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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effect of Woodpecker Damage and Wood Decay on Wood Utility Pole Strength

Steenhof, Mark January 2011 (has links)
In many regions of North America, Europe, and Australia, wood utility poles are used as main and secondary structural members for the support of electrical distribution and transmission lines. In the province of Ontario alone there are over 40000 H-frame, 6000 Gulfport, and thousands of single pole structures constructed of over 2 million wood utility poles (Pandey et al. 2010b). Currently, utility companies report an increasing number of woodpecker damage incidents on in-service utility poles (HONI 2010). In addition, many aging poles have woodpecker damage in combination with wood decay. Both these forms of degradation cause strength reductions in utility poles, making their structural integrity questionable. This has raised concerns regarding the safety of utility maintenance workers and the public, and the dependability of the electrical network. In response to these concerns, Hydro One Networks Incorporated (HONI) initiated a research project on the effect of woodpecker damage and wood decay on wood utility pole strength. The objective of the research was to develop methods of quantifying the strength reduction caused by woodpecker damage and wood decay. This information was then used to develop in-service assessment methods for determination of whether pole replacement is necessary when specific levels of woodpecker damage and wood decay are present. By developing better assessment methods, in-service utility poles will not be unnecessarily replaced, reducing maintenance costs. In this study, three analytical models were developed that predicted the theoretical cross-sectional strength reduction caused by the presence of woodpecker damage. A bending failure model was developed since, in the structural design of utility poles, bending moment stresses are known to be the critical design parameter. It was decided that the significance of shear stress in a cross-section should also be considered since the presence of woodpecker damage could cause shear stresses to be a significant parameter. As a result, a shear-bending and a shear failure model was developed to determine the significance of shear stress on cross-section behaviour. These models were developed for analysis purposes and were verified by the subsequent experimental program. A total of 28 new and in-service utility poles were received from HONI for experimental testing. The new poles were received in as-new condition, while the in-service poles received had varying levels of woodpecker damage and wood decay. The poles received were cut into 4.25 m lengths for beam testing. A single new pole and in-service specimen from each pole was tested as a control specimen without woodpecker damage to obtain reference utility pole bending strengths. The remainder of the new pole specimens were mechanically introduced with woodpecker damage, while the remainder of the in-service specimens were tested with natural woodpecker damage. The tested specimens were analyzed and the results were compared with the woodpecker damage analytical model predictions. Results indicated that the effect of woodpecker damage is well modelled by the woodpecker damage analytical models. Overall, the bending failure analytical model was preferable for cross-section analysis due to the accuracy of the model predictions and the simplicity of required calculations. It was evident from the experimental program that the presence of woodpecker damage can severely reduce the strength of utility poles, making replacement necessary according to CSA C22.3 No. 1 Cl. 8.3.1.3 (2006a). In-service specimen experimental results indicated that if wood decay is detected in wood utility poles, severe reduction in wood strength has occurred and the utility pole should be replaced. Analytical and experimental results were used to develop three application methods for determining whether utility pole replacement is necessary due to the presence of woodpecker damage. These three methods include the simplified method, the chart method, and the case-specific method. The simplified method allows determination of whether a utility pole should be replaced based only on knowledge of the most severe level of woodpecker damage present in a pole. The chart method takes into account additional factors such as the diameter of the pole at the location of the woodpecker damage and the width of the hole opening. The case-specific method is advantageous since it accounts for the parameters used in the chart method and allows the location of woodpecker damage along the length of a pole to be accounted for. The simplified and chart methods are preferable since they are relatively simple and easy to implement in the field. The case-specific method requires a full structural analysis of the utility pole in question to be undertaken and is useful for more accurately assessing whether replacement is necessary. These three methods show how the research completed can be used for improved assessment of in-service utility poles resulting in reduced unnecessary pole replacement and maintenance costs.
2

