<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)

<p>A majority of the experimental research on masonry shear wall behaviour has been done on single storey walls and on piers in many cases due to physical and equipment limitations in laboratories or time and cost constraints. Although full scale testing of multi-storey masonry shear walls has been carried out at McMaster University where the laboratory could accommodate walls up to about 8 m high, such testing is indeed very time consuming, costly, and even somewhat dangerous as the result of working at significant heights above the laboratory floor. Therefore, a decision was made to make use of scaled concrete blocks and proportionately scaled walls to conduct shear wall research over a range of wall sizes representative of walls in buildings. Half scale units have been used at McMaster University for the past 6 years and the research presented in this thesis represents the initiation of shear wall research using one-third scale concrete blocks. Therefore, one of the important and unavoidable focuses of this research is to provide a solid basis for future research on scaled shear walls.</p> <p>In terms of shear wall behaviour, the focus of this study is the flexural response of ductile reinforced masonry shear walls of various sizes and configurations. In addition to this documentation of basic shear wall response, an added objective is to initiate study of the interaction of various sizes and configurations of shear walls on the seismic performance of representative shear wall buildings as the next logical step beyond response of individual walls. To this end, an objective is to assess the results of using combinations of the tested walls contained within a conceptual structure.</p> <p>In terms of practical output, the experimental testing of shear walls will concentrate on inducing large displacements and examining the responses as they pertain to seismic parameters. The primary objective is to augment existing research focused on the displacement ductility of reinforced masonry shear walls and the force modification factor, Rd, as well as to provide a comparison between observed performance and the current design practices within the National Building Code of Canada (2005) and the masonry design standard, CSA S304.1 (2004).</p> <p>Overall, the results obtained from this study provide positive feedback for the use of fully grouted reinforced one third scale concrete block shear wall testing. The observed ductility was below the expected level, however, these results are an indicator that the current Rd value is a lower bound value. Although the relatively brittle steel presented complications and prevented full value from being achieved from the tests, when considered as lower bound results, they provide a positive indication of the resistance of ductile reinforced masonry shear walls subjected to seismic forces.</p> / Master of Applied Science (MASc)

<p>Dynamic absorbers, including the tuned mass damper (TMD) and the tuned liquid damper (TLD) , have been widely used in buildings to attenuate dynamic response. As the complexity of buildings increases, their response may become susceptible to torsional motion. The induced torsional motion can be suppressed by utilizing TMDs or TLDs. As such, the performance of different absorber arrangements are important for torsionally coupled structures. Also, a rapid design tool to reduce the computational effort for the design of the absorbers optimal parameters in torsionally coupled system is essential.</p> <p>In this study, the performance of different TMD/TLD configurations under both random and harmonic excitation are studied and evaluated. The effectiveness of the absorber configurations considered is accessed by the response reduction factor, which is defined as the ratio of the response of structure equipped with absorber(s) to the response of structure without absorber(s). Also, a preliminary design tool to determine optimal TMD parameters is developed by introducing the concept of a generalized structure-TMD system.</p> / Master of Applied Science (MASc)

<p>A computer program has been developed to compute water hammer transients in pump-discharge lines (forcemains), resulting from power failure at the pumps. The program incorporates various boundary conditions as subroutines. Hence the pump(s) can be placed anywhere in the pipeline, with or without discharge valves (or check valves), and the program can accept a large number of surge-control devices, similarly placed anywhere in the pipeline. Such devices include valves, check valves, surge tanks, one-way surge tanks, and pressure vessels. An explicit finite-differences scheme employing the method of characteristics is used throughout. It proved to be accurate and stable. The program is written in a dimensionless and general form. Several checks were made to prove the validity of the computer model. Comparisons with field observations, graphical analysis, and/or water hammer design charts were made, depending on the data available in the literature for each boundary condition. An exhaustive search through the literature was made. Computer plots are developed which proved valuable in presenting the results. The computer model was applied to the water hammer problem in the Ancaster forcemain, and a "best" protective device is suggested.</p> / Master of Engineering (ME)

<p>A mathematical model to compute the dynamic response of asymmetric shear wall-frame building structures is presented. The formulation is developed in detail for the case of one axis of symmetry. Also, the method is derived for the case of relatively uniform stiffining element with respect to height and it is based on the continuous approach. The lateral load resisting elements, as elastic continua, are combined by using the equilibrium and compatibility conditions to yield a coupled set of partial differential equations. Eigenvalues and eigenvectors are determined using numerical procedures and results are presented to show the natural periods and mode shapes for several practical structures. The total dynamic response of such structures subjected to earthquake ground motions is determined and results are presented for excitation due to several different earthquakes. The response results are compared with those obtained by using a static analysis with the objective of evaluating the adequacy of such static loading provisions and developing guidelines to define situations for which a detailed dynamic response computation is required.</p> / Master of Engineering (ME)

<p>A procedure based on the finite element method was developed for simulating the excavation of underground openings in rock for the actual initial state of stress in the field for various K conditions. This procedure can also incorporate orthotropic behaviour due to rock bedding, and other directional variations in the elastic properties of rock. This excavation simulation was then coupled into the time-dependent analysis of underground openings to study the influence of rock squeezing using the incremental initial strain method. Appropriate stress-strain-time relationships and strain accumulation methods are readily incorporated into this finite element program. (A survey of time-dependent constitutive relationships for rock is given to guide in the selection of appropriate creep laws.) The excavation and creep simulation aspects were then extended to model underground linings and lining placement strategies. This includes the ability to consider the lining and the rock as two different materials with rough or jointed interfaces between them. Further, this simulation allows for creep of the rock before lining installation, and creep of the rock and concrete lining after its construction for appropriate rock and concrete constitutive relationships. The full simulation procedure (excavation, creep and lining) was used to study an actual tunnel constructed in squeezing rock. There is reasonable agreement between the predicted performance and measured performance to date, and this comparison with monitored field information is continuing.</p> / Master of Engineering (ME)

<p>An experimental programme was carried out involving both plane strain and triaxial compression tests on a dry sand. A comparison between both methods is presented to show the influence of the intermediate principal stress on the angle of shearing resistance of failure, the shear characteristics and the failure criterion. The Mohr-Coulomb theory was used as a failure criterion. The angle of shearing resistance at failure in plane strain tests was higher than in triaxial tests. Shear strength values at failure were higher in plane strain tests than in triaxial tests. All stress-strain curves in both plane strain and triaxial test have a similar shape.</p> / Master of Engineering (ME)