Theses

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  • Stress:  conceptualization, framing, and induction
    Stress: conceptualization, framing, and induction
    Past research has often conceptualized stress from a deficit-oriented approach. This approach is unbalanced, often associating stress with negative events and outcomes. The current study examined stress from the Transactional Model, and proposed alternative ways to conceptualize stress. In addition, both psychosocial and physiological stressors were utilized to induce stress. Study aims were threefold: (1) to examine beliefs about stress and effects of framing on changes to perceptions of stress, (2) to examine the comparative effects of two different stress-induction methods, and (3) to explore the interactive effects of framing and stress-induction on subjective perceptions of stress and measures of stress reactivity. Results confirmed a deficit-orientation of stress within the sampled population. Comparative effects of both stressors highlighted differential stress responses based on task demands and appraisal. Finally, interactive effects of framing and stress-induction provided support for alternative conceptualizations of stress in adaptive coping.
    Stripping Them of Legal Status: The Making and Unmaking of the Exotic Dancer Visa Program
    Stripping Them of Legal Status: The Making and Unmaking of the Exotic Dancer Visa Program
    This paper explores the factors which influenced the making and unmaking of this controversial and internationally unique temporary visa program. Through a review of literature, public documents, and media records I deconstruct this policy; analyze its rationalities, assumptions and mechanisms; and conclude with a discussion on the implications for foreign-born exotic dancers whose lives are marked by Canadian politics turmoil. I argue that the government's decision to discontinue the program has negatively impacted the human rights and quality of life of foreign-born exotic dancers who, quite possibly, made the dangerous transition to the existing group of undocumented workers in Canada. While the Exotic Dancer Visa Program was problematic in many ways these migrant women were protected by legal status, thus decreasing, but not eliminating, their vulnerability as women, as immigrants, and as workers.
    Strong is beautiful(?): A multimodal analysis of strength and beauty in female and male sports commercials
    Strong is beautiful(?): A multimodal analysis of strength and beauty in female and male sports commercials
    Taking inspiration from Naomi Wolf’s The Beauty Myth, this major research paper examines the ways in which strength and beauty are constructed in female and male sports commercials. Building off of themes such as the sport-media complex, encoding and decoding models of communication, media representations of women and post-feminism, this paper is concerned with exposing the disparities between media representations of female and male athletes. Using the Women’s Tennis Association’s “Strong is Beautiful” ad campaign in tandem with AT&T’s “Paul George Strong” ad, the questions that guide this major research paper are: • How does strength act as a reductive concept? • How is the word “beautiful” encoded in the “Strong is Beautiful” ad campaign? • At what level (i.e. connotative or denotative) do the words “strong” and “beautiful” operate in the “Strong is Beautiful” television commercial? • At what level does the word “strong” operate in the “Paul George Strong” television commercial? And finally, what does the “Strong is Beautiful” television commercial and the “Paul George Strong” television commercial communicate about the beauty myth in sport? What do these commercials say about post-feminism in sport? Employing social semiotic theory and multimodal analysis, this paper concludes that strength is applied universally to the female athletes in the “Strong is Beautiful” commercial which solidifies the term as a male standard. As a result, the term has an oppressive connotation when used to describe female athletes thereby contradicting the very notion of what a female athlete should be: empowered.
    Structural Design Issues For Integral Abutment Bridges
    Structural Design Issues For Integral Abutment Bridges
    In recent years, integral abutment bridges have been increasingly used in Canada due to their low maintenance costs. Whereas a rational guideline to determine the maximum length and skew angle limits for integral bridges due to temperature variations do not exist in bridge codes. As such, structural behavior of integral bridges subjected to temperature variation was investigated through a numerical modeling. First, detailed 3D finite-element models were developed. The accuracy of finite-element models was validated against data collected from filed testing available in the literature on integral bridges subjected to the seasonal temperature variations and truck loading. Then, a parametric study was carried out to study the effects of key parameters on the performance of integral bridges when subjected to temperature variations. The numerical results indicated that number of design lanes, bridge length, abutment height, abutment-pile connection, pile size and skew angle had a significant impact on the behavior of integral bridges. Based on the data generated from the parametric study, new limits for the maximum length and skew angle of integral bridges based on displacement-ductility limit state of piles were established. Literature review revealed that live load distribution among girders in integral bridges due to truck loading conditions is as yet unavailable. This study is extended to develop new equations to estimate girder live load distribution factors for integral bridges. First, 2D and 3D finite-element models (FEMs) of integral bridges were developed. Then, a parametric study was performed to study the effects of parameters such as abutment height, abutment thickness, wingwall length, wingwall orientation, number of design lanes, span length, girder spacing and number of intermediate diaphragms. The results indicated that the live load distribution factors obtained from the FEMs were lower than those obtained from current CHBDC equations. Consequently, sets of empirical expressions were developed in the form of reduction factors that can be applied to CHBDC live load distribution factors to accurately calculate the girder distribution factors. Also, other set of equations for the live load distribution factors were developed in a similar form as that specified in CHBDC for possible inclusion in the bridge code.
