<p>A Frustum Confining Vessel (FCV) was developed by McMaster University and Berminghammer Foundation Equipment Ltd., which provides an environment for the testing of reduced-scale piles (physical model). This vessel is intended to produce stress distributions within sand specimens, which resemble field conditions, however at a smaller geometric scale. This thesis presents the findings of the experimental and analytical investigations conducted on the FCV device. A technique for measuring normal stresses in dry sand is developed, and the stresses and displacements measured at specific locations within the sand specimens are used to calibrate the finite element model. Finite element simulations are used to evaluate different aspects of the responses, which cannot be directly measured in the experiments. The fundamentals of dimensional analysis are reviewed and a set of primitive variables for the pile-soil system is presented. Using the Buckingham-π theorem, a derived set of dimensionless groups is thereby proposed for the study of pile-soil interaction. The scaling factors necessary for the extrapolation of results from model to prototype conditions are obtained via similarity analysis. It is suggested that the lack of gravity scaling in the FCV device does not introduce significant distortions in the physical model provided that stress distributions, particularly horizontal stresses, are properly controlled by FCV loading. In relation to physical modeling of piles, a criterion for the acceptance of testing conditions is established, and the suitability of the current device is assessed in terms of the mentioned criterion. It is found that the current device does not completely meet the acceptance criteria. The improvement on testing condition is thereby sought by redesigning the vessel's shape. Alternative shapes for the vessel are investigated by means of finite element modeling. A redesigned shape, which offers optimal stress conditions for the purposes of physical modeling, is presented.</p> / Doctor of Philosophy (PhD)

<p>For asphaltic concrete surface courses, the surface texture of the exposed coarse aggregate in the key factor influencing the skid resistance performance of the pavement. With time, this surface texture is altered by the dynamic, interactive processes of polishing, wear or abrasion and weathering. In this study, four types of aggregate which are available in Ontario - traprock, limestone, steel slag and blast furnace slag - were subjected to these processes in order to evaluate their surface texture characteristics. The study was completed in terms of both quantitative analyses of laboratory samples and qualitative analyses of field and laboratory samples. Two major aspects were surface texture evaluation using the scanning electron microscopy, and the simulation of weathering influences on skid resistance. Both chemical and x-ray diffraction analyses were completed to support the evaluation.</p> <p>From the study, two new concepts - positive and negative rejuvenating processes and Potential Rejuvenating Value (PRV) - were developed. Steel slag, with a relatively high PSV, low AAV and potential negative rejuvenation was found to be the most desirable aggregate in terms of skid resistance performance.</p> / Master of Engineering (ME)

<p>Short and long term capacities of slender concrete block masonry walls subject to eccentric axial loads were investigated. A finite element model was developed to include both the geometric and the material nonlinearities. To analyze large members, a combined macro-micro finite element model for the masonry assemblage was also developed by which the advantages of the micro material analysis, using the theory of plasticity, as well as the interaction among the different constituent materials were accounted for within the macro finite element model.</p> <p>Utilizing the finite element model, parametric studies were conducted to cover wide ranges of the parameters which affect behaviour. The geometric, loading, and the material parameters as well as their interactions were involved in this study.</p> <p>Three simplified methods were developed to provide some rational design approaches. The first method, called "Lumped Area Method", provides a closed form solution for the wall capacity. In the second method, Moment Magnifier Method, a rational method for determining the modulus of rigidity was empirically developed to be used in the calculation of the moment magnification factor. In the third method, Deflection method, the theory of structural mechanics was used to determine the secondary moments using a secant modulus of rigidity which was numerically developed.</p> <p>Experimental creep tests were carried out on ungrouted and grouted masonry prisms built with normal weight blocks, and ungrouted prisms built with light weight blocks. Creep data were collected for almost 400 days under two levels of sustained stresses. Creep functions were statistically developed and were incorporated in the finite element-creep analysis.</p> <p>Another set of parametric studies was conducted to investigate the long term capacities of masonry walls. Also, the Lumped Area Method was extended to account for the creep effect in predicting the long term capacity.</p> / Doctor of Philosophy (PhD)

<p>A mathematical model to predict the bed sediment and suspended sediment load as a function of time and distance along a one-dimensional quasi-steady receiving area is described. The model called TOTSED, uses the modified. Einstein approach for bed load calculations and the Einstein approach for suspended load calculations. The plug flow reactor is used for the inflow load (sediment pollutograph) calculations.</p> <p>The model was verified and calibrated using data obtained from a sampling program carried out in Chedoke Creek outfall channel in Coote's Paradise in Hamilton during summer 1980. Similar computations were carried out using the HEC-6 program. TOTSED predictions compare favourably with both HEC-6 and the observed data. TOTSED has been modified to be a new block of the SWWM program.</p> / Master of Engineering (ME)

