For this thesis, an all-welded plate girder, having a ratio of web depth to web thickness of 372, was used. Two panels of this girder had stiffener spacings to web depth of 1 to 1 and 1 to 2. The girder was subjected to loadings considerably in excess of theoretically calculated buckling loads for the two panels. Web stresses were measured at three sections of the girder and these were compared to theoretically calculated values. Bending stresses were measured at the extreme fibres of one section. The variations in stress along one pair of stiffeners was also recorded. [...]

Results are presented on the shear strength of four simple beams, without web reinforcement. All beams had the same over all dimensions. The only difference was that two beams were common monolithic beams while the other two had cast in an artificial diagonal crack at each end. The artificial cracks were located in different positions and with different inclinations. The beams were tested with concentrated loads at third-points.

Between 1920 and 1950 an oil gasification plant operated on a property adjacent to Kettle Creek about 0.2 km from the mouth of Port Stanley harbour on Lake Erie, Ontario, Canada. Oil tar wastes from the gasification plant were stored on the site until it was eventually abandoned in 1987. At that time the Ontario Ministry of the Environment (MOE) determined that the site was contaminated with heavy metals and polycyclic aromatic hydrocarbons (PAHs) and that some of this waste had been flowing into Kettle Creek through the George Street drain in the village of Port Stanley for an undetermined period of time. The site was completely remediated in 1995 and the flow of contaminated water from the drain ceased. However, sediment sampling revealed the presence of heavy metals and PAHs in Kettle Creek, the inner and outer harbours, and in Lake Erie. From a drinking water source protection perspective, there was an interest in identifying the oil tar contaminants and assessing contaminated sediment transport within the Elgin Area Water Treatment Plant intake protection zones (IPZs). The effectiveness of conventional treatment processes currently available within Elgin Area Water Treatment Plant (WTP) in removing these contaminants was also evaluated. According to historical monitoring data from various compartments including soil, sediment, groundwater and surface water, three types of contaminants were identified, including heavy metals (Sb, As, Cd, Cr, Cu, Fe, Pb, Ni, Se, V and Zn), PAHs and volatile organics (benzene, toluene, phenols). Due to extremely low toxicity and exposure probability, some unregulated contaminants (iron, vanadium, zinc, phenol and some PAHs) were removed from the final contaminant list and were not discussed from the perspective of treatment. A technique developed by the USEPA to characterize and track contaminant plumes in water, the fingerprint analysis of leachate contaminants (FALCON), was for the first time investigated for its suitability as a tool to assist with the interpretation of contaminated sediment transport in surface water originating from a former oil/coal gasification plant and its potential to help assess drinking water intake protection zones. A source fingerprint based on 4 heavy metals (As, Cr, Pb, Ni) and 6 polycyclic aromatic hydrocarbons (PAHs) from 12 sampling sites in a contaminant-impacted harbour was generated. This source fingerprint of the contaminated harbour sediments was then compared to 48 fingerprints generated at other sites in the vicinity of two intake protection zones of a drinking water treatment plant. The source fingerprint did not match fingerprints of sites upstream from the contaminant input source in the creek which fed the small harbour and other potential contamination sources to the east and west in the lake. However, the source fingerprint did match most sites in an outer harbour and some outside the harbour break walls, including sediments collected from within the drinking water intake pipe ~3 km to the east of the harbour. A high correlation between water intake sediments and the source fingerprint demonstrated that contaminated sediments have reached water intake. However, no exceedances of the target contaminants were reported in intake surface water in the period from 1990 – 2010. It was also found that the correlation between the source fingerprint and those in the intake has been decreasing over the period for which data are available, confirming the success of remediation efforts. Surface water monitoring has demonstrated that PAH concentrations are lower than detection limits and only iron (Fe) exceeds the Ontario Drinking Water Quality Standards (ODWQS) aesthetic objective. The concentrations of oil tar contaminants in treated water were all below the MOE regulated concentrations, indicating that the current Elgin Area Water Treatment Plant configuration is effectively removing any oil tar contaminants present in raw water. Critical raw water concentrations (CRWCs), which represent maximum raw water concentrations that can reliably be removed by the Elgin WTP, were predicted for each oil tar contaminant. The probability of each contaminant exceeding the CRWC was then estimated using a Log Pearson Type III distribution. Copper was found to be the contaminant with the highest exceedance probability. A point system was designed to evaluate the cost-effectiveness of other treatment alternatives and to select the most appropriate of these to improve the robustness of the WTP. Granular activated carbon (GAC) was determined to be the most cost-effective compared to other techniques and hence is considered as the most suitable technique to be implemented in the plant in order to improve its robustness as it relates to dissolved heavy metal species and PAHs.

