An experimental and analytical investigation was conducted to study the behavior of diagonal knee moment end-plate connections and a multiple row extended moment end-plate connection. Diagonal knee moment end-plate connections differ from typical moment end-plate connections because of the large pitch distance required between the top flange and first row of tension bolts. The large pitch distance is outside of the geometric parameters of all previous research. Design solutions are presented for five moment end-plate connections with provisions added to accommodate these parameters. The analytical investigation focused on the limit states of end-plate yielding and bolt rupture. Yield-line analysis was used to predicted end-plate yielding and a simplified Kennedy method proposed by Borgsmiller and Murray (1995) was used to predict bolt rupture including and excluding prying forces. An experimental investigation was conducted to verify the design solutions. Five knee area specimens and one plate girder specimen were tested in this study. The analytical and experimental results are analyzed and compared. For the test specimens that failed in the connection, the predicted results proved to be conservative. Recommendations are presented at the end of the study as well as sample calculations. / Master of Science

Timber moment resisting connections have gained considerable interest in structural design due to the numerous advantages offered by timber as a lightweight, renewable, sustainable, and aesthetically pleasing material. This research focuses on investigating the feasibility and potential benefits of hybrid timber-steel moment connections in enhancing the seismic performance and ductility of timber structures. The objective is to evaluate the response modification factors of the hybrid timbersteel moment-resisting frames to see if this type of moment connection has the ability to perform like steel moment-resisting frames in lateral loadings. The process by which the studied frames were designed was focused on preventing damage to timber elements by inducing inelastic deformations exclusively in the steel beams, while the remaining parts of the frame retain their elasticity. Nonlinear static analysis is employed to evaluate the force modification factors and nonlinear behavior of the selected structures. In this study, a total of 18 frames with different span lengths, numbers of stories, and seismicity levels were analyzed to comprehensively investigate their seismic performance. The frames were designed to represent a range of practical configurations commonly found in timber structures. The span lengths of 4, 6, and 8 meters were considered. The number of stories were 2, 4, and 6, and the frames were located in Montreal, QC, and Vancouver, BC, which are known for having varying seismic conditions. By considering a diverse set of frames, this study tried to provide a comprehensive understanding of the behavior and performance of different timber frame structures under seismic loading, taking into account the effects of span length, number of stories, and regional seismic conditions. The results of the analysis offer a preliminary understanding of the seismic performance and potential advantages of steel-timber moment connection frames. However, it should be noted that further research is needed to conduct full-scale experimental tests to validate the proposed connections and gather more accurate data. The findings from this study have the potential to contribute to the development of new seismic provisions for moment connection timber frame systems, advancing the field of timber structural design and offering potential design schemes that increase ductility and performance in timber moment resisting connections.

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Le principal objectif de la thèse est l'étude des relations entre les différents espaces des moduIes provenant de connections sur des fibrés vectoriels sur des variétés algébriques. Les classes suivantes de connections sont considérées: la classe des connections méromorpbes avec diviseur de pôles fixè D et ses sous-classes des connections intégrables, connections logarithmiques intégrables et connections logarithmiques intégrables avec une structure parabolique sur D. La question la plus fascinante est la relation entre l'espace des modules des connections et celui des fibrés vectoriels sous-jacents. L'application naturelle oubliant la seconde composante de la paire (fibré vectoriel, connection) est bien définie uniquement au-dessus du lieu des fibrés vectoriels semistables, puisque uniquement ceux-ci ont une théorie de modules conséquente. La première partie de la thèse fournit un exemple pratique d'une famille de connections logarithmiques de rang 2 sur une courbe elliptique, pour laquelle la question de la (semi)stabiIilé des fibrés vectoriels sous-jacents est complètement résolue. Les connections logarithmiques sous considération sont les images directes de connections régulières sur des fibrés en droites au-dessus de revêtements doubles de genre 2 de la courbe elliptique, appelés bielliptiques. Nous donnons une paramétrisation explicite de telles connections, déterminons leur monodromie et leur groupe de Galois différentiel. Le fibré vectoriel sous-jacent de rang 2 est décrit en termes de transformées élémentaires et d'applications birationnelles des surfaces réglées. Dans la seconde partie, nous construisons les espaces de Kuranishi (ou déformations verselles) pour les quatre classes de connections. Les espaces tangents et les espaces d'obstructions de la théorie des déformations sont définis comme l'hypercohomologie d'un complexe approprié de faisceaux, et l'espace de Kuranishi est une fibre de l'application d'obstruction formelle. Dans la troisième partie, nous esquissons la construction de GlT des espaces des moduIes pour les quatre classes de connections et utilisons le théorème des slices étales de Luna pour représenter le germe de l'espace des moduIes des connections comme le quotient de l'espace de Kuranishi par le groupe des automorphismes de la fibre centrale. Cette méthode est utilisée pour déterminer les singularités de l'espace des modules des connections dans des exemples, en particulier, ceux provenant des courbes bielliptiques. / The logarithmic connections studied in Chapter 1 are direct images of regular connections on line bundles over genus-2 double covers of the elliptic curve. We give an explicit parametrization of ail such connections, determine their monodromy, differential Galois group and the underlying rank-2 vector bundle. The latter is described in terms of elementary transforms. The question of its (semi)-stability is addressed. ln Chapter 2, we construct the Kuranishi spaces (or versai deformations) for the four connection classes: the class of meromorphic connections with fixed divisor of poles D and its subclasses of integrable. integrable logarithmic and integrable logarithmic connections with a parabolic structure over D. ln Chapter 3, we use the Kuranishi spaces to describe the local structure of the moduli spaces of connections and their relation to the moduli spaces of underlying vector bundles.

