<p>Provisions for the design of masonry walls is subject to uniformly distributed pressure normal to the surface of the wall differ significantly from country to country. These differences may be attributed both to differences in design philosophy and to a general lack of conclusive or widely accepted experimental and analytical research. Most of the previous research in this area was concerned with brick masonry and with practical rather than well defined support conditions. Also, the available design methods were not accurate or rational. Therefore, this study was initiated to investigate the flexural behaviour of hollow concrete block masonry both experimentally and analytically and to assess the design methods for laterally loaded walls.</p> <p>The experimental program included 30 full scale wall tests representing different support conditions and aspect ratios. In addition, stack bonded prisms and wallettes were used to determine the flexural tensile strengths. The full scale tests were performed using a test facility designed to accommodate tests of masonry panels up to 6.0 m long by 3.6 m high and to provide well defined support conditions. The observed behaviours of the walls were compared to other walls of the same series and to other tests to investigate the effects of variability, aspect ratio, support conditions, and the presence of either precompression along the top panel or precracking near the panel center.</p> <p>A nonlinear finite element model capable of reproducing the observed behaviour of the walls was developed and used to extend the knowledge of masonry wall behaviour to include untested conditions and configurations. In this model, the anisotropic nature of the masonry, the nonlinearity due to cracking, and the effects of the transverse shear were taken into considerations. Also, the existing biaxial failure criteria were examined and proposed macroscopic biaxial failure criterion was incorporated in the finite element model to predict the strengths and the failure modes for masonry assemblages. This criterion accounted for the anisotropic and composite nature of masonry and was based on physical interpretations rather than being strictly a phenomenological criterion.</p> <p>Finally, the available design methods were compared using the extended data from the analytical model and design a method based on elastic plate theory was proposed. This method was rationally developed to predict first cracking and failure capacities for masonry panels simply supported on three or four sides for a wide range of aspect ratios.</p> / Doctor of Philosophy (PhD)

<p>Design of earthquake-resistant structures has been an important area in both research and engineering practice for decades. Realistic determination of seismic loading on structures is one of the governing design criteria for design of new buildings or evaluation of existing structures. For the nuclear industry, the performance of structures is extremely important owing to public safety concerns.</p> <p>This report explores the methodologies used to calculate seismic-induced soil pressure applied onto partially embedded structures. A critical review was performed on different methods developed in the past, which includes simplified analytical approaches based on either yielding wall theory or rigid wall theory and detailed dynamic analysis with the consideration of soil-structure interaction effects. Assumptions, range for appropriate application, and corresponding shortcomings of these methods are identified. Several critical issues that have significant impact on the soil-structural response but are not sufficiently taken into account in most existing models, are identified. These include embedment effects, interface boundary conditions and material nonlinearity. Following the review, a detailed seismic analysis using the finite element method is carried out to explore the effects of embedment effects, interface boundary conditions and material nonlinearity on seismic earth pressure. A simplified CANDU 6 reactor building excited by an artificial strong ground motion is used in this analysis. The seismic earth pressures obtained from this detailed seismic analyses under various conditions are then compared with the simplified approaches to evaluate their accuracy.</p> / Master of Engineering (ME)

<p>The report describes an interactive computer program that can be used to determine the steady state piezometric surface profile for given flow conditions in various hydraulic networks. The program is designed for use in a time-sharing mode to facilitate the setup, calibration and modification of cross-sectional data defining a hydraulic network. The network may include open channels (either natural or man made) or closed conduits, or both, in configurations of single reach, multiple tributaries or bifurcated branches with its resultant "island" flows. In addition, bridges, weirs, culverts and manholes can be modelled as transitional structures. There is a choice of six resistance laws which are selected during run time. The network geometry file is stored on secondary devices such that relatively large systems can be handled on computers of moderate size. A large part of the report comprises a set of Appendices which can serve as independent manuals for the use and modification of the programs.</p> / Master of Engineering (MEngr)