    Structural Design Issues On GFRP-Reinforced Concrete Bridge Barriers
    Structural Design Issues On GFRP-Reinforced Concrete Bridge Barriers
    In the era of bridge rehabilitation, glass fibre reinforced polymer (GFRP) bars are considered an alternative solution to steel reinforcement to eliminate steel corrosion. In this thesis, a new bridge barrier reinforcement layout was proposed incorporating GFRP bars with anchorage heads. However, it was observed that no design provisions or research data in the literature were found to design the anchorage at barrier-deck slab junction. As such, pullout tests were conducted on GFRP bars embedded in concrete slabs, to determine their pullout strength. Also, testing to-collapse of full-scale bridge barrier under static loading was conducted to determine its load carrying capacity. In addition, finite element analysis of the barrier wall and deck slab portion was performed in order to examine the level of accuracy of the specified factored applied moments due to vehicle impact at the barrier-deck junction. The experimental findings qualified the proposed GFRP-reinforced barrier detailing when subjected to simulated vehicle impact loading.
    Structural Health Monitoring of the Rebecca Street (William Anderson) Bridge
    Structural Health Monitoring of the Rebecca Street (William Anderson) Bridge
    This research investigation is to employ a Structural Health Monitoring (SHM) strategy for the Rebecca Street Bridge to provide accurate information regarding the structural behavior and performance of the bridge during regular operation. The research investigation included visual inspection and structural assessment using the MIRA 3D shear wave tomographer to evaluate the bridge structural condition. The overall structural condition of the bridge is good and no major deterioration was noted. However, the voids detected during the shear wave scans could form void clusters in the future, leading to potential cracking and delamination. A monitoring strategy was developed based on the crack width and moment curvature of the concrete cross section using reliability analytical models that would allow for lifetime monitoring. The prediction models used the Bridge Condition Index (BCI) to evaluate the structural condition of the bridge. The future works for the Rebecca Street Bridge includes periodic monitoring as recommended.
    Structural behavior and shear bond capacity of composite slabs with high performance concrete
    Structural behavior and shear bond capacity of composite slabs with high performance concrete
    Many research works have been conducted on the behavior of composite slabs with profiled steel deck to study the longitudinal shear bond resistance using the m-k method. In this study, experimental investigations are conducted to evaluate the shear bond characeristics of composite slabs. 15 composite slabs are tested to study the effect of different high performance concrete (HPC) mixes namely engineered cementitious composites (ECC) and self-consolidating concrete (SCC), diverse profile sheets (with embossments or without embossments) and variable shear span on load-deflection characteristics, stress-strain development in concrete/steel, cracking/crack propagation and failure modes. The values of shear bond parameters (m and k) derived from the test results can be used for the design of composite slabs.
    Structural behaviour of composite slab with high performance concretes
    Structural behaviour of composite slab with high performance concretes
    Composite slabs with profiled steel deck and concrete toping have gained wide acceptance as they lead to faster, lighter and economical construction. Extensive research works have been conducted on the behaviour of composite slabs to study their structural behavior and steel-concrete interface shear bond resistance which primarily governs the failure. However, the use of emerging highly durable engineered cementitous composite (ECC) in composite slab is new and no research has been conducted yet. High strain hardening and intrinsic crack width characteristics of ECC can significantly improve structural performance of composite slabs through enhancing ductility, energy absorbing capacity and steel-concrete shear bond. In this study, experimental investigations are conducted to evaluate the shear bond characteristics of composite slabs made with ECC and conventional self-consolidating concrete (SCC) using Code based m-k method. Twelve slab specimens having variable shear span and two types of profiled steel deck were tested under four point loading. The performance of ECC and SCC composite slabs are compered based on load-deflection response, stress-strain development in concrete and steel, failure modes, energy absorbing capacity and steel-concrete shear bond parameters (m and k) and bond stress.
    Structural behaviour of insulated foam-timber panels under gravity and lateral loading
    Structural behaviour of insulated foam-timber panels under gravity and lateral loading
    A Structural Insulated Panel (SIP) is a structural element of expanded polystyrene insulation (EPS) core sandwiched between two oriented-strand boards (OSB). This research proposes SIPs in low-rise residential construction (i.e. houses and low-residential building), replacing the traditional conventional joist floors and stud walls. This research investigates (i) developing expressions for flexural, compression, monotonic racking and cyclic lateral load capacities of SIPs as compared to the joist/stud wall construction. In this study, the proposed design of SIPs was based on (i) generally established theory for analysis, (ii) assessment of full-scale SIP panels by a loading tester, and (iii) computer modeling using the finite-element modeling. The research program included (i) testing SIP walls in axial compression and bending, (ii) racking and cyclic testing on SIP shear walls, (iii) development of finite-element computer models of the tested SIP panels and verifying those using experimental findings, (iv) correlation between experimental findings and design equations for strength and serviceability available in the literature and wood design Standards. Modification factors of these equations were developed to allow structural engineers to design SIP panels in residential construction more economically reliably. Experimental results showed that SIP panels are being “as good as” the conventional wood-framing of identical sizes, with respect to flexural, compressive, racking and cyclic loading. Also, results showed SIP walls have a greater ability to dissipate energy under racking and cyclic loading that the stud wall system. Therefore, SIP walls can be used so efficient in seismic zones. Based on cyclic lateral load test results, the values of ductility-related force modification factor (Rd) for stud wall, short SIP wall and long SIP wall were calculated as 8%, 22% and 14% lower than the NBCC required value for anchored wall (Rd = 3.0), respectively. In addition cyclic lateral load test results showed that the values of over-strength-related force modification factor (Ro) for stud wall, short SIP wall and long SIP wall were observed to be 17%, 20% and 14% higher than the recommended value of NBCC (Ro = 1.7) for anchored wall, respectively. So, it is concluded that the over-strength factor indicates a confident reserve of resistance in interconnected wall segments.
