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1
İşleyen, Ümmü K., Rahim Ghoroubi, Ömer Mercimek, Özgür Anil, and Recep Tuğrul Erdem. "Behavior of glulam timber beam strengthened with carbon fiber reinforced polymer strip for flexural loading." Journal of Reinforced Plastics and Composites 40, no. 17-18 (April 9, 2021): 665–85. http://dx.doi.org/10.1177/0731684421997924.
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In the last 20 years, the use of wooden structures and their dimensions have gradually increased. The wood application has increased in different structures such as multistory buildings, sports, industrial facilities, road and railway bridges, power transmission lines, and towers. The widespread use and size of wood structures have increased the research on developing special types of wood products supported by composite materials. Laminated wood elements are the leading composite wood materials. Laminated wooden beams allow making much larger openings than standard solid wood structural elements. The development of the sizes and usage areas of wooden structures has increased the capacity of glulam structural elements and reveals the need to improve their performance. Carbon fiber reinforced polymers (CFRPs) are the most suitable options for increasing the bearing capacity values of glulam beams and improving general load–displacement behaviors. In this study, the use of CFRP strips in different layouts to increase glulam wooden beams and the application of CFRP fan-type anchors in the CFRP strip endpoints are the studied variables. Anchored and non-anchored glulam wooden beams reinforced with CFRP strips with different layouts were tested using a three-point bending test. The ultimate load capacity, initial stiffness, displacement ductility ratio, energy dissipation capacity, failure mechanisms, and general load–displacement behavior of wooden beam test specimens were obtained and interpreted as a result of the experiments.
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Shin, Yukyung, Chang-Deuk Eom, and Sang-Joon Lee. "Structural Performance Evaluation on Stress-Laminated Timber Bridge Deck Using Finite Element Analysis." Journal of the Korean Wood Science and Technology 42, no. 1 (January 25, 2014): 20–26. http://dx.doi.org/10.5658/wood.2014.42.1.20.
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Bakht, Baidar, John Maheu, and Tatiana Bolshakova. "Stressed log bridges." Canadian Journal of Civil Engineering 23, no. 2 (April 1, 1996): 490–501. http://dx.doi.org/10.1139/l96-053.
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The stressed log bridge was conceived as a means of recycling discarded utility timber poles, or logs, which are difficult to dispose because of having been treated with preservatives. To minimize wastage, the logs are trimmed to obtain two parallel flat surfaces, against which they are stacked and laterally stressed as in the familiar stress laminated wood decks. The log decks introduced in this paper are recommended to be stressed by means of aramid or glass fibre tendons which are inert and extremely flexible; because of which, the prestress losses can be virtually eliminated. The paper presents the details of the design, construction, and testing of a prototype stressed log bridge built to demonstrate the concept. The bridge was post-tensioned with aramid fibre cables known by the trade name of PARAFIL ropes. The tendons were first stressed to the maximum level corresponding to a high pressure that can be sustained by the wood and then, within half an hour, destressed to about 68% of the initial force. Observations over a period of about 10 months have confirmed that restressing of the deck is not required. Mainly because of economy, the use of glass fibre reinforced plastic rods is recommended instead of the aramid fibre cables. Key words: aramid fibre, bridge, glass fibre, log, prestress losses, stress laminated wood deck, timber bridge.
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Son, Whi-Lim, Joo-Saeng Park, and Kwang-Mo Kim. "Life Cycle Assessment of Timber Arch-Truss Bridge by Using Domestic Pinus rigida Glued-Laminated Timber." Journal of the Korean Wood Science and Technology 42, no. 1 (January 25, 2014): 1–12. http://dx.doi.org/10.5658/wood.2014.42.1.1.
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Bakht, Baidar, and Tharmalingham Tharmabala. "Steel–wood composite bridges and their static load response." Canadian Journal of Civil Engineering 14, no. 2 (April 1, 1987): 163–70. http://dx.doi.org/10.1139/l87-028.
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The proposed steel–wood composite bridges incorporate longitudinal steel girders which are composite with wood deckings consisting of longitudinal laminates. The laminated decking is usually transversely prestressed. By orienting the laminates longitudinally, advantage can be taken in longitudinal bending of the dominant modulus of elasticity of wood. The paper shows that the load-carrying capacity of an existing slab-on-girder bridge with steel girders and deteriorated noncomposite concrete deck slab can be considerably enhanced by using the proposed system. The paper presents results of static load tests on two types of shear connector, some composite beams, and half-scale model of a bridge. Test data confirm the effectiveness of the composite system. Key words: bridges, composite bridges, steel–wood composite bridges, laminated wood decks, shear connectors, composites.
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Moga, Ligia, and I. Moga. "Thermal Bridges At Wood Frame Construction." Journal of Applied Engineering Sciences 5, no. 2 (December 1, 2015): 65–71. http://dx.doi.org/10.1515/jaes-2015-0023.
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Abstract The paper presents the results of numerical analysis on the effects of thermal bridges at wood frame buildings with or without thermal insulation placed on the exterior surface of the wall. The heat flow crossing the wooden thermal bridges, respectively the linear heat transfer coefficients ψ and the temperature factors fRsi, can be established based on the plane temperature field in stationary thermal regime. The “PSIPLAN” computer program used to determine the temperature field, derived from the original program “CIMPLAN” with its first version developed in 1980. The program allows graphic description of the plane section of a thermal bridge and discretizes automatically the section on both axes in accordance with the stipulations of the EN ISO 10211-1:1995 standard and EN ISO 10211:2007 standard. The computer program generates automatically the system of equations that is solved using iterative methods until the heat flows on the two surfaces of the section are balanced. The calculation results are presented with numerical values and in a graphical manner by isothermal surfaces. The program has various libraries that include several types of wood thermal bridges.
