<p dir="ltr">In steel girder bridges, corrosion at girder ends is often caused by deicing salts mixed with water that leak through expansion joints, accelerating deterioration in the girder ends. This leads to a loss of cross-sectional area, reducing structural resistance to shear and bearing. This dissertation investigates the impact of corrosion on the structural capacity of steel girders and proposes improved procedures for estimating the residual shear and bearing strength of corroded steel girders. Additionally, this study evaluates the feasibility of close-range photogrammetry (CRP) for section loss measurement and estimating residual strength through finite element analysis.</p><p dir="ltr">Large-scale experiments were conducted on steel girders with three types of end configurations: unstiffened ends, ends with full-depth bearing stiffeners, and ends with partial-depth transverse connection plates. These experiments provided critical insights into failure modes, deformation characteristics, and strength degradation in shear and web local crippling capacities due to corrosion-induced section loss. The findings highlighted the sensitivity of different failure modes to strength reduction, influenced by the length, height, and extent of the section loss, with significant differences observed across the various girder end configurations.</p><p dir="ltr">Finite element models were developed and benchmarked against experimental results to capture failure modes, load-bearing capacity, and force-displacement behavior. Parametric analysis was conducted using these benchmarked models to understand the impact of different corrosion parameters on the strength of corroded steel girders. Reduction factors for practical residual strength estimation were developed from regression analysis of the parametric study results.</p><p><br></p><p dir="ltr">Photogrammetry was employed to reconstruct 3D models of steel girders with section loss. Thickness measurements from the 3D models were validated against ultrasonic thickness gauge results. Finite element models utilizing the thickness measurements from these 3D point cloud models were developed to estimate the strength of the steel girder, and these estimates were validated against experimental results.</p><p dir="ltr">In conclusion, this research advances the understanding of the impact of corrosion on the strength of steel girders and contributes to the advancement of inspection and assessment procedures for corroded steel girders.</p>

La *voix plurielle* de sept narrateurs raconte une histoire. La spectatrice-auditrice écoute, transcrit, collige et cherche à travers les mots, les archives et les écrits, une scène probable, originaire, fondatrice de l'imaginaire. Cette quête attentive vise à démontrer comment l'entourage, la formation spécialisée et l'espace physique d'apprentissage constituent les premiers facteurs décisifs qui contribuent à façonner l'imaginaire de Mario Saia, un des architectes les plus importants au Canada. Elle aborde la période fondamentale de son enfance et les premières années de sa pratique, mais porte principalement sur les années 1958 à 1964, alors que lui et ses confrères fréquentent l'École des beaux-arts, devenue à ce moment l'École d'architecture de Montréal. Durant ce laps de temps, des réformes importantes en éducation ont lieu au Québec. Elles concordent avec la transformation de l'enseignement en architecture qui délaisse peu à peu l'académisme des Beaux-Arts pour s'inscrire dans la modernité. Suivant l'approche biographique narrative, sept témoins de cette époque relatent comment la passion pour l'architecture, la vie étudiante, l'atmosphère du lieu et l'inspiration que leur apportent trois enseignants d'exception compensent les lacunes générales de l'enseignement. Le regard tourné vers les grands précurseurs du modernisme européen, ces étudiants construisent leur identité propre et entreprennent leur thèse de fin de cursus. Pour le jeune Saia, ce dernier projet de thèse, ses études spécialisées en Écosse et ses stages de travail à Montréal et au Danemark lui permettent de développer ses aptitudes de recherche, d'amorcer une approche philosophique et de mettre en pratique ses connaissances techniques. Trait par trait, touche par touche, sur papier calque, s'esquissent un projet, une carrière. Se tend finalement le cordeau des réalisations signées Mario Saia. Cette histoire racontée tisse un lien entre toutes ces étapes, révèle un imaginaire qui se concentre sur l'habitat humain, aborde une œuvre architecturale que fonde cet imaginaire. / La *voix plurielle* recount a story. The spectator listens, transcribes, collates, and searches through texts, archives and writings. Such careful research aims to demonstrate how an entourage, highly specialized training, and a physical learning-space shaped the imaginary of Mario Saia, one of the most significant architects in Canada. The work explores the fundamental period of his childhood and the first years of his practice, but mainly focuses on the years 1958 to 1964, when he attended the *École des beaux-arts*, which at that time became the *École d'architecture de Montréal*. During this duration of time, Quebec saw significant reforms in education. These were consistent with the transformation of architectural education which gradually moved away from Beaux-Arts academicism to embrace modernity. Following a narrative/biographical approach, seven witnesses from this period relate how a passion for architecture, student life, the atmosphere of the place, and the inspiration of three exceptional teachers compensated for more general educational shortcomings. Admiring the great precursors of European modernism, these students constructed their self-identities and undertook their final thesis. For the young Saia, this last thesis project, specialized studies in Scotland, and internships in Montreal and Denmark allowed him to develop research skills, initiate a philosophical approach, and operationalize his technical knowledge. Line by line, touch by touch, on tracing paper, a project, a young architect outlines his career. Finally, the long string of achievements by Mario Saia is extensive. This storytelling weaves together these stages, revealing an imaginary that focuses on human habitat and an architecture based in the imaginary.