<p>Many of the existing reinforced concrete (RC) structures performed poorly during recent earthquakes. Most of these structures were designed for gravity loads only with inadequate lateral load resistance. Several of the construction details in existing gravity load designed buildings do not conform to current code requirements for seismic design and may lead to nonductile inelastic behaviour. The objective of this research program is to investigate the use of steel systems for the rehabilitation of existing nonductile RC buildings. The study is limited to low-and mediumrise frame buildings. A beam-column element capable of representing the behaviour of nonductile RC frame members is developed. The model is capable of representing the strength decay of nonductile RC members and the effects of the axial force on the yield moment and the deformation capacities of the member at peak strength. A procedure for evaluating the damage to nonductile RC structures following an earthquake is developed. The damage procedure depends on calculating the deterioration of the building stiffness and lateral load carrying capacity due to the application of the earthquake loading. The building stiffness and lateral load carrying capacity before and after the application of the earthquake loading were determined by conducting a pushover analysis. Two nonductile RC buildings, three- and nine-stories, representing low-and mediumrise existing nonductile structures, were analyzed using various ground motion records. The seismic behaviour of the nonductile buildings when rehabilitated using various structural steel systems was determined. The investigated steel systems include the addition of concentric X-bracing, eccentric bracing and attached steel frames. The effectiveness of the various steel systems in rehabilitating the three- and nine-story buildings were examined. The effect of the distribution of the steel bracing along the height and along the bays of the RC frames on the seismic performance of the rehabilitated building was studied. A simplified approach was proposed for selecting the proper brace distribution. The seismic performance of the nonductile three-story budding when using well designed eccentric bracing rehabilitation was compared with the performance of the building when using concentric bracing. The relationship between the deformation capacity of the rehabilitated building and the link deformation angle was evaluated. The distribution of the link strength along the building height was investigated. The seismic performance of the rehabilitated nine-story building was evaluated when using both flexible and stiff steel frames.</p> / Doctor of Philosophy (PhD)

<p>This research set out to investigate reported anomalies in the calculation of COD balances in biological nutrient (nitrogen and phosphorus) removal (BNR) activated sludge systems. For non-BNR systems, accurate COD balances are consistently attainable from experimental measurements. That is, influent COD can be accounted for in the effluent flow, waste sludge stream, and mass of oxygen utilised for carbonaceous oxidation. For BNR systems, in a number of instances where COD balances have been performed, the balances do not close. That is, the sum of the COD leaving the system is as much as 20% less than the COD entering the system, and thus there is an apparent COD 'loss'. In attempting to explain the problem, a laboratory based experimental program was developed which isolated specific areas of interest within BNR systems. The study involved two main experimental phases. In the first experimental phase, a closed denitrification assay technique was developed. This assay technique allowed specific aspects which have relevance to be evaluated: the nitrate-to-oxygen conversion factor, and the yield of activated sludge organisms under anoxic conditions. The advantages of the closed assay were that all of the needed COD balance terms were independently measurable, and the denitrification system was sealed which isolated the assay environment from the surrounding environment and minimised the effects of external inputs (i.e. oxygen transfer from the air to the liquid). In the second experimental phase, an excess biological phosphorus removal (EBPR) system was operated to investigate the influence of the influent COD to phosphorus ratio on EBPR biological activity and COD balance calculations. The EBPR system was a laboratory - scale sequenching batch reactor (SBR) which was extensively monitored over an eight month period. This allowed for the investigation of several factors such as, the rate of anaerobic phosphorus release and COD uptake, the ratio of anaerobic phosphorus released to COD taken up, and the rate of aerobic phosphorus uptake. The system also allowed for the calculation of COD balances. The main body of this thesis is presented as a series of five papers. The first aper (Chapter 3) presents a study on the nitrate-to-oxygen conversion factor for denitrification which theoretically is 2.86 gO₂/gNO₃-N. That is, when nitrate replaces oxygen as electron acceptor, the mass of nitrate reduced can be converted to oxygen equivalence - for purposes of COD balancing - through the use of this conversion factor. Calculations from a series of denitrifying experiments resulted in an observed conversion factor of 2.96 gO₂/gNO₃-N. However, the observed factor could not be distinguised statistically from the theoretical value, hence confirming the theoretical factor. The second paper presents a study of sludge production under anoxic (denitrifying) and aerobic conditions. Decreased sludge production and COD 'losses' are confounded in nutrient removal activated sludge systems. Hence this portion of the investigation was initiated to separate these two influences. Batch tests were performed under anoxic (denitrifying) and aerobic conditions using various organisms. The results show that COD balances were achieved, but differences in sludge production under the two conditions indicate a difference in true yield between the environments. An anoxic yield of 0.402 mg particulate COD/mg consumed COD was determined and compared with an observed aerobic yield of 0.645 mg particulate COD/mg consumed COD. These results dispel the assertion that less sludge production results because of COD 'losses'. That is, decreased sludge production in BNR systems can at least in part be explained by a lower yield during unaerated periods. The third and fourth papers (Chapters 5 & 6) present the results from the EBPR system. The third paper conccentrates on the results from the SBR and the influence of the various influent COD to phosphorus ratios. Five different influent ratios were investigated ranging from 8 to 98 (mgCOD/mgP) using a synthetic feed with acetate as the sole carbon source. The phosphorus content of the waste sludge increased from 4 to 17 per cent of the total solids as the influent COD:P ratio decreased. However, complete anaerobic COD uptake was observed irrespective of the phosphorus content of the sludge. Also, COD balances on the reactor averaged 1.04 indicating no apparent COD 'loss' in the system. The fourth paper presents the results of batch tests performed on the waste sludge from the SBR. Anaerobic batch tests were designed to determine the influence of the SBR steady state influent COD to phosphorus ratio on the kinetics and stoichiometry of the system's microbial community. In particular, the rate of substrate uptake increased from 104 to 211 mgCOD/gVSS/hr as the influent ratio decreased. Similarly, the rate of phosphorus release increased from 17 to 166 mgP/gVSS/hr as the influent ratio decreased. The batch test results showed that the ratio of COD taken up to phosphorus released under anaerobic conditions varies with the phosphorus content of the sludge. The observed release ratio increased from 0.17 to 0.79 mgP/mgCOD as the phosphorus content increased. The final paper (Chapter 7) presents a theoretical biochemical model for EBPR systems. The proposed model makes a distinction between glycogen accumulating organisms (GAOs) and polyphosphate accumulating organisms (PAOs) but suggests that significant populations of both types of organisms exist in most EBPR systems. That is, it is proposed that only in systems that are stressed does one type of organism dominate the mixed community. The biochemical models of Comeau et al. (1986) and Wentzel et al. (1986) were merged with the biochemical model of Satoh et al. (1994) to form a comprehensive model for EBPR system activity. The two-organism model provides several advantages over single organism models including the ability to predict variable rates of reaction and a variable anaerobic COD uptake to phosphorus release ratio.</p> / Doctor of Philosophy (PhD)