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Eamon, Chris, Andrzej S. Nowak, Michael A. Ritter, and Joe Murphy. "Reliability-Based Criteria for Load and Resistance Factor Design Code for Wood Bridges." Transportation Research Record: Journal of the Transportation Research Board 1696, no. 1 (January 2000): 316–22. http://dx.doi.org/10.3141/1696-33.
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Recently AASHTO adopted a load and resistance factor design code for highway bridges. The new code provides a rational basis for the design of steel and concrete structures. However, the calibration was not done for wood bridges. Therefore, there is a need to fill this gap. The development of statistical models for wood bridge structures is discussed. Recent test results provided a considerable amount of new data for sawed wood and glulam components. Statistical methods provide a good tool for development of rational models for loads and resistance. Because of the random nature of load and resistance, reliability is a convenient measure of structural performance that also provides a rational basis for comparison of wood and other structural materials. The results of a recent project that led to development of rational design criteria for wood bridges are presented. The structural reliability of selected wooden bridges designed by the AASHTO codes are determined, and inadequacies in load distribution and material resistance in the current specifications are identified.
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Rizzo, Fabio. "Aeroelastic Response of Suspended Pedestrian Bridges Made of Laminated Wood and Hemp." Infrastructures 5, no. 7 (July 20, 2020): 60. http://dx.doi.org/10.3390/infrastructures5070060.
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The work described in this paper investigated, by calculating critical flutter speed, the aeroelastic response of suspended pedestrian bridges made of a laminated wood structure and hemp cables and compared them to bridges with a steel structure and harmonic steel cables. Critical flutter speed was estimated using a numerical two degree of freedom (2-DOF) generalized deck model based on finite-element modal analysis. The critical flutter speeds of two sets of 25 different structural configurations, obtained by varying the deck chord and the permanent deck loads, made of steel and of laminated wood respectively, were estimated using experimental flutter derivatives obtained from 30 wind tunnel experiments. One of the most significant results was that pedestrian bridges made of laminated wood and hemp have a higher torsional frequency than those made of steel and that this affects critical flutter speed. A case study was performed and discussed by analyzing the structural and aeroelastic response of a 250 m pedestrian bridge with a 12 m deck chord and two approximately 32 m tall towers.
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Taylor, Raymond J. "Field applications of prestressed laminated wood bridge decks." Canadian Journal of Civil Engineering 15, no. 3 (June 1, 1988): 477–85. http://dx.doi.org/10.1139/l88-064.
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The concept of prestressing laminated wood bridge decks was conceived in Ontario in 1976 as a method of upgrading existing deteriorated nailed laminated wood decks. The success of this technique as a method of rehabilitation prompted considerable research and development aimed at introducing it into new construction. This work led to the formation of a comprehensive set of design specifications, which have since been adapted into the Ontario highway bridge design code and were included in the 1983 edition.Since its inception in 1976, the prestressed wood concept has been used many times, and by 1985, more than 16 bridges incorporated the concept in various ways. The objective of this paper is to discuss a number of these field structures in order to demonstrate the flexibility of the prestressed wood deck system. In new construction, the system has been applied to both longitudinally and transversely laminated decks including on-site deck assembly as well as a preassembled deck panel system.The paper describes the applicability of the system, construction sequence, and field problems. In addition, construction costs for some of the applications, as derived from field data, are discussed. Key words: wood, bridges, prestressed wood decks, laminated decks, preassembled deck panels.
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Yazdani, Nur, Joy O. Kadnar, James A. Kainz, and Mike Ritter. "Parametric Study on Behavior of Stress-Laminated Southern Pine Bridge Decks." Transportation Research Record: Journal of the Transportation Research Board 1740, no. 1 (January 2000): 85–95. http://dx.doi.org/10.3141/1740-11.
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Stress-laminated timber bridge decks have gained popularity in the United States in recent years. As with all wood exposed to the environment, wood for these decks must be treated with preservatives. There has been reluctance to build chromated copper arsenate (CCA)-treated wood bridges because of concerns about dimensional stability. Because no research has been undertaken to investigate the use of CCA-treated southern pine stress-laminated bridge decks, a good resource for economical rural bridges has remained untapped. The objective of the present study was to evaluate the performance of various wood preservatives on stress-laminated southern pine bridge decks. A total of nine decks with seven different preservatives were built and exposed to the environment for more than 2 years. Force levels in prestressing rods and wood moisture contents from each deck were continuously monitored. It was found that the short-term variations in the rod stress levels are less for decks with oil-type preservatives than for decks with CCA preservatives. The long-term performances of decks with both preservative types were found to be similar. The anchorage effect on deck performance was found to be negligible.
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Jaeger, Leslie G., and Baidar Bakht. "Effect of butt joints on the flexural stiffness of laminated timber bridges." Canadian Journal of Civil Engineering 17, no. 5 (October 1, 1990): 859–64. http://dx.doi.org/10.1139/l90-096.
