Canadian construction participants have long recognized that accepting the lowest price bid does not guarantee maximum value. Achieving a value-based procurement approach is a challenge, particularly for the Canadian public sector clients who are limited in their ability to evaluate the competitive bids based solely on the low-bid award system. Bid and cost data from 218 projects from three major public sector construction clients in the Greater Toronto Area are evaluated. Compared to the other clients, the cost escalation is significantly higher for the client that does not have a standard prequalification policy. Increased contractor competition (high number of bids) and a large price gap between low bid and other bids are correlated to higher cost escalation for the non-prequalifying client. Also, the organizational culture of the non-prequalifying client is less results-oriented. The research demonstrates the importance of prequalifying for clients that award based solely on the low bid.

A study of existing research shows a need for an investigation of the bond properties of anchorage systems for GFRP bars including; straight, anchor heads and bends. The standard pullout test was modified to improve testing efficiency, accommodate bend tests, as well as reduce variability of concrete properties across specimens. Based on the results of the experimental work it was concluded that the surface profile of GFRP bars influences the post-peak phase of the bond stress-slip curve. It was also found that GFRP bars with anchor heads would still require a considerable embedment length to develop the bars’ full strength. Bend strengths of three GFRP manufacturers were determined to be between 58 and 80% of the strength of the straight portion of the same bar, while the development length of a two legged stirrup was found to be between five and ten times the bar diameter for all bar types.

A study of existing research shows a need for an investigation of the bond properties of anchorage systems for GFRP bars including; straight, anchor heads and bends. The standard pullout test was modified to improve testing efficiency, accommodate bend tests, as well as reduce variability of concrete properties across specimens. Based on the results of the experimental work it was concluded that the surface profile of GFRP bars influences the post-peak phase of the bond stress-slip curve. It was also found that GFRP bars with anchor heads would still require a considerable embedment length to develop the bars’ full strength. Bend strengths of three GFRP manufacturers were determined to be between 58 and 80% of the strength of the straight portion of the same bar, while the development length of a two legged stirrup was found to be between five and ten times the bar diameter for all bar types.

This thesis investigated the dissolution of dense non aqueous phase liquids (DNAPL) source zones in the subsurface and the effectiveness of enhanced bioremediation for the treatment of chlorinated ethene DNAPLs, using numerical modeling. For this purpose, an existing multiphase numerical model was extended to include comprehensive models for the processes of dissolution and reaction. The first part of the thesis examined DNAPL dissolution. First, a thermodynamic-based dissolution model was validated using experimental data from two complex heterogeneous DNAPL releases. Model predictions for DNAPL spatial distribution and effluent concentrations agreed well with experimental measurements, without requiring calibration. This is the first successful application of a predictive dissolution model in the literature. Model results showed the important effects of relative permeability and interfacial areas on dissolution rates. Then, the thermodynamic dissolution model was compared to simpler models typically used in the literature. Five Sherwood-Gilland (SG) empirical correlations were evaluated and their limitations were illustrated. A new dissolution model was proposed that combined the predictive ability of the thermodynamic model and the simplicity of SG models, and is applicable for complex source zones. Lastly, the relationship between the DNAPL source architecture and downstream concentrations was investigated, focusing on multistage concentration profiles. A new upscaled model was proposed that is able to capture such complex behavior. In the second part of this thesis the thermodynamic dissolution model was combined with a model for reductive dechlorination of chlorinated ethenes to simulate DNAPL bioremediation. Simulations were conducted for simple DNAPL source zones to investigate the impact of dissolution-related processes on bioremediation effectiveness. Dissolution kinetics and back-partitioning of daughter products in the DNAPL were shown to affect dechlorination. Then, the investigation was extended to DNAPL source zones of complex architectures in heterogeneous domains, illustrating the importance of the source zone architecture for the effectiveness of DNAPL bioremediation. Overall, this thesis presents a comprehensive numerical model that will be an important research tool for evaluating the effectiveness of in-situ bioremediation for DNAPL source zones, and will provide the means for a better understanding and control of the critical factors affecting this technology in the field.

This thesis investigated the dissolution of dense non aqueous phase liquids (DNAPL) source zones in the subsurface and the effectiveness of enhanced bioremediation for the treatment of chlorinated ethene DNAPLs, using numerical modeling. For this purpose, an existing multiphase numerical model was extended to include comprehensive models for the processes of dissolution and reaction. The first part of the thesis examined DNAPL dissolution. First, a thermodynamic-based dissolution model was validated using experimental data from two complex heterogeneous DNAPL releases. Model predictions for DNAPL spatial distribution and effluent concentrations agreed well with experimental measurements, without requiring calibration. This is the first successful application of a predictive dissolution model in the literature. Model results showed the important effects of relative permeability and interfacial areas on dissolution rates. Then, the thermodynamic dissolution model was compared to simpler models typically used in the literature. Five Sherwood-Gilland (SG) empirical correlations were evaluated and their limitations were illustrated. A new dissolution model was proposed that combined the predictive ability of the thermodynamic model and the simplicity of SG models, and is applicable for complex source zones. Lastly, the relationship between the DNAPL source architecture and downstream concentrations was investigated, focusing on multistage concentration profiles. A new upscaled model was proposed that is able to capture such complex behavior. In the second part of this thesis the thermodynamic dissolution model was combined with a model for reductive dechlorination of chlorinated ethenes to simulate DNAPL bioremediation. Simulations were conducted for simple DNAPL source zones to investigate the impact of dissolution-related processes on bioremediation effectiveness. Dissolution kinetics and back-partitioning of daughter products in the DNAPL were shown to affect dechlorination. Then, the investigation was extended to DNAPL source zones of complex architectures in heterogeneous domains, illustrating the importance of the source zone architecture for the effectiveness of DNAPL bioremediation. Overall, this thesis presents a comprehensive numerical model that will be an important research tool for evaluating the effectiveness of in-situ bioremediation for DNAPL source zones, and will provide the means for a better understanding and control of the critical factors affecting this technology in the field.