Effect of Woodpecker Damage and Wood Decay on Wood Utility Pole Strength

Steenhof, Mark January 2011 (has links)
In many regions of North America, Europe, and Australia, wood utility poles are used as main and secondary structural members for the support of electrical distribution and transmission lines. In the province of Ontario alone there are over 40000 H-frame, 6000 Gulfport, and thousands of single pole structures constructed of over 2 million wood utility poles (Pandey et al. 2010b). Currently, utility companies report an increasing number of woodpecker damage incidents on in-service utility poles (HONI 2010). In addition, many aging poles have woodpecker damage in combination with wood decay. Both these forms of degradation cause strength reductions in utility poles, making their structural integrity questionable. This has raised concerns regarding the safety of utility maintenance workers and the public, and the dependability of the electrical network. In response to these concerns, Hydro One Networks Incorporated (HONI) initiated a research project on the effect of woodpecker damage and wood decay on wood utility pole strength. The objective of the research was to develop methods of quantifying the strength reduction caused by woodpecker damage and wood decay. This information was then used to develop in-service assessment methods for determination of whether pole replacement is necessary when specific levels of woodpecker damage and wood decay are present. By developing better assessment methods, in-service utility poles will not be unnecessarily replaced, reducing maintenance costs. In this study, three analytical models were developed that predicted the theoretical cross-sectional strength reduction caused by the presence of woodpecker damage. A bending failure model was developed since, in the structural design of utility poles, bending moment stresses are known to be the critical design parameter. It was decided that the significance of shear stress in a cross-section should also be considered since the presence of woodpecker damage could cause shear stresses to be a significant parameter. As a result, a shear-bending and a shear failure model was developed to determine the significance of shear stress on cross-section behaviour. These models were developed for analysis purposes and were verified by the subsequent experimental program. A total of 28 new and in-service utility poles were received from HONI for experimental testing. The new poles were received in as-new condition, while the in-service poles received had varying levels of woodpecker damage and wood decay. The poles received were cut into 4.25 m lengths for beam testing. A single new pole and in-service specimen from each pole was tested as a control specimen without woodpecker damage to obtain reference utility pole bending strengths. The remainder of the new pole specimens were mechanically introduced with woodpecker damage, while the remainder of the in-service specimens were tested with natural woodpecker damage. The tested specimens were analyzed and the results were compared with the woodpecker damage analytical model predictions. Results indicated that the effect of woodpecker damage is well modelled by the woodpecker damage analytical models. Overall, the bending failure analytical model was preferable for cross-section analysis due to the accuracy of the model predictions and the simplicity of required calculations. It was evident from the experimental program that the presence of woodpecker damage can severely reduce the strength of utility poles, making replacement necessary according to CSA C22.3 No. 1 Cl. 8.3.1.3 (2006a). In-service specimen experimental results indicated that if wood decay is detected in wood utility poles, severe reduction in wood strength has occurred and the utility pole should be replaced. Analytical and experimental results were used to develop three application methods for determining whether utility pole replacement is necessary due to the presence of woodpecker damage. These three methods include the simplified method, the chart method, and the case-specific method. The simplified method allows determination of whether a utility pole should be replaced based only on knowledge of the most severe level of woodpecker damage present in a pole. The chart method takes into account additional factors such as the diameter of the pole at the location of the woodpecker damage and the width of the hole opening. The case-specific method is advantageous since it accounts for the parameters used in the chart method and allows the location of woodpecker damage along the length of a pole to be accounted for. The simplified and chart methods are preferable since they are relatively simple and easy to implement in the field. The case-specific method requires a full structural analysis of the utility pole in question to be undertaken and is useful for more accurately assessing whether replacement is necessary. These three methods show how the research completed can be used for improved assessment of in-service utility poles resulting in reduced unnecessary pole replacement and maintenance costs.
3

Characterization Of Impact Damage And Fiber Reinforced Polymer Repair Systems For Metallic Utility Poles

Johnson, Cara 01 January 2013 (has links)
Previous studies have demonstrated that the behavior of fiber reinforced polymers (FRPs) bonded to metallic utility poles are governed by the following failure modes; yielding of the metallic substrate, FRP tensile rupture, FRP compressive buckling, and debonding of FRP from the substrate. Therefore, an in situ method can be devised for the repair of utility poles, light poles, and mast arms that returns the poles to their original service strength. This thesis investigates the effect of damage due to vehicular impact on metallic poles, and the effectiveness of externally-bonded FRP repair systems in restoring their capacity. Damage is simulated experimentally by rapid, localized load application to pole sections, creating dents ranging in depth from 5 to 45% of the outer diameter. Four FRP composite repair systems were selected for characterization and investigation due to their mechanical properties, ability to balance the system failure modes, and installation effectiveness. Bending tests are conducted on dented utility poles, both unrepaired and repaired. Nonlinear finite element models of dented and repaired pole bending behavior are developed in MSC.Marc. These models show good agreement with experimental results, and can be used to predict behavior of full-scale repair system. A relationship between dent depth and reduced pole capacity is developed, and FRP repair system recommendations are presented
4

Evaluation of Roadside Collisions with Utility Poles and Trees at Intersection Locations