In a 2001 study, Paul M. Goodrum examined the impact of equipment technology on productivity in the U.S construction industry between 1976 and 1998. This research and its results have been included in a larger discussion about productivity trends in the U.S, since then. The objective of this research is to extend the Goodrum study to the period between 1995 and 2009, so that further insight into long term trends and effects can be obtained. The study begins with a brief review of the research that has been completed in the last ten years with respect to the analysis of construction productivity trends in the U.S., Canada, and other developed countries. Then the study examines the characteristics common to all construction projects and factors affecting construction productivity, because an accurate understanding of the correlation between these factors will lead to improved productivity. A statistical significance test (t-test) is used as a method of measuring the validity of the observed changes in productivity between 1995 and 2009. The main finding of this research is that there is a slight improvement in partial factor productivity in the United States between 1995 and 2009 as measured using the Means estimating manuals while the labor productivity remains almost the same between 1995 and 2009. Through statistical significant test (t-test), it is found that the construction partial factor productivity have changed significantly between 1995 and 2009.Finally, samples of construction typical projects were taking as an example to show how the mentioned productivity improvements will affect the construction industry in the United States. The result of this study can be used as a guideline for planners, decision makers, owners, engineers, and contractors to develop insight with respect to the challenge of improving productivity in the North American construction industry. The implementation of the findings of this study will also be helpful for any specific project, because the duration of the project can be decreased and the productivity of the construction increased. The research provides some recommendations which may assist others who are interested in working in this area.

Corrosion is the number one deterioration mechanism that decreases the service life of the concrete structures. Many structures in severe environments have experienced an unacceptable loss in serviceability earlier than anticipated due to corrosion. Advanced composite materials in the form of externally bonded fiber reinforcing polymer (FRP) sheets have been successfully used for rehabilitation and strengthening of infrastructure in lieu of traditional repair techniques such as steel plates bonding. FRPs are used because of their light weight, ease of application, non-corrosiveness material, and high strength. The current study comprised of testing eighteen reinforced concrete beams to investigate the confinement provided by carbon fiber-reinforced polymer (CFRP) sheets on the bond strength of corroded tension lap splices under static loading. The beams were 200mm wide by 300mm high by 2000mm. Each beam was reinforced on the tension side with two steel bars (2 M 15 or 2 M20 steel bars) spliced at mid span in the constant moment region. The nominal concrete strength was 43 MPa and the yield stress of the steel reinforcement was 400MPa. The test variables were the concrete cover to bar diameter ratio (c/d) which varied from 1.5 to 2.67, the level of corrosion (0% and 2.5% mass loss), and the presence or absence of transverse CFRP wrapping. The corrosion in the steel bars was induced by means of accelerated technique withan impressed current density of 150mA/cm2. The specimens were instrumented by strain gauges on the steel reinforcement, concrete, and CFRP sheets. Linear variable differential transformer (LVDT) was used to measure mid span deflection. The specimens were tested to failure in four point bending. The test results showed that all beams failed by bond splitting. The reduction in the ultimate bond strength due to a 2.5% corrosion level ranged between 16% and 25% depending on the c/d ratio. The reduction in the ultimate bond strength due to a 5.0% corrosion level ranged between 20% and 45% depending on the c/d ratio. FRP wraps were effective in confining the tension splice region. The failure in the FRP repaired beams was more ductile and more gradual although the final mode of failure was splitting of the concrete cover. A new, (Ktr,f,) accounting for the presence and amount of FRP confining tension lap-splice was proposed.

