en els processos de prendre de decisions per optimitzar el funcionament, proporcionar manteniment, reparar i, possiblement, substituir elements estructurals. Un sistema de monitoratge típic comprèn una xarxa de sensors encarregats de mesurar diferents paràmetres rellevants. Tot i això, l'elevat cost dels sensors comercials representa una limitació crítica per a la seva implantació. Per superar el cost elevat de la instrumentació, es poden desenvolupar i validar sensors de baix cost per a aplicacions de SHM. En aquest treball de fi de màster es fa una campanya experimental per a l'Anàlisi Modal Operativa (OMA) d'un pont de carretera utilitzant dos acceleròmetres: un prototip de baix cost (LARA: Low-cost Adaptable Reliable Accelerometer) i un de comercial (PCB 907A61). Amb la finalitat d'avaluar la fiabilitat de les dades adquirides per LARA i validar-les com a acceleròmetres de baix cost per a la monitorització de la salut estructural, es van instal·lar aquests sensors en un pont de carretera ubicat a Andoain, País Basc. Els resultats obtinguts per a cada tipus d'acceleròmetre es van comparar amb el Criteri de Garantia Modal (MAC) i es va avaluar la diferència entre les freqüències pròpies calculades. A més, els paràmetres modals obtinguts durant la campanya experimental es van fer servir per calibrar un model d'elements finits del pont en estudi. Aquest procés es va fer per obtenir una representació més propera a l'estat real de l'estructura. Las aplicaciones de monitorización de la salud estructural (SHM) están recibiendo cada vez más atención, esto se debe a que mediante su aplicación se puede lograr la detección y caracterización de los daños en una fase de prevención. Además, SHM es un proceso diseñado para proporcionar información precisa y exacta relacionada con el estado y el rendimiento de una estructura a lo largo del tiempo. Cabe destacar que esta monitorización también puede ayudar en los procesos de toma de decisiones para optimizar el funcionamiento, proporcionar mantenimiento, reparar y, posiblemente, sustituir elementos estructurales. Un sistema de monitorización típico comprende una red de sensores encargados de medir diferentes parámetros relevantes. Sin embargo, el elevado coste de los sensores comerciales representa una limitación crítica para su implantación. Para superar el elevado coste de la instrumentación, se pueden desarrollar y validar sensores de bajo coste para aplicaciones de SHM. En este trabajo de fin de máster se realiza una campaña experimental para el Análisis Modal Operativo (OMA) de un puente de carretera utilizando dos acelerómetros: un prototipo de bajo coste (LARA: Low-cost Adaptable Reliable Accelerometer) y uno comercial (PCB 907A61). Con la finalidad de evaluar la fiabilidad de los datos adquiridos por LARA y validarlos como acelerómetros de bajo coste para la monitorización de la salud estructural, se instalaron estos sensores en un puente de carretera ubicado en Andoain, País Vasco. Los resultados obtenidos para cada tipo de acelerómetro se compararon bajo el Criterio de Garantía Modal (MAC) y se evaluó la diferencia entre las frecuencias propias calculadas. Además, los parámetros modales obtenidos durante la campaña experimental se utilizaron para calibrar un modelo de elementos finitos del puente en estudio. Este proceso se realizó a fin de obtener una representación más cercana al estado real de la estructura. Structural health monitoring (SHM) applications are increasingly getting more attention. It is due to the fact that through their implementation, the detection and characterization of damage during a prevention phase can be achieved. Furthermore, SHM is a process designed to provide precise and accurate information associated with the condition and performance of a structure over time. It should be noted that SHM can also help with decision-making processes to optimize the operation, provide maintenance, repair, and possibly replace structural elements. A typical monitoring system comprises a network of sensors in charge of measuring different relevant parameters. However, the high cost of commercial sensors can be a critical limitation for their implementation. To overcome the high cost of instrumentation, low-cost sensors can be developed and validated for SHM applications. This Master's thesis carries out an experimental campaign for the Operational Modal Analysis (OMA) of a highway bridge using two accelerometers: a low-cost prototype (LARA: Low-cost Adaptable Reliable Accelerometer) and a commercial one (PCB 907A61). In order to evaluate the reliability of the data acquired by LARA and to validate it as a low-cost accelerometer for structural health monitoring, these accelerometers were mounted on a highway bridge located in Andoain, Basque Country. The results obtained for each type of accelerometer are compared by using the Modal Assurance Criteria (MAC) and assessing the difference between the analyzed eigenfrequencies. Moreover, the modal parameters obtained during the experimental campaign are used to calibrate a finite element model of this bridge. This analytical model is calibrated to have a closer representation of the real state of the structure.