The Regulation of Gatherings Act 205 of 1993 is a old order piece of legislation, but gives full recognition to the right to freedom of assembly and expression. These rights are entrenched in sections 16 and 17 of the Bill of Rights and enjoy a generous interpretation. Section 5 of the Act creates limitations on these rights, as the responsible officer of a local authority is allowed to prohibit a gathering when he has reasonable grounds to believe that the police will not be able to prevent traffic disruption, injury or substantial damage to property. Given the fact that this limitation serves to protect a compelling state interest, it constitutes a reasonable and justifiable limitation in terms of section section 36 of the Bill of Rights. / Law / LL.M.

The constitutionality of affirmative action in terms of section 8 of Act 200 of 1993 is investigated. The study contends that in constitutional interpretation it is permissible to have recourse to ethical precepts as long as these are anchored within the four corners of the Constitution. It is contended that the •equality clause• does not prescribe equality of outcome in favour of substantive equality of opportunity. It is asserted that group-based affirmative action may justifiably be attacked as being unconstitutional; either on the basis that it infringes the nonbeneficiary's equality rights in terms of sections 8(1) and 8(2) or that it falls beyond the constitutional protection afforded to affirmative action in terms of section 8(3). Furthermore, group-based modalities of affirmative action may also not constitute a permissible limitation on the fundamental right to equality, if compared to an individual-based socio-economic affirmative action model. / Jurisprudence / LL. M.

Text in Afrikaans, abstract in English / Writer investigates the constitutionality of section 18(4)(d) of the Child Care Act 74 of 1983 against the backdrop of the South African common law and the common law of comparative legal systems. In the South Africa law the mother of an illegitimate child has guardianship. The natural father does not have parental power which weakens his legal position. In analysing the judgement of the Constitutional Court, writer criticises the court for stating that in the case of a newborn baby the kind of discrimination which section 18( 4 )( d) authorises against a natural father may be justifiable in the initial period after the child is born. The constitutional position of the natural father in American jurisprudence is discussed at length. Writer concludes that the natural father has to take positive steps to vest a right to be heard in an adoption application. Proposals for legal reform are also made. / Private Law / LL. M. (Law)

Section 33(1)(b) is fraught with borrowed provisions. The end-product marries German and Canadian features. The failure of the German Constitutional Courts to interpret the "essential content of a right" precipitated the adopted infant's bumpy landing in South Africa. That the sibling still lacks identity is evidenced by our Constitutional Court's evasive and superficial treatment of the clause. Section 33(1)(a) - proportionality prong enables judges to justify their neglect of Section 33(1)(b). The opinion is expressed that Section 33(1){b) demands interpretation but to date it has been shrouded in vagueness. After all without demarcating boundaries with sufficient precision and highlighting where the State may not tread the State may trespass. Alternatively the limitable nature of human rights could become a myth as Section 33(1)(b) could be transformed into an insurmountable hurdle for the State, rendering every right absolute in practice. A workable conceptual framework proposes an inverted, porous and value imbibing solution. / Law / LL.M.

The Companies Act of 71 of 2008 makes a number of important changes to the rules relating to capital maintenance. In line with the objectives of the Companies Act of 71 of 2008, section 44 of the Act has removed the prohibition on the provision of financial assistance by a company which was contained under the previous section 38 of the Companies Act 61 of 1973. Despite the repeal of the prohibition, a transaction which involves the provision of financial assistance by a company for the acquisition of or subscription of its own securities still needs to be effected in accordance with the requirements and conditions that are provided under the Act and Memorandum of Incorporation. To explore the new developments, within this study, the provision of financial assistance in terms of section 44 of the Companies Act of 2008 is, therefore, analysed in detail. On the other hand, the UK Companies Act of 2006 repealed the prohibition on the giving of financial assistance by private companies in most circumstances. It, however, retained the prohibition to public companies only because of the requirements of the Second Company Law Directive (77/91/EEC). This study also explores the rules of financial assistance by a company under the UK Companies Acts in detail. Though the source of financial assistance by a company both in South Africa and in English Company laws is rooted in the English decision of the Trevor v Whitworth case, currently these countries have adopted what is deemed appropriate and significant in their own countries. This study, therefore, examines and compares the rules governing the provision of financial assistance by a company in the company laws of these two countries. / Mercantile Law / LL.M. (Commercial law)