<p>In frame structures, the multi-directional motion of an earthquake has a significant effect on the structure response. The columns, especially those at the building corners, are subjected to biaxial bending from combined longitudinal, transverse, and torsional motion of the structure, with added axial loads due to overturning. Moreover, the variation of the axial forces may be independent of the variation of the other lateral forces.</p> <p>The non-ductile response of structural elements, particularily columns, has been the cause of numerous failures during earthquakes. The non-ductile behaviour of reinforced concrete columns arises from different causes such as insufficient anchorage length and bond for the longitudinal steel bars with concrete, insufficient confinement, or inadequate shear strength.</p> <p>The objective of this research program is to analytically and experimentally evaluate the non-linear behaviour of non-ductile reinforced concrete columns under lateral cyclic deformations. The experimental data was used to verify the analytical predictions.</p> <p>The analytical phase of this study included the development of an upgraded 3D beam-column element based on lumped plasticity modelling. The model accommodates flexural response by quadrilinear force-deformation relationship, and shear response by strength and stiffness degrading relationship. The model takes into account the effect of axial load variation on lateral deformation and its interaction with biaxial moments and shear, which is an important contribution.</p> <p>The 3D model was validated using experimental data available in the literature by several independent researchers for reinforced concrete columns. The calculated and experimetnal results were encouragingly close, especially considering the complexity of the response. The effect of different axial load variation paths on the response of cyclically loaded columns was studied.</p> <p>A new analytical procedure to obtain the moment-rotation and force-deflection relationships for reinforced concrete columns was developed. These relationships were used as input data for the 3D element. This procedure uses the basic mechanical and geometrical properties of the element. This procedure uses the basic mechanical and geometrical properties of the element. It takes into consideration the effect of bond-slip of tensile bars, buckling of compression bars as well as flexure and shear deformations. This procedure was verified using available experimental data. The comparision showed good agreement. A parametric study to evaluate the effect of variation in section and material properties was also conducted.</p> <p>The experimental phase of this study included testing three reinforced concrete short columns under cyclic lateral loads and constant axial load. The first specimen, which represents columns designed according to current code (CSA A23.3-94), failed in a non-ductile shear manner. The second specimen was identical to the first one but rehabilitated using anchored carbon fibre reinforced polymers (CFRP). A significant increase in the displacement ductility of the column was achieved. The third specimen represents a non-ductile short column designed according to pre-1970 codes and rehabilitated using anchored CFRP wraps. Increased ductility was achieved. Two different techniques to reduce concrete bulging at column sides were evaluated in the two rehabilitated specimens; namely, by using through steel rods and fibre anchors. Both techniques proved to be effective.</p> / Doctor of Philosophy (PhD)

<p>Field and laboratory investigations were carried out to explore sediment oxygen demand (SOD) and its component parts. An in situ measurement device was built, tested and applied in Hamilton Harbour. Techniques were developed to measure SOD and oxygen uptake by chemical oxidation (CSOD). Sediment samples were taken from Hamilton Harbour and seven other lakes in Northern Ontario and Cape Breton Island. All samples were analyzed for organic content and selected samples were placed in laboratory columns. Experiments were conducted in which oxygen uptake was measured within the columns under controlled conditions. Sediment oxygen demand was fractioned into portions attributable to chemical oxidation, biological respiration and direct macroinvertebrate respiration.</p> <p>Models were selected to describe the dependence of each portion of SOD on oxygen concentration and temperature. Where possible, mechanistic explanations are presented for the models selected. Results indicate that the chemical portion of SOD is dependent on oxygen concentration in the manner of a first-order reaction and that it responds to temperature change in a manner typical of a mixed bacterial community. At high oxygen concentrations, anaerobic metabolic activity is found to be the limiting factor in CSOD. Bacterial and macroinvertebrate oxygen uptake are dependent on oxygen concentration at low concentrations, following a Monod kinetic form. These fractions respond to temperature in the same fashion as the chemical portion. Macroinvertebrates contribute a large part of the direct respiration as well as having a profound effect on the total community respiration.</p> / Master of Engineering (ME)