Outgoing

Nowadays, low-cost accelerometers are getting more attention from civil engineers to make Structural Health Monitoring (SHM) applications affordable and applicable to a broader range of structures. The present accelerometers based on Arduino or Raspberry Pi technologies in the literature share some of the following drawbacks: (1) high Noise Density (ND), (2) low sampling frequency, (3) not having the Internet’s timestamp with microsecond resolution, (4) not being used in experimental eigenfrequency analysis of a flexible and a less-flexible bridge, and (5) synchronization issues. To solve these problems, a new low-cost triaxial accelerometer based on Arduino technology is presented in this work (Low-cost Adaptable Reliable Accelerometer—LARA). Laboratory test results show that LARA has a ND of 51 µg/vHz, and a frequency sampling speed of 333 Hz. In addition, LARA has been applied to the eigenfrequency analysis of a short-span footbridge and its results are compared with those of a high-precision commercial sensor. The authors are indebted to the Spanish Ministry of Economy and Competitiveness for the funding provided through the research project BIA2017-86811-C2-1-R directed by José Turmo and BIA2017-86811-C2-2-R. All these projects are funded with FEDER funds. The authors are also indebted to the Secretaria d’ Universitats i Recerca de la Generalitat de Catalunya, Catalunya, Spain, for the funding provided through Agaur (2017 SGR 1482). It is also to be noted that funding for this research has been provided for the Seyedmilad Komarizadehasl by the Spanish Agencia Estatal de Investigación del Ministerio de Ciencia Innovación y Universidades grant and the Fondo Social Europeo grant (PRE2018-083238).

During the last decades the use of ¿ber reinforced concrete (FRC) has been increasing and extending to different areas where structural responsibility was required, being the latest research focused on sus-pended slabs only made of FRC. This could suggest that more ¿elds of concrete structures could bene¿t from this material, including bridges. This paper presents the research about a bridge design considering FRC. An assess-ment on how the material can in¿uence both design strength and expected service response is given (sectional strength and crack width). The existing Line 2 Metrorrey’s viaduct is used as reference to perform the structural analysis and design, where both conventional and ¿ber reinforced concretes are evaluated. The bridge is modeled and analyzed by means of standard numerical analysis and current code regulations are used to obtain preliminary ultimate and serviceability design loads. The assessment of the bridge is mainly based on the veri¿cation of the bottom slab of the girder, as it is one of the major elements where FRC can provide an increase in the element performance (compared to a conventional solution). Considering the Metrorrey transverse prestressing, FRC can effectively replace the required reinforcement to ful¿ll ultimate load case while the prestress itself provides decompression in serviceability load levels. This is possible as the internal load levels require for little amount of rebar reinforcement, which can be structurally comparable to FRC mechanical contribution, similarly to previous applications of the material, such as suspended slabs. Due to higher internal forces, in terms of ULS load-bearing capacity the transversal cross-section near the pier do not bene¿t from FRC as much as the mid-span slab although its minimum serviceability reinforcement can be reduced up to 56%, as the contribution of FRC to reduce the crack width is considerable. This could turn FRC into an attractive solution for tight crack requirements as durabil-ity demand increases. The first author would like to acknowledge the funding support provided by the Spanish Ministry of Universities through the PhD grant program FPU (Formación de Profesorado Universitario). Additionally, all the authors are indebted to the Secretaria d’Universitats i Recerca of the Generalitat de Catalunya for the funding provided through AGAUR (2017 SGR 1481) and to the Spanish Min-stry of Economy and Competitiveness and the FEDER for the funding provided through the project BIA2017-86811-C2-1-R.