<p>The overall objective of this study is to obtain characteristics of seismic floor motions in a nuclear reactor structure in order to examine current procedures used in seismic qualification of nuclear power plant equipment. The study incorporates seismic data from real earthquake events and uses these records as inputs to a mathematical model of a CANDU nuclear reactor building. Seismic floor responses at typical equipment locations are calculated by standard techniques of structural dynamic analysis. Six mathematical techniques are applied to develop characterizations of each seismic floor response record. From this data a set of parameters are evolved to qualitatively and quantitatively describe the characteristics of the ensemble of floor motions. Results of a theoretical study on sine beat, limited-duration sine, and decaying sinusoidal motions are compared to the characteristics of the seismic floor motions to evaluate the realism afforded by current single frequency seismic qualification test procedures. It is concluded that single frequency test motions have a valid application in seismic qualification test programs and can realistically simulate many seismic floor motion characteristics provided that the specific type of test motion and the test procedures are well defined. Recommendations are presented for the selection of single frequency test motions and for developing the test procedures.</p> / Master of Engineering (ME)

<p>A study has been made for the ineslastic response of a thirty story frame tube structure subjected to static loading as well as dynamic excitation. The intent of this study was (i) to develop a simplified model for frame tube structures in order to compute both elactic and inelastic responses of such structures when subjected to lateral loadings, (ii) to identify the parameters that govern the behavior of frame tube structures, (iii) to assess the significance of the tube action on the elastic as well as inelastic responses, and (iv) to provide guidelines to estimate the structural responses when subjected to multiple components of earthquake ground motions.</p> <p>The simplified model reduces the 3-D frame tube system into sets of plane frame, interconnected by 3-D beam column elements. It is shown that this model gives good accuracy for each of the static and dynamic loading cases when compared with the results based on a 3-D model. The computer time involved with the planar model is at least one third that for the 3-D model. Therefore, it is beleived that the proposed model is a viable tool for the inelastic analysis of frame tube structures.</p> <p>The tube action if referred to as the forces developed in the two frames that are orthogonal to the direction of loading and which provide partial resistance to the applied loading. In order for this tube action to be effective, it is found that the frame tube should deflect like a cantilever with linear variation of axial force in the columns of the longitudinal frames and almost uniform axial force in the columns of the transversal frames. The key parameter that governs the inelastic dynamic response of frame tube structure was found to be the change of the post elastic story stiffness from the elastic story stiffness. For a large change of story stiffness, the bottom stories suffered large interstory drift. However, by decreasing such changes, the interstory drift became more evenly distributed along the height of the structure.</p> <p>The inelastic response when the frame tube is subjected to a bidirectional excitation is finally presented. It is found that the approximate estimates suggested by design codes underestimate the response. An alternative was proposed to give a more realistic estimate. Such scheme is the simple summation rule.</p> / Doctor of Philosophy (PhD)