Les calculs de chromodynamique quantique sur réseau prévoient, que pour un potentiel baryonique nul et une température de T ∼ 173 MeV , il devrait être possible d'observer une transition de la phase de la matière hadronique vers un plasma de quarks et de gluons. Les collisions d'ions lourds ultra-relativistes devraient permettre de mettre en évidence ce changement de phase. Les saveurs lourdes peuvent être utilisées pour sonder les premiers instants des collisions pendant lesquels la température est la plus élevée. Le LHC va permettre d'étudier les collisions entre noyaux de plomb et les collisions entre protons à une énergie jamais égalée : √s = 5.5 TeV (√sNN = 14 TeV ) pour le plomb (les protons). Le détecteur ALICE est dédié à l'étude des collisions d'ions lourds mais peut également mesurer les collisions entre protons. Il est équipé d'un spectromètre à muons conçu pour l'étude des saveurs lourdes. Cette thèse présente les performances du spectromètre pour la mesure de la section efficace de production inclusive des hadrons beaux (B) et charmés (D) dans les collisions proton-proton. La première étape de cette mesure consiste à extraire les distributions des muons de décroissance des hadrons B et D. L'étape suivante consiste à extrapoler les distributions aux sections efficaces de production inclusive des hadrons. Cette thèse contient également une étude préliminaire des performances du spectromètre pour la mesure du rapport de modification nucléaire et de l'observable associée nommée RB=D dans les collisions plomb-plomb de centralité0−10%. L'accent est porté sur les incertitudes et l'intervalle en impulsion transverse sur lequel ces observables pourront être mesurées. / Lattice quantum chromodynamics calculations predict a transition from the phase of hadronic matter to quark and gluon plasma for a temperature T ∼ 173 MeV and a vanishing baryonic potential. Ultra-relativistic heavy ion collisions allow to highlight this phase transition. Heavy flavours can be used to probe the first instants of the collisions where the temperature is the highest. The LHC will provide proton-proton and lead-lead collisions at unprecedented large energy (√s = 14 TeV and √sNN = 5.5 TeV respectively). The ALICE detector is dedicated to heavy ion collisions but it can also measure proton-proton collisions. The detector includes a muon spectrometer. The spectrometer has been disigned to measure heavy flavours. This PhD thesis presents the performance of the spectrometer to measure beauty hadrons (B) and charmed hadrons (D) inclusive production cross-section in proton-proton collisions. The first step of the measurement consists in extracting heavy hadron decayed muon distributions. The next step consists in extrapolating these distributions to heavy hadrons inclusive production cross-section. This PhD thesis also presents a preliminary study of the performance of the spectrometer for the measurement of the nuclear modification factor and the associated observable named RB=D in 0−10% central heavy ions collisions. Uncertainties and transverse impulsion range of extraction of the observables have been investigated.