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Prestressed and nailed laminated timber bridge decks are made from laminates which, because of their being usually shorter in length than the deck span, are butt-jointed at regular intervals. In calculating deflections of such decks, it is usual to ignore the reduction in flexural rigidity of the deck caused by the presence of the butt joint. The effect of butt joints on the flexural rigidity of the laminated deck is studied analytically, and it is shown that the deflections of a deck having such joints may be significantly larger than those of a deck without them. A simple method is presented to account conservatively for the presence of butt joints in the calculation of the deflections of a prestressed laminated timber deck. Key words: timber bridge, laminated deck, butt joint, prestressed wood deck.
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Visser, Rien, W. Michael Aust, Tom Gallagher, Tal Roberts, and Matt Poirot. "Cost of Six Different Stream Crossing Options in the Appalachian Area." Southern Journal of Applied Forestry 27, no. 1 (February 1, 2003): 66–70. http://dx.doi.org/10.1093/sjaf/27.1.66.
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Abstract Permanent and temporary forest bridges are an integral part of achieving environmental Best Management Practices (BMPs) for harvesting operations. Within Virginia Tech's Fishburn Forest, five stream crossings have been installed to improve access and to provide a demonstration area for continuing education purposes. Approximately 1 mile of abandoned road was re-opened and improved, and 850 tons of gravel used to form the new running surface. In addition to a number of existing fords, three new culvert crossings and five new bridges were installed. These include a 70 ft low-water concrete culvert crossing, a two-span 31 ft wooden stringer bridge, and three different types of stress-laminated bridges. This article provides basic information regarding permit acquisition and environmental considerations for stream crossings. Location, design, and installation procedures for a variety of permanent and temporary forest bridges are presented. Finally, an evaluation of bridge installation costs, including materials, labor, and machinery requirements, are shown for the various permanent and temporary crossing types. South. J. Appl. For. 27(1):66–70.
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Dahoua, Lamri, and Fakhridine Boymatov. "Endurance of the wooden bridge reinforced by the dowel plates." Studia Geotechnica et Mechanica 40, no. 3 (October 20, 2018): 202–7. http://dx.doi.org/10.2478/sgem-2018-0023.
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Abstract The most important piece of road infrastructure is bridges. Wooden bridges have advanced constantly during the past decades. The trend began in Scandinavian countries but has also now gained significant ground in Russia. This research studies experimental endurance potential of the joints of the wooden beam while considering the coefficient of asymmetry of the cycle, which corresponds to the actual operating conditions. Performance analysis of the composite bars is carried out based on the experiment; the development of a special methodology for calculating the joints of wooden elements with the dowel plates for their better endurance is also introduced in this paper. The results of experimental studies on the performance of bending composite wooden bridge bars based on dowel plates operating under cyclic influences thus determine the endurance limit of wood for composite wooden bridge beams based on dowel plates. The calculation technique and interdependence of the endurance coefficient affecting the asymmetry coefficient of the bent composite wooden bridge bars on the dowel plates under cyclic loading are considered. The experimental data on the endurance of composite wooden bridge beams have been obtained, and separate analysis has been made of the compounds under cyclic loading performance; a method has been developed for calculating the bent composite wooden bridge bars reinforced by the dowel plates under cyclic influences.
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Zhang, Ji Mei, Jing Long Pan, and Hong Bo Dong. "Experimental Study of Deformation Characteristic and Application on External Prestressed Wooden Beam." Applied Mechanics and Materials 204-208 (October 2012): 4647–53. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.4647.
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People have widely uesd long- history wooden buildings in the ancient and mordern architecture.But the modulus of elasticity of the wood is smaller as well as the fact that the stiffness of wood is lower. In order to solve the problem of deficiency of the stiffness of large-span wooden beam from the practical engineering, this paper presents the method of external prestressed wooden beam, and the calculation method of deflection of wooden beam through model test of 1:2 scale. In addition to it, the paper also analyzes the factors which affect stiffness of wooden beam. The result shows that stiffness of this kind of wooden beam is greatly improved compared with the common wooden beam in the same cross section. Steel has a predominant tensile characteristics, it is an effective method to reduce undue deflection of large-span wooden beam by external prestress method. This construction techniques has greatly applicational value in the reinforcement and strengthening ancient buildings and modern design and construction of large-span timber structure buildings and bridges.
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Kromoser, Benjamin, Martin Ritt, Alexandra Spitzer, Rosemarie Stangl, and Friedrich Idam. "Design Concept for a Greened Timber Truss Bridge in City Area." Sustainability 12, no. 8 (April 16, 2020): 3218. http://dx.doi.org/10.3390/su12083218.
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Properly designed wooden truss bridges are environmentally compatible construction systems. The sharp decline in the erection of such structures in the past decades can be led back to the great effort needed for design and production. Digital parametric design and automated prefabrication approaches allow for a substantial improvement of the efficiency of design and manufacturing processes. Thus, if combined with a constructive wood protection following traditional building techniques, highly efficient sustainable structures are the result. The present paper describes the conceptual design for a wooden truss bridge drawn up for the overpass of a two-lane street crossing the university campus of one of Vienna’s main universities. The concept includes the greening of the structure as a shading design element. After an introduction, two Austrian traditional wooden bridges representing a good and a bad example for constructive wood protection are presented, and a state of the art of the production of timber trusses and greening building structures is given as well. The third part consists of the explanation of the boundary conditions for the project. Subsequently, in the fourth part, the conceptual design, including the design concept, the digital parametric design, the optimization, and the automated prefabrication concept, as well as the potential greening concept are discussed, followed by a summary and outlook on future research.
