<p>Multilayer elastomeric bearings are a type of seismic isolation device that mitigates seismic damage by lengthening the fundamental period of a low-rise structure. Carbon fiber reinforced elastomeric isolators (FREIs) have been identified as a cost effective alternative to bearings reinforced with steel shims. The stable unbonded fiber reinforced elastomeric isolator (SU-FREI) is an evolution of the FREI. In an attempt to reduce costs even further, FREI bearings of a specific aspect ratio and shape factor have been investigated in an unbonded application with successful results. SU-FREI bearings have shown potential as a viable solution for a more affordable and efficient method of seismic base isolation. Several experimental test procedures were employed in this thesis to further investigate the performance of SU-FREI bearings.</p> <p>The first objective of this research was to compare the dynamic properties of unscragged SU-FREI bearings at parallel and diagonal orientations. Square 1/4 scale SU-FREI bearings were subjected to cyclic excitation under design axial load at 0° (parallel) and 45° (diagonal) orientations. Square SU-FREI bearings achieved acceptable base isolation characteristics at both orientations despite subtle differences in their mechanical properties. Stable rollover (SR) deformation was observed for both orientations.</p> <p>The stability of SU-FREI bearings under dynamic excitation was the next topic investigated in this thesis. To achieve this, 1/4 scale square SU-FREI bearings were subjected to cyclic testing under incrementally increasing lateral displacement amplitudes and axial loads. It was found that the critical buckling load under dynamic excitation decreases with increasing lateral excitation amplitude. SU-FREI bearings exhibited acceptable performance at axial loads well in excess of expected design axial loads.</p> <p>In addition, an ultimate shear properties test was performed in order to investigate rollout instability in SU-FREI bearings. Rollout was not observed in bearings tested in this study. Test results did however highlight the stiffening effect of vertical facial contact throughout roll over deformation.</p> <p>Finally, SU-FREI bearings underwent cyclic testing under serviceability and fatigue conditions. Serviceability tests were performed on 1/4 scale SU-FREI bearings at lateral displacement amplitudes corresponding to those expected from a 1 in 10 year return period wind pressure. Fatigue testing was performed on 1/4 scale bearings at a lateral displacement amplitude equal to the total design displacement (D_TD) as required by ASCE 7-05. SU-FREI bearings displayed adequate scragged performance under both serviceability and fatigue testing. Both effective stiffness and damping remained within acceptable limits throughout these tests.</p> / Master of Applied Science (MASc)

<p>The purpose of this thesis is to set up simple computational models which require limited climatical data as input, in order to provide estimates of runoff during the spring-summer melt season for drainage basins in the Baffin Region. Due to the limitation of meteorological data in Arctic areas, the models were developed with only the major components of the hydrologic cycle, the components chosen on logical, physical basis with the restriction that the number of parameters be kept to a minimum.</p> <p>The models were used to generate daily average flows for the Duval River drainage basin. Unlike southern areas the major contribution of precipitation is snow which is retained until the ablation season which lasts from one to four months in Arctic areas. Observed and simulated results were found to be in agreement in terms of both volume and time distribution.</p> <p>As the optimised parameters are kept to a minimum it is hoped that it can be expanded for use on ungauged basins.</p> / Master of Engineering (ME)