Les réacteurs actuels produisent deux types de déchets dont la gestion et le devenir soulèvent des problèmes. Il s’agit d’abord de certains produits de fission et de noyaux lourds (isotopes de l’Américium et du Curium) au-delà de l’uranium appelés actinides mineurs. Deux options sont envisagées : le stockage en site géologique profond et/ou l’incinération de ces déchets dans un flux de neutrons rapides, c’est-à-dire, la transmutation par fission. Ces études font appel à de nombreuses données neutroniques. Malheureusement, les bases de données présentent encore de nombreuses insuffisances pour parvenir à des résultats fiables. L’objectif de ce travail est ici d’actualiser des données nucléaires et de les compléter. Nous avons ainsi mesuré la section efficace de fission de l’243Am (7370 ans) en référence à la diffusion élastique (n,p) afin de fournir des données indépendantes des mesures existantes dans la gamme des neutrons rapides (1 - 8 MeV). La réaction 243Am(n,f) a été analysée en utilisant un modèle statistique décrivant les voies de désexcitation du noyau composé d’244Am. Ainsi les sections efficaces de capture radiative (n,?) et de diffusion inélastique (n,n’) ont pu être évaluées. La mesure directe des sections efficaces neutroniques d’actinides mineurs constitue très souvent un véritable défi compte tenu de la forte activité des actinides mineurs. Pour cela, une méthode indirecte a été développée utilisant les réactions de transfert dans le but d’étudier certains isotopes du curium. Les réactions 243Am(3He,d)244Cm, 243Am(3He,t)243Cm et 243Am(3He,alpha)242Am nous ont permis de mesurer les probabilités de fission des noyaux de 243,244Cm et de l’242Am. Les sections efficaces de fission des curiums 242,243Cm(162,9 j, 28,5 ans) et de l’américium 241Am sont obtenues en multipliant ces probabilités par les sections efficaces calculées de formation des noyaux composés. Pour chaque mesure, une évaluation précise des erreurs a été réalisée à travers une étude des variances-covariances des résultats présentés. Pour les mesures de la réaction 243Am(n,f), une analyse des corrélations d’erreurs a permis d’interpréter la portée de ces mesures au sein des mesures existantes. / The existing reactors produce two kinds of nuclear waste : the fission products and heavy nuclei beyond uranium called minor actinides (Americium and Curium isotopes). Two options are considered: storage in deep geological site and/or transmutation by fast neutron induced fission. These studies involve many neutron data. Unfortunately, these data bases have still many shortcomings to achieve reliable results. The aim of these measurements is to update nuclear data and complement them. We have measured the fission cross section of 243Am (7370y) in reference to the (n,p) elastic scattering to provide new data in a range of fast neutrons (1 - 8 MeV). A statistical model has been developed to describe the reaction 243Am(n,f). Moreover, the cross sections from the following reactions have been be extracted from these calculations: inelastic scattering 243Am(n,n’) and radiative capture 243Am(n,?) cross sections. The direct measurements of neutron cross sections are often a challenge considering the short half-lives of minor actinides. To overcome this problem, a surrogate method using transfer reactions has been used to study few isotopes of curium. The reactions 243Am(3He, d)244cm, 243Am(3He, t)243cm and 243Am(3He, alpha)242Am allowed to measure the fission probabilities of 243,244Cm and 242Am. The fission cross sections of 242,243Cm(162,9d, 28,5y) and 241Am(431y) have been obtained by multiplying these fission probabilities by the calculated compound nuclear neutron cross section relative to each channel. For each measurement, an accurate assessment of the errors was realized through variance-covariance studies. For measurements of the reaction 243Am(n,f), the analysis of error correlations allowed to interpret the scope of these measures within the existing measurements.

