Wood Poles Research Articles

Effect of slenderness ratio on axial compression behavior of circular wood columns strengthened with high-performance bamboo-based composites

Developing sustainable high-performance bamboo-based composites (HPBBC) with carbon sequestration benefits as reinforcement material is of great significance in promoting the application of HPBBC and securing ancient wooden buildings. Available column reinforcement methods have damage characteristics, which are unsuitable to be applied in ancient wooden columns because the ancient building needs to be preserved in the current conditions. The wooden column was bound with HPBBC and spaced steel strips to achieve damage-free strengthening. The slenderness ratio is an essential factor affecting the mechanical properties of wood poles, which is significant to be studied. The effect of the slenderness ratio on the axial compression behavior of circular wood columns strengthened with HPBBC was investigated in this study. The test results showed that the slenderness ratio significantly influences the failure mode, load-bearing capacity, and deformability of strengthened circular wood columns. The typical failure mode of short columns was a crushing failure, while the long columns were buckling failures. The load-carrying capacity and longitudinal strain of strengthened circular timber columns decrease significantly with increasing slenderness ratio. The lateral displacements or buckling appearance increases significantly with the increasing slenderness ratios of the strengthened timber column. A load-bearing capacity formula was proposed to predict the load capacity of strengthened circular wood columns based on their axial compression damage characteristics. The error between the calculated and tested results is less than 8.2 %.

Film, fotografie, feit en fictie in het Pollino-gebergte (Zuid-Italië)

Film, photography, fact and fiction in the Pollino Mountains (Southern Italy)The film “Il Buco” (The Hole, 2022) by Michelangelo Frammartino is about a speleological expedition in the Pollino mountains (northern Calabria, Italy) in 1961. It won the Special Jury Award at the 2022 Venice Film Festival and received excellent reviews in the Dutch press (Volkskrant, Trouw, NRC, VPRO Cinema). In the film, an old shepherd at the end of his life observes a group of speleologists exploring an exceptionally deep cave. The shepherd dies just as the speleologists discover the end of the cave. To situate the death scene, Frammartino reconstructed a typical shepherd’s dwelling used in the days when the transhumance summer camps in the Pollino mountains were still used as shepherds’ summer dwellings. Frammartino based the reconstruction on black-and-white pictures from the archive of Giuseppe De Matteis, a speleologist from Turin, who took part in the expedition. De Matteis took several photographs of such shepherd´s dwellings during the period of the cave exploration, especially at the site of Mandra Vecchia, which is now part of the field study area of the Pollino Archaeological Landscape Project (PALP), led by the authors since 2020. These shepherds’ huts were made of wooden poles and planks and reinforced at ground level with limestone blocks. Other pastoral facilities, such as animal pens and sheds for cheesemaking, were located nearby. Archaeological research on the remains of these summer camps, combined with interviews, is beginning to reveal everyday life in Pollino summer camps. In this paper we bring together fact and fiction based on Frammartino’s documentary from 2021, Giuseppe De Matteis´ photo archive from the 1960s and our own fieldwork in the area.

Reuse of wooden utility poles through the combination of new and old elements

Wooden utility poles are crucial in supporting overhead telecommunication lines in Portugal. Maritime pine (Pinus pinaster Aiton) is the most common wood species used for this purpose. The durability of the poles is typically determined by the deterioration observed in their ground line. Aiming to reduce the use of new sound wooden poles, reducing the economic costs involved, and the environmental impacts, the reuse of those old wooden poles by removing the degraded part is one possible solution. This study aimed to develop and validate solutions with composed poles, specifically for the connections between the wood members, so that it is possible to more efficiently incorporate used parts into the remanufactured poles. Two types of connections were used: members joined by a cylindrical steel tube, and members joined by finger joints. The static bending moduli of elastic and rupture were tested. The mechanical properties of the reused wooden utility poles showed to be in line with the values of new sound wooden poles made of different wood species. Finally, both proposed solutions proved to be practical for use in the production of reused utility poles, which are mostly made from old timber poles.