<p>Steel structures are commonly used all over the world. Structural cold-formed steel sections can be used as the primary building members, as well as the secondary members with other structural materials. They can be used as joists, truss members, and studs; they can also be used as frame systems, floor systems and wall systems, etc.</p> <p>It is common to see openings in these plated structures for all kinds of reasons. For example, openings are needed for ancillary systems such as water pipes, plumbing, electric wiring, etc. In cold-formed steel members, openings are often introduced in the web of a joist. The existence of large openings can change the stress distribution around the opening regions, thus changing the buckling and strength characteristics of web panels. The extent to which the openings can affect the plated structures depends on the size, shape, locations and number of the openings in the web. In this study, parametric studies were performed on a total of 42 simply supported plates with centrally located square openings utilizing the finite element modeling. The parameters of interest are the size of the opening (d。/h), the slenderness ratio of the plate (h/t) and the aspect ratio of the plate (a/h). It was observed from the study that, a centrally located square opening can significantly reduce the ultimate shear strength of the plate. The opening size is the primary parameter influencing a plate's ultimate shear strength. The ultimate shear strength of a plate decreases approximately linearly as the size of the opening increases. The ultimate shear strength also decreases as the slenderness of the plate increases and tends to increase as the aspect ratio increases. The aspect ratio is found to be the least significant parameter in the sense of affecting the ultimate shear strength of plates with square openings. This study also compared the ultimate shear strength obtained from finite element modeling with that calculated from the AISI (2007) method. It was shown that the AISI (2007) tends to underestimate the ultimate shear strength of thick to moderate thick plates with square openings, but overestimate the ultimate shear strength of thin plates with square openings. A new equation for estimating the shear reduction factor (q_s) is proposed based on the finite element analysis undertaken to better estimate the ultimate shear strength of plates with centralized square openings.</p> <p>To compensate for the reduction in strength of steel members due to large openings, reinforcements may be used in practice. In this research, simply supported steel plates with an aspect ratio of 3 (a/h=3) and having a 60% reinforced square opening (d_c/h =0.6) under pure shear loads were analyzed through the finite element modeling. Four slenderness ratios (h/t), namely h/t=50, 100, 150 and 200 were considered. Three reinforcement schemes, namely the flat-reinforcement, the lip-reinforcement and the angle-reinforcement, are applied on the plates to evaluate the effectiveness of these three reinforcement schemes. It was observed from the research that all three reinforcement schemes were capable of restoring the shear strength of plates with square openings. However, the flat-reinforcement is found to be the most efficient way of the three reinforcement schemes considered.</p> / Master of Applied Science (MASc)

<p>This report describes an experimental investigation into the potential use of return flow from rectangular harbour resonators incorporated into semi-infinite harbour entrances. The mechanism studied includes: the bandwidth of the reduced energy spectrum transmitted into a harbour, the concomitant reflected wave spectra and the energy available for return flow. This report is intended to provide data for the design of on-channel harbour resonators so as to eliminate or reduce the transmission of a selected band of harmful wave frequencies and to maximize the energy of scouring currents so as to prevent the influx and deposition of littoral sediments in harbour entrances. Observations were also made of the potential danger to small vessels provided by the movement of waves into and out of the resonators. The vessels would probably be ejected from the resonator without risk of battering, although the motion locally in the mouth of the resonator will be amplified.</p> / Master of Engineering (ME)

<p>This work presents the results of a pilot plant study where a completely submerged rotating biological contactor was used for denitrification of domestic wastewater.</p> <p>The literature review emphasizes the existing knowledge on RBC operation and design fundamentals. A brief summary of the theory of denitrification has been presented as this subject already has been presented in detail by various authors.</p> <p>Dye studies were performed for 4 stage series operation and single stage operation. A two CSTR with interchange flow model seemed to fit the hydraulic model for single stage operation. The dye responses was observed to be function of biological growth which in turn varied with temperature.</p> <p>"Zero order" kinetics were shown to represent the data obtained for denitrification rates at hydraulic loadings of 2.5 1/min and 4.0 1/min best for the range of NO3+NO2-N concentrations studied.</p> <p>An energy of activation of 16,500 kcal/mole was calculated for hydraulic loading range of 2.5-4.0 1/min.</p> / Master of Engineering (ME)