In the last decade, Fiber Reinforced Concrete (FRC) has allowed engineers to enhance the performance of different structural concrete members. From previous experiences in building flat slabs, it has been found that FRC members are capable of withstanding loads with either none or very reduced amounts of reinforcement. It has been proven that FRC enhances the resistance capabilities of flat elements under common internal forces (bending moment, one-way shear, punching, etc.). Given the compressive behavior of top slabs in bridge decks, the amount of minimum reinforcement placed in it might be higher than required by structural analysis. Considering the use of FRC in top slabs, an increased durability and/or an important reduction of reinforcement quantities could be achieved. In this research the results of the structural behavior of a top slab for a beam-and-slab deck considering the use of FRC are presented. It has been accounted for specific bridge loads and geometry layouts not found in other structural elements, such as building slabs. The structural analysis is done by means of global numerical model of the bridge, which has led to a combined transversal flexure and compressions in the longitudinal direction of the slab. The results show that minimum reinforcement at ultimate load can be slightly reduced (ranging from 12 to 18%) while providing an enhanced cracking control, which would turn into a durability performance increase of the slab. The first author would like to acknowledge the funding support provided by the Spanish Ministry of Uni-versities through the PhD grant program FPU (Formación de Profesorado Universitario). Additionally, all the authors are indebted to the Secretaria d’Universitats i Recerca of the Generalitat de Catalunya for the funding provided through AGAUR (2017 SGR 1481) and to the Spanish Ministry of Economy and Competitiveness and the FEDER for the funding provided through the project BIA2017-86811-C2-1-R.

In this paper, the project case of Qiwu bridge in Jiangxi Province using link slab action between simply sup-ported spans is introduced. The structural system of Qiwu Bridge consists of a series of 3 simply supported steel-concrete composite spans connected at the pier supports by a link slab, so at this point only continuity through the concrete slab is achieved (semi-continuous bridge). This solution has both advantages of smooth driving condition of continuous bridge and enhancement of durability by removing expansion joints and clear structural behavior as simply supported spans. A non-linear finite element model of Qiwu Bridge was estab-lished through ABAQUS to simulate and predict the mechanical response and structural performance of this semi-continuous solution. Numerical results showed that the removal of the shear connection between steel beams and concrete slab close to the supports magnificently increased the stress level in the shear stiffness mutation region and made it easier to crack. A monitoring plan is also introduced to follow the actual structural response of Qiwu bridge during construction and along the service life to check the long-term performance of the proposed solution. The monitoring system is also described in the paper and the preliminary results during the early construction stages are also presented.

Nowadays, the seismic study of corroded reinforced concrete elements is a matter of increasing concern, in particular as regards links such as bridges in infrastructural networks. As the first step in an ongoing research, a prestressed concrete bridge overpass (continuous two spans with one central pier between the bents) was selected to perform response spectrum seismic analyses considering corrosion degradation. This was based on the development of a finite element model of the structure and allowed the assessment of the degrading seismic capacity of the reinforced concrete bridge pier at different periods caused by general and pitting corrosion. For this purpose, corrosion models from existing literature were used. An unchecked factor of this first research step is that corrosion can also affect bonding between the longitudinal reinforcing bars and concrete, thus increasingly reducing ductility and safety performance. Moreover, in a corroded structure bond strength and confinement capacity can also decrease due to the transverse reinforcement area loss, and concrete cover cracking and spalling. The new step developed in this work focuses on the bonding failure effects due to corrosion processes and how this affects the seismic performance of the deteriorated pier. The analysis is based on the introduction and validation of an empirical model for the assessment of the remaining bonding in corroded concrete elements with respect to experimental results.

Structural Health Monitoring (SHM) of bridges is getting special attention of infrastructure management agencies, due to its success in minimizing maintenance costs. The acquisition of structural behaviour data and its analysis to assess the structural condition are critical tasks of SHM. In this paper both are addressed. A cost - effective measurement equipment based on triaxial accelerometers is developed. It is coupled with an operational modal analysis tool that allows extracting natural frequencies, mode shapes and damping under operational loads. Both, hardware and software, are tested in a case study of a railway bridge of the Madrid Metro network. Other measurement equipments are deployed to compare results. Natural frequencies are calculated, showing a good correlation between the different systems. The obtained results provide relevant information about the global behaviour of the structure. Therefore, the proposed cost - effective solution could be used in a SHM system for continuous bridge monitoring. The first author would like to acknowledge the funding support provided by the Spanish Ministry of Uni-versities through the PhD grant program FPU (Formación de Profesorado Universitario). Additionally, all the authors are indebted to the Secretaria d’Universitats i Recerca of the Generalitat de Catalunya for the funding provided through AGAUR (2017 SGR 1481) and to the Spanish Ministry of Economy and Competitiveness and the FEDER for the funding provided through the project BIA2017-86811-C2-1-R.