<p>In the application of cold formed steel structural members, holes are usually cut in the webs of sections for passing pipes or conduits. The Canadian standard for the design of cold formed steel sections does not provide sufficient design information for theses conditions. However, the American Iron and Steel Institute has recently provided design guidelines for sections with circular perforations based on limited available experimental data.</p> <p>The purpose of this study is to determine the effect of size and shape of openings on the axial load behaviour of cold formed sections having different flat width-to-thickness ratios of webs.</p> <p>A total of fifty five stub column tests were performed to provide design guidelines for stiffened plates with openings. Cold formed lipped channel steel sections were selected for the tests. Circular, square or slotted holes were cut in the centres of webs. The diameter, or width of the openings, varied from 0 to 0.6 times the flat width of the web. The tests were performed under axial compression and centering of the specimen was done with the help of strain gauges. Load versis axial shortening and out-of-plane deflections curves are plotted. Experimental buckling loads of the sections are obtained using the strain reversal method. Ultimate loads of the stub columns are calculated using the effective width approach given in North American codes. An empirical relationship was derived from the experimental data for the effect of square of circular openings in the web on the strength of cold formed sections.</p> <p>It was found that the buckling load of a section decreases with respect to the buckling load of an unperforated section when size (diameter or width) of the opening is 20% of the flat width of the web but increases as the size of the opening is increased to 60%. The ultimate strength of sections with circular and square openings changes insignificantly when the size of the openings is 20% of the flat width of web. However, it drops to about 87% when the opening size is increased to 60%.</p> <p>The shape of the opening influences the degree of reduction in strength. The shapes in increasing order of influence are circular, square and slotted openings. The maximum drop in compressive strength, about 14%, was for the section with a slotted opening, of width of about 48% of the web flat width. It also shows the importance of both the longitudinal and transverse dimensions of the opening. The design guidelines provided by the American Iron and Steel Institute (1986) are conservative. The equation proposed herein accurately predicts the effect of square or circular perforations on the strength of the cold formed steel sections.</p> / Master of Engineering (ME)

During pile installation, the stresses and void ratios in the surrounding soils change significantly, creating large displacements, soil disturbance and the development of excess porewater pressures. The disturbed soils, especially fine grain soils, tend to regain their strength over time due to both the consolidation of the excess porewater pressure and thixotropic behavior of soil particles. In this research, the pile installation process and the subsequent consolidation, the thixotropy and load tests for several test piles were modeled using finite element (FE) model. A new elastoplastic constitutive model, which was developed based on the disturbed state concept (DSC) and critical state (CS) theory, was implemented to describe the clayey soil behavior. The developed model is referred as critical state and disturbed state concept (CSDSC). Pile installation was modeled by applying prescribed radial and vertical displacements on the nodes at the soil-pile interface (volumetric cavity explanation), followed by vertical deformation to activate the soil-pile interface friction. The soil thixotropic effect was incorporated in the proposed model by applying a time-dependent reduction parameter, which affects both the interface friction and the soil shear strength parameter. The results obtained from the FE numerical simulation included the development of excess porewater pressure during pile installation and its dissipation with time, the increase in effective normal stress at the pile-soil interface, and the setup attributed to both soil consolidation and thixotropy effects at different times after end of driving. The FE simulation results using the developed model were compared with the measured values obtained from the full-scale instrumented pile load tests to verify the proposed FE model. The results obtained from verification indicated that simulating soil response using the proposed CSDSC elastoplastic constitutive model and incorporating soil thixotropic behavior in the FE model can accurately predict the pile shaft resistance. A parametric study was then conducted by varying the main soil properties, which have significant contribution in setup phenomenon. The obtained data were analyzed using existing statistical techniques and applying non-linear regression analysis. Several nonlinear regression models were developed under different sets of variables, and finally three sets of regression model were proposed to correlate the soil setup behavior to the contributing soil properties.

