Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1925. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed October 9, 2009)

Thesis (M.S.)--Oregon State University, 1981. / Typescript (photocopy). Includes bibliographical references (leaves 87-90). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1988. / Typescript (photocopy). Includes bibliographical references (leaves 63-65). Also available on the World Wide Web.

Wood crossarms provide an efficient economical, structural, and sustainable solution to the distribution and transmission of electric utilities. The majority of these crossarms are made from two species of wood, Douglasir (Pseudotsuga menziesii) and southern pine (Pinus spp.). In this study 210 solid-sawn wood crossarms (120 pieces of Douglasir/ 90 pieces of southern pine) were evaluated with non-destructive (NDTs) and destructive testing to determine if NDT could be used to predict crossarm performance. Three NDTs were conducted. Subsequently, destructive testing in which each specimen was broken in accordance to ASTM D-198 for modulus of elasticity (MOE) and modulus of rupture (MOR) was performed. After testing each specimen the non-destructive data was compared to the destructive testing results by mean comparisons and correlations. In this study it was found that the E-computer (NDT) produced the strongest correlation in both species to destructive values, especially MOE.

No description available.

Wood is one of the oldest and most common material used in construction. Since the beginning of the electrification in Canada in late 19th-century, wood poles have been widely used to provide structural support to electric transmission and distribution lines. For example, electrical network in Ontario has over 2 millions distribution poles across the province. Wood poles are typically exposed to severe environmental conditions, which cause deterioration due to wood rotting, insect attack, and weathering. The wood deterioration resulting in loss of strength can compromise the structural integrity of poles. Typical life expectancy of wood varies from 35 to 50 years depending on the environmental condition and type of wood. Electrical distribution infrastructure in Canada is aging. For example, the average age of in-service wood poles in Ontario is estimated to be 29 years with a standard deviation of 15 years. About 300,000 wood poles have been in-service for more than 45 years, which are rapidly reaching to end of expected service life. Different types of non-destructive testing (NDT) methods have been historically used for the condition assessment of wood poles. However, current methods are based on simple concepts that do not consider the variations of wave velocity and wave attenuation in an orthotropic material. The goal of this research investigation is to develop an advanced and reliable NDT technique for in-situ inspection and assessment of wood poles in order to remove unsafe poles from service, extend the service life of sound poles, and support optimum replacement strategies for the renewal of wood pole infrastructure. The thesis presents a new methodology for condition assessment of wood poles using ultrasonic testing based on theoretical, numerical, and experimental studies. The research covers areas such as signal processing, dynamic characterization, statistical reliability analysis, numerical simulations, and laboratory testing. Wood is modeled as a cylindrical orthotropic material with uncertainties in its elastic and mechanical properties. The arrival time of compressional waves as well as full-waveform analysis are used for an integrated evaluation of wood pole. A simplified model of P-wave propagation in pole cross-sections is developed; which allows to (a) estimate the elastic moduli in the radial and tangential directions by solving the inverse problem, and (b) compute the probability density function of P-wave velocity. Both of these parameters are critical for condition assessment; however, they are not available in the literature because of the complexities associated with modelling wood as an orthotropic material. A new specialized software is developed for (a) general signal processing, (b) non-destructive condition assessment of wood poles, and (c) management of a statistical database for the assessment of wood poles. Based on the proposed methodology, a new clamping device is designed and built for the ultrasonic testing of wood poles in the field. The basic background for signal processing covering Fourier analysis, frequency response and impulse response functions, and the complex exponential method for dynamic system identification is reviewed and summarized. The elastic and mechanical properties for most common species of wood used as poles are summarized from the literature, including the main statistical distributions used for their probabilistic characterization. The calibration and basic assumptions for the simulation of wave propagation in orthotropic media using finite element analysis are explained in detail. Numerical modelling is based on finite element method under plain strain condition. The numerical model is calibrated using theoretical results and validated using experimental results from laboratory testing of a new red pine pole. After calibrating the model, numerical simulations were performed to understand ultrasonic wave propagation in cross-sections of sound and decayed wood poles sections. Results of numerical simulations of ultrasonic wave propagation in pole cross-sections are presented. The effect of a void in the cross section on the ultrasonic measurement is discussed. A sample of 8 wood pole cross-sections were subjected to laboratory ultrasonic tests. In the testing, a transmitter was placed at four positions around the pole circumference. For each transmitter position, five receivers were used. The transmitter-receiver system was calibrated to evaluate its transfer function and thus eliminate the inherent characteristics of the transmitter-receiver system from the actual measurements. The experimental results of the condition assessment of new and decayed pole samples are presented in the thesis. The effect of a hole in a new pole was studied and the results were compared with the numerical analysis. A blind test is performed on an aged red pine pole. The predicted areas of decay from the ultrasonic measurements are in good agreement with the actual decay observed from dissecting the pole sections. In summary, the experimental and numerical results presented in this thesis show that the proposed methodology can be successfully applied for condition assessment of in-service wood poles in the electrical network. This method will contribute to cost-effective life cycle management of energy infrastructure as a whole.

