Includes bibliographical references (p. 91-94).

This thesis presents ground control best practices in weak rock environments including an augmentation to the existing Span Design curve by adding 463 case histories of RMR76 values ranging from 25 to 60. A Neural Network analysis of this data has been added and compared to the existing Span Design data of 292 case histories. Ground support is almost always used in weak rock environments, though the type of support used can vary widely. The development of the weak rock augmented Span Design Curve has also been calibrated to four different support categories; Category A: Pattern Friction Sets, Category B: Pattern Friction Sets with Spot Bolting of Rebar, Category C: Pattern Friction Sets with Pattern Rebar Bolts and Category D: Cablebolting, Shotcrete, Spiling, Timber Sets or Underhand Cut and Fill. Category A is considered “Unsupported” with an average Factor of Safety less than 1.2. Categories B, C and D are considered “Supported” with average Factors of Safety greater than 1.2. All categories are compared the original Critical Span Design Curve presented by Lang (1994). However, only Category A can be accurately compared to the original Critical Span Design Curve as it is “Unsupported” as well. Category A yields good results, however, Categories B, C and D do not, but still demonstrate that spans can remain stable at lower RMR76 values. Design of underground man-entry type excavations in North America relies heavily upon empirical analysis. This design requires a higher Factor of Safety than other non-man entry type excavations. A comparison of the calculated ½ span failure Factor of Safety between all the categories is also presented. The contribution this research provides to the mining industry is the "Unsupported" Weak Rock Updated Span Design Curve and awareness pertaining to the potentially detrimental effects of using resin grounted rebar in weak rock masses and the false sense of security that the use of resin grouted rebar may instill. It is also shown that spans in the “Unstable” zone of the new “Unsupported” Weak Rock Updated Span Design Curve can possibly be stabilized if detailed engineering design is applied to obtain “Supported” status.

Deep-corrugated steel culverts (with a corrugation wavelength of 400mm and amplitude of 150mm) can be used as an effective alternative for short-span bridges. Current design methods are typically based on two-dimensional finite element analysis. This thesis reports results from three-dimensional finite element analysis, with explicit modelling of the geometry of the corrugated plates (called corrugated analyses) and employing the orthotropic shell theory (called orthotropic analyses), for a specific box culvert having a 10 m span and 2.4 m rise. The results were compared to previously reported experimental data where a specific large span box culvert was tested under controlled laboratory conditions. The behaviour of the box culvert under small vertical displacement without any soil support was modelled to isolate the structure response. The box culvert was also modelled when subject to fully loaded dump truck, and when loaded using a tandem axle frame to service and ultimate loads. Both corrugated and orthotropic analyses successfully captured the response of the box culvert when backfilled and loaded using dump truck and axle frame loading. It was found that the orthotropic model overestimated the culvert stiffness at the ultimate limit state, but provided effective estimates of response up to the factored design loads. The corrugated model with geometric nonlinearity was required to capture the real behaviour of the corrugated plates up to the ultimate limit state. New insight into the failure mechanisms of the box culvert were provided by the corrugated model analysis. A parametric study was then performed for 86 different long-span box and arch culverts, examining live load spreading in the axial direction, number of loaded lanes, design truck position, culvert geometry, plate thickness, and the existence of pavement. The results were then compared to the moment and thrust equations in the 2006 Canadian Highway Bridge Design Code (CHBDC) to check the performance of the current design equations. CHBDC equations overestimated the earth and live load bending moments, and did not give the correct trend for different spans. CHBDC thrust equations were found to underestimate the earth and live load thrust values for arch culverts. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2011-04-26 15:33:45.103

There is evidence that cholesterol presents an important risk factor for Alzheimer’s disease (AD), but the direction of this relationship is modified by age. High cholesterol during midlife and low cholesterol during late life are both associated with an increased risk for AD. This dissertation research engaged a life span approach to study the relationship between cholesterol, AD and cognitive functioning among older adults. The purpose of this research was to determine if trajectories of cholesterol from midlife through late life differ according to AD status and if these trajectories are associated with cognitive functioning during old age. This research employed a secondary analysis of cognitive, phenotypic and genetic data collected from subjects of the Framingham Heart Study (FHS) Original and Offspring Cohorts. Aim One involved creating three summary scores of the FHS neuropsychological battery. ROC analysis was used to determine which score best differentiated between cognitively normal, impaired and dementia subjects. Aim Two used generalized additive mixed models to examine trajectories of total, HDL and total/HDL cholesterol ratio according to AD status in the Original Cohort. Aim Three used mixed-effects models to examine the relationship between subject-specific trajectories of total cholesterol and cognition during old age. Aim One determined that a summary score that provided equal weight to each assessment in the FHS neuropsychological battery best differentiates between subjects classified as cognitively normal, cognitively impaired and dementia. The findings from Aim Two indicated that there are subtle differences in the longitudinal trajectories of total, HDL and total/HDL ratio according to AD status. The findings from Aim Three provide limited evidence for a relationship between subject-specific trajectories of total cholesterol and cognitive functioning later in life. Older adults in the highest quartile for cognitive functioning had lower total cholesterol at approximately 55 years of age, but there were no differences in the mean trajectories of total cholesterol according to cognitive functioning later in life. The findings from this research suggest that older adults with high cognitive functioning have lower total cholesterol during midlife, but life span cholesterol trajectories do not appear to be associated with AD status or cognitive function.