This report presents the reliability-based analysis of the calibration of resistance factors for the Load and Resistance Factor Design (LRFD) of axially loaded drilled shafts. AASHTOs 2012 LRFD Bridge Design Specifications recommends various resistance factors for the design of deep foundations; however, since these values are not specific to any one region, they are very conservative. For Louisiana or Mississippi, the adoption of such recommended resistance factors could substantially increase foundation sizes. Therefore, it is necessary to develop a database of drilled shaft load tests performed in the regions of Louisiana, Mississippi, and surrounding states with similar soil conditions. Sixty-nine drilled shaft load tests were collected from the Louisiana and Mississippi Departments of Transportation to develop this database. The measured nominal resistances of the drilled shafts were determined at various settlement criteria using the provided static load test data, and the predicted resistances were calculated from soil boring data using both the 1999 Federal Highway Administration (FHWA) drilled shaft design method (Brown et al.) and the 2010 FHWA design method (ONeill and Reese). The performance of each design method is evaluated through statistical analyses of the predicted resistances versus the measured resistances, and FOSM and the Monte Carlo simulation method are utilized to perform the LRFD calibration of the resistance factors for the Strength I Limit State as defined by AASHTO. The calibration performed in this study confirms that the Monte Carlo simulation method is a more accurate and reliable method in determining the resistance factors; it also shows that while the 2010 FHWA drilled shaft design method is a more accurate method, it produces smaller total resistance factors than the 1999 FHWA design method.

This work is an attempt to develop a physically realistic model to understand the behavior and failure of rocks, especially under the extreme conditions of High Pressure and High Temperature (HPHT). A platform is laid in the preliminary work where 1D pure and ductile damage models are developed respectively. These models are based on an elasto-plastic model with an additional governing equation incorporated to facilitate the inclusion of damage. This additional governing equation is called the damage evolution equation. In the ductile damage model, it is assumed that the damage is driven and controlled by plasticity. The concepts developed in the preliminary work of 1D modeling are then taken into the study of 3D problems. The main problems studied are: the unconstrained uniaxial compression, the completely constrained uniaxial compression and the dynamic indentation problem. The dynamic indentation problem is the representation of an idealized rock drilling process. The results from the indentation problem are found to be in good qualitative agreement with the experimental results (Abd Al-Jalil, Y.Q 2006).

This thesis presents a case study on an urban arterial corridor consisting of four intersections located in Baton Rouge, Louisiana. The research evaluates alternative roundabout designs in order to improve traffic flow through a currently congested corridor. The objectives of the research were to evaluate the effect of roundabouts in an urban arterial corridor, select the best alternative for the given corridor characteristics, and test the capacity of the alternative roundabout corridors. The three alternatives that were considered as part of this study were the existing signalized corridor, a partial two-lane roundabout corridor, and a partial three-lane roundabout corridor. Field data was used to model the alternatives in VISSIM, a micro-simulation software. Statistical analysis software, SAS Enterprise Guide 6.1, was used to analyze the results and determine if there were significant differences between the results for each alternative and each intersection. The performance measures used to compare the alternatives were average vehicle travel time, average delay per vehicle for each corridor, and average delay per vehicle at each intersection. The results showed that the overall alternative roundabout corridors provided a benefit over the existing signalized corridor for the existing traffic volumes tested. The partial three-lane roundabout provided the lowest vehicle travel times and lowest average delay due to the added capacity. For the higher traffic volumes at the interchange, the partial two-lane roundabout had a higher average vehicle travel time exiting the exit ramp than the existing corridor. The statistical analysis of the average vehicle delay at each intersection indicated that there were no significant differences between the alternatives at a five percent level of significance at the interchange. These results revealed potential operational issues roundabouts encounter at an interchange intersections.