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Wan Mohamad, Wan Hazira, Zakiah Ahmad y Ashari Abd. Jalil. "Bending Strength of Glulam from Selected Malaysian Hardwood Timber". Advanced Materials Research 879 (enero de 2014): 237–44. http://dx.doi.org/10.4028/www.scientific.net/amr.879.237.
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Malaysian government has already built the first glulam structure in Malaysia with the aim of demonstrating the potentialities of using indigenous hardwood timber for glulam. Since Malaysia possesses a vast variety of timber species, hence there is a need to identify suitable species for glulam manufacturing. This paper presents the bending performance of Malaysian hardwood glulam beams, manufactured from different categories namely heavy, medium and light hardwood timbers. A series of tests were carried out on the glulam beam that includes bending test, delamination test and shear test of glue line. Results in this study will be useful to manufacturers interested in using Malaysian hardwood for glulam beams.
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Szumigała, Maciej, Ewa Szumigała y Łukasz Polus. "An Analysis of the Load-Bearing Capacity of Timber-Concrete Composite Beams with Profiled Sheeting". Civil and Environmental Engineering Reports 27, n.º 4 (20 de diciembre de 2017): 143–56. http://dx.doi.org/10.1515/ceer-2017-0057.
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Abstract This paper presents an analysis of timber-concrete composite beams. Said composite beams consist of rectangular timber beams and concrete slabs poured into the steel sheeting. The concrete slab is connected with the timber beam using special shear connectors. The authors of this article are trying to patent these connectors. The article contains results from a numerical analysis. It is demonstrated that the type of steel sheeting used as a lost formwork has an influence on the load-bearing capacity and stiffness of the timber-concrete composite beams.
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Hassan, Osama A. B. y Christopher Johansson. "Glued laminated timber and steel beams". Journal of Engineering, Design and Technology 16, n.º 3 (4 de junio de 2018): 398–417. http://dx.doi.org/10.1108/jedt-12-2017-0130.
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Purpose This paper aims to compare glued laminated timber and steel beams with respect to structural design, manufacturing and assembly costs and the amount of greenhouse gas emissions. Design/methodology/approach This paper presents structural design requirements in conformance with EN 1993: Eurocode 5 and Eurocode 3. With the help of these standards, expressions are derived to evaluate the design criteria of the beams. Based on the results of life-cycle analysis, the economic properties and environmental impact of the two types of beam are investigated. In this paper, the effect of beam span on the design values, costs and carbon dioxide emissions is analysed when investigating aspects of the structural design, economy and environmental impact. Different cross-sections are chosen for this purpose. Findings The study shows that the glued laminated (abbreviated as “glulam”) beams have a smaller tendency to lateral torsional buckling than the steel beams, and that they can be cheaper. From an environmental point of view, glulam beams are the more environmentally friendly option of the two beam materials. Furthermore, glulam beams may have a direct positive effect on the environment, considering the carbon storage capacity of the wood. The disadvantage of glued wood is that larger dimensions are sometimes required. Research limitations/implications Wind load and the effect of second-order effects have not been considered when analysing the static design. Only straight beams have been studied. Furthermore, the dynamic design of the beams has not been investigated, and the bearing pressure capacity of the supports has not been analyzed. We have investigated timber beams with a rectangular cross-section, and steel beams of rolled I-sections, known as “HEA profiles”. The cost analysis is based mainly on the manufacturing and assembly costs prevalent on the Swedish market. The only environmental impact investigated has been the emission of greenhouse gases. The design calculations are based on the European standards Eurocode 5 and Eurocode 3. Practical implications To achieve sustainability in construction engineering, it is important to study the environmental and economic consequences of the building elements. By combining these two effects with the technical design of buildings made of steel and/or timber, the concept of sustainable development can be achieved in the long run. Social implications The study concerns sustainability of building structures, which is an important of the sustainable development of the society. Originality/value The paper contains new information and will be useful to researchers and civil engineers.
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Fajman, Petr y Jiri Maca. "Historical Timber Structures with Selected Joints". Applied Mechanics and Materials 769 (junio de 2015): 25–28. http://dx.doi.org/10.4028/www.scientific.net/amm.769.25.
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Repairs of historical timber structures lead to connecting existing and new beams. The requirements for beam authenticity make use of older ways of connecting. The first type is the splice of beams in bending with the scarf joint, rafters and tie-beams are joined with the dovetail and, finally, the connection of the main joist with the strut is by the mortise carve.
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Pupsys, Tomas, Marco Corradi, Antonio Borri y Leon Amess. "Bending Reinforcement of Full-Scale Timber Beams with Mechanically Attached GFRP Composite Plates". Key Engineering Materials 747 (julio de 2017): 212–19. http://dx.doi.org/10.4028/www.scientific.net/kem.747.212.
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This paper presents the results of an experimental campaign aimed to evaluate the performance of timber beams strengthened in bending using GFRP (Glass Fiber Reinforced Polymer) plates mechanically attached with high-strength metal screws. Modest ratios of GFRP composite reinforcement can increase beam load-carrying capacity and manipulate failure mode from the brittle tensile in the unreinforced beams to a more extensible failure in the strengthened timber beams. Application of mechanical reinforcement presents a solution of reversibility, compatibility and durability for reinforced timber. The experimental campaign focused on load-deflection relationship and failure modes in order to increase the bending capacity and stiffness of the timber beam. Oak beams with dimensions 145 x 145 x 2450 mm were reinforced with un-bonded pultruded GFRP plates. Hexagon head coach screws 16 mm diameter, 130 mm length, grade 8.8, were used to mechanically attach the reinforcement along with 34 mm outer diameter fender washers, distributing the fastening load away from the screw’s position. All beams were tested until failure under the four-point bending configuration. Experimental results demonstrate the effectiveness of the reinforcement method and ability to reversibly repair the timber, representing a capability to be utilised in the new constructions or restoration of timber structures.
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Abdulla, Aziz, Reem Mahmoud y Ammar Khazaal. "Toughness of Timber Beams Strengthened with Jute Fibers". Tikrit Journal of Engineering Sciences 27, n.º 3 (25 de diciembre de 2020): 94–112. http://dx.doi.org/10.25130/tjes.27.3.11.
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This research involves investigating the toughness behavior of timber beams strengthened by jute fibers with various forms of strengthening. Ten timber specimens with dimensions (70×100×1000) mm are divided into four groups and loaded under a third point loading. The experimental program was carried out to investigate shear and flexural strengthening effects on toughness, toughness indices, ultimate loads, and the mid-span deflection of the tested beams. One beam as a control beam (un-strengthened beam), four specimens are wrapped in U technique in single and double layers along the whole length of the beam in full and strips wrapping technique, three specimens are wrapped in full technique along the whole length of the beam in full and strips wrapping technique, three timber specimens wrapped in flexural strengthening technique with two, four, and six layers of jute fibers. The results show that jute fibers strengthening increases the toughness ratios of timber beams by about (175%-320%), (190%-401%), and (106%-240%) for U, full, and flexural strengthening techniques, respectively, at the ultimate loads compared with the control beam. Furthermore, it is found that the highest toughness ratio is when the beam is wrapped in full strengthening technique.