Wood is one of the oldest and most common material used in construction. Since the beginning of the electrification in Canada in late 19th-century, wood poles have been widely used to provide structural support to electric transmission and distribution lines. For example, electrical network in Ontario has over 2 millions distribution poles across the province. Wood poles are typically exposed to severe environmental conditions, which cause deterioration due to wood rotting, insect attack, and weathering. The wood deterioration resulting in loss of strength can compromise the structural integrity of poles. Typical life expectancy of wood varies from 35 to 50 years depending on the environmental condition and type of wood. Electrical distribution infrastructure in Canada is aging. For example, the average age of in-service wood poles in Ontario is estimated to be 29 years with a standard deviation of 15 years. About 300,000 wood poles have been in-service for more than 45 years, which are rapidly reaching to end of expected service life. Different types of non-destructive testing (NDT) methods have been historically used for the condition assessment of wood poles. However, current methods are based on simple concepts that do not consider the variations of wave velocity and wave attenuation in an orthotropic material. The goal of this research investigation is to develop an advanced and reliable NDT technique for in-situ inspection and assessment of wood poles in order to remove unsafe poles from service, extend the service life of sound poles, and support optimum replacement strategies for the renewal of wood pole infrastructure. The thesis presents a new methodology for condition assessment of wood poles using ultrasonic testing based on theoretical, numerical, and experimental studies. The research covers areas such as signal processing, dynamic characterization, statistical reliability analysis, numerical simulations, and laboratory testing. Wood is modeled as a cylindrical orthotropic material with uncertainties in its elastic and mechanical properties. The arrival time of compressional waves as well as full-waveform analysis are used for an integrated evaluation of wood pole. A simplified model of P-wave propagation in pole cross-sections is developed; which allows to (a) estimate the elastic moduli in the radial and tangential directions by solving the inverse problem, and (b) compute the probability density function of P-wave velocity. Both of these parameters are critical for condition assessment; however, they are not available in the literature because of the complexities associated with modelling wood as an orthotropic material. A new specialized software is developed for (a) general signal processing, (b) non-destructive condition assessment of wood poles, and (c) management of a statistical database for the assessment of wood poles. Based on the proposed methodology, a new clamping device is designed and built for the ultrasonic testing of wood poles in the field. The basic background for signal processing covering Fourier analysis, frequency response and impulse response functions, and the complex exponential method for dynamic system identification is reviewed and summarized. The elastic and mechanical properties for most common species of wood used as poles are summarized from the literature, including the main statistical distributions used for their probabilistic characterization. The calibration and basic assumptions for the simulation of wave propagation in orthotropic media using finite element analysis are explained in detail. Numerical modelling is based on finite element method under plain strain condition. The numerical model is calibrated using theoretical results and validated using experimental results from laboratory testing of a new red pine pole. After calibrating the model, numerical simulations were performed to understand ultrasonic wave propagation in cross-sections of sound and decayed wood poles sections. Results of numerical simulations of ultrasonic wave propagation in pole cross-sections are presented. The effect of a void in the cross section on the ultrasonic measurement is discussed. A sample of 8 wood pole cross-sections were subjected to laboratory ultrasonic tests. In the testing, a transmitter was placed at four positions around the pole circumference. For each transmitter position, five receivers were used. The transmitter-receiver system was calibrated to evaluate its transfer function and thus eliminate the inherent characteristics of the transmitter-receiver system from the actual measurements. The experimental results of the condition assessment of new and decayed pole samples are presented in the thesis. The effect of a hole in a new pole was studied and the results were compared with the numerical analysis. A blind test is performed on an aged red pine pole. The predicted areas of decay from the ultrasonic measurements are in good agreement with the actual decay observed from dissecting the pole sections. In summary, the experimental and numerical results presented in this thesis show that the proposed methodology can be successfully applied for condition assessment of in-service wood poles in the electrical network. This method will contribute to cost-effective life cycle management of energy infrastructure as a whole.