STRUCTURAL ANALYSIS OF THE ECOEARTH SANDWICH SYSTEM

The eco earth sandwich is a construction system with a CMU foundation, braced vertically with treated wood poles and horizontally with steel rods and rammed earth. A reinforced concrete crowning beam confines a steel panel envelope, developed as an alternative wall using local resources, materials, and workforce. The Con Lo Que Hay 14 (CLQH 14) workshop, which translates to “With What is Available, edition 14 workshop,” developed the eco earth sandwich for a small suburban community center in the Ecuadorian Andes, based on vernacular contained earth criteria. The model is a one-story structure in which the resistance of its conforming elements will be evaluated in a theoretical approach. Earthquake resistance: Compression and tensile stresses and cutting effects produced at the foot of the wall will be evaluated. Verifying its effectiveness as a one-story self-standing structure and the possibility of becoming bearing walls. Future studies are planned with laboratory structural stress load tests.

Rehabilitation of Wooden Utility Poles with Sprayed-GFRP Composites

Rehabilitation of Wooden Utility Poles with Sprayed-GFRP Composites

Vaiadel kuhjalava ja selle ehitamine Matsalu rahvuspargis / Constructing a haystack base in Matsalu national park

Haymaking is a traditional craft that began to fade in the second half of the 20th century. The gradual disappearance of the traditional ways of making hay was due to the rapid development of modern agricultural techniques, which made the need for older techniques obsolete. Before the advent of hay packers, hay was mainly stored in barns or haystacks. As barns became more common beginning in the early 20th century, haystacks were the most common way of preserving hay (photos 1, 3, 4). To help structure the haystack and prevent the bottom of the pile from rotting, it was first necessary to build a haystack base (photo 2). In the case of wetlands and flooded meadows, haystacks had to be built on tall wooden poles to protect them against flooding (photos 5, 6). Although some descriptions of the construction of a traditional haystack have survived in the archives, there is no written information on haystack bases built on poles. Fortunately, there are some local people who still remember such haystack structures as well as some historically valuable photographs that have survived. Based on these old photos and local people’s memories, we organised a workshop on making a haystack base in Matsalu National Park, aimed at preserving and presenting the local heritage. In this article, we will look at the haystack, and in particular at the haystack base needed to build it on. The first part of the article gives an overview of the necessity and importance of the haystack in farm and folk culture. A separate section is devoted to the construction of the haystack bed on poles. The second part of the article is an auto-ethnographic overview of a workshop on the building of a haystack base on the Kasari riverbank in the village of Kelu. Along with photographic material, the article also gives an overview of the different stages of the build and some details about the construction. Keywords: woodcrafts, haystack, haystack base, traditional agriculture, workshop

Developing a Sprayed-Glass Fiber-Reinforced Polymer Retrofitting System for Decommissioned Wooden Utility Poles

Wooden utility poles are vulnerable to degradation and decay, which requires maintenance or replacement. The strengthening and retrofitting techniques for wooden poles are either prone to corrosion or encountering installation difficulties. However, the use of sprayed fiber-reinforced polymer (FRP) composites seems to be a viable solution as it has proven its efficiency and applicability for reinforced concrete members and connections. This study includes a comprehensive experimental program where the mechanical properties of the sprayed-glass FRP (GFRP) composite was evaluated in terms of tensile, compressive and shear strength, in addition to its bond strength to wood and confinement efficiency. Afterwards, the results of the material testing phase were implemented on full-scale old utility poles to evaluate their structural performance with varying composite thicknesses and sprayed zone lengths. The behavior of the retrofitted poles reflected remarkable effectiveness for the sprayed-GFRP composite and highlighted the need for a design model for the optimum length for the sprayed zone. Two simplified analytical models were introduced which predicted the failure loads and locations for the tested poles and estimated the required length for the retrofitted zone, which all agreed well with the experimental results of the tested poles.