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Zhang, Xiaofeng, Youfu Sun, Mingbin Liu y Ruyuan Yang. "Research Progress on Repair and Reinforcement of Beams in Timber Building". MATEC Web of Conferences 275 (2019): 01019. http://dx.doi.org/10.1051/matecconf/201927501019.
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Timber building has been widely used for its renewable, excellent structural performance and aesthetic value. The “beam” is one of the most important components in the upper structure of a timber structure; beam as the main force component is under long-term loading may cause it to crack and resulting in a reduced safety factor. In this paper, the predecessors' research results are analyzed and summarized from the perspectives of the damage reinforcement methods of timber beams in ancient building and modern building, as well as the research hot-pots of modern timber beams, in order to lay the foundation for subsequent related research..
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Hu, Yafeng, Yang Wei, Si Chen, Yadong Yan y Weiyao Zhang. "Experimental Study on Timber−Lightweight Concrete Composite Beams with Ductile Bolt Connectors". Materials 14, n.º 10 (18 de mayo de 2021): 2632. http://dx.doi.org/10.3390/ma14102632.
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A timber–lightweight−concrete (TLC) composite beam connected with a ductile connector in which the ductile connector is made of a stainless−steel bolt anchored with nuts at both ends was proposed. The push−out results and bending performance of the TLC composite specimens were investigated by experimental testing. The push−out results of the shear specimens show that shear–slip curves exhibit good ductility and that their failure can be attributed to bolt buckling accompanied by lightweight concrete cracking. Through the bending tests of ten TLC composite beams and two contrast (pure timber) beams, the effects of different bolt diameters on the strengthening effect of the TLC composite beams were studied. The results show that the TLC composite beams and contrast timber beams break on the timber fiber at the lowest edge of the TLC composite beam, and the failure mode is attributed to bending failure, whereas the bolt connectors and lightweight concrete have no obvious breakage; moreover, the ductile bolt connectors show a good connection performance until the TLC composite beams fail. The ultimate bearing capacities of the TLC composite beams increase 2.03–3.5 times compared to those of the contrast beams, while the mid-span maximum deformation decrease nearly doubled.
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Shekhorkina, S., К. Shliakhov y А. Sopilniak. "EXPERIMENTAL INVESTIGATION OF LOAD-BEARING CAPACITY AND DEFLECTIONS OF FULL-SCALE GLUED LAMINATED TIMBER BEAMS". Odes’kyi Politechnichnyi Universytet Pratsi 2, n.º 61 (2020): 5–11. http://dx.doi.org/10.15276/opu.2.61.2020.01.
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With the transition to the design of timber structures in accordance with European standards, problems arise in assessment of the load-bearing capacity of glued timber structures that are caused by insufficient amount of data about the physical, mechanical and deformation properties of glued timber, which is produced in Ukraine. The aim of the work was to determine the load bearing capacity in bending and deflection of a glued timber beam under the action of a concentrated load in the middle of the span. Two glued laminated timber beams were used in the experiment. Both beams were made using lumber from pine wood and a moisture-curing onecomponent polyurethane adhesive Kleiberit PUR 510 FiberBond. The beams have the dimensions of the cross-section: width of 120 mm and height of 180 mm. The length of the beams was 9880 mm. Each beam consisted of 9 layers of 20 mm thick lamellas glued together. Considering the absence of the data on the strength class of the beam material, the theoretical load bearing capacity and deflection were determined according to the characteristics of the GL24h class (minimum strength class), and amounted to 722 kgf and 19.1 cm, respectively. As a result of the tests, the failure load and the deflection of the beams were determined, and the dependences of the deflection on the load were obtained. The actual deflection of the beams determined was 251 mm and 275 mm, which is 1.31 and 1.44 times higher than the predicted deflection. Accordingly, the failure load determined experimentally is 1.96 and 2.03 times higher than the theoretical value. During the tests, the features of the deformation and the nature of the destruction of the beams were investigated. Wherein, the determining factor was the presence of defects in timber and lamellas joints along the length in the most stressed layers. Based on the data obtained, recommendations on manufacturing aimed at the increasing the bending strength of glued laminated timber beams are given. The results obtained will be further used in the development of structural solutions for hybrid timber-concrete floors.
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Keenan, F. J., J. Kryla y B. Kyokong. "Shear strength of spruce glued—laminated timber beams". Canadian Journal of Civil Engineering 12, n.º 3 (1 de septiembre de 1985): 661–72. http://dx.doi.org/10.1139/l85-073.
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The effect of size on longitudinal shear strength has been well established for Douglas-fir glued–laminated (glulam) timber beams. The present study examined whether this phenomenon exists in glulam beams made of spruce. The experiment consisted of three projects in which beams of various sizes were tested under concentrated mid-span load. The project A beams had clear spruce webs and white elm flanges with cross-sectional dimensions varying from 25 × 25 mm to 75 × 75 mm. The project B beams had spruce glulam webs with Douglas-fir flanges; cross sections ranged from 20 × 100 mm to 90 × 200 mm. In project C, three groups of 10 replications of commercially representative sizes of glulam beams were made from stiffness-rated spruce–pine–fir lumber. The beam cross sections were 76 × 200 mm, 76 × 400 mm, and 127 × 400 mm.The results indicated that depth, width, and shear plane had significant effects on the longitudinal shear strength of the beams in project A. Depth, width, and shear span of the small glulam beams in project B also had highly significant effects on shear strength. However, no effects of depth and width on the shear strength of glulam beams in project C were found. Regression analysis showed no dependence of shear strength on sheared volume for the beams of all three projects. The three-parameter Weibull model also failed to predict the near-minimum shear strength of spruce glulam beams. The results suggested that the lower-bound shear strength of spruce glulam beams is a constant (regardless of beam volume) and could be used as a single characteristic value for glulam design in shear. Further review of published data indicates that this may also be the case for Douglas-fir glulam but with a lower characteristic value than for spruce.
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Naychuk, Anatoly Yakovlevich. "Estimation of Load-Bearing Capacity and Stiffness of Timber Beams with Through-Thickness Cracks". Advanced Materials Research 778 (septiembre de 2013): 361–68. http://dx.doi.org/10.4028/www.scientific.net/amr.778.361.
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The results of experimental and theoretical study of the load-bearing capacity and stiffness of wooden beams with through-thickness cracks depending on their length and location throughout the height of cross-section are given. The analysis of the regularity of change of stress-strain state, stress intensity factors (SIF) and at crack tips, deflections and timber beams load-bearing capacity depending on beam span length versus cross-section height, crack length versus span length, crack location throughout beam height was made. It has been established that load-bearing capacity and stiffness of timber beams with through-thickness cracks depends not only on the crack length, but its location throughout cross-section height as well. Procedure of assessing load-bearing capacity and stiffness of timber beams with through-thickness cracks based on fracture mechanics methods is given.
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Boytemirov, Farid A., Dmitry D. Koroteev y Makhmud Kharun. "Design of Timber Single-Span Beam with Steel Reinforcement". Materials Science Forum 972 (octubre de 2019): 111–17. http://dx.doi.org/10.4028/www.scientific.net/msf.972.111.