<p>Over the years, rapidly varying channel flow and discontinuities in the solution of fluid mechanics problems have provided stimulation and challenge to numerical modelers. Traditional finite difference and finite element methods produce accurate but oscillatory solutions. Attempts to selectively eliminate these parasitic waves have been only partially successful in that the cost of a smoother profile was a lower accuracy solution. It is common to employ either internal and external dissipation parameters or a provision of dispersive interface.</p> <p>In this thesis, the problem of rapidly varying open channel flow is represented by a pair of nonlinear partial differential equations which are solved by a powerful moving finite element technique. The method developed in this research is based on the linking of a novel Lagrangian mode solution with the convenience of the Eularian grid at each time step. This second order scheme was employed in solving a variety of devised and reported open channel flow problems with near discontinuities.</p> <p>Comparisons with solutions obtained using the finite difference and finite element methods with Crank-Nicholson centred weightings demonstrates the quality improvements which have been achieved by this moving element scheme. The basic scheme was further generalized in both spatial and temporal dimensions. Sensitivity analysis of these generalized parameters established the grid size relaxations for a variety of problems. The moving element technique solved near discontinuous and gradually varied flow problems both in supercritical and subcritical regimes.</p> <p>An alternate form of Petrov-Galerkin weighting function was tested and found to give promising results. Further experimentation and testing are required before implementation.</p> <p>The robustness of the solution procedure is indicated by the adaptation of the model from the numerical and laboratory experiment stage to field problems. The model was successfully applied to the Teton Dam break flood and flood routing problem in the (Ontario) Grand River basin. Sensitivity analysis with very mild sloped channels with topographical features such as sudden expansions and offchannel storage suggest that the Eulerian-Lagrangian mode algorithm provides the missing link between the fluid mechanics of discontinuities and a practical tool for the modelling of rapidly varying open channel flow.</p> / Doctor of Philosophy (PhD)

<p>A variable source area model called TOPMODEL was modified to incorporate urban areas in both the topographic index and the mechanism of surface runoff generation. The revised model was applied to a small catchment in the Hamilton-Wentworth area. A Geographic Information System was utilized to delineate the Ancaster Creek Catchment and produce Digital Elevation Models (DEM). FORTRAN programs in conjunction with the DEM were used to compute topographic indiced that explicitly accounted for urban areas. Additional FORTRAN programs were modified to determine flow rates from this semi-urbanized catchment. Model testing was conducted in three phases: 1)a study of aggregation and scale effects using a partially revised model (TOPURBAN v.1) on three separate time periods; 2) a fully revised model (TOPURBAN v. 2) tested on six time periods; 3) comparisons between a conventional Hortonian flow model and TOPURBAN v. 2. Ten different DEM sizes were used to compute topographic indiced and TOPURBAN v. 1 was applied during the snow-free period of a wet, dry and median year. Four separate parameters were optimized. The results indicated that three of the four calibrated parameters varied only slightly with DEM size but the hydraulic conductivity increased with increasing grid cell size. Twenty-one statistics were compute to evaluate TOPURBAN v. 1's performance for predicting flow with regard to DEM size. The statistics indicated that the DEM size of 50m produces the most optimum conditions for the best TOPURBAN v. 1 performance. TOPURBAN v. 1 was later modified to create TOPURBAN v. 2 which better accounted for the storage in urban areas that was not considered in version 1. The new version added an additional calibration parameter and was tested on 6 data series in total. TOPURBAN v. 2 increased Nash and Sutcliffe Efficiency by anywhere from 2% to 8%. This increase proves that TOPURBAN v. 2 is a suitable model for combining urban areas into a hillslope hydrology scheme. TOPURBAN v. 2 was compared to the conventional Hortonian-Flow model QualHYMO, on all 6 continuous series, on two single events, and on the regional storm. TOPURBAN v. 2 out-performed QualHYMO in the single event tests and in the continuous series simulations by anywhere from 20% - 80% in Nash and Stutcliffe Efficiency. Estimates of peak flow rate for the regional storm were within roughly 35% of the estimate provided by MacLaren Plansearch Ltd. in the Spencer Creek Watershed Study that included the Ancaster Creek Catchment.</p> / Doctor of Philosophy (PhD)