Twin-I girder bridge systems are representative structures used in bridge industrialization construction. They have advantages including structure simplification, material save and accelerated construction, but the system using two main girders limits the span and makes the lateral effect more significantly. The general suitable spans range from 25m to 45m, which limits the use of twin-girder bridges. To increase the span limit, the use of tube as top flange and high strength steel can improve structure behavior and increase bridge spans. In the paper, parametrical study and structure optimization were conducted to investigate the behavior of tubular flange girder bridges using high strength steel. Parameters including cross-beam arrangement, stiffeners, tube size were studied. Comparisons between the systems using ordinary steel and that using high strength steel were conducted.

Bridges and critical transport infrastructure are primary assets and systems that underpin human mobility and activities. Loss of bridge functionality has consequences on entire transport networks, which are also interconnected with other networks. Cascading events then unfold in the entire system of systems, leading to significant economic losses and societal disruption to business and society. Recent natural disasters have revealed the vulnerabilities of bridges and critical assets to diverse hazards (e.g. floods, blasts, earthquakes), some of which are exacerbated due to climate change. The assessment of bridge and network vulnerabilities by quantifying their capacity and functionality loss and adaptation to new requirements and stressors is thus of paramount importance. The aim of this work was try to understand the main compound hazards, stressors and threats that have short- and long-term impacts on the structural capacity and functionality of bridges and the impact of bridge closures on network operability. The main drivers of bridge restoration and reinstatement were also considered. Loss of performance, driven by redundancy and robustness of a bridge, is the first step to be considered in the overall process of resilience quantification. Resourcefulness is the other main component of resilience analysed in this work. Peer Reviewed Objectius de Desenvolupament Sostenible::13 - Acció per al Clima Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura