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Krause, Martin, Klaus Mayer, Prashant Kumar Chinta, and Ute Effner. "Ultrasonic Imaging of Defects in Building Elements Made from Timber." Advanced Materials Research 778 (September 2013): 312–20. http://dx.doi.org/10.4028/www.scientific.net/amr.778.312.
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There is a great demand for non-destructive testing methods for quality assurance and to assess the safety and durability of wooden structures. Ultrasonic echo technique with shear waves in the frequency range of 50 kHz is one of those promising methods and is already frequently applied for usual and glued laminated timber. The article describes the development and first results for an imaging method for this purpose. The highly anisotropic properties of the ultrasonic velocity have to be considered. A 3D-SAFT (Synthetic Aperture Focusing Technique) imaging scheme is developed initially for synthetic data resulting from modelling the elastic wave propagation. The main part of the paper describes the experimental validation of this evaluation technique by experimental studies applying automated ultrasonic scanning techniques. 3D ultrasonic imaging results are described for test specimens made from pine and spruce wood. Another object of investigation was a pedestrian bridge made from siberian larch.
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Wang, Zhi Feng, Xian Yan Zhou, and Da Hai Zhang. "Structural Condition Evaluation of an In-Service Glued-Laminated Timber Bridge Based on the Dynamic and Static Testing." Applied Mechanics and Materials 847 (July 2016): 31–37. http://dx.doi.org/10.4028/www.scientific.net/amm.847.31.
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The structural use of wood has increased steadily in recent times, including a renewed interest in the use of timber as a bridge material. As the only environment-friendly and resource-saving building material, wood has been gradually uesd for short and medium span bridges in China. In 2014, The domestic largest single-span glued-laminated timber (glulam) deck arch bridge crossing a freeway was completed and put into operation in Zhangjiajie City, central China' Hunan province. In order to know the bearing capacity of superstructures and assess its working conditions, in-site static and dynamic testings has been carried out. Many measures including finite element simulation, field test and comparision between test results and calculated results have been employed to study responses of the bridge under static loads and dynamic loads as well. The researches indicate this glulam footbridge has performed well in service and appear to be cost effective when compared with the cost of installing traditional concrete and steel bridges.
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Fortino, Stefania, Petr Hradil, Keijo Koski, Antti Korkealaakso, Ludovic Fülöp, Hauke Burkart, and Timo Tirkkonen. "Health Monitoring of Stress-Laminated Timber Bridges Assisted by a Hygro-Thermal Model for Wood Material." Applied Sciences 11, no. 1 (December 24, 2020): 98. http://dx.doi.org/10.3390/app11010098.
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Timber bridges are economical, easy to construct, use renewable material and can have a long service life, especially in Nordic climates. Nevertheless, durability of timber bridges has been a concern of designers and structural engineers because most of their load-carrying members are exposed to the external climate. In combination with certain temperatures, the moisture content (MC) accumulated in wood for long periods may cause conditions suitable for timber biodegradation. In addition, moisture induced cracks and deformations are often found in timber decks. This study shows how the long term monitoring of stress-laminated timber decks can be assisted by a recent multi-phase finite element model predicting the distribution of MC, relative humidity (RH) and temperature (T) in wood. The hygro-thermal monitoring data are collected from an earlier study of the Sørliveien Bridge in Norway and from a research on the new Tapiola Bridge in Finland. In both cases, the monitoring uses integrated humidity-temperature sensors which provide the RH and T in given locations of the deck. The numerical results show a good agreement with the measurements and allow analysing the MCs at the bottom of the decks that could be responsible of cracks and cupping deformations.
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Pinheiro, Luís Henrique Bueno, José Antônio Matthiesen, and Jorge Luís Akasaki. "Study of Timber and Concrete with Rubber Waste Composite Beams Applied to Bridges." Key Engineering Materials 634 (December 2014): 266–77. http://dx.doi.org/10.4028/www.scientific.net/kem.634.266.
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In order to overcome the hydrographic network, the landforms, and the most different types of barriers, many timber bridges were constructed around the world, especially in secondary roads where the raw materials (wood) can be found in the vicinity, what reduces the construction costs.The deck can be made of reinforced concrete with the purpose of increasing the durability, strength and stiffness of these structures, and using rubber particles can not only decrease the costs and impact on the environment, but can also confer some advantages on the structure, such as a better impact absorption, and a lower cracking due to the abrasion wear, water absorption or self-weight.The analysis of the bending behavior of these superstructures was performed through the study of ten mixed T section composite beams, with wooden web (mimicking the stringers) and a reinforced concrete top flange (mimicking the deck) with varying rubber waste percentage. Steel bars set to “X”, glued with epoxy resin on the wood, allowed the connection between wood and concrete, reducing manufacturing costs with high shear strength resistance. The constituent materials were characterized mechanically and the composite beams were equipped with a dial indicator and strain gauges, and then broken in flexure tests. At the same time, the rubber particles percentage was correlated with the following parameters: stress, strain, elasticity modulus, loads and displacements, what enabled us to find which rubber addition percentage was most adequate in order for this kind of structure to be in accordance with the project requirements for the resistance.
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Obelić, Bogomil, Ines Krajcar Bronić, Jadranka Barešić, Željko Peković, and Ante Milošević. "Dating of the Old Bridge in Mostar, Bosnia and Herzegovina." Radiocarbon 49, no. 2 (2007): 617–23. http://dx.doi.org/10.1017/s003382220004251x.
