Technical University of Nova Scotia Theses
Permanent URI for this collectionhttps://hdl.handle.net/10222/80530
This collection includes theses from the Technical University of Nova Scotia (TUNS) (1978-1997) and the original Nova Scotia Technical College (NSTC) (1907-1977). In 1997 TUNS amalgamated with Dalhousie University, temporarily becoming DalTech, a separate college within Dalhousie.
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Item Open Access The ferromagnetic phase in Silmanal and related alloys(Nova Scotia Technical College, 1969) Kazi, Hamiduzzaman Akram.; Doctor of Philosophy; Department of Metallurgical EngineeringItem Open Access STRENGTH OF BUILT-UP TIMBER COLUMNS(Nova Scotia Technical College. Dept. of Civil Engineering., 1976) VAN DYER, DAVID BIR; Doctor of Philosophy; Department of Civil Engineering; Malhotra, S. K.At the present only a limited amount of information is provided by various timber codes and specifications for the design of built-up timber columns. Very little information is provided for designing layered timber columns and no information is given for braced columns. The design method provided for spaced columns is based on empirical tests and formulas. The objective of the present investigation is to develop a rational procedure for the analysis and design of mechanically connected built-up timber columns including layered, braced and spaced columns. The theory developed takes into account the effect of interlayer slip and is applicable to columns failing in the elastic as well as inelastic ranges of stress. The test material is Construction Grade No. 1 .Eastern Spruce lumber. Connector types used are common wire nails, steel bolts and split ring connectors. The philosophy and the procedure presented herein are applicable to other species of wood as well. The investigation is conducted in three phases. The primary aim of phase one is a general theory for predicting the load-slip behaviour of timber joints subjected to interlayer slip. Some 250 connections fabricated from three to seven members and fastened with various types of connectors are tested. Good agreement is observed between the theory and the experimental results; the overall average difference between the two is about five percent. In addition, 2,130 compression tests are conducted to evaluate physical, strength and elastic properties of the test materials. Phase two provides a general theory, incorporating the results of phase one, for predicting the buckling stresses of built-up timber columns. To verify the theory, a comprehensive test program is conducted on some 400 columns, including layered, braced and spaced columns of various dimensions built up from two to seven members and covering the range of slenderness ratio values from thirty-four to one hundred and fifty. The cross-sections investigated have one or two axes of symmetry. Statistical techniques are applied to analyse the test data. Good agreement is observed between the theoretical predictions and the experimental results. The overall average difference observed between the predictions and the experimental results is about six and one-half percent. Incorporating the results of phases one and two in phase three, a rational procedure, using dimensionless coefficients called 'Buckling Coefficients', is developed for the de s ign of built-up timber columns. This design method is simple to apply and is applicable to elastic as well as inelastic columns.Item Open Access Ultimate bending strength of timber beams(1980) Bazan, Ibrahim M. Mahdy; Doctor of Philosophy; Malhotra, S.K.The current design method of calculating bending strength of timber beams is based on elastic theory, that is, on working stress approach. The elastic theory does not hold true beyond the proportional limit of stress and thus does not describe the actual behavior of timber beams in the inelastic range up to failure. The broad objective of this study is to develop a rational approach of evaluating the ultimate bending strength of timber beams. The scope of the research is to cover various sizes of clear beams and of beams with strength reducing characteristics such as knots. An ultimate bending strength theory for timber beams is developed. The theory predicts the ultimate moment capacity of the beam using compressive and tensile strength values of the beam material obtained from direct tests on small clear specimens. A comprehensive experi mental program is carried out to verify the theory. Tests were conducted on some two hurdred and fifty-five (255) eastern spruce and Douglas-fir beams. Beams of five different sizes were subjected to central and third-point loading. Good agreement is observed between the theory and experimental results. Tests were also performed on some one thousand and nine hundred (1900) small specimens matched with the beams to determine direct compressive and tensile strengths of the test material. The ultimate tensile strength of the test material is observed tQ be two to three times the ultimate compressive strength. The actual behavior of the test beams is investigated by measuring strain at various levels along the beam depth. A linear variation of the strain distributi.on is observed along the depth for all stages of loading up to failure. It is observed that, at the proportional limit in bending as obtained from the load-deflection curve, the neutral axis is aporoximately at the center of beam depth. Beyond the proportional limit, the neutral axis shifted gradually towards the tension side, and at ultimate load, the movement of the neutral axis ranged between five to fifteen percent of the beam depth. The proporti ona 1 1 imit 5.;tress in bending is not si gni fi cantly affected by the depth of the beam. For beams subjected to third-point loading, this stress is equal to the ultimate compressive strength of the beam material obtained from direct tests . But for centrally loaded beams, the proportional limit stress in bending is about eleven percent greater than the corresponding value for similar beams loaded at third-span points . The maximum tensile stress developed at the extreme fiber of a beam at failure is statistically less than the ultimate strength in direct tension obtained from tests on small size standard soecimens. The actual value is dependent on the depth of the beam and is smaller as the depth is increased. The effect of method of loading of the beam on maximum tensile stress at failure is found to be the same as the effect on the prooortional limit-stress. The difference between both methods of loading is about eleven percent. An empirical fonnula relatinq the maximum tensile stress at failure in a beam to its size is derived . It is observed that the presence of knots influenced the type of failure of the beam. Beams containing small knots failed in a compressiontension sequence, while beams with relatively large knots near the edge of the tension zone failed in tension without any compression failare. The 1 oad-defl ecti on and 1 oad strain curves of the beams with 1 a rge knots xxvii indicated that the flexural behavior of these beams is elastic up to fa i lure . To account for the weakeninq effect of knots on compressive ·and tensile strengths in a beam, correlation equations between the strength and size and location of knots, are obtained. The concept presented in this thesis has the advantage that the ultimate moment capacity of a given timber beam for both elastic and inelastic behaviors, could be predicted from two known mechanical oroperties of the beam material, and it is simple to apply .~Item Open Access Your Body is a Battleground: Queering the Halifax Citadel(1997) Nycum, Benjamin