Bridges, as the structures built to cross obstacles and generally has a relative larger span, play a key role in the road traffic. Pre-tensioned concrete structure is widely used in the bridge construction due to its superiority and advantages. However, with the mass exchange of its environment (water, CO2 and other chemical agents), the prestressing strand would be easy to corrode. Strand corrosion can cause concrete cracking, degrade the bond performance at the strand-concrete interface, lead to prestress loss, and deteriorate the capacity of beams. The present study mainly focuses on the concrete cracking, prestress loss and flexural capacity of pre-tensioned concrete beams after strand corrosion. The main research works are as follows: (1) The relationship between corrosion-induced crack widths and filling proportion of corrosion products has been established. The effect of stirrups on corrosion-induced cracking has also been investigated. An empirical model for crack width, considering the filling proportion of corrosion products and twisting shape of strand, is developed. The proposed model is validated by experimental data. Results show that the filling of corrosion products extends with crack propagation until a critical width. Beyond the critical width, the rust filling extent keeps stable. When the stirrups are used, the critical crack width decreases by 20%, comparing to that without stirrups. (2) The influence of prestress on the strand corrosion-induced concrete cracking is investigated by both experimental and analytical approaches. Experimental data on the critical time of cover cracking, crack width and corrosion loss obtained from the accelerated corrosion test are presented. An analytical model, incorporating the coupled effects of prestress and strand corrosion, is proposed to predict the global process of concrete cracking from initiation to propagation. Results show that prestress can accelerate the corrosion-induced cracking process. By varying prestress from 0 to 75% of strand tensile strength, the critical time of cover cracking decreases by 22% and the crack propagation rate increases by 9%. It is found that the proposed model is accurate in predicting corrosion-induced crack width in prestressed concrete beams. (3) A novel model is proposed to predict the corrosion-induced prestress loss in pre-tensioned concrete beams. The coupling effects of concrete cracking and bond degradation are included into the model. The effective prestress in eight corroded pre-tensioned concrete beams under various stress levels is conducted by the four-point flexural test. Experimental results are employed to verify the proposed model. Prestress loss in corroded pre-tensioned concrete beams depends on corrosion level. Corrosion-induced concrete cracking may not degrade bond strength and effective prestress unless the corrosion level exceeds 6.6%. As corrosion further progresses, bond strength and effective prestress reduce monotonically, and then decrease to zero when the corrosion level reaches 34.0%. (4) An analytical model, incorporating the effects of strand cross-section reduction, material deterioration, concrete cracking and bond degradation, is developed to predict the flexural capacity of corroded prestressed concrete beams. Additionally, the effects of flexural cracks are also included in the model. An equivalent bond stress concept is introduced to consider the effect of flexural cracks, which is further implemented into the flexural capacity prediction of corroded PC beams. The proposed model is validated by the experimental results collected from the previous studies. The flexural capacity deterioration of prestressed concrete beams depends on corrosion degree. Strand corrosion less than 5.5% leads to a slight decrement of flexural capacity. As corrosion progresses, the flexural capacity will exhibit a significant deterioration.; Les ponts sont des structures destinées au franchissement des obstacles et ayant généralement une portée plus large que ces obstacles. Ils jouent un rôle clé dans le trafic terrestre. Le béton précontraint est largement utilisé dans la construction des ponts. Cependant, vu les échanges de masse avec l’environnement (eau, CO2 et autres agents chimiques ...), les armatures de précontrainte ont tendance à se corroder. Comme le produit corrodé a un volume plus important que le matériau sain, la corrosion peut provoquer des fissurations dans les enrobages en béton, et par conséquence, la dégradation de la structure et sa capacité de la résistance. La sécurité et la durabilité de la structure sont alors menacées. La présente étude a été menée pour bien comprendre et bien maîtriser cette pathologie dans les structures en béton précontraint. On étudiera la capacité de résistance de poutres en béton précontraint en prenant en compte l’influence de la corrosion. Ce mémoire est composé de 6 chapitres. D’abord, une analyse bibliographique est menée dans le premier chapitre. Puis, dans le chapitre deux, la relation entre l’ouverture des fissures et le taux de remplissage du produit corrodé dans les fissures a été établie par une approche expérimentale, notamment par l'essai de corrosion accélérée. Cette équation empirique est validée par des données expérimentales. Les résultats expérimentaux montrent que le taux de remplissage du produit de corrosion a un fort lien avec l’ouverture de la fissure, jusqu'à une valeur critique. Lorsque l’armature transversale est utilisée, l’ouverture critique diminue de 20% par rapport au cas sans armature transversale. Ensuite, dans le chapitre trois, l'influence du niveau de précontrainte sur l’ouverture de fissuration est étudiée à la fois par des approches expérimentales et analytiques. On présentera d’abord les essais de corrosion accélérée sur des poutres avec différents niveaux de précontrainte. Puis un modèle analytique prenant en compte les effets couplés de la précontrainte et de la corrosion des armatures, est proposé pour prédire le processus global de fissuration de l’enrobage. Les résultats montrent que la précontrainte peut accélérer le processus de fissuration induit par la corrosion. En faisant varier la précontrainte de 0 à 75% de la résistance d’armature, le temps correspondant à l’amorçage de fissuration diminue de 22% et le taux de propagation de la fissure augmente de 9%. Dans le chapitre quatre, un modèle est proposé pour prédire la perte de précontrainte à cause de la corrosion dans les poutres en béton précontraint. Des essais de flexion à quatre points ont été réalisés sur huit poutres en béton précontraint sous différents niveaux de précontrainte, avec des armatures corrodées. Les résultats expérimentaux sont utilisés pour valider le modèle proposé. La chute de précontrainte dans les poutres et la résistance mécanique ont un fort lien avec la corrosion. Lorsque le niveau de corrosion est inférieur à 6,6%, il n’y a pas de perte de résistance significative. Puis, avec l’augmentation du taux de corrosion, la résistance des liaisons béton-armature et la précontrainte effective diminuent progressivement, jusqu'à zéro lorsque le niveau de corrosion atteint 34%. Finalement, dans le cinquième chapitre, un modèle analytique pour prédire la résistance en flexion de poutres en béton précontraint corrodées a été proposé. Dans ce modèle, la réduction de la section d’armature, la détérioration des matériaux, la fissuration du béton et la dégradation des liaisons entre béton et armature ont été pris en compte. Le modèle proposé est validé par les résultats expérimentaux. A partir de 5,5%, la résistance en flexion a été fortement perturbée par la corrosion d’armature. Le dernier chapitre présente les conclusions générales et les perspectives.