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 28, 2007) Vita. Includes bibliographical references.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Wood poles are popular and widely used in the Power Supply Industries in all over the world because of their high strength per unit weight, low installation and maintenance costs and excellent durability. Reliability of these components depends on a complex combination of age, usage, component durability, inspection, maintenance actions and environmental factors influencing decay and failure of components. Breakdown or failure of any one or more of these components can lead to outage and cause a huge loss to any organisation. Therefore, it is extremely important to predict the next failure to prevent it or reduce its effect by appropriate maintenance and contingency plans. In Australia, more than 5.3 million wooden poles are in use. This represents an investment of around AU$ 12 billion with a replacement cost varying between AU$1500-2500 per pole. Well-planned inspection and maintenance strategies considering the effect of environmental and human factors can extend the reliability and safety of these components. Maintenance and sophisticated inspection is worthwhile if the additional costs are less than the savings from the reduced cost of failures. Objectives of this research are to: * Investigate decay patterns of timber components based on age and environmental factors (e.g. clay composition) for power supply wood pole in the Queensland region. * Develop models for optimizing inspection schedules and Maintenance plans. Deterioration of wood poles in Queensland is found mostly due to inground soil condition. It is found that the moisture content, pH value (Acidity/ alkalinity), bulk density, salinity and electrical conductivity have influence over the deterioration process. Presence of Kaolin or Quartz has some indirect effect on the degradation process. It allows more water to be trapped inside the soil that cause algae, moss and mould to grow and attack the wood poles. On the other hand, by virtue of permeability, soils with high quartz content allows more water to infiltrate, preventing the growth of micro-organism. This research has increased fundamental understanding of inground wood decay process, developed testing methods for soil factors and proposed integrated models for performance improvement through optimal inspection, repair and replacement strategies considering durability, environmental and human factors in maintenance decisions. A computer program is also developed to analyse "what if" scenario for managerial decisions. This research has enhanced knowledge on the wood decay process in diverse environmental conditions. The outcomes of this research are important, not only to users of timber components with ingrond decay but also to the wood industry in general (the housing sector, railways for wooden sleepers and other structural applications such as timber bridges). Three refereed conference papers have already come out of this research and two more papers for refereed journal publication are in the process. This research can be extended to develop models for: * Qualitative as well as quantitative research database on lab/field wood decay process; * Assessment of the residual life of timber infrastructure; * Optimal condition monitoring and maintenance plans for timber components showing inground decay; And * Cost effective decisions for prevention of timber components and mitigation. Findings of this research can be applied to other equipment or assets showing time dependent failure rate and can be extended further to consider age/usage replacement policies, downtime and liability costs.