Nonlinear seismic soil-structure interaction (SSI) analyses are often completed using the equivalent linear frequency domain analysis method as it is simple to use and computationally efficient. However, the method is inherently linear and a better strategy is to employ the nonlinear time domain analysis method, which is computer intensive but can more accurately simulate nonlinear soil behavior. In this thesis, the two methods are evaluated using the Hualien LSST field data. For the nonlinear time domain analyses, the utilized Hualien LSST finite element model is initially verified by comparing its linear responses to those obtained via the linear frequency domain analysis method; which is also verified against the multi-step analysis approach. In the frequency domain, the equivalent linear analyses are completed by an industry collaborator. The results show that two methods generate similar responses for the low intensity earthquakes but differ for the more intense and amplified earthquakes.

Nonlinear seismic soil-structure interaction (SSI) analyses are often completed using the equivalent linear frequency domain analysis method as it is simple to use and computationally efficient. However, the method is inherently linear and a better strategy is to employ the nonlinear time domain analysis method, which is computer intensive but can more accurately simulate nonlinear soil behavior. In this thesis, the two methods are evaluated using the Hualien LSST field data. For the nonlinear time domain analyses, the utilized Hualien LSST finite element model is initially verified by comparing its linear responses to those obtained via the linear frequency domain analysis method; which is also verified against the multi-step analysis approach. In the frequency domain, the equivalent linear analyses are completed by an industry collaborator. The results show that two methods generate similar responses for the low intensity earthquakes but differ for the more intense and amplified earthquakes.

This study presents experimental results from nine large-scale circular concrete columns reinforced with longitudinal and transverse glass fiber-reinforced polymer (GFRP) bars. These specimens were tested under lateral cyclic quasi-static loading while simultaneously subjected to constant axial load. Based on the measured hysteretic loops of moment vs. curvature and shear vs. tip deflection relationships, a series of parameters related to ductility and flexural strength are used to evaluate the seismic behavior of each column. The results showed that concrete columns reinforced with GFRP bars have stable post-peak branches and can achieve very high levels of deformability. Longitudinal GFRP bars maintained their stiffness at high strains and transverse GFRP spirals provided increasing confinement for the entire duration of the test without any spiral damage. The tests showed that, as an innovative material with excellent corrosion resistance GFRP bars can be successfully used as internal reinforcement in ductile concrete columns.

This study presents experimental results from nine large-scale circular concrete columns reinforced with longitudinal and transverse glass fiber-reinforced polymer (GFRP) bars. These specimens were tested under lateral cyclic quasi-static loading while simultaneously subjected to constant axial load. Based on the measured hysteretic loops of moment vs. curvature and shear vs. tip deflection relationships, a series of parameters related to ductility and flexural strength are used to evaluate the seismic behavior of each column. The results showed that concrete columns reinforced with GFRP bars have stable post-peak branches and can achieve very high levels of deformability. Longitudinal GFRP bars maintained their stiffness at high strains and transverse GFRP spirals provided increasing confinement for the entire duration of the test without any spiral damage. The tests showed that, as an innovative material with excellent corrosion resistance GFRP bars can be successfully used as internal reinforcement in ductile concrete columns.

Bioenergy production from forest resources offers opportunities to reduce greenhouse gas (GHG) emissions associated with fossil fuel use, reduce non-renewable energy consumption, and provide investment and employment in the forestry sector. These opportunities, however, must be considered within the broader contexts of forest systems. Of particular interest is how bioenergy opportunities impact carbon storage within the forest. This thesis develops a method to integrate life cycle assessment and forest carbon analysis approaches to quantify the total GHG emissions associated with forest bioenergy. Bioenergy production and utilization decisions are then investigated to evaluate opportunities to increase GHG mitigation performance. An accounting method is developed to evaluate the impact of emissions timing on the cost-effectiveness of GHG emissions reductions from biomass-based electricity generation. Applying the integrated life cycle assessment/forest carbon analysis method to a case study of forest bioenergy production in Ontario reveals significant reductions in forest carbon associated with bioenergy production. Wood pellet production from standing trees or harvest residues (displacing coal in electricity generation) would increase total GHG emissions over periods of approximately 40 and 15 years, respectively. Ethanol production (displacing gasoline) would increase GHG emissions throughout the 100-year model period if produced from standing trees; emissions would increase over a period of approximately75 years if produced from harvest residues. Strategic ethanol production decisions (e.g., process energy source, co-location with other processes, co-product selection) can improve GHG mitigation. Co-production of biomass pellets with ethanol performs best among co-product options in terms of GHG emissions; co-location with facilities exporting excess steam and biomass-based electricity further increases GHG mitigation performance. Delayed GHG reductions due to forest carbon impacts the cost of GHG emissions reductions associated with electricity production from forest biomass. Cost-effectiveness is heavily dependent on the time horizon over which global warming impacts are measured and influences the ranking of biomass electricity pathways (biomass co-firing is the most cost-effective pathway between 2020 and 2100; biomass cogeneration is the most cost-effective pathway beyond year 2100). The accounting tools and methods developed within this thesis will to help inform decision-makers in the responsible development of forest bioenergy opportunities and associated policies.