Bridges, as the structures built to cross obstacles and generally has a relative larger span, play a key role in the road traffic. Pre-tensioned concrete structure is widely used in the bridge construction due to its superiority and advantages. However, with the mass exchange of its environment (water, CO2 and other chemical agents), the prestressing strand would be easy to corrode. Strand corrosion can cause concrete cracking, degrade the bond performance at the strand-concrete interface, lead to prestress loss, and deteriorate the capacity of beams. The present study mainly focuses on the concrete cracking, prestress loss and flexural capacity of pre-tensioned concrete beams after strand corrosion. The main research works are as follows: (1) The relationship between corrosion-induced crack widths and filling proportion of corrosion products has been established. The effect of stirrups on corrosion-induced cracking has also been investigated. An empirical model for crack width, considering the filling proportion of corrosion products and twisting shape of strand, is developed. The proposed model is validated by experimental data. Results show that the filling of corrosion products extends with crack propagation until a critical width. Beyond the critical width, the rust filling extent keeps stable. When the stirrups are used, the critical crack width decreases by 20%, comparing to that without stirrups. (2) The influence of prestress on the strand corrosion-induced concrete cracking is investigated by both experimental and analytical approaches. Experimental data on the critical time of cover cracking, crack width and corrosion loss obtained from the accelerated corrosion test are presented. An analytical model, incorporating the coupled effects of prestress and strand corrosion, is proposed to predict the global process of concrete cracking from initiation to propagation. Results show that prestress can accelerate the corrosion-induced cracking process. By varying prestress from 0 to 75% of strand tensile strength, the critical time of cover cracking decreases by 22% and the crack propagation rate increases by 9%. It is found that the proposed model is accurate in predicting corrosion-induced crack width in prestressed concrete beams. (3) A novel model is proposed to predict the corrosion-induced prestress loss in pre-tensioned concrete beams. The coupling effects of concrete cracking and bond degradation are included into the model. The effective prestress in eight corroded pre-tensioned concrete beams under various stress levels is conducted by the four-point flexural test. Experimental results are employed to verify the proposed model. Prestress loss in corroded pre-tensioned concrete beams depends on corrosion level. Corrosion-induced concrete cracking may not degrade bond strength and effective prestress unless the corrosion level exceeds 6.6%. As corrosion further progresses, bond strength and effective prestress reduce monotonically, and then decrease to zero when the corrosion level reaches 34.0%. (4) An analytical model, incorporating the effects of strand cross-section reduction, material deterioration, concrete cracking and bond degradation, is developed to predict the flexural capacity of corroded prestressed concrete beams. Additionally, the effects of flexural cracks are also included in the model. An equivalent bond stress concept is introduced to consider the effect of flexural cracks, which is further implemented into the flexural capacity prediction of corroded PC beams. The proposed model is validated by the experimental results collected from the previous studies. The flexural capacity deterioration of prestressed concrete beams depends on corrosion degree. Strand corrosion less than 5.5% leads to a slight decrement of flexural capacity. As corrosion progresses, the flexural capacity will