Mattox, Todd Berry 15 November 2007 (has links)
The United States averages 40,000 traffic fatalities annually. The American Association of State Highway and Transportation Officials (AASHTO) Roadside Design Guide cites run-off-the-road crashes as contributing greatly to this statistic, with about one-third of all traffic deaths [1]. This number has remained relatively constant over the past four decades, and despite a major increase in vehicle miles traveled (VMT), the rate of fatalities per 100 million vehicle miles traveled has declined. However, this relatively large number of run-off-the-road crashes should remain a major concern in all roadway design. The Highway Safety Act of 1966 marks a defining moment in the history of roadside safety [ ]. Before this point, roadways were only designed for motorists who remained on the roadway, with no regard for driver error. As there was no legislation or guidelines concerning roadside design, roadways constructed prior to 1966 are littered with fixed objects directly off of the edge of pavement. Fortunately, many of these roads have reached their thirty year design lives and have become candidates for improvement. The following report examines roadside crashes on nine Atlanta urban arterial roadways. Accident type, severity, and location for all crashes on these were evaluated. It is found roadside collisions with utility poles and trees were more prone to occur at intersection locations than midblock locations. Also for the studied roadway corridors, on average, roadside collisions were more likely to result in serious injury or fatality. Based on these findings initial recommendations are offer for improving clear zone requirements.
5

Failure Analysis Of Impact-damaged Metallic Poles Repaired With Fiber Reinforced Polymer Composites

Slade, Robert Arthur 01 January 2012 (has links)
Metallic utility poles, light poles, and mast arms are intermittently damaged by vehicle collision. In many cases the vehicular impact does not cause immediate failure of the structure, but induces localized damage that may result in failure under extreme service loadings or can promote degradation and corrosion within the damaged region. Replacement of these poles is costly and often involves prolonged lane closures, service interruption, and temporary loss of functionality. Therefore, an in situ repair of these structures is required. This thesis examines the failure modes of damaged metallic poles reinforced with externally-bonded fiber reinforced polymer (FRP) composites. Several FRP repair systems were selected for comparison, and a set of medium and full-scale tests were conducted to identify the critical failure modes. The material properties of each component of the repair were experimentally determined, and then combined into a numerical model capable of predicting global response. Four possible failure modes are discussed: yielding of the unreinforced substrate, tensile rupture of the FRP, compressive buckling of the FRP, and debonding of the FRP from the substrate. It was found that simple linear, bilinear, and trilinear stress-strain relationships accurately describe the response of the composite and substrate components, whereas a more complex bond-slip relationship is required to characterize debonding. These constitutive properties were then incorporated into MSC.Marc, a versatile nonlinear finite element program. The output of the FEM analysis showed good agreement with the results of the experimental bond-slip tests.
6

Le poteau d’utilité publique, icône d’un autre siècle?