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The famous single-arch stone bridge over the Neretva River in Mostar, Bosnia and Herzegovina, was built in 1557–1566 by the order of Ottoman Sultan Süleyman the Magnificent. During the reconstruction of the Old Bridge, which was destroyed during the war in 1993, remnants of 2 older wooden bridges were found at the same location. Six wood and 2 charcoal samples were dated using the radiocarbon method. Wood samples with visible tree rings were taken for dendrochronological dating. The results point to several periods of construction and repairs to the bridge and the towers at each end, spanning from the 12th to 18th century. Calibrated 14C and dendrochronological ages were in good agreement.
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Haroske, Gesa, Ulrich Diederichs, and Vít Petranek. "Bacterial Deteriorations of Wooden Pile Foundations due to Permanent Soil and Water Contact." Advanced Materials Research 923 (April 2014): 153–60. http://dx.doi.org/10.4028/www.scientific.net/amr.923.153.
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Many structures resting on pile foundations, which are surrounded by water in the soil for decades or centuries. In the context of status explorations or assessments questions arise concerning their conservation status and their durability. The paper presents the results of extensive in situ studies and laboratory tests, which were performed on older wooden pile foundations of port facilities, bridges and building foundations in the framework of planning of maintenance measures. In the focus of this work are studies on the biotic attack to the woods and its effect on the density and strength characteristics of the piles. Inter alia, the investigations have revealed that the wood under the said anaerobic conditions suffers deterioration due to bacterial attack, rarely by higher fungi. As discovered by microscopic investigations on thin sections, the bacterial attack appears as a partial degradation in the individual wood cells, especially in the middle lamella of the late wood cells and the dots. As indicated by the results of the of the density and strength test results, the bacterial attack is - compared to fungal attack - a very slow but steady process. It causes also strength reduction of the woods and losses of the load bearing capacity of the structures, and has to be taken into account in the static assessments.
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Björngrim, Niclas, Per-Anders Fjellström, and Olle Hagman. "Factory-mounted and retrofit passive resistance sensors adapted to monitor moisture content in timber bridges." BioResources 12, no. 4 (August 16, 2017): 7218–27. http://dx.doi.org/10.15376/biores.12.4.7218-7227.
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The biggest threats to the longevity of a timber bridge are rot and decay. Wood protection by design, inspections, and monitoring of the bridge for elevated moisture content will ensure that the full service life of the structure can be achieved. Today’s sensors for moisture content measurements are limited in their functionality and range. This paper presents a sensor that can be both factory installed and retrofitted, which can measure the moisture content through the cross-section of the member in a timber bridge. The sensor has been mounted on Sundbron bridge during manufacturing and retrofitted on Gislaved bridge. The ensuing measurements helped to adjust a design flaw on Gislaved bridge. Monitoring of Sundbron showed that the bridge deck dried up after the bridge had been exposed to sleet and snow during the on-site assembly of the stress laminated bridge deck.
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Sandhyavitri, Ari, Fakhri Fakhri, Rizki Ramadhan Husaini, Indra Kuswoyo, and Manyuk Fauzi. "Added values of the local timbers materials for main bridge frame structures utilizing laminating composites technology." Journal of Applied Materials and Technology 2, no. 1 (December 4, 2020): 50–58. http://dx.doi.org/10.31258/jamt.2.1.50-58.
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The objectives of this article are to seek the opportunity to enhance the local Indonesia timber material physical performances (encompassing the low-class quality of III and IV timbers with the Modulus of Elasticity (MOE) = 5,000 - 9,000 MPa) utilizing laminated composite technology to become higher-class timber quality (class II) with the Modulus of Elasticity (MOE)> 15,000 MPa so that it can be used as an alternative material for constructing the bridge mainframe structures (girder beams) especially for the Indragiri Hilir regency, Riau Province, Indonesia. This regency needs several hundred small-medium bridges for connecting 20 districts, 39 wards, and 197 villages using local materials such as local timbers. This laminating technology is not a new technology but the utilization of this technology for constructing the main bridges structures is challenging and limited to the implementation in the civil construction industrial sector. This study composed 2 types of the low-class quality (lcq) of timber materials (such as Shorea sp and Shorea peltata Sym) and 2 types of medium class-quality (mcq) ones (Dipterocarpus and Calophyllum) for constructing the main bridge structures. Based on the laboratory test results utilizing 80% of lcq materials and 20% mcq ones, these composite timber materials may increase the timbers MOE by 145% to 166% from the existing MOE value of the mcq solid timbers. Based on the simulations these laminated composites wooden bridge girders 2 x (70x20) m2, these timber materials have passed all the tests and the application of this technology may improve the lcq timber values and it could be used for an alternative material of the bridge girder's main structures.
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Utkin, V. A., P. N. Kobzev, and E. G. Shatunova. "COMPOUND RUNS OF LOGS CALCULATION: ACCOUNTING OF LONGITUDINAL FORCES’ AND BENDING MOMENTS’ INTERACTION." Russian Automobile and Highway Industry Journal 17, no. 1 (March 5, 2020): 136–49. http://dx.doi.org/10.26518/2071-7296-2020-17-1-136-149.
