<p>Based on a limited number of experiments, the current practice is to use fully welded link-column connections for links in eccentrically braced frames (EBFs). Since the use of field welded connections has its limitations, the use of bolted connections may be an attractive alternative. The extended end plate bolted connection (EEP) was selected for use in link-column join applications in eccentrically braced frames.</p> <p>The link-column connection is required to behave in a ductile manner. This would enable the shear link to develop its full plastic capacity and thus the EBF would be able to dissipate the earthquake input energy. In addition, the link-column connection should not result in any degradation of the EBF lateral stiffness. To test the ability of EEP connections to satisfy both those requirements, a two phase research program was performed.</p> <p>The first phase of study is experimental in nature and involves the testing of end plate connections under severe cyclic loading. The cyclic load is used to model the severe load reversals associated with a major seismic event. The effect of bolt size, end plate thickness and the use of end plate stiffeners on the performance of the joint was evaluated. It was found that properly designed EEP connections showed ductile performance. Links with extended end plate connections developed ultimate forces and reached deformation angles comparable to those with fully welded connections. Guidelines for designing EEP connections for link-column joints are proposed.</p> <p>Because of the severe inelastic behaviour of the shear links, their proper modelling is important for the accurate analysis of an EBF. In the second phase of this research, a simple yet effective link element model is developed. This model was included in the computer code DRAIN-2DX, of Prakash and Powell (1992). Comparisons with previous and current results confirm the accuracy of this new link model.</p> <p>An extensive dynamic analysis of EBFs with semi-rigid joints was conducted to shed some light on the effect of EEP connections on the performance of EBFs. A six-story, three-bay EBF and a twenty-story, single-bay EBF were selected. These EBFs were subjected to several strong ground motion records. The developed shear link model was used in the computer modelling of these frames. Several designs of these frames involving different degrees of connection flexibility are analyzed. The various design responses are compared to each other to determine the effect of connection flexibility on the response of EBFs. It was found that properly designed bolted EEP connections can be used as alternative to welded link-column joints in eccentrically braced frames.</p> / Doctor of Philosophy (PhD)

<p>The strength properties of fiber concrete have received much attention in the past with little emphasis being placed on the workability of the composite in its fresh state. Both field and laboratory studies have identified workability of the composite as a potential problem due to fiber addition resulting in field strengths lower than those obtained in the laboratory. Therefore, in addition to studying strength properties such as fatigue, the workability of fiber concrete was considered in detail.</p> <p>To obtain an optimum mix in terms of strength and workability, fiber length and concentration are of considerable importance. In the initial stages of the study, direct pull-out tests were completed to determine the optimum fiber length i.e. the fiber length just sufficient to allow full bond development under ideal conditions. The theoretical critical fiber length (1.8 cm) was found to correspond closely with the experimental optimum length of 1.27 to 1.91 cm.</p> <p>Emphasis was placed on the static and fatigue flexural strengths which are important properties required for rigid pavement design. Compression, split cylinder and impact resistance strengths were also considered. The tests indicated the importance of adequate workability with respect to obtaining improved strength performance with fiber addition. An increase in fiber length and/or concentration, decreased the workability of the composite resulting in an increased number of flaws decreased compaction and decreased uniformity of fiber distribution. The relative strength increase or decrease was dependent on the predominant influence; i.e. strength loss due to increased flaw generation or strength increase due to the fiber addition. The only significant factor influencing workability besides adjusting the fiber length and/or content was with the use of super-plasticizers.</p> / Master of Engineering (ME)

<p>This study focuses on sludge settleability and SVI-type measures. Quantification of sludge settleability is crucial. This usually is done via empirical relationships. Parameters used in these relationships require measurement of sludge zone settling velocity in column settling tests over a wide range of concentrations. Due to the extensive experimental effort involved, several alternative measures (e.g. SVI, DSVI, SSVI) have gained favour for monitoring sludge settleability at full-scale treatment facilities. There is considerable debate over which SVI-type measure is best. The study also includes a section on one-dimensional settling tank models. These models often are incorporated into wastewater treatment process simulators. Many of the one-dimensional settling tank models proposed to date are plagued by numerical instability and solution problems. Background for this thesis is provided in Chapter 2. Included in this section is background on settling tests used to quantify the effect of suspended solids concentration on sludge settling velocity. Chapter 2 also provides background on the development of secondary settling tank modelling. The main body of this thesis is presented as a series of four papers. The first paper (Chapter 3) addresses the considerable confusion which exists as to the best SVI-type parameter and experimental technique to use. A simple mechanistic model was developed and used to evaluate the effects of biosolids characteristics and test parameters on SVI-type indices. The model explains many of the artifacts associated with SVI and questions the validity of correlations for zone settling parameters based on SVI-type measures. The second paper (Chapter 4) examines the approach of correlating SVI-type measures with zone settling velocity (ZSV) parameters for use in flux theory analysis (design or operating charts). Correlations were assessed using the model developed in Chapter 3. The results show that use of the correlations may lead to erroneous results. The third paper (Chapter 5) presents experimental data to demonstrate that differences in column height and sludge concentration can lead to large differences in calculated SVI for a given sludge. The model developed in Chapter 3 was used to further highlight these potential problems and evaluate the effects of sludge characteristics and test parameters on SVI-type indices. The paper raises considerable doubt regarding the validity of correlations for zone settling parameters based on SVI-type measures. An alternative SVI-based method was proposed for determining zone settling parameters. The fourth paper (Chapter 6) outlines the approaches commonly used in one-dimensional layered secondary settling tank models. Two cases were examined: steady-state for a continuous flow secondary settling tank, and unsteady-state for a batch settling test. These cases were used as a basis to provide a rational explanation of numerical solution and stability problems that historically have plagued the one-dimensional layered modelling approach. The results show that the approach of introducing flux constraints into one-dimensional models should be avoided.</p> / Doctor of Philosophy (PhD)