Turcotte, Yolaine 11 1900 (has links)
Le réseau de distribution aérien, ou plus simplement le réseau de poteaux de bois et ses câbles, est encore aujourd’hui omniprésent dans la majorité des villes du Québec. Pour plusieurs, le réseau de poteaux d’utilité publique semble appartenir à une autre époque. Pourtant, les poteaux et câbles ne sont pas près de disparaître, au contraire, ils ne cessent de se transformer. Depuis peu, de plus en plus d’équipements s’ajoutent sur le réseau: boîtiers techniques, nombre de câbles, appareillages au sommet des poteaux, antennes de communication, etc. Bien que les équipements du réseau de distribution aérien soient des éléments produits industriellement, ceux-ci intègrent rarement les services du design industriel au moment de leur conception initiale. Cette recherche étudie le système de distribution aérien sous l’angle de la « pensée design ». L’intention de cette étude est d’analyser les impacts de la présence du réseau aérien en milieux urbains et a pour objectif d’orienter les pratiques de conception de ce type d’équipements. Pour ce faire, dans une optique transdisciplinaire, diverses approches ont été sollicitées dont: l’approche systémique, l’approche paysage et les approches des partenaires des réseaux. Au moyen d’une recherche documentaire et d’observations faites sur le terrain, la recherche vise à dresser un portrait général du réseau de distribution aérien et les défis qui y sont associés. La recherche expose, dans un état des lieux, les résultats issus des questions analytiques de recherche suivantes: de quoi est composé le réseau de distribution aérien, quels sont les intervenants sur le réseau, quelles sont leurs interactions, quels sont les points de vue des différentes catégories d’acteurs en relation avec le réseau, quels sont les impacts reliés à la présence du réseau en milieux urbains et quelle a été son évolution au fil des années. Dans la perspective de l’approche design, chercher à comprendre une problématique de façon plus large permet de s’assurer que l’on répond au bon problème, que l’on considère tous les facteurs en cause visant ainsi à réduire les répercussions négatives sur les contextes de vie actuels et futurs. Les principaux constats de cette recherche démontrent que la composition du réseau de distribution, avant même de considérer les nouveaux usages et l’ajout de nouveaux équipements, présente des lacunes importantes. La gestion entre les divers partenaires du réseau de distribution pose aussi problème. L’ajout de nouveaux équipements sur le réseau, combiné aux multiples équipements apparaissant sur les voies publiques laisse entrevoir l’atteinte d’un niveau de saturation des milieux urbains. Les façons de faire hermétiques et «cristallisées» des partenaires du réseau ne collent pas avec les initiatives et aspirations générales en matière d’aménagement. En étudiant la problématique du réseau de distribution par le biais de la pensée design, l’approche design cherche à déceler, de façon proactive, les opportunités de design qui permettront de mieux gérer l’apparition et l’intégration des nouveaux équipements sur les poteaux. Cette démarche permet d’envisager des solutions qui visent à limiter les répercussions collatérales une fois en contexte et qui, du même coup, adressent des problématiques connexes. Finalement, à la lumière de l’état des lieux, cette recherche propose des critères de conception de futurs réseaux de distribution, élaborés dans l’esprit de l’approche design. / The aerial distribution network, also known as the utility network, comprised of wooden poles and its cables, is still omnipresent in the majority of Québec’s cities. Although many perceive the public utility poles as belonging to another era, they are not ready to disappear; quite the opposite, they don’t cease to evolve. Recently, more and more pieces of equipment have been added to the network: technical contraptions, additional cables, apparatuses mounted on the summit, antennas for wireless communication, etc. Although these devices are industrially produced, the service of industrial designers has been rarely solicited during their initial conception. This research examines the aerial distribution system from a design prospective, an angle of the « new » design approach also called design thinking. The intent of this study is to analyze the impact of the aerial distribution network on the urban environment with the goal of better guiding future design practices of such infrastructures. In order to do so with a transdisciplinary mind-set, several approaches have been solicited: the systemic approach, the landscape approach and the approach of system partnership. Through literature search and field observation the research intends to obtain a holistic view of the aerial distribution network and its challenges. Through inventory, the research exposes the results of our analytical questioning: what does the aerial distribution network consist of, who intervenes with and within the network, what are their interactions, what are the viewpoints of the different categories of actors with regards to the network, how does the presence of the network impact the urban landscape and how has it evolved over the years. From a design perspective, seeking to understand an overall problem situation helps to insure that the right problems are being addressed, that all contributing aspects are being taken into account and thus diminishing negative repercussions on the current and future contextual situations. The main findings of this research show that the current composition of the distribution network has significant shortcomings, even without taking into consideration the newly added services, uses and equipment. Management among service providers using the network is also facing challenges. The add-on of devices combined with all other equipment that gradually appear on public streets allow us to anticipate a level of saturation within the urban landscape. The hermetic and « crystallized » practices of the service providers that share the network are neither in line with the initiatives nor with the general aspirations when it comes to urban planning. Studying the problem situation of the distribution network using a design approach allows us to proactively isolate design opportunities that aim for the improvement of the existing situation, with regards to the newly appearing equipment on the poles. This approach encourages solutions that limit collateral repercussions once in its contextual environment and addresses at the same time other problem areas. Finally, the analysis of the research results allows us to enumerate a series of guidelines for the design of a future distribution network, which have been elaborated from a design perspective.
7

Le poteau d’utilité publique, icône d’un autre siècle?