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Introduction. Studying the designing and constructing experience of beam bridges with composite log girders indicates the possibility of the load bearing capacity rising of the structures and their further usage in the IV and V categories bridges’ construction under A-11 and H-11 loads. The purpose of the research is to evaluate the effect on the magnitude and distribution of shear forces in shear bonds, considering the permissible pliability of fixation in wood and on the nature of the stress state change in the rods of the composite girders.Materials and methods. The authors presented the construction of the composite girder in the form of three rows united by means of tie bolts and gaskets of four-tier single-row composite girders and made of edged logs. The proposed studying method of a composite girder stress-strain state with discrete placement of concentrated shear bonds in the joints based on the classical method of forces for rod systems, taking into account the interaction of longitudinal forces and bending moments arising in the rods composing the girder of unknown forces in the shear bonds.Results. The determination of single displacements with joint account of bending and stretching-compression deformations haв a significant impact on the redistribution of shear forces in the direction of increasing them in the support zones and reducing them in the middle of the span, and, consequently, on the design of the connecting elements. The character of distribution of normal stresses on the stretching-compression indicated the rods’ girders between relationships under the eccentric compression (stretching).Discussion and conclusions. The proposed solutions demonstrate the most accurate assessment of the composite girders in the structures of spans wooden bridges and present the application possibility in modern conditions.Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.
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Khvostik, M. Yu, and M. A. Starodubtseva. "Studies of the constructed rail seat supports." Vestnik of the Railway Research Institute 76, no. 6 (December 28, 2017): 371–76. http://dx.doi.org/10.21780/2223-9731-2017-76-6-371-376.
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In recent decades, the use of constructed sleepers on the world's railways has been increasing: the United States, the EU countries, Japan and China. Such sleepers, having positive performance qualities of wooden sleepers (good elasticity and dielectric properties, manufacturability during laying and during repair work), do not have negative qualities of wood. The article reviews the US and EU standards for testing sleepers made of constructed materials. The classification of such sleepers is given. Examples of testing of such sleepers by specialists of JSC “VNIIZhT” for the period from 1999 to 2016 are given, including sleepers from modified wood, wooden sleepers with elastomeric coating, composite sleepers from recycled high-density polyethylene with glass-filled polymer. Features of the Russian requirements to the constructed sleepers are considered. Composite rail seat supports are promising in application. Possessing the advantages of wooden sleepers (bars), they have higher wear resistance, lower life cycle costs (recyclable), are more homogeneous and do not rot. Damping properties of composite sleepers contribute to solving the problem of reducing noise and vibration from rolling stock. In addition, their use is one of the ways to reduce the negative impact of rail transport on the environment. With a feasibility study, such sleepers will successfully replace other types of rail seat supports. Spheres of rational application of composite rail seat supports are heaving sections of the railway track, areas with weak soils, turnouts, tracks on bridges, railway tunnels, and underground tracks. Taking into account the tendency to expand the polygon for laying composite sleepers, including railway tracks, metro routes and land transport in the Russian Federation, Kazakhstan and other CIS countries, it is advisable to develop a single interstate standard containing safety requirements and test methods for constructed rail seat supports.
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Zhou, Jiale, Chuanxi Li, Lu Ke, Jun He, and Zhifeng Wang. "Experimental Study on Loading Capacity of Glued-Laminated Timber Arches Subjected to Vertical Concentrated Loads." Advances in Civil Engineering 2020 (May 22, 2020): 1–9. http://dx.doi.org/10.1155/2020/7987414.
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Glued-laminated timber arches are widely used in gymnasiums, bridges, and roof trusses. However, studies on their mechanical behaviours and design methods are still insufficient. This paper investigates the in-plane loading capacity of circular glued-laminated timber arches made of Douglas fir. Experiments were conducted on four timber-arch models with different rise-to-span ratios under concentrated loads at mid-span and quarter-point locations. The structural responses, failure modes, and loading capacity of the timber arch specimens were obtained. The results show that the timber arches presented symmetric and antisymmetric deformation under mid-point and quarter-point loading conditions, respectively. The downward shifting of the neutral axis of the cross section was observed under mid-point loading condition, which contributes to higher loading capacity compared to that under quarter-point loading condition. The loading condition significantly affects the ultimate loads and the strain distribution in the cross section. Based on the design formula in current standards for timber structures, an equivalent beam-column method was introduced to estimate the loading capacity of the laminated timber arches under vertical concentrated loads. The moment amplification factor in the formula was compared and discussed, and the value provided in the National Design Specification for Wood Construction was recommended with acceptable accuracy.
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Fernández-Golfín, Juan I., Maria Conde Garcia, and Marta Conde Garcia. "Improving the accuracy of wood moisture content estimation in four European softwoods from Spain." Forest Systems 30, no. 1 (February 25, 2021): e002. http://dx.doi.org/10.5424//fs/2021301-17798.