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Vital problem, occurring in the operation process of structures such as timber beams, is the increase of their bearing capacity and span length with keeping their height. One of the possible ways to solve this problem is steel reinforcement of such structures. The aim of the research work is to show possibility of increasing bearing capacity of single-span reinforced timber beams and develop the main points of calculation and design of such structures. The beam is reinforced symmetrically by 2 rods d28 with both sides with Ar=24.63 cm2 (4d28 A300). The reinforcement is placed in compressed and stretched areas. Reinforced timber structures are designed on two groups of limit conditions. Design on the first limit condition (normal and tangential stress) is made using geometric characteristics of rectangular section of reinforced timber beam. Design on the second limit condition is made taking onto account the timber elastic nodule and inertia moment for reinforced timber beam. The main features of joint work of timber and reinforcement, which can increase operation reliability of bearing structures, are shown in the research work.
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Tsalkatidis, Themistoklis. "Numerical simulation and analytical study of glulam timber beams". International Journal of Engineering & Technology 3, n.º 2 (7 de abril de 2014): 129. http://dx.doi.org/10.14419/ijet.v3i2.2140.
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Glulam beams or glued-laminated beams consist of sawn lumber laminations (timber) bonded with an adhesive material. This paper, through the mathematical description of the contact conditions that apply at the interfaces of glulam beams and the development of two three-dimensional finite element models by the use of the ANSYS software package, studies the flexural properties of unreinforced (UGB) and reinforced (RGB) glulam beams. The first computational model presents an unreinforced glulam beam that has been produced by three wood laminations of dimensions 6 by 3.6 by 176 cm. The latter one describes a reinforced glulam beam, which has been produced by gluing a 0.15 cm thick steel plate at the bottom edge of the previously described beam. The computational analysis indicates that the two glulam beams have significantly different bearing capacities under the same load and support conditions. The failure mode of the UGB is brittle whereas the one of the RGB is ductile. The numerical results of both models are in close agreement with experimental ones from the international literature. Keywords: Glulam Timber Beams, Numerical Simulation, Contact.
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Klapálek, Pavel y Lenka Melzerová. "Effect of Distribution of Knots on the Strength of the Glued Laminated Timber Beams". Applied Mechanics and Materials 732 (febrero de 2015): 365–68. http://dx.doi.org/10.4028/www.scientific.net/amm.732.365.
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This article will examine the effect of the knots distribution on strength of glued laminated timber beams. A finite element model was made to simulate glued laminated timber beams with defects (knots) to simulate and predict behavior in areas containing knots while bending. This model was then compared with results from static bending test of glued laminated timber beam. The initial position of the rupture was then compared with FEM model [6], so the influence of knots on strength could be determined.
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Chen, Li Ping, Guo Jing He y Hong Zhi Xiao. "Review on Shear Connectors in Timber-Concrete Composite Beams". Applied Mechanics and Materials 744-746 (marzo de 2015): 274–78. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.274.
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The timber-concrete composite (TCC) beam is a new type of structural member, which formed by combing a timber beam and an upper concrete flange using different types of connectors. Compared with the traditional timber beam, the bending and stiffness of the composite beam is proved. In composite structure, the important factor of the structure is the shear connector. So structural efficiency of a TCC highly depends on the stiffness of the interlayer connection. This paper presents a survey on the state-of-the-art of shear connectors for TCC beam research in the past and recent years. And put forward to the subsequent study of shear connectors in TCC beams.
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Mahmoud, Reem Thaker, Aziz Ibrahim Abdulla y Ammar S. Khazaal. "Behavior of Timber Beams Strengthened by Jute Fibers". Journal of advanced Sciences and Engineering Technologies 3, n.º 1 (3 de enero de 2020): 1–20. http://dx.doi.org/10.32441/jaset.03.01.01.
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The study involves strengthening timber beams by known jute fibers with various forms of strengthening and comparison the bending test results with the control beams and beams strengthened by steel plates. Twenty-two timber specimens with dimensions (70×100×1000) mm are divided into eight groups and loaded under a one-point load. The work is carried out to study the flexural and shear strengthening effects on behavior of the tested beams. Four specimens wrapped in U technique in single and double layers, along the whole length of the beam in full and strips wrapping technique, seven beams bonded in full and spiral configuration, seven timber specimens wrapped in flexural strengthening technique with single and multiple layers, and two samples strengthened by steel plates. The results show that jute fibers strengthening are improved the ultimate loads of timber beams by between (30%-101%) compared with the control beams for different types of strengthening and by about (80%, 85%) using steel plates strengthening. On the other hand, the mid-span deflection are decreased by between (28%-45%) at the same load. Furthermore, it is found that the highest ultimate load deflection is when the beam wrapped in full strengthening technique. The ductility, stiffness, toughness at yield load and toughness at ultimate load are increased by between (21%-51%), (10%- 73%), (45%-373%), and (57%-401%), respectively. The jute fibers strengthening have high elasticity performance and prove that the jute fibers materials have a large potential to act as a structural strengthening material.
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Du, Hao, Xiamin Hu, Zhixiang Sun y Weijie Fu. "Shear stiffness of inclined screws in timber–concrete composite beam with timber board interlayer". Advances in Structural Engineering 23, n.º 16 (15 de julio de 2020): 3555–65. http://dx.doi.org/10.1177/1369433220940814.
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The timber board interlayer is applied as the formwork for the pouring of concrete slab in various practical applications of timber–concrete composite structures, with the rehabilitation of timber buildings, in particular. At present, there are few studies performed to study the shear stiffness of inclined screws in timber–concrete composite beams with timber board interlayer. In this article, eight groups of shear tests were carried out to study the shear stiffness of inclined screws in timber–concrete composite beams with timber board interlayer. The key parameters included the embedment depth of the screw connector into timber, screw diameter, the thickness of concrete slab, and concrete strength. As indicated by the test results, the shear stiffness of the inclined screws was improved as the embedment depth of screw into timber and screw diameter increased. When the embedded depth of screw into concrete remained unchanged, the thickness of concrete slab and concrete strength exhibited no significant impact on the shear stiffness of inclined crossing screws. On the basis of the theory of a beam on a two-dimensional elastic foundation, the calculation method for predicting the shear stiffness of inclined screw in timber–concrete composite beams with interlayer was proposed. The comparisons demonstrated that the shear stiffness of inclined screw can be well predicted using the calculation method.
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Gugutsidze, G. y F. Draškovič. "Reinforcement of timber beams with carbon fibers reinforced plastics". Slovak Journal of Civil Engineering 18, n.º 2 (1 de junio de 2010): 13–18. http://dx.doi.org/10.2478/v10189-010-0006-4.