<p>An investigation is made into the coupled lateral - torsional response on frame buildings to horizontally directed earthquake excitation. Attention is confined to the accuracy of the static code provision on torsional effect with special reference to the National Building Code of Canada 1977 (NBC 77).</p> <p>A mathematical model to compute the dynamic response of a building is presented. The formulation of the general equation of motion to a monosymmetrical building is developed in detail. The static storey torque is compared with the dynamic torque computed by using the response spectrum technique as outlined in the Commentary K of NBC 77. It has been found that the sympathetic coupled translational torsional resonance occurs at the buildings with small eccentricities. To uniform structure, the static code torque estimate is good if the effect of sympathetic coupled resonance is not significant. To building with large eccentricities, sympathetic resonance is unlikely to occur and the current NBC requirement of doubling the computed torque for design is a very conservative requirement.</p> <p>To buildings with eccentrical offset, NBC 80 proposes a modification on the definition of structural eccentricity. A study in this aspect is made through the floor torques comparison between dynamic analysis and static codes calculations. The results show that the improvement by NBC 80 is only partial. Buildings with eccentric offsets are irregular buildings, only a dynamic approach can lead to a realistic estimate of the torque distributions.</p> / Master of Engineering (ME)

<p>Extensive interest in the exploitation of the natural resources of the Canadian High Arctic has been generated by the petrochemical and mining industries. This, in conjunction with the recent rapid growth of many communities in the Arctic has resulted in the need for reliable sources of potable water. Basic data deficiencies in the Arctic however preclude the use of traditional techniques for predicting the temporal distribution of runoff or peak from rates.</p> <p>An interactive computer program using a modified energy budget concept has been developed to permit the simulation of average daily discharges from small watersheds in the Baffin region. All available hydrometeorologic data are utilized by the model which is formatted in a manner to facilitate data manipulation. Sensitivity analyses can thus be carried out to determine the sensitivity of a watershed's response to various meterologic parameters.</p> <p>Calibration and subsequent verification of the model against data collected from two watersheds in the Baffin region yielded a high correlation between recorded and simulated discharges.</p> / Master of Engineering (ME)

<p>The vulnerability of concrete to sulphate attack has been recognized and studied for at least two centuries. The basic needs that prompted that study were: (a) there are no available Canadian Standards on the sulphate resistance of slag cements; and (b) slag cements in general are not well known in Canada. There were three main phases in the study: Phase One - involved 76.2 by 152.4 mm (3 by 6 inch) concrete cylinders made from actual field mixes and subjected to various sulphate solutions representative of field conditions; Phase Two - involved an accelerated test program employing 25.4 and 25.4 by 285.75 mm (1 by 1 by 11½ inch) mortar prisms and 50.8 mm (2 inch) mortar cubes stored in more concentrated sulphate solutions; and Phase Three - followed along the same lines as Phase Two, but encompassed a wider range of samples, solutions and tests. The slag cement studied in detail was cementitious hydraulic slag meeting CSA A363. Experimental results show that: the sulphate attack is generally intensified with higher sulphate concentrations but the degree of attack is not proportional to concentration; Na₂SO₄ and K₂SO₄ solutions produced more rapid deterioration than MgSO₄ solutions; sulphate attack increases in rate and magnitude as the C₃A content of the portland cement increases and as the alumina (Al₂O₃) content of the slag cement (i.e. pelletized blastfurnace slag) increases; the higher the slag cement content of the blended cement, the greater its resistance; and a 50 per cent slag cement (cementitious hydraulic slag)/50 per cent Type 10 portland cement blend appears to be equivalent in sulphate resistance to a Type 50 portland cement. No abnormal, or significant, amount of ettringite was found in any of the specimens examined, which tends to substantiate one hypothesis that ettringite formation has little to do with sulphate expansion. The 76.2 by 152.4 mm concrete cylinder program did not yield any significant results. The accelerated mortar test procedure was found to be the most reliable test for evaluating a cements' sulphate resistance performance in a relatively short time, and it is recommended that this test be adopted as a standard.</p> / Master of Engineering (ME)