Full textAbstract:
Aim of study: To obtain improved models to predict, with an error of less than ± 2.0%, the gravimetric moisture content in four different softwoods commonly present in the Spanish and European markets, based on electrical resistance measurements. This improved moisture content estimation is useful not only for assessing the quality of wood products, especially in the case of laminated products, during the transformation and delivery process, but also for accurately monitoring the evolution of moisture in wood present in bridges and buildings, which is of great importance for its maintenance and service life improvement.Area of study: The study was carried out on samples of Scots, laricio, radiata and maritime pines of Spanish provenances.Material and methods: On 50x50x20 mm3 solid wood samples (36 per species, 9 per condition), conditioned at 20ºC (±05ºC) and 40±5%, 65±5%, 80±5% or 90±5% Relative Humidity (RH), electrical resistance and oven-dry moisture content was measured. The Samuelsson's model was fitted to data to explain the relationship between the two variables. The accuracy of the model was evaluated by the use of an external sample.Main results: With the proposed mathematical functions the wood moisture content can be estimated with an error of ±0.9% in the four species, confirming the effectiveness of this nondestructive methodology for accurate estimation and monitoring of moisture content.Research highlights: our results allow the improvement of the moisture content estimation technique by resistance-type methodologies.Keywords: Resistance-type moisture meter; species correction.Abbreviations used: MC: Moisture content; RH: relative Humidity; R: electrical resistance; RP: wood electrical resistance measured parallel to the grain; RT: electrical resistance measured perpendicular (transversally) to the grain; GM-MC: gravimetrically measured moisture content.
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Conde Garcia, Maria, Marta Conde Garcia, and Juan I. Fernández-Golfín. "Improving the accuracy of wood moisture content estimation in four European softwoods from Spain." Forest Systems 30, no. 1 (April 28, 2021): 002. http://dx.doi.org/10.5424/fs/2021301-17798.
Full textAbstract:
Aim of study: To obtain improved models to predict, with an error of less than ± 2.0%, the gravimetric moisture content in four different softwoods commonly present in the Spanish and European markets, based on electrical resistance measurements. This improved moisture content estimation is useful not only for assessing the quality of wood products, especially in the case of laminated products, during the transformation and delivery process, but also for accurately monitoring the evolution of moisture in wood present in bridges and buildings, which is of great importance for its maintenance and service life improvement.Area of study: The study was carried out on samples of Scots, laricio, radiata and maritime pines of Spanish provenances.Material and methods: On 50x50x20 mm3 solid wood samples (36 per species, 9 per condition), conditioned at 20ºC (±05ºC) and 40±5%, 65±5%, 80±5% or 90±5% Relative Humidity (RH), electrical resistance and oven-dry moisture content was measured. The Samuelsson's model was fitted to data to explain the relationship between the two variables. The accuracy of the model was evaluated by the use of an external sample.Main results: With the proposed mathematical functions the wood moisture content can be estimated with an error of ±0.9% in the four species, confirming the effectiveness of this nondestructive methodology for accurate estimation and monitoring of moisture content.Research highlights: our results allow the improvement of the moisture content estimation technique by resistance-type methodologies.Keywords: Resistance-type moisture meter; species correction.Abbreviations used: MC: Moisture content; RH: relative Humidity; R: electrical resistance; RP: wood electrical resistance measured parallel to the grain; RT: electrical resistance measured perpendicular (transversally) to the grain; GM-MC: gravimetrically measured moisture content.
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Kozyr, I. A., K. I. Panchenko, and O. V. Chornyy. "VASYNSKYI BARROW OF THE MIDDLE SKYTHIAN AGE." Archaeology and Early History of Ukraine 31, no. 2 (June 25, 2019): 300–314. http://dx.doi.org/10.37445/adiu.2019.02.22.
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The article presents the results of a study from the excavation of the barrow of middle Scythian time in Vasyne (Znamensky district, Kirovograd region). Barrow was located in the upper reaches of the river Beshka, the right tributary of the Ingulets in its upstream. The main Scythian burial was committed on the surface of the ancient horizon. A complex wooden burial structure constructed of oak was partially burnt, but well preserved. In the center of the entire burial facility was a ground-based square ten-column wooden tomb (5.5 Ч 5.5 m) with a flat ceiling, around which a «pyramid» was built of horizontal layers of raw tree trunks, logs and logs, preserved to a height of 0.9—1,4 m. «Pyramid» at the level of the ancient horizon was surrounded by thin (5—7 cm) wooden flooring. The overall diameter of the wooden structure reached 19 m.
The southern sector of the «pyramid» was covered with a layer of clay. The nature of the firing of the wooden masonry, the good preservation of the wood, some structural details of the «pyramid» itself, the presence of a clay pavement with products indicate the use of burning technology without access to air. The mound enclosed the annular ditch with two bridges in the western and eastern sectors.
The burial was accompanied by numerous remnants of the treasure in the form of fragments of ancient amphoras, including plump-throated Chios, thin-walled antique black-figureed kilik, fragments of stucco vessels, and animal bones. In the filling of the tomb, remains of funeral gifts that fell after the destruction of the floor were found: fragments of wooden trays or stretchers, fastened with iron and bronze brackets with sacrificial food; the ruined bones of the horse, next to which was found a handful of mummified millet grains.
The burial itself was completely robbed. The skeleton of the buried and funeral inventory were absent. At the bottom of the tomb, only the skeleton of a servant with a bone piercing and a bronze tip of a basic type arrow lost by robbers were found.
Undoubtedly, the most interesting find was a stone anthropomorphic stele of gray granite, 2.65 m high, which depicts a standing warrior with a set of weapons, a rhyton and two hryvnia.
According to the totality of finds in the mound and images on the stele, it is possible to attribute the time of its construction to the turn of the 6th—5th centuries. BC. The scale of the wooden burial structure, the ditch around the mound, the find of a granite stele, the remains of a treyne and sacrifices indicate that a representative of the Scythian military aristocracy was buried here.
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Yeh, Harry, and Nobuo Shuto. "Tsunami Forces and Effects on Structures." Journal of Disaster Research 4, no. 6 (December 1, 2009): 375–76. http://dx.doi.org/10.20965/jdr.2009.p0375.