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Reinforcement of timber beams with carbon fibers reinforced plasticsWood is a polymeric material with many valuable features and which also lacks some negative features. In order to keep up with high construction rates and the minimization of negative effects, wood has become one of the most valuable materials in modern engineering. But the use of timber material economically is also an actual problem in order to protect the environment and improve natural surroundings. A panel of scientists is interested in solving these problems and in creating rational structures, where timber can be used efficiently. These constructions are as follows: glue-laminated (gluelam), composed and reinforced wooden constructions. Composed and reinforced wooden constructions are examined less, but according to researches already carried out, it is clear that significant work can be accomplished in creating rational, highly effective and economic timber constructions. The paper deals with research on the formation of composed fiber-reinforced beams (CFRP) made of timber and provide evidence of their effectiveness. The aim of the paper is to investigate cross-bending of CFRP-reinforced gluelaminated timber beams. According to the results we were able to determine the additional effectiveness of reinforcement with CFRP (which depends on the CFRP material's quality, quantity and module of elasticity) on the mechanical features of timber and a whole beam.
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Szumigała, Maciej, Marcin Chybiński y Łukasz Polus. "Preliminary Analysis of the Aluminiumtimber Composite Beams". Civil and Environmental Engineering Reports 27, n.º 4 (20 de diciembre de 2017): 131–41. http://dx.doi.org/10.1515/ceer-2017-0056.
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Abstract This paper presents a new type of composite structures - aluminium-timber beams. These structures have an advantage over other existing composite structures, because they are lighter. However, their application may be limited due to the high price of aluminium alloys. The authors of this article made an attempt to calculate the load-bearing capacity of an aluminium-timber beam.
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Čechavičius, Rimantas. "INVESTIGATIONS INTO THE DEFLECTION OF REINFORCED MULTI-LAYER PRESTRESSED TIMBER BEAMS UNDER SHORT- AND LONG-TIME SHEAR/MEDINIŲ DAUGIASLUOKSNIŲ ARMUOTŲ SIJŲ STANDUMO TYRIMAI VEIKIANT TRUMPALAIKĖMS IR ILGALAIKĖMS SKERSINĖMS JĖGOMS". JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 4, n.º 4 (31 de diciembre de 1998): 266–73. http://dx.doi.org/10.3846/13921525.1998.10531416.
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The article continues a series of papers dealing with the investigations into the strength of multi-layer beams under the action of shear [1, 2]. The results of research on the stiffness of timber reinforced beams are presented. As a result of experiments the authorial certificates of five inventions were obtained. One of them is the certificate of the invention SU 1091047 A, G 01 M5/00 “The equipment of experiment of building constructions” [3]; it is also described in the paper. The objective of the experiments was to check the new method of increasing load-bearing capacity of timber multi-layer beams: prestress of separate wooden layers across the axis of the element, described in the above-mentioned papers [1,2]. The results of investigations in stiffness of 28 timber reinforced beams of different cross-section and the way of manufacture under the action of shear are given in the paper. Sixteen beams were tested by static short-time loading and the rest twelve by static long-time loading. All beams failed because of shear. It was determined that deflections of timber reinforced beams under short-time design loads independently on the constructions are much larger (in average 1.48–1.88 times) than those calculated according to the running standards. Because of insufficient evaluation of the shear influence on the deflections the author offers to make it more precise with the help of coefficient k c in the formula (1): for timber reinforced beams without prestressing k c = 2.75, for multi-layer beams with prestressing k c = 1.75. Deflections of timber reinforced beams, of multi-layer beams with prestressing among them at the time of failure under short-time loading are in average 4.75–5.08 times and under long-time loading—5.59- 6.75 times bigger than those calculated according to the codes of practice for the same beams under design loads. Deflections at the time of timber reinforced beams, that have not failed because of longtime loading and have been tested by static short-time loading were smaller than those fixed during a long-time testing under much smaller (0.50÷0.78 V u,t ) loads, but the deflections of the same beams under design loads are close to those (f et /f e =0.97÷0.99) calculated according to the codes of practice. The efficiency of the experiments of building structures may be significantly enlarged when using the test equipment, presented in the invention SU 1091047 [3], the formula of which is as follows: the equipment of building structure test consists of the beam with support, loading and measuring devices and differs in setting of the structure loading devices on different sides of the beam for increasing the effect of the experiment (Fig 7).
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Monteiro, Sandra, Alfredo Dias y Sérgio Lopes. "Transverse Distribution of Concentrated Loads on Timber Composite Floors". Proceedings 2, n.º 23 (1 de noviembre de 2018): 1421. http://dx.doi.org/10.3390/proceedings2231421.
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Timber-concrete composite floors can be seen as bi-dimensional elements constituted by repeatable longitudinal elements (timber beams) connected through an element capable to spread the load on the transverse direction (concrete slab). This is usually a fact to “take advantage of” in terms of design, in the light of current regulations, with the analysis of a “T-shape” beam. Nevertheless, when concerning the action of concentrated loads, considering them supported entirely by the beam to which they are applied can result in a disadvantage rather than an advantage. This study focus on the distribution of load in the transverse direction when composite floors are subjected to concentrated loads. There were analyzed not only timber-concrete composite floors, that already have proven their value, but also relatively new solutions as those using cross laminated timber (CLT) combined with steel beams. The results show that the load received by “the loaded beam” can be far from 100%.
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Kieslich, Hubertus y Klaus Holschemacher. "Lateral Load Bearing Behavior of Timber-Concrete Composite Constructions". Advanced Materials Research 778 (septiembre de 2013): 665–72. http://dx.doi.org/10.4028/www.scientific.net/amr.778.665.
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The idea to combine the building materials timber and concrete is well known since the 20th of the last century. While timber is beneficial in bearing tensile forces, concrete on the contrary sustains compressive forces very well. Thus, connecting both materials in the way that loads can be transferred between them, their advantages can be used to improve the load bearing capacity of structures. A lot of researches were carried out to investigate different problems of timber-concrete composite (TCC) constructions during the last years. Yeoh et al. [1] for example gave an overview of different full-scale short-term collapse tests in order to evaluate the load bearing behavior of different TCC systems. Nevertheless, some questions are still very few explored, among them is the lateral load bearing behavior of TCC constructions. These structures can be considered as 3 dimensional plane structures, being able to distribute loads along and perpendicular to the span of the timber beams. A concentrated load (applied to one beam of the TCC construction) will deflect it due to bending. All beams are connected with each other because of the concrete slab. For this reason adjacent beams also deflect even if no loads are applied to them directly. These beams contribute to the load bearing of the loaded beam and relieve it partly from the loads, reducing stress in this beam. The described behavior, of distributing loads perpendicular to the span, is called lateral load bearing behavior. This paper will report on short-term bending testes of TCC slabs, carried out at Leipzig University of Applied Sciences. Several slabs have been tested. Each of them had a span of 3.9 m, consisting of three timber beams (10/20 cm) and a connecting concrete slab (thickness 6 cm). Only the middle beam was loaded in the third part points. During the test deflections, as well as strains, at different points were recorded. Additionally, the concrete properties were determined and push out tests were carried out. Overall, seven TCC slabs were manufactured and tested. With the slabs several parameters have been varied, e.g. the type of concrete, the stiffness of the connection system, and the center distance of the timber beams. By varying these three parameters, their effect on the lateral load distribution was examined by measuring deflection and strain at different points of the composite slab. A timber beam ceiling, as reference sample, without concrete topping was tested additionally. The experiments and its results will be described in detail in the paper.