This study aims to contribute to an understanding of politically connected audit committees on audit fees and the audit process in an emerging market, using the case of Malaysia. Malaysia offers an interesting and important setting as Malaysian companies are highly concentrated and politically sensitive. In particular, the study seeks to: (i) examine the level of political connections represented in the audit committees associated with the level of audit fees incurred by Malaysian public listed companies; and (ii) examine whether politically connected audit committees have an impact on the audit process. Currently, there is scant evidence on the influence of politically connected audit committees on audit fees and the audit process. The study draws upon agency and resource dependence theories, which suggest that politically connected audit committees serve two important functions: monitoring on behalf of the shareholders, and providing resources to the companies. For the purpose of this study, a mixed method approach (archival data analysis and interviews) has been adopted. Four hypotheses are tested: (1) There is a positive relationship between the proportion of audit committee members who are senior government officers (SGO) and audit fees; (2) There is a positive relationship between the proportions of audit committee members who are politicians and audit fees; (3) There is a positive relationship between the percentage of government shares and audit fees; and (4) There is a positive relationship between audit committee characteristics (independence, size, meeting and financial expertise) and audit fees. In addition, the knowledge obtained from the interviews with Big 4 auditors and members of audit committees from the selected companies provide further insights on the influence of political connections on the audit process. The results of the study indicate that politically connected audit committees (identified by members who are either senior government officers or politicians) have a significant association with the incidence of higher audit fees. This suggests that politically connected audit committees are able to capitalise on their connections to influence companies and create direct demand for the auditors to increase their audit effort, as measured by audit fees. Contrary to expectations, this study did not find a significant relationship between government shares and audit fees. This result may be explained by the fact that government shares are managed by a variety of institutions on behalf of the government, and differences in the objectives and characteristics of the institutions that administer the shares can weaken the demand for higher efforts from auditors. An in-depth analysis of the interviews further reveals that political connections do affect the audit process. It appears that the existence of political connections leads to an increase in audit work such in a variety of ways, such as auditor-client negotiations, private meetings with audit committees and re-engineering the scope and planning of the actual audit work. One of the issues that emerges from these findings is that companies highly value political connections to obtain external resources given the uncertainties in the business environment. Also, the findings highlight the need for stronger corporate governance to mitigate the higher inherent audit risks in politically connected companies.