Тренди світового ринку чавуну та чавунних виливків в першій чверті XXI століття

The analysis of the world market of iron and iron castings in 2002-2022 is presented. During the period from 2002 to 2022, the production of iron in the world grew at an average annual rate from 5.7 to 1.3%. An increase in the domestic consumption of iron by the producing countries was noted. The main consumers of cast iron are steel and cast iron production. The volumes of production, export, import, and consumption of cast iron compared to world GDP in 2002, 2012, and 2022 are shown. The top ten producers of cast iron in 2018 and 2022 are presented. Ukraine occupies the 12th position. A comparison of the dynamics of the production of iron and cast iron shows that during 2002-2021, the average annual growth rate of production of cast iron in the world was 4.0%, and that of cast iron was 2.0%. The ratings of the world manufacturers of iron castings in 2018 and 2021 were considered. The production of iron castings in the world is characterized by both increasing (2002-2011) and stable production (2012-2021). Today, cast iron remains the most widely used casting material. The main reasons for the long-lasting dominance of cast iron in a wide range of products are related to its mechanical and physical properties and its competitive price. If all ferrous alloys in the global foundry production make up more than 80%, then we are living in the Iron Age. The review provides two examples from the "cast iron world" that describe the development of centrifugal casting of high-strength cast iron pillars with lengths from 9 to 30 m and with a casting cycle time of up to 12 minutes for a base pillar. Such utility poles weigh less than wooden poles and are much lighter than concrete poles, have high fire resistance, withstand significant wind loads and have a service life of more than 75 years, surpassing both steel and wood. It was also noted that cast iron is actively used for the production of household utensils, with a projected increase in its output. Keywords: market, cast iron, cast iron castings, trends, production.

Material-economic aspects of wooden pole fence-buildings

This paper examines different aspects of wooden pole fence-buildings through two different perspectives. In the first part of the article, the material-economic conditions and the nature of the crafts involved in the building technique is examined through a sloyd-theoretical perspective. By comparing approaches and methods of the wooden pole fence building-technique with those of domestic sloyd rather than architecture, an attempt is made at understanding the techniques epistemological nature. The versatile nature of the building technique is emphasized, and its regenerative qualities highlighted. The second part takes a closer look at the craft procedures involved in the making of a wooden pole fence-building through a processual reconstruction of a small barn based on a filmed documentation of the building process from the 1930s. Through practical experiments, attempts are made to understand and recreate the craft procedures documented in the film. Questions about the selection of wood for the barn and how material conditions affect the craft procedures are discussed. A filmed documentation of three of the procedures of the reconstruction gives an insight into the process.

Traditional fishing methods practiced by Ao and Sumi tribes in Dikhu River of Nagaland, India

Traditional fishing knowledge dates back to the early fish catching techniques passed down from forefathers in most of the Naga communities, Nagaland. Traditional fishing is mainly practiced for household consumption and is considered less intensive than industrial fishing practices, which can negatively impact riverine sustainability. However, there is a risk of loss of traditional knowledge in recent times. Hence, an effort was made to comprehend and document the indigenous traditional knowledge associated with fishing practices utilized by the Ao and Sumi tribal communities residing along the banks of Dikhu River. The diverse array of traditional fishing equipment and techniques employed has been categorised based on their specific functions, resulting in the documentation of three types of fishing gears, four fishing accessories, one fishing craft and three other types of fishing techniques. However, in some regions, use of detrimental fishing like dynamites and harsh chemicals were encountered. The results indicate that local fishers continue to rely on indigenous fishing practices for sustenance, and the majority of traditional fishing gears are constructed using locally available eco-friendly materials such as bamboo, wooden poles and cotton twine. The information obtained in this study can be preserved and implemented in contributing better resource management.

Evaluation of Power Transmission Lines Hardening Scenarios Using a Machine Learning Approach

Abstract The power transmission infrastructure is vulnerable to extreme weather events, particularly hurricanes and tropical storms. A recent example is the damage caused by Hurricane Maria (H-Maria) in the archipelago of Puerto Rico in September 2017, where major failures in the transmission infrastructure led to a total blackout. Numerous studies have been conducted to examine strategies to strengthen the transmission system, including burying the power lines underground or increasing the frequency of tree trimming. However, few studies focus on the direct hardening of the transmission towers to accomplish an increase in resiliency. This machine learning-based study fills this need by analyzing three direct hardening scenarios and determining the effectiveness of these changes in the context of H-Maria. A methodology for estimating transmission tower damage is presented here as well as an analysis of impact of replacing structures with a high failure rate with more resilient ones. We found the steel self-support-pole to be the best replacement option for the towers with high failure rate. Furthermore, the third hardening scenario, where all wooden poles were replaced, exhibited a maximum reduction in damaged towers in a single line of 66% while lowering the mean number of damaged towers per line by 10%.