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GLIŠOVIĆ, Ivan, Marko PAVLOVIĆ, Boško STEVANOVIĆ y Marija TODOROVIĆ. "NUMERICAL ANALYSIS OF GLULAM BEAMS REINFORCED WITH CFRP PLATES". Journal of Civil Engineering and Management 23, n.º 7 (13 de julio de 2017): 868–79. http://dx.doi.org/10.3846/13923730.2017.1341953.
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This paper presents an analysis of bending behaviour of glued laminated timber (glulam) beams reinforced with carbon fibre reinforced polymer (CFRP) plates, based on finite element numerical modelling. Nonlinear 3-dimensional model was developed and validated by experimental tests carried out on unreinforced beams and beams reinforced with two different reinforcement arrangements. Suitable constitutive relationships for each material were utilised in the model, as well as anisotropic plasticity theory for timber in compression. Adhesive bond between CFRP plate and timber was modelled as a perfect connection. Beam failure in the model was defined by maximum stress criterion. The predicted behaviour of beams has shown good agreement with the experimental results in relation to load-deflection relationship, ultimate load, elastic stiffness and strain profile distribution. The non-linear behaviour of reinforced beams before failure was also achieved in the numerical analysis, confirming the finite element model to be accurate past the linear-elastic range. Experimentally tested reinforced beams usually failed in tensile zone after compressive plasticization of top lamination, which was also simulated in the numerical model. The results proved that the load carrying capacity, stiffness and ductility of glulam beams were successfully increased by addition of CFRP plate at tension side of the section.
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Xiao, Run Hua, Jian Chun Li y Ri Jun Shrestha. "Investigations of Vibration Based Condition Assessment of Timber Beams Strengthened with Fiber Reinforced Polymer". Advanced Materials Research 831 (diciembre de 2013): 53–57. http://dx.doi.org/10.4028/www.scientific.net/amr.831.53.
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In recent years, research trend on structural condition assessments have largely shifted toward utilizing vibration based methods for structural damage detection and evaluation. On the other hand, research and applications on use of fiber reinforce polymer (FRP) on timber for strengthening or repair damaged timber members in various types of timber structures has also become increasingly popular. Although the application of FRP for repair and/or strengthening of structures has been researched for a long time, research on non-destructive assessment or evaluation of the effectiveness and reliability after FRP repairing or strengthening is yet to be carried out. In this paper, the authors made an attempt on investigation of such issue utilizing Damage Index method, which is a robust vibration-based approach for damage detection. The investigation was aiming at localizing and quantifying damage in timber beams and, more importantly evaluating the effectiveness after the damage was repaired. An experimental program was carried out on five laminated veneer lumber (LVL) beams. Various damage scenarios (i.e. severe, medium, light damage) are introduced on these beams and then repaired with carbon fiber reinforced polymer (CFRP). Experimental results indicate that the use of CFRP was effective in repairing the damaged timber beams. Utilizing Damage Index method can accurately detect the damage location. However, the investigation also shows that direct application of the Damage Index for evaluation of the effectiveness of rehabilitation of the damaged timber beam is not satisfactory. Further investigation and modification of the Damage Index method will be carried out in next stage research.
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Wang, Jiejun, Ying Lu, Yun Lei y Haolei Wang. "Comparative Study on Flexural Behavior of Steel–Timber Composite beams and Glued Timber I-Beams". Journal of Engineering Science and Technology Review 13, n.º 6 (diciembre de 2020): 175–86. http://dx.doi.org/10.25103/jestr.136.24.
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Lukin, Mikhail, Evgeny Prusov, Svetlana Roshchina, Maria Karelina y Nikolay Vatin. "Multi-Span Composite Timber Beams with Rational Steel Reinforcements". Buildings 11, n.º 2 (29 de enero de 2021): 46. http://dx.doi.org/10.3390/buildings11020046.
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Wooden multi-span beams with steel reinforcement were studied experimentally on a stationary stand using an eight-point loading scheme that simulated a load uniformly distributed over the beam span. The studies were carried out on beams with a span of 4.8 m with a cross-sectional area of 40 mm × 80 mm, reinforced in the stretched zones of the cross-section with rods made of hot-rolled steel reinforcement of A400 class. The rational zones for the location of reinforcements in the tensioned and compressed zones of the beams were determined. The rational placements of reinforcement in the support and span zones was based on the numerical simulation of the volumetric stress state calculated using the finite element method. It was experimentally confirmed that the failure of wood composite beams had a plastic nature and occurred only along normal sections. This excluded the possibility of brittle fracture from shear stresses and ensured the operational reliability of structures as a whole. It was shown that the proposed rational reinforcement of wooden beams increased their bearing capacity by 175% and reduced bearing deformability by 85%. The results obtained indicated high efficiency of the application of the developed method of reinforcement in beams of roofs and floors of buildings.
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Dong, Shi Hai, Jiang Feng Dong y Q. Y. Wang. "Experimental Study on Properties of Different Angles of FRP Shear Reinforced Timber Beams". Advanced Materials Research 860-863 (diciembre de 2013): 1310–15. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.1310.
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Study of fiber reinforced plastics (i.e. CFRP, BFRP and AFRP) for rectangular beams reinforcement effect, using the FRP were 90o vertically and 45o slantingly parceled 10 rectangular timber beams shear performance, recorded specimen failure process. This paper analyzes the different FRP reinforcement plies, different reinforcement on beam properties of specimen, failure mode, bearing capacity, load-deflection relationship and strain distribution. The results showed that: FRP changed beams brittle failure mode, improve the beam bending, shear performance, ultimate bearing capacity increased by 28.2%~55.1%, the stiffness of the specimen and also improved ductility. In addition, its more effective to paste the FRP sheets vertically than slantingly with the angle of 45°. Using FRP strengthening beams the performance of the method is effective, the method can significantly improve the performance of wood. To improve the utilization efficiency of wood, expand the application range of timber provides useful reference.
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Aguwa, J. I. y S. Sadiku. "Reliability Studies on Timber Data from Nigerian Grown Iroko Tree (Chlorophora excelsa) as Bridge Beam Material". International Journal of Engineering Research in Africa 8 (diciembre de 2012): 17–35. http://dx.doi.org/10.4028/www.scientific.net/jera.8.17.