<p>The research work of this thesis is concerned with the local buckling behaviour and the post-local buckling strength of perforated cold-formed steel (CFS) members subjected to axial compression loading.</p> <p>Cold-formed steel sections are widely used nowadays as primary and secondary framing members in low-rise steel buildings. Although CFS members are essentially thin-walled framing elements, with a major susceptibility to local buckling, these members maintain a considerable reserve of post-local buckling strength prior to yielding. The post-local buckling strength of CFS members is largely affected by the sectional non-uniform material properties after the forming operation, the initial imperfections, the large deformation behaviour after buckling, and the possibility having utility perforations in the plate components of the members.</p> <p>A finite element-based analytical model has been developed in this thesis to investigate the post-local buckling behaviour and the ultimate strength of non-performated and perforated CFS compression members. A large deformation degenerated shell finite element was used to model the surface of CFS sections. The kinematic formulation of the degenerated shell element was enhanced using the method of "assumed strain fields", to eliminate any locking program problem of the element. Special consideration was given in the finite element model to the geometric imperfections and the loading technique of CFS compression members.</p> <p>Tensile coupon tests and residual stress tests were performed on CFS channel sections, in order to determine the effects of the cold forming operation on the distribution of the material properties across CFS sections. based on the results of these tests, analytical models for the stress-strain relationship, the yield strength distribution, and the residual stress distribution across CFS sections were developed and incorporated in the finite element model of CFS compression members.</p> <p>A seris of CFS channel stub-column tests was performed to verify the deformation and ultimate strength predictions of the proposed finite element model. The tests were also used to investigate the effects of perforations on the behaviour and load capacity of CFS members in compression. The finite element model was then used to assess the axial stress distribution and the effective design width of perforated plates of CFS compression members. This assessment was performed through a parametric study on the perforation and the plate parameters.</p> <p>Two effective design width equations for stiffened compression plates with square and elongated perforations were developed, based on the analysis of the finite element results. The ultimate load predictions of the two equations were compared to the stub-column test results of this thesis, and several other test results from the literature. The proposed equations proved to give accurate and safe predictions for the effective design width and the ultimate strength of perforated CFS compression members.</p> / Doctor of Philosophy (PhD)

<p>Cable-stayed bridges have been gaining popularity in the last few decades as a viable, efficient, economical and aesthetically appealing design for spanning medium to long crossings. The construction of these bridges in seismic regions has created a need to more fully understand their dynamic behaviour and seismic response.</p> <p>The objectives of this research work are to: (1) define a dynamic modal analysis procedure suitable for cable-stayed bridges, and (2) use the developed procedure to study seismic response characteristics of cable-stayed bridges.</p> <p>The research program was divided into four main stages: (1) development of analytic models for estimating frequencies of two of the main structural systems of cable-stayed bridges (i.e. deck and tower); (2) a 3-D model of Quincy Bayview Bridge was used as a prototype structure to study the modal characteristics of cable-stayed bridges and investigate the effect of major geometric parameters on the modal characteristics of cable-stayed bridges; (3) eigenvectors and load dependent Ritz vectors were examined to compare their appropriateness as bases for modal transformation of the equation of motion of cable-stayed bridges. A seismic response study was conducted of the Quincy Bayview Bridge in each vector basis to judge which is more appropriate for dynamic and seismic analysis of cable-stayed bridges. Frequency cut-off criteria were proposed that would ensure the inclusion of all important modes in a dynamic analysis; and (4) the proposed criteria were applied in a seismic response study that used a 3-D finite element model of the Quincy Bayview Bridge. The study investigated the effect of frequency content of ground motion on the seismic response of cable-stayed bridges with different deck supports.</p> <p>The results of the study showed that modal characteristics of cable-stayed bridges are most affected by the cable arrangement, the tower shapes, and deck supports. Almost the same number of eigenvectors or Ritz vectors are required to ensure the inclusion of all important modes in a modal analysis. To ensure the inclusion of all important modes, it is proposed to calculate an upper limit frequency using the developed analytic models, generate modal vectors up to the set limit and then check the effective modal mass of these vectors to meet a pre-set percentage of the total mass. The study showed that seismic response of a cable-stayed bridge is strongly dependent upon the deck support condition, and the frequency content of input motion. It also showed that towers are less sensitive to changes in frequency content of the ground motion than the deck.</p> / Doctor of Philosophy (PhD)