    Structural behaviour of reinforced high performance concrete frames subjected to monotonic lateral loading.
    Structural behaviour of reinforced high performance concrete frames subjected to monotonic lateral loading.
    This thesis describes the structural performance of reinforced one storey flexural and shear-critical frames made of high performance concretes (HPCs) such as: self-consolidating concrete (SCC), engineered cementitious composite (ECC) and ultra-high performance concrete (UHPC) subjected to monotonic lateral loading. The performance of SCC/ECC/UHPC frames are described based on load-deformation/moment-rotation responses, stiffness, strain developments, crack characterization, failure modes, ductility and energy absorbing capacity. The experimentally obtained moment and shear capacities of the frames are compared with those obtained from Codes and other existing design specifications. Overall, ECC frames showed better performance in terms of higher energy absorbing capacity and ductility compared to SCC/UHPC frames. ECC/UHPC frames showed higher load carrying capacity compared to SCC frames. ECC and UHPC shear-critical frames without shear reinforcement were able to prevent shear failure due to fiber bridging and crack control characteristics contributing to the enhanced shear resistance of the matrix.
    Structural behaviour of ultra high performance fibre reinforced concrete composite members
    Structural behaviour of ultra high performance fibre reinforced concrete composite members
    The aging and deterioration of reinforced concrete infrastructures in North America present major technical and economical challenges to infrastructure owners. To effectively address some of the challenges, there is a need to develop innovative and cost-effective systems. The main objective of this research was to develop composite members of ultra-high performance fibre reinforced concrete and normal strength concrete or high strength concrete (UHPFRC-NSC/HSC). In order to achieve this objective, the first phase of this research investigates the structural behaviour of UHPFRC with varying fibre content beams without web reinforcement. Test results indicated that the addition of 1% of steel fibres effectively improves the shear strength of UHPC beams by 77% due to the crack-bridging stress that develops across the crack surface. In the second phase, experimental studies were carried out on UHPFRC-NSC/HSC prisms and beams without stirrups to investigate the flexural and shear capacity of those composite members. Each beam specimen was designed to have the UHPFRC layer in tension and the NSC/HSC layer in compression. Additional varied parameters included fibre volume content, and shear connectors were investigated. Test results showed that the performance of the proposed composite system in terms of the flexural and shear capacity was successfully enhanced. All composite beams failed in shear at a force that is 1.6 to 2.0 times higher than that of the NSC/HSC beam's resistance. Test results showed that the effect of using HSC versus NSC in the composite beam was negligible, and the bond strength between the two concrete material layers (UHPFRC and NSC/HSC) was significantly high that the addition of shear connectors was unnecessary. In the third phase, an analytical and finite element models to predict the ultimate shear capacity of UHPFRC composite beams were proposed and validated with the experimental results. The results of the finite element analysis showed that the size effect in structures made of UHPFRC material has little influence on the shear capacity. Finally a comparison between the finite element model and the analytical model indicated that both models developed in this research are capable of predicting the shear behaviour of UHPFRC and UHPFRC-NSC/HSC beams.
    Structural health monitoring of two-way slabs based on random decrement technique
    Structural health monitoring of two-way slabs based on random decrement technique
    The current research attempts to explore the feasible use of a Structural Health Monitoring method for a two-way slab system through the effective vibration based damage diagnostic technique of Random Decrement (RD). Experimental investigations have been conducted on a total of four reinforced concrete two-way slab specimens. The slabs behaviour was examined under static loading. The results were presented in terms of load-deflection relationship at service and ultimate load, crack pattern and failure modes. At each stage of loading, the ambient vibration excitation test has been performed to investigate the extent of damage at the cracking, yield, and ultimate states through changes in dynamic parameters obtained from RD signatures. Additional applications of RD technique were performed on two-way slabs, first, to explore the location of damage by Multi-Channel Random Decrement using FBG sensor arrays. Secondly, RD technique was utilized to evaluate the extent of damage under successive equal dynamic impacts.