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This paper provides the results of structural reliability analysis carried out on the data of Nigerian grown Iroko tree (Chlorophora excelsa), to ascertain its structural performance as timber bridge beams. Five pieces of 50mm x 75mm x 3600mm of Nigerian grown Iroko hardwood were bought, seasoned naturally and 200 pieces of samples were prepared for determination of their strength properties, (which include bending strength parallel to grain, tensile strength parallel to grain, compressive strength parallel to grain, compressive strength perpendicular to grain and shear strength parallel to grain) at a moisture content of 18%, in accordance with the British Standard BS 373 of 1957. Statistical analysis was carried out using the strength properties for determination of mean, standard deviation, coefficient of variations, confidence limits and Chi-Square goodness of fits. Structural analysis and design of a timber bridge beam using the determined data from the Nigerian grown Iroko timber, in accordance with BS 5268 were carried out under the Ultimate Limit State of loading (ULSL). Reliability analysis was carried out to ascertain its level of safety using First-Order Reliability Method (FORM). Sensitivity analysis was also carried out by varying the depth of beam, imposed live load, breadth of the beam, unit weight of the Iroko timber, span of the beam as well as the end bearing length. The result revealed that the Nigerian grown Iroko timber is a satisfactory structural material for timber bridge beams at depth of 400mm, breadth of 150mm and span of 5000mm under the ULSL. The probabilities of failure of the Nigerian grown Iroko timber bridge beam in bending, shear, compression and deflection are respectively, under the specified conditions of loading.
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Martínez-Martínez, Juan Enrique, Mar Alonso-Martínez, Felipe Pedro Álvarez Rabanal y Juan José del Coz Díaz. "Finite Element Analysis of Composite Laminated Timber (CLT)". Proceedings 2, n.º 23 (6 de noviembre de 2018): 1454. http://dx.doi.org/10.3390/proceedings2231454.
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In the research for sustainable construction, cross-laminated timber (CLT) has gained popularity and become a widely used engineered timber product. However, there are few numerical studies of the structural behaviour of CLT. Among other issues, the orthotropic properties of CLT complicate finite element analysis (FEA). This paper presents a finite element model (FEM) to predict the structural behaviour of CLT beams subjected to sustained flexural loading. This numerical model includes a material model based on the orthotropic material properties of different timber species. Furthermore, the orientation and the properties of each layer are considered. Most of the previous studies simulate CLT beams as a homogeneous material. However, in this work the CLT beam is modelled as a composite material made up of five layers with different orientations and properties. Bonded contacts are used to define the interaction between layers. In addition, nonlinearities, such as large displacement, are used to simulate the behaviour of CLT beams. The model provides the load-displacement relationship and stress concentration. Tsai-Wu failure criteria is used in the simulation to predict the failure modes of the CLT beams studied.
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Johns, Kenneth C. y Simon Lacroix. "Composite reinforcement of timber in bending". Canadian Journal of Civil Engineering 27, n.º 5 (1 de octubre de 2000): 899–906. http://dx.doi.org/10.1139/l00-017.
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A promising use for high performance composite materials is to reinforce timber beams. The present paper studies the use of carbon and glass fibres to reinforce sawn timber sections. Consideration is given to strength phenomena of commercial timber alone and in reinforced sections in bending and shear. Anchorage length considerations for composite strips applied to the underside of simple beams are discussed. Experimental results are presented for three geometries of reinforcement using matched samples of 25 pairs of beams, reinforced and not. Results establish that the wood itself in the composite section shows strength increase, and that the increase in moment resistance of the reinforced beams is far greater than that predicted by simple models.Key words: composite material, timber, reinforcement, bending, shear.
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Svecova, D. y R. J. Eden. "Flexural and shear strengthening of timber beams using glass fibre reinforced polymer bars — an experimental investigation". Canadian Journal of Civil Engineering 31, n.º 1 (1 de enero de 2004): 45–55. http://dx.doi.org/10.1139/l03-069.
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An experimental program was undertaken at The University of Manitoba to test timber stringers strengthened with glass fibre reinforced polymer (GFRP) bars. Various strengthening schemes were investigated as a means of increasing the load carrying capacity of timber stringers in shear and flexure. The shear strengthening was achieved by inserting GFRP dowels in the centre of the cross section along the length of the stringers. The flexural strengthening used the concept of near-surface-mounted GFRP bars. Fifty beams were tested to evaluate the performance of the various strengthening schemes. The behaviour of the beams is described in terms of mode of failure, mechanical properties, and load–deflection behaviour. This study found that strengthening timber stringers with GFRP reinforcement increased the ultimate strength of the stringers and reduced its variability. It is believed that the shear and flexural GFRP reinforcements act as a truss member within the timber beam and bridge the local defects and discontinuities of the timber.Key words: timber, glass fibre reinforced polymer, bridge, stringers, dowels, strengthening, ductility.
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Islam, Md Mashfiqul, Ashfia Siddique, Alireza Pourhassan, Md Arman Chowdhury y Jarin Tasnim. "Flexural Capacity Enhancement of Timber Beams Partially Confining the Principal Compression Arch using Carbon Fiber Reinforced Polymer Composites". Transportation Research Record: Journal of the Transportation Research Board 2673, n.º 11 (12 de junio de 2019): 276–85. http://dx.doi.org/10.1177/0361198119851051.
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Timber is widely used as a structural element because of its engineering and mechanical properties. This study focuses on the flexural behavior of timber beams externally reinforced with carbon fiber reinforced polymer (CFRP) composites at the tension face and the responses of the fundamental principal compression arch because of confinement from end anchorage. Beams of three different types of timber are studied. All the beams had the same length, width, and span length and were tested under four-point loading. Different CFRP lamination techniques were adopted, with and without U-clamp confinement as end anchorage, to investigate the flexural capacity enhancement of CFRP strips as reinforcement for timber beams. The profile of the principal compression arch is estimated experimentally from fundamental flexural strain-along-depth phenomena by post-processing high definition images extracted from test videos employing digital image correlation technique (DICT) in the MATLAB R2011a framework. Similar responses were found from finite element analysis using ANSYS 11.0. Effective confinement of the principal compression arch produced significant enhancements of flexural capacities and stiffness in the strengthened timber beams.
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Kinjo, Hitoshi, Yusuke Katakura, Takeo Hirashima, Shuitsu Yusa y Kiyoshi Saito. "Deflection behavior and load-bearing period of structural glued laminated timber beams in fire including cooling phase". Journal of Structural Fire Engineering 9, n.º 4 (10 de diciembre de 2018): 287–99. http://dx.doi.org/10.1108/jsfe-01-2017-0009.
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Purpose This paper aims to discuss the fire performance of glulam timber beams based on their deflection behavior and load-bearing period, which were obtained from load-bearing fire tests under constant load conditions. Design/methodology/approach In this report, the fire performance, primarily deflection behavior and load-bearing period of glued laminated (glulam) timber beams will be discussed from the standpoint of load-bearing fire tests conducted during the cooling phase under constant load conditions. Then, based on the charring depth and the per section temperature transformation obtained from loading test results, the load-bearing capacity of the glulam timber beams will be discussed using the effective section method and the strength reduction factor, which will be calculated in accordance with the European standards for the design of timber structures (Eurocode 5). Findings In the cooling phase, the charring rate is decreases. However, as the temperature in the cross section rises, the deflection is increases. The failure mode was bending failure because of tensile failure of the lamina at the bottom of the beam. Moreover, a gap caused by shear failure in a growth ring in the beam cross-section in the vicinity of the centroid axis was observed. Shear failure was observed up until 1 to 3 h before end of heating. The calculated shear strength far exceeded the test results. Shear strength for elevated temperature of glued laminated timber is likely to decrease than the shear strength in Eurocode 5. Originality/value Unlike other elements, a characteristic problem of timber elements is that their load-bearing capacity decreases as they are consumed in a fire, and their bearing capacities may continue to degrade even after the fuel in the room has been exhausted. Therefore, the structural fire performance of timber elements should be clarified during not only the heating phase but also the subsequent cooling phase. However, there are few reports on the load-bearing capacity of timber elements that take the cooling phase after a fire into consideration.
