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Collision on a Pole Found in Soil
Published in Arnold C.Y. Yong, Nelson T.K. Lam, Scott J. Menegon, Collision Actions on Structures, 2023
Arnold C.Y. Yong, Nelson T.K. Lam, Scott J. Menegon
A pole can be secured to the ground by having it embedded into soil, or by casting the pole into a concrete base slab forming a pole-slab assemblage that is then placed in a shallow pit. The mechanism of the two types of poles in withstanding a collision is very different. With a soil-embedded pole, the design approach is to treat the pole as a flexible element that responds to a collision action mainly by flexure. A compact section can be chosen in order to safeguard against premature failure by local buckling, or by shear. Guidelines in relation to the required depth of embedment of the pole into the subgrade have been provided. With a free-standing pole-slab assemblage, the stability to resist overturning is by virtue of the self-weight of the concrete slab. With both design approaches, algebraic expressions for predicting the maximum displacement and slope of deflection of the pole for a given collision scenario have been presented. Both design methodologies are illustrated with worked examples.
Cost-of-Service Methodology
Published in J. Lawrence, P.E. Vogt, Electricity Pricing, 2017
Poles of various heights and classes are used to support overhead conductors, transformers, and other distribution equipment. As discussed previously, conductors create a voltage path to customers; thus, a major function of the poles is to support the voltage path. The placement of poles is based on the geographical dispersion of customers. While distribution poles are spaced generally a few hundred feet apart along an express corridor, poles are also placed typically at customer lot lines so that a service line of a customer does not cross over the property of an adjacent customer. Thus, more poles are required to reach customers in rural settings due to long distances (low customer density), but more poles are also needed in higher density urban and suburban settings.
Poles, Cross Arms, Pins, Racks, and Insulators
Published in Anthony J. Pansini, Electrical Distribution Engineering, 2020
The life of wood poles, under “normal” conditions of soil and weather, when they are treated and maintained with reasonably effective preservatives, has been estimated to be from 25 years to over 100 years. These figures have been used in making economic studies, in establishing sinking funds for the retirement of poles (and other wood structures), and in designing pole lines calling for considerably larger and stronger poles than initially necessary. In view of the continuing changes in consumer requirements, in civic and traffic requirements, and in the materials and methods employed in providing electric service, the higher longevity considerations (100 years, or even 50 years) appear to be somewhat unrealistic.
A study on operating lifetime estimation for electrical components in power grids on the basis of analysis of maintenance records
Published in Journal of International Council on Electrical Engineering, 2019
Ryuhei Shiomi, Hironobu Shimasaki, Hirotaka Takano, Hisao Taoka
These states mean that the target component cannot keep its stable operation. Figure 1 shows distribution of the operating lifetime for the concrete electric poles in the target record. In Figure 1, the authors remove cases that have shorter operating lifetime than 20 years as irregular cases. This is because cases of accidental repair or replacement are included in the maintenance record without any additional information (available in the other record). As shown in Figure 1, the average lifetime of the electric poles is set by 40.8 years, and it uses as the base value of the former estimation. This result almost matches with our knowledge and experience which regards their lifetime as 30–40 years [7].
A review on condition assessment technologies for power distribution network infrastructure
Published in Structure and Infrastructure Engineering, 2023
Sahan Bandara, Pathmanathan Rajeev, Emad Gad
Utility poles are used in power distribution networks to support overhead cables and other attachments. Similar to cross-arms, predominant source of utility poles are wood. However, alternate materials such as steel, concrete, and composites are also being used. Typical service life of a hardwood or softwood timber utility pole is around 40–60 years. Evaluation of the structural integrity of poles is essential thorough out the service life in order to identify potential defects and to estimate the residual strength. A wide range of condition assessment techniques are employed by asset managers for the routine inspection of in-service poles. Figure 4 shows the categorisation of these condition assessment techniques.
Seismic performance evaluation of existing light poles on elevated highway bridges
Published in Structure and Infrastructure Engineering, 2021
Dionysius M. Siringoringo, Yozo Fujino, Ayami Nagasaki, Takuro Matsubara
Poles carrying mast for lighting, traffic signs or transmission lines are important elements to provide improved safety, security, and aesthetics for highway users and associated facilities. Most of these poles are designed as free-standing cantilevers with limited or almost no redundancy in the structural system. They are flexible and can vibrate easily during strong wind or earthquake. Light and sign poles mounted on the elevated highway bridge may be subjected to even more severe problem because as a secondary structural system, the vibration is directly influenced by bridge vibration in addition to external excitation source.