Solving the problem of wooden poles ignition due to insulator contamination - in theory and practice

Solving the problem of wooden poles ignition due to insulator contamination - in theory and practice

How to keep the lights on: Lessons from major blackouts over the last 35 years [Editors’ voice

At the time of this writing, in January 2023, Québec is remembering the 1998 ice storm, which occurred on Friday, 9 January, 34 years ago. Falls of more than 100 mm of freezing rain literally pulverized part of the Hydro-Québec electrical network, blacking out more than 4 million people. This day has gone down in history as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Black Friday</i> . About 24,000 wooden poles, 900 pylons, and 3,000 km of power lines were cut down. Some households would only find power after five to six weeks ( <xref ref-type="fig" rid="fig1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Figure 1</xref> ). Such a weather-driven blackout was not the first to hit Québec province. On 13 March 1989, solar winds disrupted the Earth’s magnetic field, causing seven static var compensators (SVC) to disconnect from the grid in 1 min, due to excessive harmonics currents. Following the loss of the dynamic voltage support provided by the SVCs, the instability of the power system became inevitable. A major outage of the entire Québec network resulted, leaving 6 million people without power for 9–12 h.

Study on mechanical properties and application in communication pole line engineering of glass fiber reinforced polyurethane composites (GFRP)

Reinforced concrete poles, wooden poles and steel poles are commonly used in communication pole line engineering, but there are numerous shortcomings, which can’t be ignored. In this paper, a scheme of applying glass fiber reinforced polyurethane composites (GFRP) instead of traditional materials to manufacture poles in communication pole line engineering is proposed. The technical properties and bending moment of GFRP poles were studied through material test and bending performance test. Furthermore, Abaqus was used to carry out finite element analysis on GFRP pole, and physical and mechanical properties of GFRP and traditional materials were compared. Referring to GB/T 51421–2020 and DL/T 5219–2014, structural design of GFRP pole and foundation was carried out, respectively. Finally, economic benefit of GFRP pole was analyzed, then an innovative installation method of GFRP pole was proposed. Results show that GFRP has high stiffness, light weight, high strength and durability. Besides, GFRP pole has sufficient flexural bearing capacity, and foundation has excellent overturning stability, which lays a foundation for the application of GFRP in communication pole line engineering.

Full Scale Evaluation of GFRP Confined Softwood after Long-Term Exposure to High Humidity Environment

Plantation softwood timber poles are associated with low natural durability, and it is also not clear what the effects of the high humidity environment on the long-term performance of composite action integrity of such a system. This paper presents a durability study for the proposed composite poles using (GFRP) glass fiber-reinforced polymer as a confinement system on wooden poles sourced from plantation softwood timber. Radiata pine poles of 6 m length were wrapped with multiple layers of 0°/90° woven roving biaxial E-glass fiber sheets through a wet layup process as confinement. The prepared GFRP softwood poles were then subjected to high humidity environmental conditions of up to 95 ± 2% relative humidity and 22 ± 2 °C temperature for a period of 30 months. Various lengths of confinement were considered in this study ranging from 0% to 70% of the span length. The poles had a span length of 5.4 m and were tested using a three-point bending test. Results showed that the proposed confinement system of GFRP-softwood provided a satisfactory long-term performance and the high humidity environment did not greatly affect the improvement in the mechanical performance that the GFRP system provided.

Discovering fire events in the HAS1 settlement on the Dhofar coast (Oman) by a multi-methodological study of mollusk shells

AbstractMollusk shells from archeological deposits are often exposed to high temperatures through human-caused or natural heating events. While heat exposure affects reliability of mollusk shells for environmental reconstructions based on geochemistry, it can provide a valuable source of information on past human behaviors and human–environment interactions. We analyzed burned and not-burned bivalve and gastropod specimens collected within two megalithic circular structures in the HAS1 settlement in Oman (Late Iron Age and Classical Period). Through a multi-methodological approach, we investigated shell microstructure using scanning electron microscopy (SEM), shell mineralogy using X-ray diffraction (XRD), and shell stable-isotopic composition (δ18O, δ13C) using isotope-ratio mass spectrometry (IRMS) to infer the temperatures these specimens were exposed to and to reconstruct the processes responsible for heating the shells. Thermal response of aragonite and calcite shells having different microstructures were also determined. We found that mollusk shells at this site were exposed to three temperature ranges: a) no exposure or &lt;300°C, b) between 250°C and 500°C, and c) ≥500°C. The heat source was likely a fire which engulfed the entire settlement, which is also supported by evidence of carbonized wooden poles found in situ inside the circular structures.