<p>The main purpose of this research is to implement and evaluate the effectiveness of a coupled model (MIKE SHE / MIKE 11) for Spencer Creek watershed (Ontario), and later to use this model for climate change impact study using Canadian Global Climate Model (CGCM 3.1) data and Canadian Regional Climate Model (CRCM 4.2) data. Both the CRCM and the CGCM data are downscaled using a Statistical Downscaling Method (SDSM) and a Time Lagged Feedforward Neural Network (TLFN).</p> <p>The hydrologic modeling results show that the coupled model captured the snow storage quite well with a correlation coefficient of 0.5-0.8. It also provided a good representation of evapotranspiration (ET) in the catchment with higher values in late spring and early summer months. The simulated streamflows are consistent with the observed flows at different sites with a Nash-Sutcliffe coefficient of around 0.4-0.5. The model couldn't capture the extreme or mixed events such as freezing rain in winter and rain on snow processes in early spring. Using a conservative climate change scenario, downscaled RCM with TLFN and SDSM yields smaller changes than raw RCM projections, but the downscaling with SDSM produces smaller changes than TLFN. With downscaled GCM scenarios, the coupled MIKE SHE/MIKE 11 model predicted 1-5% annual decrease in snow storage for 2050s and 5-22% increase with RCM scenarios. Similarly, with downscaled GCM scenarios, the coupled model predicted 1-10% increase in annual ET for 2050s and 2-22% increase with TLFN downscaled RCM scenario. But with SDSM downscaled RCM scenario, the model showed around 10% decrease in annual ET. Those results are consistent with the downscaled results for maximum and minimum temperatures. The coupled model predicted 10-25% increase in annual streamflows for all the stations with downscaled GCM scenarios- which is consistent with the predicted changes in the snow storage and ET. With raw RCM scenarios, the model predicted 5- 12% increase in annual streamflow, and 3-30% decrease with downscaled RCM results showing consistency with predicted increase in ET and the negative to small increase in precipitation. Overall, the wide range of projected future changes in hydrologic processes predicted by this study can be useful for understanding the integrated effect of climate change in this complex catchment.</p> / Master of Applied Science (MASc)

<p>The Light Weight Deflectometer (LWD) is a smaller version of the Falling Weight Deflectometer (FWD) non-destructive test for determining the properties of the pavement-subgrade systems. Unlike the FWD, normally having up to 9 sensors measuring load-deflections histories, the LWD records the data using a central geophone located right under the loading plate. Up to two sensors can be attached to the device though. Therefore, the limited information obtained from the LWD creates some difficulties for the backcalculation.</p> <p>Elastostatic method of backcalculation layer elastic moduli of pavement structures does not take into account the dynamic nature of tests. Another limitation of the elastostatic approach is that it gives only one piece of information from each loaddeflection history recorded by a geophone. The number of unknowns typically exceeds two (at least pavement and subgrade elastic moduli for a two-layer approximation) for the real pavement-subgrade structure.</p> <p>The dynamic impedance function for the Mindlin plate idealization supported by elastic half space is calculated and related to the impedance of an equivalent single degree of freedom (SDOF) oscillator approximation. Unlike elastostatic, dynamic backcalculation provides one with two pieces of information (real and imaginary components of the dynamic impedance) allowing one to back-calculate an additional pavement-subgrade system property. It is shown, that elastostatic backcalculation gives the elastostatic stiffness value which, combined with the dynamic impedance of the Mindlin plate model, allows one to estimate an effective sub grade modulus E_s. and elastic modulus of pavement E_p or an equivalent asphalt thickness h_a. The presence of shallow bedrock indicated, however, the backcalculation with the simplified model can be problematic.</p> <p>The back-calculation approach suggested in this study is applied to sets of in-situ and simulated data. A frequency domain analysis showed some limitations for backcalculation of pavement-subgrade properties for real LWD data.</p> <p>The low frequency LWD and FWD devices (up to 50-80 Hz), as well as the higher frequency IE test (20 kHz), are compared in terms of temperature sensitivity of the respective responses. Non-isothermal computer simulations were performed and comparison was made. The results demonstrate that the LWD is more sensitive to temperature changes in the pavement layer than the FWD. Back-calculated elastic moduli of the sub grade did not show any sensitivity to temperature fluctuations. The impact echo test response showed high sensitivity of the response to temperature changes in thin pavements (up to 100 mm thick).</p> / Master of Applied Science (MASc)