<p>In this dissertation research, grey mathematical programming (GMP) and grey fuzzy mathematical programming (GFMP) methods have been developed for the first time for decision making under uncertainty, and applied to case studies for municipal solid waste (MSW) management planning in the Regional Municipality of Hamilton-Wentworth (RMHW), Ontario, Canada.</p> <p>The GMP/GFMP approaches have improved upon existing mathematical programming methods, such as fuzzy mathematical programming, stochastic mathematical programming, and interval mathematical programming, by introducing concepts of grey systems and grey decisions into ordinary mathematical programming (MP) and fuzzy mathematical programming (FMP) framework. The developed methods allow uncertain information (presented as grey numbers) to be effectively communicated into the optimization processes and resulting solutions, such that feasible decision alternatives can be generated through the interpretation and analysis of the grey solutions according to projected applicable system conditions. Moreover, the proposed GMP/GFMP solution algorithms do not lead to more complicated intermediate models, and thus have lower computational requirements and are applicable to practical problems.</p> <p>Four GMP (grey linear programming (GLP), grey quadratic programming (GQP), grey integer programming (GIP), and grey dynamic programming (GDP)) and four GFMP (grey fuzzy linear programming (GFLP), grey fuzzy quadratic programming (GFQP), grey fuzzy integer programing (GFIP), and grey fuzzy dynamic programming (GFDP)) methods have been developed. The GFMP improved upon the GMP through the introduction of concepts of fuzzy decisions and FMP into the GMP frameworks to better reflect system uncertainties and generate grey solutions with higher certainty and improved applicability. The use of the GFMP approaches may be particularly pertinent for GMP problems with model stipulations fluctuating within wide intervals but the related membership function information for admissible violations of system objectives and constraints is known. The GMP/GFMP pairs are all directly linked (GLP-GFLP, GIP-GFIP, and GDP-GFDP) except for the GFQP which is not linked to the GQP but instead is linked to and improves upon the GFLP since it enables the modelling of constraints with independent uncertain characteristics. In comparison, the GQP was formulated by including the effects of economies of scale within the GLP modelling framework. In terms of the difference between the GIP/GFIP and GDP/GFDP, the GIP/GFIP methods provide a "one step" optimization process which is convenient for modelling formulation and solution, but may require computers with high capacities and speeds when large scale problems with a multitude of variables and time stages are to be solved, while the GDP/GFDP methods could potentially solve such a problem by dividing the planning horizon into several stages, but may require more effort for the dynamic analysis and computation of the stage submodels. The effectiveness of the methods and their solution algorithms have been demonstrated through a series of comparisons between the MP/GMP/GFMP solutions, as well as related sensitivity analyses.</p> <p>The GMP and GFMP methodologies were applied to case studies of short term waste flow allocation and long term facility expansion for the waste management system in the RMHW. Through examining the relationships and conflicts between different system components, a GLP model was formulated for the waste flow allocation planning problem, and a GIP model was formulated for the facility expansion planning problem. The grey solutions provided optimal and stable ranges for system objective function values and decision variables, which could be used for generating decision alternatives through adjusting/shifting the decision variable values within their solution intervals and making relevant tradeoffs between different system objectives/restrictions according to projected applicable conditions. Generally, the short term waste flow allocation solutions were useful for adjusting or justifying the existing waste flow allocation patterns, and the long term capacity planning solutions provided optimal times, sizes and locations of the waste management facility developments/expansions. Sensitivity analyses of the effects of system condition variations on the model solutions were also conducted.</p> / Doctor of Philosophy (PhD)

<p>The finite element method has recently become a well established technique in solving geotechnical problems, and has in the past few years been applied in glaciology to stimulate ice mass flow problems. In fact, the models available have advanced much more rapidly than knowledge of the physical parameters and laws which describe ice needed in the simulation process. In this thesis, several functional flow laws are developed.</p> <p>These laws, it is hoped, will lead to a better flow simulation for ice masses. Parameters such as grain size, age, and fabric, though poorly controlled in the testing of ice, are very important to the flow characteristics of ice as can be shown from a consideration of dislocation movements. A more systematic treatment of these parameters is needed.</p> <p>The influence of initial stresses on flow behaviour not considered in previous finite element method simulations of glacier flow, is shown to be significant. Two finite element schemes are compared, and a scheme based on an implicit approach appears to be somewhat faster in computer time.</p> <p>The importance of temperature to glacier flow is considered in this thesis. It is shown that non-isothermal conditions significantly affect the flow of ice masses.</p> <p>The functional flow laws, and the non-isothermal temperature distribution are used to stimulate flow of the Barnes Ice Cap. The simulation is found to be poor compared to observed results. It is felt that a consideration of initial stresses, better temperature distribution data, and improved flow laws are needed before the finite element method simulation will lead to satisfactory results.</p> / Master of Engineering (ME)