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Khelifa, M., N. Vila Loperena, L. Bleron y A. Khennane. "Analysis of CFRP-strengthened timber beams". Journal of Adhesion Science and Technology 28, n.º 1 (9 de julio de 2013): 1–14. http://dx.doi.org/10.1080/01694243.2013.815096.
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Al-Hayek, Hanan y Dagmar Svecova. "Flexural Strength of Posttensioned Timber Beams". Journal of Composites for Construction 18, n.º 2 (abril de 2014): 04013036. http://dx.doi.org/10.1061/(asce)cc.1943-5614.0000431.
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Green, David W., Thomas M. Gorman, James W. Evans y Joseph F. Murphy. "Mechanical Grading of Round Timber Beams". Journal of Materials in Civil Engineering 18, n.º 1 (febrero de 2006): 1–10. http://dx.doi.org/10.1061/(asce)0899-1561(2006)18:1(1).
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Bell, Kolbein y Trond Even Eggen. "Stability of Timber Beams and Columns". IABSE Symposium Report 85, n.º 9 (1 de enero de 2001): 30–36. http://dx.doi.org/10.2749/222137801796348421.
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Bocchio, Nicoletta, Paola Ronca y Jan-Willem Van De Kuilen. "Impact Loading Tests on Timber Beams". IABSE Symposium Report 85, n.º 6 (1 de enero de 2001): 19–24. http://dx.doi.org/10.2749/222137801796348818.
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Klapálek, Pavel, Lenka Melzerová y Tomáš Plachy. "Pulse Method Used for Non-Destructive Assessment of Glued Laminated Timber Beams". Applied Mechanics and Materials 827 (febrero de 2016): 231–34. http://dx.doi.org/10.4028/www.scientific.net/amm.827.231.
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This text is focused on GLULAM (glued laminated timber) beams and determination of their properties. This text is mainly focused just on part of more complex research of glued laminated timber beams. This text is focused on pulse method, which is used to determine the dynamic modulus of elasticity of GLULAM beams. This text will describe how the pulse method works, with basic description, describes the tested material and compare the results of testing. In the conclusion we discuss the results, make conclusions and describe the way of our further research of glued laminated timber beams.
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Rodacki, Konrad. "The Load-Bearing Capacity of Timber-Glass Composite I-Beams Made with Polyurethane Adhesives". Civil and Environmental Engineering Reports 27, n.º 4 (20 de diciembre de 2017): 105–20. http://dx.doi.org/10.1515/ceer-2017-0054.
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Abstract This article discusses the issue of composite timber-glass I-beams, which are an interesting alternative for load-bearing beams of ceilings and roofs. The reasoning behind the use of timber-glass I-beams is the combination of the best features of both materials - this enables the creation of particularly safe beams with regard to structural stability and post-breakage load capacity. Due to the significant differences between the bonding surfaces of timber and glass, a study on the adhesion of various adhesives to both surfaces is presented at the beginning of the paper. After examination, two adhesives were selected for offering the best performance when used with composite beams. The beams were investigated using a four-point bending test under quasi-static loading.
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FORTI, N. C. S., T. L. D. FORTI, A. E. P. G. A. JACINTHO y L. L. PIMENTEL. "Finite element analysis of composite concrete-timber beams". Revista IBRACON de Estruturas e Materiais 8, n.º 4 (agosto de 2015): 507–28. http://dx.doi.org/10.1590/s1983-41952015000400006.
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AbstractIn the search for sustainable construction, timber construction is gaining in popularity around the world. Sustainably harvested wood stores carbon dioxide, while reforestation absorbs yet more CO2. One technique involves the combination of a concrete slab and a timber beam, where the two materials are assembled by the use of flexible connectors. Composite structures provide reduced costs, environmental benefits, a better acoustic performance, when compared to timber structures, and maintain structural safety. Composite structures combine materials with different mechanical properties. Their mechanical performance depends on the efficiency of the connection, which is designed to transmit shear longitudinal forces between the two materials and to prevent vertical detachment. This study contributes with the implementation of a finite element formulation for stress and displacement determination of composite concrete-timber beams. The deduced stiffness matrix and load vector are presented along to numerical examples. Numerical examples are compared to the analytical equations available in Eurocode 5 and to experimental data found in the literature.
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Zhu, Yan Mei, Lang Li, Min Hou y Qing Yuan Wang. "Mechanical Performance of Timber Beams Reinforced by FRP Sheets". Applied Mechanics and Materials 275-277 (enero de 2013): 1199–202. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.1199.
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In order to improve the mechanical performance of timber beams, five rectangular-section beams were used in flexural test and ten for shearing. The effects of FRP types i.e. CFRP, BFRP and AFRP, layers of FRP sheets and the way FRP sheets pasted were studied. The failure pattern, load-deflection curve, strain distribution and ultimate load capacity of the specimens were analyzed. The results indicate that the ultimate load carrying capacity of beams were increased by 15.4% to 55.1% varyingly with the reinforcement of FRP, besides, the stiffness and ductility were improved also. The improvements were lower in the specimens with material defects such as the existence of knags and shrink cracks. It’s more effective to paste the FRP sheets slantingly with the angle of 45° than vertically. However, the effect on the initial stiffness is not distinct whether reinforced or not. The analysis of strain and stress distribution manifests that the plane cross-section assumption is efficient in design and calculation of FRP reinforced timber beam.
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Sógel, K. "Timber beams subjected to long - term loading". Slovak Journal of Civil Engineering 18, n.º 3 (1 de septiembre de 2010): 21–26. http://dx.doi.org/10.2478/v10189-010-0013-5.
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Timber beams subjected to long - term loadingWood is a significant structural material, which is often used for timber bearing structures. Elements of timber structures must especially satisfy safety requirements, which are expressed by the ultimate limit states in the established standards. The structure must also satisfy the serviceability limit states. Local and global deformations make it impossible for the structure to serve the purpose it was designed for. It is important to take the deflections and their possible increase into account in the design to provide a structure which can be used during the whole period of service. Based on earlier examinations, it is known that a timber element over the course of long-term loading shows creep behavior. The structure of wood is able to adapt to the conditions of the surrounding environment. The properties of wood are especially affected by the relative humidity of the air and then by the type, intensity and duration of the loading. The most important factors affecting the serviceability of timber structures are volume changes caused by humidity and additional deflections caused by the effects of long-term loading. These phenomena emphasize the importance of serviceability limit states for timber structures. The paper deals with a long-term experimental investigation of timber girders that are currently often used. The aim was to obtain the deflection curves and mark the time dependence and the final deflections. The paper will also define the approximations for simulating the time-dependent deflections and obtain the creep coefficients for calculating the final deflections of the girders investigated.