exhibit a significant deterioration.; Les ponts sont des structures destinées au franchissement des obstacles et ayant généralement une portée plus large que ces obstacles. Ils jouent un rôle clé dans le trafic terrestre. Le béton précontraint est largement utilisé dans la construction des ponts. Cependant, vu les échanges de masse avec l’environnement (eau, CO2 et autres agents chimiques ...), les armatures de précontrainte ont tendance à se corroder. Comme le produit corrodé a un volume plus important que le matériau sain, la corrosion peut provoquer des fissurations dans les enrobages en béton, et par conséquence, la dégradation de la structure et sa capacité de la résistance. La sécurité et la durabilité de la structure sont alors menacées. La présente étude a été menée pour bien comprendre et bien maîtriser cette pathologie dans les structures en béton précontraint. On étudiera la capacité de résistance de poutres en béton précontraint en prenant en compte l’influence de la corrosion. Ce mémoire est composé de 6 chapitres. D’abord, une analyse bibliographique est menée dans le premier chapitre. Puis, dans le chapitre deux, la relation entre l’ouverture des fissures et le taux de remplissage du produit corrodé dans les fissures a été établie par une approche expérimentale, notamment par l'essai de corrosion accélérée. Cette équation empirique est validée par des données expérimentales. Les résultats expérimentaux montrent que le taux de remplissage du produit de corrosion a un fort lien avec l’ouverture de la fissure, jusqu'à une valeur critique. Lorsque l’armature transversale est utilisée, l’ouverture critique diminue de 20% par rapport au cas sans armature transversale. Ensuite, dans le chapitre trois, l'influence du niveau de précontrainte sur l’ouverture de fissuration est étudiée à la fois par des approches expérimentales et analytiques. On présentera d’abord les essais de corrosion accélérée sur des poutres avec différents niveaux de précontrainte. Puis un modèle analytique prenant en compte les effets couplés de la précontrainte et de la corrosion des armatures, est proposé pour prédire le processus global de fissuration de l’enrobage. Les résultats montrent que la précontrainte peut accélérer le processus de fissuration induit par la corrosion. En faisant varier la précontrainte de 0 à 75% de la résistance d’armature, le temps correspondant à l’amorçage de fissuration diminue de 22% et le taux de propagation de la fissure augmente de 9%. Dans le chapitre quatre, un modèle est proposé pour prédire la perte de précontrainte à cause de la corrosion dans les poutres en béton précontraint. Des essais de flexion à quatre points ont été réalisés sur huit poutres en béton précontraint sous différents niveaux de précontrainte, avec des armatures corrodées. Les résultats expérimentaux sont utilisés pour valider le modèle proposé. La chute de précontrainte dans les poutres et la résistance mécanique ont un fort lien avec la corrosion. Lorsque le niveau de corrosion est inférieur à 6,6%, il n’y a pas de perte de résistance significative. Puis, avec l’augmentation du taux de corrosion, la résistance des liaisons béton-armature et la précontrainte effective diminuent progressivement, jusqu'à zéro lorsque le niveau de corrosion atteint 34%. Finalement, dans le cinquième chapitre, un modèle analytique pour prédire la résistance en flexion de poutres en béton précontraint corrodées a été proposé. Dans ce modèle, la réduction de la section d’armature, la détérioration des matériaux, la fissuration du béton et la dégradation des liaisons entre béton et armature ont été pris en compte. Le modèle proposé est validé par les résultats expérimentaux. A partir de 5,5%, la résistance en flexion a été fortement perturbée par la corrosion d’armature. Le dernier chapitre présente les conclusions générales et les perspectives.