<p>Much of the experimental research on shear wall elements in reinforced masonry has been performed on shear walls in isolation. These elements have typically been removed from their structural system and artificial idealized loading is placed on them. Testing is limited to these types of experiments because of limitations of laboratory equipment or the potential cost constraints of attempting tests on full building systems. Full-scale testing as well as some reduced scale testing has been performed at McMaster University over recent years. However, in order to examine larger walls as well as full building structures, the focus of research has turned more towards reduced-scale testing. First, half-scale tests were completed, and now, as part of a new test program, testing utilizes one-third scale concrete blocks.<br /><br />This thesis focuses on the ductile response of a one-third scale reinforced, fully grouted, concrete block shear wall building. As the name implies, the lateral load resisting system consists solely of reinforced masonry shear walls. Documentation is presented of the building response in terms of stiffness, torsion and post-yielding lateral loading. Further examination is presented related to the diaphragm action and associated inter-wall coupling behaviour. The load-displacement characteristics of the structure are then broken down into the response of the individual shear wall elements within the structure. These response characteristics are then related back to previous studies of the same wall configurations tested in isolation.<br /><br />The primary objective of the thesis is to provide a foundation to build a relationship between the behaviour of reinforced masonry shear walls tested in isolation and their behaviour in a building or system setting. This, along with future research in this area will provide comparisons between current design practice and observed performance for the purpose of potentially amending design practices related to seismic provisions as found in the National Building Code of Canada (2010) as well as the masonry design standard C5A 5304.1 (2004).<br /><br />The results of this study show a positive response for the use of one-third scale testing as well as testing of full systems. Although relatively brittle reinforcing steel limited the ability of the structure to achieve the expected ductility level the test results did show excellent promise for the hypothesis presented. This experimental program showed the potential of reinforced masonry shear walls to resist seismic loading while acting as part of a structural system.</p> / Master of Applied Science (MASc)

<p>The subject of this study is the mechanical response of soil masses consisting of numerous strata in their elastic range. The study comprises analytical, experimental and numerical aspects and provides an insight to the concept of 'equivalent' homogeneous cross-anisotropic material indicating that a system of strata can be replaced by an equivalent transversely isotropic material. <br /><br />The elastic material properties of such an equivalent transversely isotropic are derived analytically, based on the elastic constants of the constituents. The experimental study is carried out to investigate and verify the concept of the equivalent transversely isotropic material. The experiments involve triaxial tests on samples of two types of homogeneous clay, as well as tests on layered samples consisting of the homogeneous materials. In the numerical part of the study, the tests conducted in the experiments, were simulated via finite element analysis. A comparison is made between the elastic constants obtained from the mathematical formulation, the experiments and FE simulations.</p> / Master of Engineering (ME)

<p>Concrete undergoes volume change as it changes phases from plastic to solid. Volume change due to water movement and losses within the concrete are referred to as chemical and autogenous shrinkage and drying and plastic shrinkage are due to water exchange with the surrounding environment. Shrinkage strains need to be investigated as they can have detrimental effects on the serviceability and durability of concrete.</p> <p>For this study, an experimental program was developed using fractional factorial principles to investigate the effects of curing regime and concrete mixture namely, water to cement ratio (w/c) , water content (w), maximum aggregate size (size), silica fume replacement percent (SF), ground granulated furnace slag replacement percent (GGBFS), and volume of coarse aggregate (CA), on the magnitude of autogenous and drying shrinkage. A new test setup was developed to measure autogenous shrinkage, capillary pressure and temperature. The results were found to concur with those reported in the literature, i.e., moist cured samples exhibit chemical shrinkage and that air cured samples exhibit both chemical and drying shrinkage and that the magnitude of the latter is much greater than the former. Values of drying shrinkage are found to range from 450 to 800 μm/m. The results also revealed that all the parameters studied do contribute to shrinkage but not to the same degree. An increase in the volume and size of coarse aggregate is found to produce concrete that exhibits less drying shrinkage strains. The addition of SF as cement replacement is found in general to increase shrinkage strains. The statistical investigation has revealed that the following parameters, CA volume, w/c², CA², w/c*SF, w/c*GGBFS, size*SF, size*CA, w/c*w*size, w/c*SF*GGBFS, and w/c*SF*CA are statically significant to a 90% confidence level.</p> <p>For autogenous shrinkage, w/c is found to be a significant parameter. The results also revealed that increasing the amount of chemical admixtures, WRA and VEA, has led to a significant increase in strains. Autogenous strains were found to occur when there is a rise in capillary suction pressure, occurring due to self-desiccation.</p> <p>Seven models proposed in the literature to estimate strains due to shrinkage were evaluated using the experimental data. The majority of these models have been adopted by North American, European or Japanese concrete standards. The assessment has revealed that only two models, namely B3 and ACI - 209 are somewhat adequate in their predictions of strains in concrete that is 28 days or older. Regression models developed in this study are found to provide a better estimation of the concrete shrinkage strains at 3 days, 7 days, 14 days, 28 days and 119 days.</p> / Master of Applied Science (MASc)