Capital renewal is an essential decision in sustaining the serviceability of infrastructure. Effectively allocating limited renewal funds amongst numerous asset components represents a large-scale combinatorial optimization problem that is difficult to solve. While various mathematical optimization techniques have been presented in the published literature, they are not very effective in handling the complexities and huge calculations related to large scale problems. More recently new evolutionary-based techniques, such as genetic algorithms (GA) have been introduced for finding near-optimum solutions to large-scale problems. Experimenting with this technique for asset renewal problems has revealed that GAs performance rapidly degrades with problem size. For instance, a previous research by Hegazy and Elhakeem (2010), could improve fund allocation for only a portion of total existing components (maximum of 8000 asset components) with degradation in optimization performance by increasing number of components. To address larger scale problems, this research investigates both evolutionary and advanced mathematical optimization techniques and seeks a goal of handling models consist of at least 50,000 asset components. To enhance the performance of GAs for large-scale optimization problems, three aspects were considered: (1) examining different problem formulations such as integer, on-shot-binary, and step-wise binary formulation; (2) experimenting with commercial GA-based tools; and (3) introducing an innovative segmentation method to handle groups of smaller size problems, and then integrating the results. To identify the best segmentation method, similarity-based segmentation is compared to random segmentation and was found to have superior performance. Based on the results of numerous experiments with different problem sizes and comparison with previous results obtained by Hegazy and Elhakeem (2010) from the same prototype used in this study, the GAs + Segmentation approach is found to handle a problem size of 50,000 components, with better solution quality (improved optimum solution), and no noticeable degradation of optimization performance by increasing the problems size. In addition to evolutionary algorithms, performance of one of the advanced mathematical programming tools (GAMS), and its powerful optimization engine (CPLEX), are investigated. For the mathematical representation of the asset renewal problem, best formulation is selected with regard to the definitions of easy-to-solve integer programming (IP) formulations. To reduce internal calculations, the GAMS mathematical model is coded to interact with original spreadsheet data by using GAMS data exchange (GDX) files. Based on experimentations, using advanced mathematical tools with strong (easy-to-solve) IP formulations, improved the solution quality even further in compare to GA + Segmentation. In conclusion, this research investigated both evolutionary and advanced mathematical optimization techniques in handling very large-scale asset renewal problems, and introduced effective models for solving such problems. The developed models represent a major innovative step towards achieving large cost savings, optimizing decisions, and justifying fund allocation decisions for infrastructure asset management. While the focus of this research is on educational buildings, the developed optimization models can be adapted to various large-scale asset management problems.

The temperature of 0°C, the phase change point of water-ice, is among the most influential factors on the hydrology of the temperate regions that experience winter. Many cryospheric processes, such as snow and ice melt, avalanches, freshwater ice breakup, and ice jam floods, are triggered by the arrival of the above-0°C air temperatures. Moreover, such 0°C based changes can have significant cascading impacts on other parts of the physical environment as well as related socio-economic activities. This research adopts an extensive analytical approach to examine the changes in the sign of mean JFM (January-February-March) and MAM (March-April-May) air temperatures, in the 0.5° × 0.5° land grid cells of the Northern Hemisphere (20.25°N-89.75°N), during the period 1901-2009. The goal is to identify grid cells in which JFM or MAM temperatures used to be primarily below freezing, however, changed sign permanently some time during 1901-2009 due to an advancement in the arrival timing of the annual above-0°C temperature. Considering that air temperature fluctuates and can cross 0°C several times during the entire period of study, four different modelling techniques are employed to detect the shift points in the trend function as well as mean level of the time series and to determine the year when the model rises above 0°C (y₀) in a given location. Model-specific criteria are set to determine y₀ in cases of multiple positive 0°C crossings. The techniques applied include i) trend shift detection techniques: Model 2 and Model 3 (Perron and Yabu, 2009b; Kim and Perron, 2009), ii) Multivariate Adaptive Regression Splines (Friedman, 1991), and iii) the R method (Rodionov, 2004,2006). This thesis provides a thorough discussion of these techniques and reviews their strengths and weaknesses relative to the research goals. In addition to y₀, the time of the onset of warming that causes a time series to permanently rise above 0°C (y_w) is identified. The applied methods divide the entire domain of the time series into sub-regions in which the data are approximated by polynomials of degree zero or one. The segment which encompasses y₀ is termed the 'segment of interest' (S_interest). The combination of S_interest and the segment(s) with positive slope that immediately follows S_interest forms a section referred to as the 'section of total warming' (S_W_total ). The non-parametric Mann-Kendall test, following the modified trend-free pre-whitening approach (Burn et al., 2004), is conducted to examine if the warming during S_interest, which causes the temperature to turn positive, is significant. The same test is applied to S_W_total to determine if the total warming subsequent to y_w is significant. Only the locations with significant warming during S_interest and S_W_total are selected. A bootstrap analysis (Cunderlik and Burn, 2002), conducted to determine the field significance of the results, indicates that local trends are also globally significant. 
A thorough comparative evaluation of all the above-mentioned techniques determines that Model 2 is the technique that best meets the analysis goals. Analytical results indicate that during JFM, y₀ most commonly takes place in the following zones (referred to as 'transition area'). It should be noted that only the grid cells with significant warming during S_interest and S_W_total are considered: i) North America, western U.S; ii) Europe, highest density in central Europe; iii) southwestern and central Asia, a small region consisting of some parts of Uzbekistan, Kazakhstan, and Iran; iv) central-eastern Asia, a small area in western China most of which lies in the Taklamakan Desert; v) easternmost Asia, some grid cells from east-central China, South Korea, and Japan. During MAM, over North America, the transition area of Model 2 is principally located in Canada and extends from northeastern British Columbia to the Atlantic regions. In Eurasia, northern Europe, European Russia, southern Russia, northern Mongolia, and northeastern China form the great portion of the transition area. It should be noted that except for a few high-elevation regions located in lower latitudes, the grid cells with y₀ taking place during MAM are located north of those with y₀ occurring during JFM. Results also indicate that y₀ of the majority of locations occurs during the 1960-2008 interval. During MAM, the transition area of Model 2 in east-central Canada and Eurasia exhibits a clear pattern of increase in y₀ values with latitude. This characteristic is also observed in some regions during JFM. The y_w values are most commonly distributed over the period 1901-1980 with a peak during 1960-1980. The rate of warming over S_interest and S_W_total generated by Model 2 is 0.01-0.1(°C/year). The spatial and temporal variability in the results is believed to be related to variations in climate, elevation effects, and/or large-scale atmosphere and ocean circulations, all of which require further evaluation for proper attribution of effects.