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Giongo, Ivan, Gianni Schiro y Daniele Riccadonna. "Innovative pre-stressing and cambering of timber-to-timber composite beams". Composite Structures 226 (octubre de 2019): 111195. http://dx.doi.org/10.1016/j.compstruct.2019.111195.
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Mirski, Radosław, Dorota Dziurka, Monika Chuda-Kowalska, Jakub Kawalerczyk, Marcin Kuliński y Karol Łabęda. "The Usefulness of Pine Timber (Pinus sylvestris L.) for the Production of Structural Elements. Part II: Strength Properties of Glued Laminated Timber". Materials 13, n.º 18 (11 de septiembre de 2020): 4029. http://dx.doi.org/10.3390/ma13184029.
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The paper assessed the feasibility of manufacturing glued structural elements made of pine wood after grading it mechanically in a horizontal arrangement. It was assumed that the pine wood was not free of defects and that the outer lamellas would also be visually inspected. This would result in only rejecting items with large, rotten knots. Beams of the assumed grades GL32c, GL28c and GL24c were made of the examined pine wood. Our study indicated that the expected modulus of elasticity in bending was largely maintained by the designed beam models but that their strength was connected with the quality of the respective lamellas, rather than with their modulus of elasticity. On average, the bending strength of the beams was 44.6 MPa. The cause of their destruction was the individual technical quality of a given item of timber, which was loosely related to its modulus of elasticity, assessed in a bending test. Although the modulus of elasticity of the manufactured beam types differed quite significantly (11.45–14.08 kN/mm2), the bending strength for all types was similar. Significant differences occurred only during a more detailed analysis because lower classes were characterized by a greater variation of the bending strength. In this case, beams with a strength of 24 MPa to 50 MPa appeared.
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Deresa, Simret T., Jinjun Xu, Cristoforo Demartino, Giovanni Minafò y Gaetano Camarda. "Static Performances of Timber- and Bamboo-Concrete Composite Beams: A Critical Review of Experimental Results". Open Construction & Building Technology Journal 15, n.º 1 (31 de marzo de 2021): 17–54. http://dx.doi.org/10.2174/1874836802115010017.
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The use of composite beams made with traditional concrete and bio-based materials (such as timber and bamboo) is a valuable solution to reduce the environmental impact of the building sector. Timber-Concrete Composite (TCC) beams have been used for decades in structural applications such as new buildings, refurbishment of old timber structures, and bridges. Recently, different researchers suggested composite beams based on engineered bamboo, commonly named Bamboo-Concrete Composite (BCC) beams. This study presents a systematic comparison of structural performances and connection behavior of TCC and BCC beams under short-term static load. TCCs beams are compared to BCC ones using similar shear connectors. The most important aspects of the two composite systems are compared: mechanical behavior of connectors and structural behaviors of full-scale composite beams (e.g., failure modes, connection stiffness, connection shear strength, ultimate load-carrying capacity, maximum deflection and composite efficiency). This comprehensive review indicates that BCC beams have similar or even better structural performances compared with TCC.
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Váquez, Manuel C. Touza, Azahara Soilán Cañás y David Lorenzo Fouz. "Evaluation of the Load-Carrying Capacity in Bending of Large Cross Section “Pitch Pine” Beams in Standing Structures". Advanced Materials Research 778 (septiembre de 2013): 410–17. http://dx.doi.org/10.4028/www.scientific.net/amr.778.410.
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This paper deals with the procedure followed in order to define a visual grading protocol to determine the mechanical properties of existing old pitch pine timber beams with large sections. The commercial name pitch pine comprises several species in the group of southern yellow pines, being the Longleaf pine or Georgia pitch pine (Pinus palustris) the most important. Old growth Pinus palustris, was very much appreciated for its rigidity, density, strength properties and natural durability. In Spain, many of the buildings constructed with this timber (named as pino tea) are nowadays under rehabilitation processes which, in some cases, will change the previous use of the building. All these interventions require understanding the mechanical properties of the timber. The structural properties of the aged pitch pine timber are unknown and there is not any European stress grading standard to enable the classification of the existing elements. For this reason, a total of 45 large section pitch pine pieces were visually analyzed and graded according to Spanish standard UNE EN 56.544 [. After this, the beams were tested according to UNE EN 408 [ in order to determine their modulus of rupture and flobal modulus of elasticity. All beams were tested keeping their original positions in the building and a new classification system for old beams is proposed based on a reduced number of chief visual grading parameters and taking into account their position into the beam.
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Cavalli, Alberto y Marco Togni. "The Influence of Routed Grooves on the Bending Behavior of Old Timber Beams". Advanced Materials Research 778 (septiembre de 2013): 393–401. http://dx.doi.org/10.4028/www.scientific.net/amr.778.393.
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Old timber structures represent an important portion of the World cultural heritage: wooden buildings materials and building techniques are part of our history and their conservation is an essential contribution to cultural diversity and global cultural wealth. In recent times, the methods and approaches used to assess and to maintain timber in historic buildings have evolved considerably and various techniques for timber repair and strengthening were developed and deeply investigated. A very common and widely used technique for the timber strengthening-repair is realized by inserting reinforcement materials in grooves cut in the original sound wood. The proposed reinforcement materials are various (fiber reinforced plastic materials, steel bar/s or plate/s, wood and wood products) and the grooves number and depth are variable. Several researches were conducted to determine the Modulus of Elasticity (MOE) of old timber members strengthened with the described technics. A common approach is to consider the strengthened timber beam as a composite one and the MOE of the wooden part correspondent to the original. In practice, the timber members work together with strengthened materials, and the strengthening intervention is planned taking into account both original timber and strengthening material MOEs. The basic assumption of this approach is that the slots executed along the timber length have no effect on the timber MOE. The aim of this research is to investigate the effects of the routed grooves cut along the wooden beams, on the bending MOE of old timber members, to provide important information for the strengthening interventions plan.
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Sandhyavitri, Ari, Fakhri Fakhri, Rizki Ramadhan Husaini, Indra Kuswoyo y 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, n.º 1 (4 de diciembre de 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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Kawalerczyk, Jakub, Marcin Kuliński, Dorota Dziurka y Radosław Mirski. "The possibility to use a side-timber in glulam beams manufacturing for structural applications". Annals of WULS, Forestry and Wood Technology 113 (31 de marzo de 2021): 65–73. http://dx.doi.org/10.5604/01.3001.0015.2334.
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The possibility to use a side-timber in glulam beams manufacturing for structural applications. The aim of presented study was to determine the mechanical properties of three-layered glued structural beams manufactured with the use of side-timber pieces as an outer layers and the fragmented main yield as an inner layer. Four types of beams were pressed and tested in terms of four-point bending strength and modulus of elasticity. Variants differed from each other in the direction of the fibers in the inner layer and in the presence of adhesive layer between the fragmented wood. Studies have shown that the bending strength of the beams depended on the calculation method. Moreover, no significant effect of the inner layer arranging method on the bending strength of the beams was found. The values of modulus of elasticity (MOE) were low. The presented study is a starting point for further investigations concerning the possible way of the rational application of fragmented timber pieces and the side-timber for structural applications.