Until recently, investigations on the fire resistance of steel joints have been neglected by structural engineers under the arguments that the design resistance of connections at room temperature is usually higher than the resistance of the connected members and that the temperature increases more slowly in the joint zone (high concentration of mass, low exposure to radiative fluxes) than in the adjacent beams and columns. However, brittle failures of connection components have been observed especially during the cooling phase of real fires for two main reasons: the high sensitive and nonreversible character of the resistance of bolts and welds at elevated temperatures and the development of high tensile thrusts. The present thesis is a contribution to the understanding of the thermomechanical behaviour of simple connections in steel beam-to-column joints subjected to natural fire conditions, with a special attention to the behaviour of these connections during the cooling phase. The distribution of temperature in joints has been analysed by use of numerical models built in SAFIR software. The simplified methods presently mentioned in the Eurocodes are discussed and new methods, calibrated on the results of numerical simulations, are proposed in the present work to predict the temperature profile in steel beams and joints covered by a flat concrete slab under fire. An existing method aimed at evaluating the distribution of internal forces in restrained steel beams (and by extension, in joints) under natural fire has been analysed in detail. Several modifications have been added in order to improve his method and to extend its field of application. The final version of this analytical method has been implemented and validated against numerical results. An experimental programme aimed at characterising the mechanical behaviour of bolts and welds under heating and subsequent cooling is described in the present thesis. The properties of the tested specimens, the thermal loading applied to these specimens, the test set-ups and the results of the tests are reported in detail. Mechanical models for bolts loaded in tension or in shear have been calibrated on the experimental results. The loss of resistance of bolts and welds due to their non-reversible behaviour under heating and subsequent cooling has been quantified. Finally, a large part of the thesis is dedicated to the development of component-based models representing the action of common simple connections under natural fire conditions and to the analysis of the behaviour of these connections as a part of a sub-structure or large-scale structure. These simple models can be used for parametric analyses because it conciliate a reasonable time of definition of the data, an acceptable time of simulation and a good degree of accuracy of the results. Recommendations for the design of connections have been defined. The ductility of connections has a major influence on the occurrence of connection failures and classes of ductility for connections, dependant of the fire loading, have been defined in this work. / Jusque très récemment, la recherche sur la résistance au feu des assemblages métalliques a été délaissée par les ingénieurs sous le prétexte que la résistance de calcul des assemblages à froid est habituellement supérieure à celle des éléments connectés et que léchauffement est plus lent dans la zone dassemblage que dans les poutres et colonnes adjacentes (grande concentration de matière, exposition réduite aux flux radiatifs). Toutefois, les ruptures fragiles de composants dassemblages sont observées, notamment durant la phase de refroidissement pour deux raisons principales : caractère sensible et non-réversible des boulons et des soudures aux élévations de température et apparition defforts de traction importants. La présente thèse sinscrit comme une contribution à la compréhension des phénomènes gouvernant le comportement des assemblages simples poutre-poteau sous conditions de feu naturel. Une attention spéciale est portée au comportement de ces assemblages durant la phase de refroidissement. La distribution de température dans les assemblages a été analysée grâce à des modèles numériques mis au point dans le programme SAFIR. Les méthodes simplifiées actuellement mentionées dans les Eurocodes actuels sont discutées et de nouvelles méthodes, calibrées sur les résultats numériques, sont proposées dans ce travail pour prédire le profil de température dans les poutres et assemblages métalliques couverts dune dalle en béton sous feu. Une méthode existante destinée à évaluer la distribution des efforts internes dans les poutres en acier restraintes (et par extension, dans les assemblages) sous feu naturel a été analysée en détail. Plusieurs modifications ont été proposées pour améliorer cette méthode et étendre son champ dapplication. La version finale de cette méthode analytique a été implémentée et validée avec des résultats numériques. Une série de tests expérimentaux destinée à caractériser le comportement mécanique des boulons et des soudures sous échauffement et refroidissement est décrite dans cette présente thèse. Les propriétés des spécimens testés, le traitement thermique qui leur est appliqué, le montage des essais et les résultats obtenus sont rapportés en détail. Des modèles mécaniques pour les boulons soumis à traction ou cisaillement sont calibrés sur les mesures expérimentales. La perte de résistance des boulons et des soudures causée par leur comportement non-réversible sous échauffement et refroidissement a été quantifiée. Finalement, une large part de la thèse a été dédiée au développement de modèles basés sur la méthode des Composantes pour représenter laction des assemblages simples courants sous feu naturel et lanalyse de leur comportement dans une sous-structure ou une structure complète. Ces modèles simples permettent de concilier un temps de définition des données raisonnable, un temps de calcul acceptable et un bon niveau de précision des résultats. Des recommandations pour le dimensionnement des assemblages ont été énoncées. Il est démontré que la ductilité des connections a une influence majeure sur lapparition de ruptures dans les assemblages et des classes de ductilité, dépendant du chargement au feu, ont été définies dans ce travail.

A new three-dimensional finite solid element (3D FE) model for dowel-type wood connections was developed using the concept of a beam on a nonlinear wood foundation, which addresses the intricate wood crushing behaviour under the connector in a dowel type connection. In order to implement the concept of wood foundation with solid elements, a 3D FE wood foundation model was defined within a prescribed foundation zone surrounding the dowel. Based on anisotropic plasticity material theory, the material model for the foundation zone was developed using effective foundation material constants that were defined from dowel-embedment test data. New 3D FE single nail connection models were developed that incorporated the wood foundation model. The 3D wood foundation model was justified and validated using dowel-embedment test data with a range of dowel diameters, from a 2.5-mm nail to a 25.4-mm bolt. The connection models provided successful results in simulating the characteristics of load-slip behaviour that were experimentally observed. Based on the success of the single nail connection models, several applications of the 3D FE connection models were investigated including statistical wood material models, bolted connection models and a multiple nail connection model. Throughout the application studies, discussion of the benefits and limitations of the new model approach using the 3D FE wood foundation are presented. Also, future areas of study are proposed in order to improve the 3D FE dowel-type wood connections models.

The fire resistance of timber connections is relatively unknown in the construction and design industries even though they are widely used. This research focuses on the fire resistance of nailed, screwed, bolted and self-drilling doweled connections in laminated veneer lumber (LVL) timber. These connections have been found to have high strength under cold or normal temperature but hardly achieved 30 minutes fire rating in the furnace tests. To establish the performance of connections, an investigation was carried out on the compressive strength of connections by having compressive tests using an Instron Testing Machine. Similar connections were tested at simulated fire conditions under constant load in a custom-built furnace. The different fasteners used and the arrangement of the connections gave different connection strengths at ambient and elevated temperature.