Coal Tar Distillate (Creosote)—The First and Still Great Choice to Preserve Utility Poles

Abstract Creosote, a coal tar distillate product, has been used to preserve wooden utility poles for well over 100 years. Such use began in the late 1800s and continues to this day. Creosote’s efficacy in protecting wood from decay, termite attach, and general weathering has been demonstrated by actual performance of poles in utility service and in documented field and laboratory testing. The American Wood Protection Association has standardized and long recognized the efficacy of creosote preservation. With production of pentachlorophenol ending after 2022, preservation may easily convert to creosote preservative. Creosote preservative also is an environmentally sound choice in that used poles can be used as fuel and otherwise, creosote degrades biologically. Wood is sustainable as new trees are grown to replace poles while the poles are sequestered carbon. Utility service life of creosote preserved wooden poles typically lasts for 70 to over 100 years with inspection and maintenance. Utilities can expect new creosote preserved poles to last into the next century.

Некоторые аспекты проблемы защиты птиц от поражения электрическим током на воздушных линиях электропередачи в Казахстане

Некоторые аспекты проблемы защиты птиц от поражения электрическим током на воздушных линиях электропередачи в Казахстане

Pentachlorophenol causes redox imbalance, inhibition of brush border membrane and metabolic enzymes, DNA damage and histological alterations in rat kidney

Pentachlorophenol (PCP) is a synthetic organochlorine compound that is widely used in biocide and pesticide industries, and in preservation of wood, fence posts, cross arms and power line poles. Humans are usually exposed to PCP through air, contaminated water and food. PCP enters the body and adversely affects liver, gastrointestinal tract, kidney and lungs. PCP is a highly toxic class 2B or probable human carcinogen that produces large amount of reactive oxygen species (ROS) within cells. This work aimed to determine PCP-induced oxidative damage in rat kidney. Adult rats were given PCP (25, 50, 100, 150 mg/kg body weight), in corn oil, once a day for 5 days while control rats were given similar amount of corn oil by oral gavage. PCP increased hydrogen peroxide level and oxidation of thiols, proteins and lipids. The antioxidant status of kidney cells was compromised in PCP treated rats while enzymes of brush border membrane (BBM) and carbohydrate metabolism were inhibited. Plasma level of creatinine and urea was also increased. Administration of PCP increased DNA fragmentation, cross-linking of DNA to proteins and DNA strand scission in kidney. Histological studies supported biochemical findings and showed significant damage in the kidneys of PCP-treated rats. These changes could be due to redox imbalance or direct chemical modification by PCP or its metabolites. These results signify that PCP-induced oxidative stress causes nephrotoxicity, dysfunction of BBM enzymes and DNA damage.

Estimation of Human Body Height Using Consumer-Level UAVs

Consumer-level UAVs are often employed for surveillance, especially in urban areas. Within this context, human recognition via estimation of biometric traits, like body height, is of pivotal relevance. Previous studies confirmed that the pinhole model could be used for this purpose, but only if the accurate distance between the aerial camera and the target is known. Unfortunately, low positional accuracy of the drones and the difficulties of retrieving the coordinates of a moving target like a human may prevent reaching the required level of accuracy. This paper proposes a novel solution that may overcome this issue. It foresees calculating the relative altitude of the drone from the target by knowing only the ground distance between two points visible in the image. This relative altitude can be then used to calculate the target-to-camera distance without using the coordinates of the drone or the target. The procedure was verified with real data collected with a quadcopter, first considering a controlled environment with a wooden pole of known height and then a person in a more realistic scenario. The verification confirmed that a high level of accuracy can be reached, even with regular market drones.