This study proposes a seismic design optimization method for steel building frameworks following the capacity design principle. Currently, when a structural design employs an elastic analysis to evaluate structural demands, the analysis results can be used only for the design of fuse members, and the inelastic demands on non-fuse members have to be obtained by hand calculations. Also, the elastic-analysis-based design method is unable to warrant a fully valid seismic design since the evaluation tool cannot always capture the true inelastic behaviour of a structure. The proposed method is to overcome these shortcomings by adopting the most sophisticated nonlinear dynamic procedure, i.e., Nonlinear Time- (or Response-) History Analysis as the evaluation tool for seismic demands. The proposed optimal design formulation includes three objectives: the minimum weight or cost of the seismic force resisting system, the minimum seismic input energy or potential earthquake damage and the maximum hysteretic energy ratio of fuse members. The explicit design constraints include the plastic rotation limits on individual frame members and the inter-story drift limits on the overall performance of the structure. Strength designs of each member are treated as implicit constraints through considering both geometric and material nonlinearities of the structure in the nonlinear dynamic analysis procedure. A multi-objective Genetic Algorithm is employed to search for the Pareto-optimal solutions. The study provides design examples for moment resisting frames and eccentrically braced frames. In the examples some numerical strategies, such as integrating load and resistance factors in analysis, grouping design variables of a link and the beams outside the link, rounding-off the objective function values, are introduced. The design examples confirm that the proposed optimization formulation is able to conduct automated capacity design of steel frames. In particular, the third objective, to maximize the hysteretic energy ratio of fuse members, drives the optimization algorithm to search for design solutions with favorable plastic mechanisms, which is the essence of the capacity design principle. For the proposed inelastic-analysis-based design method, the seismic performance factors (i.e., ductility- and overstrength-related force reduction factors) are no longer needed. Furthermore, problem-dependent capacity design requirements, such as strong-column-weak-beam for moment resisting frames, are not included in the design formulation. Thus, the proposed design method is general and applicable to various types of building frames.