Full textAbstract:
The 2004 Indian Ocean Tsunami claimed more than 220,000 lives. It was a low-probability high-consequence event. A similar disaster could strike elsewhere, particularly in the Pacific but also in Caribbean, Atlantic, and Mediterranean regions. Unlike in seismic ground shaking, there is usually a short lead-time precedes tsunami attack: from a few minutes for a local source to several hours for a distant source. Because mega-tsunamis are rare and because forewarning of these events is possible, the primary mitigation tactic to date has been evacuation. Hence, most efforts have focused on the development of effective warning systems, inundation maps, and tsunami awareness. This strategy makes sense from the standpoint of saving human lives. However, it does not address the devastating damage to buildings and critical coastal infrastructure, such as major coastal bridges, oil and LNG storage facilities, power plants, and ports and harbors. Failure in critical infrastructure creates enormous economic setbacks and collateral damage. The accelerating construction of critical infrastructure in the coastal zone demands a better understanding of design methodology in building tsunamiresistant structures. In some coastal areas such as low-elevation coastal spits or plains, evacuating people to higher ground may be impractical because they have no time to reach safety. In these situations, the only feasible way to minimize human casualties is to evacuate people to the upper floors of tsunami-resistant buildings. Such buildings must be designed and constructed to survive strong seismic ground shaking and subsequent tsunami impacts. The primary causes of structural failure subject to tsunami attack can be categorized into three groups: 1) hydrodynamic force, 2) impact force by water-born objects, and 3) scour and foundation failure. Tsunami behaviors are quite distinct, however, from other coastal hazards such as storm waves; hence the effects cannot be inferred from common knowledge or intuition. Recent research has addressed tsunami forces acting on coastal structures to develop appropriate design guidelines, and mechanisms leading to tsunamigenerated scour and foundation failures. This special issue is a compilation of 14 papers addressing tsunami effects on buildings and infrastructure. The four main groupings begin with two papers on tsunami force acting on vertical walls. Arikawa experimentally investigates the structural performance of wooden and concrete walls using a large-scale laboratory tank in Japan. Also using a similar large-scale tsunami flume but in the US, Oshnack et al. study force reduction by small onshore seawalls in front of a vertical wall. The second grouping focuses on tsunami force on 3-D structures. Arnason et al. present a basic laboratory study on the hydrodynamics of bore impingement on a vertical column. Fujima et al. examine the two types of formulae for tsunami force evaluation: the one calculated from flow depth alone and the other based on the Euler number. Lukkunaprasit et al. demonstrate the validity of force computation recommended in a recently published design guideline (FEMA P646) by the US Federal Emergency Management Agency. The other two papers look into the specific types of structures: one is for light-frame wood buildings by van de Lindt et al, and the other is for oil storage tanks by Sakakiyama et al. The topic of debris impact force is the focus of the third grouping. Matsutomi summarizes his previous research on impact force by driftwoods, followed by the collision force of shipping containers by Yeom et al. Yim and Zhang numerically simulate tsunami impact on a vertical cylinder; this paper is included in this grouping because their numerical approach is similar to that of Yeom et al. As for the fourth grouping, Shuto presents field observations on foundation failures and scours, and Fujii et al. discuss the erosion processes of soil embankments. There are two more papers: those are the application of fragility analysis to tsunami damage assessment by Koshimura et al. and evaluation of an offshore cabled observatory by Matsumoto and Kaneda. The topics presented here are undoubtedly in progress, and many revisions and improvements are still needed in order to achieve better predictability for tsunami effects on buildings and infrastructure. We hope you find the papers in this issue intriguing and the information useful, and become further interested in this important natural hazard. Lastly, we wish to express our appreciation to the authors for their timely contributions, and to the reviewers for their diligent and time-consuming efforts.
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İşleyen, Ümmü Karagöz, Rahim Ghoroubi, Ömer Mercimek, Özgür Anıl, Abdullah Togay, and R. Tuğrul Erdem. "Effect of anchorage number and CFRP strips length on behavior of strengthened glulam timber beam for flexural loading." Advances in Structural Engineering, January 21, 2021, 136943322098862. http://dx.doi.org/10.1177/1369433220988622.
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Laminated wooden beams are more preferred in the production of wooden structures than solid timber beams because they have a higher load-carrying capacity and allow larger openings to be used in the structure. The widespread use of wooden structures and the increasing size of the structures have revealed the need for strengthened laminated wooden beams and increase their ultimate load capacity. It has become necessary to develop reinforcement details to increase the ultimate load capacity of laminated wooden beams in wooden railroads or highway bridge beams, where the traffic load increases, especially in large wooden structures, in cases where large openings must be passed. Within the horizon of the study, the behavior and performance of three-layer glulam wooden beams strengthened with anchorage and non-anchorage CFRP strips with different bonding length under flexural loading were investigated experimentally. The three-point bending test was applied to glulam timber beam test specimens produced by laminating yellow pine wood material using the polyurethane adhesive. General load-displacement behaviors, ultimate load capacity, initial stiffness, displacement ductility ratios, and energy dissipation capacities were obtained. The increase in the bonding length of the CFRP strips used for strengthening in the glulam timber beam specimens and the use of CFRP fan type anchors at the strip ends increased the ultimate load capacity and initial stiffness values of the wooden beams, as well as the displacement ductility ratios and energy dissipation capacity values.