This thesis presents ground control best practices in weak rock environments including an augmentation to the existing Span Design curve by adding 463 case histories of RMR76 values ranging from 25 to 60. A Neural Network analysis of this data has been added and compared to the existing Span Design data of 292 case histories. Ground support is almost always used in weak rock environments, though the type of support used can vary widely. The development of the weak rock augmented Span Design Curve has also been calibrated to four different support categories; Category A: Pattern Friction Sets, Category B: Pattern Friction Sets with Spot Bolting of Rebar, Category C: Pattern Friction Sets with Pattern Rebar Bolts and Category D: Cablebolting, Shotcrete, Spiling, Timber Sets or Underhand Cut and Fill. Category A is considered “Unsupported” with an average Factor of Safety less than 1.2. Categories B, C and D are considered “Supported” with average Factors of Safety greater than 1.2. All categories are compared the original Critical Span Design Curve presented by Lang (1994). However, only Category A can be accurately compared to the original Critical Span Design Curve as it is “Unsupported” as well. Category A yields good results, however, Categories B, C and D do not, but still demonstrate that spans can remain stable at lower RMR76 values. Design of underground man-entry type excavations in North America relies heavily upon empirical analysis. This design requires a higher Factor of Safety than other non-man entry type excavations. A comparison of the calculated ½ span failure Factor of Safety between all the categories is also presented. The contribution this research provides to the mining industry is the "Unsupported" Weak Rock Updated Span Design Curve and awareness pertaining to the potentially detrimental effects of using resin grounted rebar in weak rock masses and the false sense of security that the use of resin grouted rebar may instill. It is also shown that spans in the “Unstable” zone of the new “Unsupported” Weak Rock Updated Span Design Curve can possibly be stabilized if detailed engineering design is applied to obtain “Supported” status.

Thesis (MBus) -- University of South Australia, 1992

Zugl.: Stuttgart, Univ., Diss., 2007.

Thesis (M.S.)--West Virginia University, 1998. / Title from document title page. "December 1998." Document formatted into pages; contains xv, 142 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 140-142).

O objetivo desta dissertação é testar o modelo de salário eficiência (shirking model) para a indústria brasileira de construção civil e seus subsetores. Esta versão do modelo de salário eficiência assume a existência de uma relação negativa entre salários e supervisão. A investigação empírica está centrada sobre a variável span of control (razão supervisores/ supervisionados) como proxy para intensidade de supervisão. Os dados utilizados para o teste de hipótese desta teoria são os da Relação Anual de Informações Sociais para os anos de 2012 e 2013. Como novidade em relação aos trabalhos anteriores, utilizamos os dados da RAIS em uma estrutura de painel de indivíduos para o período, controlando tanto os possíveis vieses de variável omitida (efeito fixo) como o de simultaneidade (span of control), bem como os dados referentes aos subsetores que constituem o setor da construção civil (construção de edifícios, obras de infraestrutura e serviços especializados para construção). Conclui-se que a hipótese de salário eficiência é corroborada pelos dados tanto para o setor como um todo como para seus subsetores. / The objective of this dissertation is to test the efficiency wage model (shirking version) to Brazilian civil construction industry and its subsectors. This version of the efficiency wage model defends the existence of a negative relationship between wages and supervision. The empirical research is focused on the variable span of control (ratio supervisors /staff) as a proxy for supervision intensity. The data used are from "Relação Anual de Informações Sociais" for the years of 2012 and 2013. As an innovation compared to previous work, we use data from the RAIS in a panel structure for individuals period, controlling the possible boas of omitted variable (fixed effect) and also the simultaneity (Instrumental Variable) as well as data relating to subsectors that constitute the construction industry (building construction, infrastructure works and specialized services for construction). It is concluded that the hypothesis of efficiency wage is supported by the data both for the sector as a whole and for its subsectors.

In today's textbooks, analyzing prestressed members and bridges takes a two-dimensional approach. Two-dimensional analysis is the only way to analyze prestressed bridges and members because otherwise the hand calculations are extremely difficult. Skewed bridges, however, need to be analyzed and designed three-dimensionally. Based on engineering inspection, it is possible to tell how a non-skewed symmetric bridge will behave. However, the knowledge of how a skewed bridge will behave cannot be obtained by inspection only. Finite element analysis can be used to model a bridge and discover how the bridge will react to dead loads and post-tensioning forces. When a bridge is built on a skew, the acute corners of the bridge support much less concrete weight than the obtuse corners of the bridge. If the post-tensioning force causes a decrease in load at the acute corners of the skewed bridge and if the skew of the bridge is great enough, there is a concern that there could be uplift at these acute corners of the bridge. Uplift at any corner of the bridge should not be allowed. The objective of this study is to investigate a simple span skewed box girder bridge to see if any uplift occurs at the acute corners of the bridge due to post-tensioning forces. After careful study of a skewed simple span cast-in-place post-tensioned box girder bridge, it was found that the post-tensioning force actually transfers more downward force into the acute corners of the bridge. Based on this study, the post-tensioning force will not cause uplift in the acute corners of the skewed bridge.