Turcotte, Yolaine 11 1900 (has links)
Le réseau de distribution aérien, ou plus simplement le réseau de poteaux de bois et ses câbles, est encore aujourd’hui omniprésent dans la majorité des villes du Québec. Pour plusieurs, le réseau de poteaux d’utilité publique semble appartenir à une autre époque. Pourtant, les poteaux et câbles ne sont pas près de disparaître, au contraire, ils ne cessent de se transformer. Depuis peu, de plus en plus d’équipements s’ajoutent sur le réseau: boîtiers techniques, nombre de câbles, appareillages au sommet des poteaux, antennes de communication, etc. Bien que les équipements du réseau de distribution aérien soient des éléments produits industriellement, ceux-ci intègrent rarement les services du design industriel au moment de leur conception initiale. Cette recherche étudie le système de distribution aérien sous l’angle de la « pensée design ». L’intention de cette étude est d’analyser les impacts de la présence du réseau aérien en milieux urbains et a pour objectif d’orienter les pratiques de conception de ce type d’équipements. Pour ce faire, dans une optique transdisciplinaire, diverses approches ont été sollicitées dont: l’approche systémique, l’approche paysage et les approches des partenaires des réseaux. Au moyen d’une recherche documentaire et d’observations faites sur le terrain, la recherche vise à dresser un portrait général du réseau de distribution aérien et les défis qui y sont associés. La recherche expose, dans un état des lieux, les résultats issus des questions analytiques de recherche suivantes: de quoi est composé le réseau de distribution aérien, quels sont les intervenants sur le réseau, quelles sont leurs interactions, quels sont les points de vue des différentes catégories d’acteurs en relation avec le réseau, quels sont les impacts reliés à la présence du réseau en milieux urbains et quelle a été son évolution au fil des années. Dans la perspective de l’approche design, chercher à comprendre une problématique de façon plus large permet de s’assurer que l’on répond au bon problème, que l’on considère tous les facteurs en cause visant ainsi à réduire les répercussions négatives sur les contextes de vie actuels et futurs. Les principaux constats de cette recherche démontrent que la composition du réseau de distribution, avant même de considérer les nouveaux usages et l’ajout de nouveaux équipements, présente des lacunes importantes. La gestion entre les divers partenaires du réseau de distribution pose aussi problème. L’ajout de nouveaux équipements sur le réseau, combiné aux multiples équipements apparaissant sur les voies publiques laisse entrevoir l’atteinte d’un niveau de saturation des milieux urbains. Les façons de faire hermétiques et «cristallisées» des partenaires du réseau ne collent pas avec les initiatives et aspirations générales en matière d’aménagement. En étudiant la problématique du réseau de distribution par le biais de la pensée design, l’approche design cherche à déceler, de façon proactive, les opportunités de design qui permettront de mieux gérer l’apparition et l’intégration des nouveaux équipements sur les poteaux. Cette démarche permet d’envisager des solutions qui visent à limiter les répercussions collatérales une fois en contexte et qui, du même coup, adressent des problématiques connexes. Finalement, à la lumière de l’état des lieux, cette recherche propose des critères de conception de futurs réseaux de distribution, élaborés dans l’esprit de l’approche design. / The aerial distribution network, also known as the utility network, comprised of wooden poles and its cables, is still omnipresent in the majority of Québec’s cities. Although many perceive the public utility poles as belonging to another era, they are not ready to disappear; quite the opposite, they don’t cease to evolve. Recently, more and more pieces of equipment have been added to the network: technical contraptions, additional cables, apparatuses mounted on the summit, antennas for wireless communication, etc. Although these devices are industrially produced, the service of industrial designers has been rarely solicited during their initial conception. This research examines the aerial distribution system from a design prospective, an angle of the « new » design approach also called design thinking. The intent of this study is to analyze the impact of the aerial distribution network on the urban environment with the goal of better guiding future design practices of such infrastructures. In order to do so with a transdisciplinary mind-set, several approaches have been solicited: the systemic approach, the landscape approach and the approach of system partnership. Through literature search and field observation the research intends to obtain a holistic view of the aerial distribution network and its challenges. Through inventory, the research exposes the results of our analytical questioning: what does the aerial distribution network consist of, who intervenes with and within the network, what are their interactions, what are the viewpoints of the different categories of actors with regards to the network, how does the presence of the network impact the urban landscape and how has it evolved over the years. From a design perspective, seeking to understand an overall problem situation helps to insure that the right problems are being addressed, that all contributing aspects are being taken into account and thus diminishing negative repercussions on the current and future contextual situations. The main findings of this research show that the current composition of the distribution network has significant shortcomings, even without taking into consideration the newly added services, uses and equipment. Management among service providers using the network is also facing challenges. The add-on of devices combined with all other equipment that gradually appear on public streets allow us to anticipate a level of saturation within the urban landscape. The hermetic and « crystallized » practices of the service providers that share the network are neither in line with the initiatives nor with the general aspirations when it comes to urban planning. Studying the problem situation of the distribution network using a design approach allows us to proactively isolate design opportunities that aim for the improvement of the existing situation, with regards to the newly appearing equipment on the poles. This approach encourages solutions that limit collateral repercussions once in its contextual environment and addresses at the same time other problem areas. Finally, the analysis of the research results allows us to enumerate a series of guidelines for the design of a future distribution network, which have been elaborated from a design perspective.

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