L’exploration d’une nouvelle physique à l’échelle d’énergie des « Tera electron Volt » (TeV) nécessite de collisionner des leptons dans de grands accélérateurs linéaires à grande luminosité. Ces collisionneurs linéaires requiert une taille de faisceau à l’echelle nanométrique au Point d’Interaction (IP).Parmi les multiples effets participant à la degradation de la luminosité, la correction de la chromaticité, l’effet du rayonnement synchrotronique et la correction des erreurs dans la ligne sont parmi les trois effets à maîtriser afin de réduire la taille du faisceau dans la Section Finale de Focalisation (FFS).Cette these propose un nouveau schéma de correction de la chromaticitè que l’on appelera “non-entrelacé”, appliqué ici au projet CLIC. Lors de l’implementation de cette nouvelle methode, il a été mis en evidence que le probléme principal est la dispersion de deuxième ordre au Doublet Final (FD), qui traverse un sextupole utilisé pour annuler les composantes géometriques restantes.L’effet du rayonnement peut être evalué par méthode de tracking des particules ou par des approximations analytiques. Afin d’inclure ces effets du rayonnement et les paramétres optiques de la ligne pendant la conception et le processus d’optimisation, l’effet Oide et le rayonnement dû aux aimants dipolaires ont été etudiés.Le résultat analytique du rayonnement synchrotronique dans les aimants dipolaires fut generalisé dans les cas avec alpha et dispersion non-nulles à l’IP. Cette généralisation est utilisée pour améliorer le code de simulation PLACET.Le rayonnement dans les aimants quadripolaires finaux imposent une limite à la taille verticale minimale du faiceau, connu comme l’effet Oide. Celui-ci est uniquement important à 3 TeV, donc deux possibilités sont explorées pour atténuer sa contribution dans la taille du faisceau : doubler la longueur et réduire le gradient du dernièr quadripole (QD0), ou integrer une paire d’aimants octupolaires, un en amont et un en aval du QD0.Une partie des exigences du FFS pour les nouveaux collisionneurs linéaire à leptons est testée expérimentalement dans l’« Accelerator Test Facility » (ATF). La réduction de la taille du faisceau d’électrons en utilisant le schéma local de correction de la chromaticité est explorée dans une extension de la ligne originale, appellé ATF2, oú deux buts furent fixés : atteindre 37 nm de taille verticale du faisceau à l’IP, et stabiliser de l’ordre du nanomètre la position verticale du faisceau à l’IP. Depuis 2014, une taille de 44 nm avec un nombre de particules d’environ 0.1 × 10^10 par paquet est atteint de manière regulière.Des cavités radio-frequence seront utilisées pour la stabilisation du faisceau, et également pour détecter le déplacement/les fluctuations du faisceau au dehors la marge tolerable pour le systéme de mesure, ainsi que des erreurs non detectées dans l’optique.Un set de trois cavités furent installées et sont utilisées pour mesurer la trajectoire du faiceau dans la région de l’IP, fournissant ainsi des informations pour reconstruire la position et l’angle à l’IP. Les specifications pour l’optique nominale d’ATF2, i.e. 1 nm de résolution sur 10 μm de gamme dynamique à un nombre de particules de 1.0 × 10^10 par paquet, n’ont pas encore été atteint.La meilleur résolution atteinte jusqu’ici correspond à 50 nm pour 0.4 × 10^10 particules par paquet, où le bruit de l’éléctronique impose une limite de 10 nm par cavité sur la résolution. La gamme dynamique est de 10 μm à 0.4 × 10^10 particules par paquet et 10 dB d’attenuation du signal des cavités, nécéssitant de mettre l’électronique à niveau. Le test du système d’asservissement pour stabiliser le faisceau a atteint une réduction de la fluctuation jusqu’a 67 nm, compatible avec la résolution des cavités. / The exploration of new physics in the “Tera electron-Volt” (TeV) scale with precision measurements requires lepton colliders providing high luminosities to obtain enough statistics for the particle interaction analysis. In order to achieve design luminosity values, linear colliders feature nanometer beam spot sizes at the Interaction Point (IP).Three main issues to achieve the beam size demagnification in the Final Focus Section (FFS) of the accelerator are the chromaticity correction, the synchrotron radiation effects and the correction of the lattice errors.This thesis considers two aspects for linear colliders: push the limits of linear colliders design, in particular the chromaticity correction and the radiation effects at 3 TeV, and the instrumentation and experimental work on beam stabilization in a test facility.A new chromaticity correction scheme, called non-interleaved, is proposed to the local and non-local chromaticity corrections for CLIC. This lattice is designed and diagnosed, where the main issue in the current state of lattice design is the non-zero second order dispersion in the Final Doublet (FD) region where a strong sextupole is used to correct the remaining geometrical components.The radiation effect can be evaluated by tracking particles through the lattice or by analytical approximations during the design stage of the lattices. In order to include both, radiation and optic parameters, during the design optimization process, two particular radiation phenomena are reviewed: the Oide effect and the radiation caused by bending magnets .The analytical result of the radiation in bending magnets in was generalized to the case with non-zero alpha and non-zero dispersion at the IP, required during the design and luminosity optimization process. The closed solution for one dipole and one dipole with a drift is compared with the tracking code PLACET, resulting in the improvement of the tracking code results.The Oide effect sets a limit on the vertical beamsize due to the radiation in the final quadrupole. Only for CLIC 3 TeV this limit is significant, therefore two possibilities are explored to mitigate its contribution to beam size: double the length and reduce the QD0 gradient, or the integration of a pair of octupoles before and after QD0.Part of the requirements of the FFS for new linear accelerators are tested in The Accelerator Test Facility (ATF). The beam size reduction using the local chromaticity correction is explored by an extension of the original design, called ATF2 with two goals: achieve 37 nm of vertical beam size at the IP, and the stabilization of the IP beam position at the level of few nanometres. Since 2014 beam size of 44 nm are achieved as a regular basis at charges of about 0.1 × 10^10 particules per bunch.A set of three cavities (IPA, IPB and IPC), two upstream and one downstream of the nominal IP and on top of separate blocks of piezo-electric movers, were installed and are used to measure the beam trajectory in the IP region, thus providing enough information to reconstruct the bunch position and angle at the IP. These will be used to for beam stabilization and could detect beam drift/jitter beyond the tolerable margin and undetected optics mismatch affecting the beam size measurements. The specifications required of 1 nm resolution over 10 μm dynamic range at 1.0 × 10 10 particules per bunch with the ATF2 nominal optics have not been yet achieved.The minimum resolution achieved is just below 50 nm at 0.4 × 10^10 particules per bunch with a set of electronics impossing a noise limit on resolution of 10 nm per cavity. The dynamic range is 10 μm at 10 dB attenuation and 0.4 × 10^10 particules per bunch, indicating the need to upgrade theelectronics. The integration to the ATF tuning instruments is ongoing. Nonetheless, feedback has been tested resulting in reduction of beam jitterdown to 67 nm, compatible with resolution.