Three tiers of bench-scale experiments were conducted to evaluate the use of laboratory column investigations for studying the transport and removal of pathogenic microorganisms (i.e. disease causing viruses, bacteria and protozoa) and pathogen-surrogates (i.e. (bio)colloids) in saturated porous media (filtration). These experiments were used to explore the effects of individual and concurrent factors on the transport and removal of a suite of (bio)colloids at a range of environmentally relevant conditions typical of natural riverbank filtration and engineered drinking water filters. Several bench-scale column designs were investigated to elucidate laboratory-scale column size factors that may affect reproducibility of (bio)colloid passage through granular media filtration. The physical and chemical factors investigated for their individual and concurrent effects on the transport of a suite of (bio)colloids included: media grain size, media uniformity coefficient, ionic strength, and the presence of natural organic matter. The suite of pathogens and (bio)colloids utilized in this study included PR772 bacteriophage, Escherichia coli RS2g bacteria, Salmonella typhimurium bacterial pathogen, and two sizes of fluorescent polycarbonate microspheres (1.1 μm and 4.5 μm). In addition to S. typhimurium, pathogenic bacterial strains of E. coli and Pseudomonas aeruginosa were isolated and used in an experiment to investigate the effects of bacterial exposure to different environmental water matrices (impacted by various land-uses) on the transport of pathogenic bacteria. Additionally, the effects of bacterial exposure to the different water matrices on cell size and surface EPS composition of the suite of bacterial pathogens were investigated. Pathogen and (bio)colloid removal was assessed for the three experiments by plotting breakthrough curves and/or removal value from each trial, followed by ANOVA to determine the statistical significance of the effect of each parameter studied on (bio)colloid removal. The outcomes of this work have several implications for the use of bench-scale column studies in (bio)colloid transport investigations to improve the understanding of natural and engineered filter performance. Laboratory bench-scale experiments using replicate glass columns proved to be a useful tool in investigating factors that affect (bio)colloid transport in saturated porous media. In contrasts to common recommendations for experimental design (e.g., column diameter (D) to collector diameter (d) ratio > 50), column and collector media designs with D/d between 15 and 116 did not have a significant effect on the reproducibility and removal of a suite of (bio)colloids in transport investigations using varying ionic strengths and flow velocities representative of natural subsurface environments. Accordingly, small scale column studies of (bio)colloid removal by filtration that are conducted at D/d < 50 should not be universally disregarded because of wall effects concerns. iv Observations of (bio)colloid removal by granular media filtration were generally consistent with colloid filtration theory. Grain size, ionic strength and the presence of natural organic matter significantly affected the removal of a suite of (bio)colloids at values representative of natural field conditions. Interaction effects were also identified between the chemical factors of ionic strength and natural organic matter, as well as between physical media characteristics of grain size and uniformity coefficient. These results suggest that synergistic effects within physical and chemical factors known to effect pathogen transport in saturated porous media should be considered when assessing pilot- and full-scale filter performance demonstrations. Differences in removal between the suite of bacterial pathogens investigated at conditions representative of subsurface filtration were small (<0.5 log), suggesting that nuances between the removal of various strains of bacteria that are present at the micro-scale may not be substantial at the macro- or field-scale. The effects of bacterial EPS on (bio)colloid transport may be more important in environments with profuse biofilm formation (unlike the “clean-bed” environments used in this study). Established and standardised methods for EPS extraction and characterization for a range of applications are necessary to improve our understanding of bacterial EPS production, and the effects of these compounds in a range of saturated porous media environments. A conceptual model was developed to encompass the current state of knowledge on bacterial EPS effects on bacterial removal and the results presented herein.

Although it is not difficult to observe the healing of induced wounds in animal embryos, mapping the forces that drive lesion closure has proved challenging. Laser microsurgery, Atomic Force Microscopy (AFM) and other techniques can provide local information at fixed times, but all are invasive and some disrupt further development. Video Force Microscopy (VFM) has been able to map driving forces during ventral furrow formation in Drosophila (fruit fly), but challenges arose when it was applied under the assumption that the only driving forces are intracellular pressures and forces (including purse string action) along cell edges. Other possible forces of relevance include far-field stresses and in-plane cellular contractions. Mapping the forces that drive wound closure is an important problem, and so far it has remained unsolved. To investigate the process of dorsal closure, this study used a cell-based finite element (FE) model to identify the mechanical signatures of a wide variety of possible driving forces. Geometric parameters were developed to characterize the associated cell shapes and tissue motions and to quantitatively compare FE simulations with each other and with experimental data. It was discovered that edge tensions and pressures were not sufficient to drive wound healing. Wound healing can only be achieved when far-field boundary motions, edge tensions and apical area tensions act together. This thesis shows that a suitable FE model can provide information about the forces that drive wound healing, and its simulations take us one step closer to understanding the mechanics of wound healing. It also contributes to our general understanding of the forces that drive morphogenetic movements and ultimately helps us to better understand cell-based processes important for human quality of life.