In 2011, a huge tsunami stroke the north-eastern Japanese coast and caused numerous devastations, especially on public infrastructures such as highways, railways, bridges, etc. As bridges are essential for the recovery and prevention of a tsunami strike in terms of transporting goods and people, the prevention of the wash out phenomenon of the upper structure of the bridge is very important. With this motivation, a study of the wash out behaviour has been carried out using the Particle Finite Element Method (PFEM) for solving fluid-structure interaction problems. To validate the simulations carried out, a comparison between the simulations and some real-life experiments has been made. In the experiments, the motion of the girder (upper part of the bridge) has been tracked during the hit of the wave. Plus, a comparison between the simulations of the same problem with different mesh sizes has been done in order to compare and judge which mesh size best fits this specific problem. It is found that the rigid body motion of the girder of the bridge shows good agreement with the experimental results, and the optimal mesh size for this problem regarding the accuracy of results and computational time is the 10-mm mesh size.

This project consists of evaluating the premature deterioration of the bridge F-12-AT located at Vail, Colorado (United States), of 220 meters-length and 4 spans, continuous composite section with a top concrete slab and double steel box girder. An alternative, consisting of a segmental precast concrete box girder bridge, will be designed and its feasibility will be discussed in terms of durability and life-cycle cost

Outgoing

This work consists in testing the Polyurethane Materials Elastocore and Elastocast in order to obtain their mechanical properties. The main objective is to determine if they can be used as flexible joints in bridge columns so as to reduce significantly damages produced by earthquakes. However, in the present study, only the results of the Elastocore samples are presented. Both types of polyurethanes are amorphous thermosetting polyether polyol-based polymers. Elastocast samples are prepared manually mixing Elastocast Resin and Isocyanate. Elastocore samples are prepared by the BASF company. Different types of tests have been conducted: compression, relaxation and cyclic tests. The mechanical properties of Elastocore are obtained from the results of the compression tests. Compression tests have been performed at six different rates in order to observe the different behavior of the material depending on the loading rate. The results showed that the Yield Strength and Modulus of Elasticity are sensitive to the loading rate. Higher rates imply higher values of both parameters. Mattock's model has also been used to obtain the mechanical properties of Elastocore. The values of the mechanical properties obtained with this method are similar to the ones obtained directly from the test. Moreover, the results showed that the Yield Strength and Modulus are sensitive to the loading rate as well. Finally, the structural analysis conducted by professor Sideris and Mohammad T. Nikoukalam is summarized. They performed structural tests of columns with a flexible joint at the base made of Polyurethane Materials. They applied axial and lateral loads to the columns and studied the different behaviors of the different Polyurethane Materials in order to determine the best option for this application.

During the last strong earthquakes, the impact between closely adjacent structures was reported as one of the major causes of collapse in buildings and bridges. This impact is also called seismic pounding and is due to the different dynamic characteristics of those neighboring structures that make them to vibrate out of phase and become them in potentially dangerous. In the case of bridges, seismic pounding is the impact produced between deck-deck and deck-abutment. In the common engineering practice, bridges are designed with expansion joints or gaps to allow the expansion of the deck because of temperature, shrinkage or creep of concrete. Since this gap cannot be removed generally, it is a vulnerable part of the bridge when earthquake occurs. In addition, seismic pounding produces severe damage in bridges and even collapse. In this study, a detailed overview of the last strongest earthquakes since San Francisco earthquake in 1906 until Tohoku earthquake in 2011 is presented focusing on different types of damages produced in bridges. Within all these different ways of failure and unlike other types of damages, seismic pounding has been less studied although it was demonstrated to be one of the main causes of damages in bridges during the last great earthquakes. Unidirectional and bidirectional seismic pounding are distinguished and a deep review in the literature is provided to know what has been done so far in the field of seismic pounding simulation in bridges. After that, a brief introduction of physical nature of impact as well as the main existing impact force models divided into linear and non-linear are presented. Then, a proposed impact force model based on a modified Kelvin-Voigt model where frictional forces are involved is developed. This proposed contact element is implemented as a biaxial contact element in an open-source computer program called OpenSees. This computer program was developed at University of Berkeley (California) and is based on the Finite Element Method. It is widely used in earthquake research because of is a powerful tool to deal with dynamic problems where non-linearity’s are involved. Moreover, the new contact element was validated for unidirectional directional using an experiment carried out at Harbin Institute of Technology (China) with encouraging results. Finally, three real and different bridges located in California are taken as seed bridges to study seismic pounding in bridges. Furthermore Kobe, Loma Prieta, Chi-Chi and Landers earthquake are chosen as input ground motions in order to have two pulse-like (Kobe and Loma Prieta) and two far-field (Chi-Chi and Landers) earthquakes. The isolated bridges are modeled in OpenSees and subjected to 2,688 non-linear time history analysis simulations where the gap and the skew angle of decks are the parameters used to study the seismic bridge response. The results show how important the skew angle is and its influence in the performance of the bridge being 45º the worse scenario when pounding occurs.

Infrastructures are a key factor for economy. Among them, transportation infrastructures are vital for human life and economy. And within the transportation networks, bridges are key elements for connecting people and delivering goods. For this reason, bridges have been built since many centuries ago and, in some way, the advances (and sometimes geographical expansions !!) of ancient cultures all over the world have been related to their ability of constructing permanent bridges. The most representative of this could be the Roman Empire. After many centuries of bridge construction, nowadays we face a long history of experiences that allow us to look to the evolution of bridge engineering along years and, based on that, to try to extrapolate what is the most feasible to come in the next future. The evolution in bridge engineering has been strongly linked to the key advances in the following areas: materials, construction processes and modelling. Construction techniques and bridge typologies at the beginning were governed by the mechanical properties and performance of available materials at that time. In fact, when the available materials were stone and masonry ( materials that work well in compression but not in tension), the characteristic bridge type was the arch and the construction process the scaffolding of the complete structure because the arch action needs the complete structure to develop. For centuries the arch was the only available bridge type regarding permanent bridges. Of course, suspension and beam configurations were also available but normally with temporary use due to the durability limitations of materials working in tension (vegetal fibres) and bending (timber). Only the appearance in the 19 th