• Title, Summary, Keyword: composite timber

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A finite element model for long-term analysis of timber-concrete composite beams

  • Fragiacomo, M.
    • Structural Engineering and Mechanics
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    • v.20 no.2
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    • pp.173-189
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    • 2005
  • The paper presents a finite element model for studying timber-concrete composite beams under long-term loading. Both deformability of connection system and rheological behaviour of concrete, timber and connection are fully considered. The creep of component materials and the influence of moisture content on the creep of timber and connection, the so-called "mechano-sorptive" effect, are evaluated by means of accurate linear models. The solution is obtained by applying an effective step-by-step procedure in time, which does not require storing the whole stress history in some points in order to account for the creep behaviour. Hence the proposed method is suitable for analyses of composite beams subjected to complex loading and thermo-hygrometric histories. The possibility to accurately predict the long-term response is then shown by comparing numerical and experimental results for different tests.

Analysis of behaviour for hollow/solid concrete-filled CHS steel beams

  • Kvedaras, Audronis Kazimieras;Sauciuvenas, Gintas;Komka, Arunas;Jarmolajeva, Ela
    • Steel and Composite Structures
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    • v.19 no.2
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    • pp.293-308
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    • 2015
  • Interaction between the external thin-walled steel tube and the internal concrete core significantly increases the bending resistance of composite beams and beam-columns in comparison with the steel or concrete members. There is presented a developed method for design of hollow and solid concrete-filled steel tubular beams based on test data, which gives better agreement with test results than EC4 because its limitation to take an increase in strength of concrete caused by confinement contradicts the recommendation of 6.7.2(4) that full composite action up to failure may be assumed between steel and concrete components of the member. Good agreement between the results of carried out experimental, numerical and theoretical investigations allows recommending the proposed method to use in design practice.

Experimental study of the behavior of composite timber columns confined with hollow rectangular steel sections under compression

  • Razavian, Leila;Naghipour, Morteza;Shariati, Mahdi;Safa, Maryam
    • Structural Engineering and Mechanics
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    • v.74 no.1
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    • pp.145-156
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    • 2020
  • There are separate merits and demerits to wood and steel. The combination of wood and steel as a compound section is able to improve the properties of both and ultimately increase their final bearing capacity. The composite cross-section made of steel and wood has higher hardness while showing more ductility and the local buckling of steel is delayed or completely prevented. The purpose of this study is to investigate the behavior of composite columns enclosed in wooden logs and the hollow sections of steel that will be examined in a laboratory environment under the axial load to determine the final bearing capacity and sample deformation. In terms of methodology, steel sheet and carbon fiber reinforced polymer sheet (FRP) are tested to construct hollow rectangular sections and reinforce timber. Besides, the method of connecting hollow sections and timber including glue and screw has been also investigated. As a result, timber lumber enclosed with carbon fiber-reinforced polymer sheets in which fibers are horizontally located at 90° are more resistant with better ductility.

Structural Properties of Steel-glulam Composite Column

  • Jang, Sang-Sik;Kim, Yun-Hui;Shin, Il-Joong
    • Journal of the Korean Wood Science and Technology
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    • v.38 no.5
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    • pp.399-404
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    • 2010
  • A new green home designed to save money while at the same time saving the environment with some of the finest green features available in the market. Composite column composed of structural steel and structural glued laminated timber is avery Eco-friendly building products for design building because that use recycled or second hand. For compare to compressive strength of structural glued laminated timber (glulam), structural steel, and composite column (steel-glulam), tested compressive strength of each specimen. 1) structural glued laminated timber : Theoretical compressive strength is 151.6 kN similar to elastic limits. 2) structural steel (H type) : Theoretical compressive strength is 148.2 kN little under the elastic limits. 3) structural steel (D type) : Theoretical compressive strength is 147.3 kN upper than the elastic limits. 4) composite column : Actual elastic limits are about 600 kN. Result in, composite column improve compressive strength of Structural steel column and provide structural stability of the building.

Results of Delamination Tests of FRP- and Steel-Plate-Reinforced Larix Composite Timber

  • LEE, In-Hwan;SONG, Yo-Jin;SONG, Da-Bin;HONG, Soon-Il
    • Journal of the Korean Wood Science and Technology
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    • v.47 no.5
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    • pp.655-662
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    • 2019
  • This study evaluated the multi-bonding performances of timbers as well as those of reinforcement and timber to obtain data for preparing guidelines regarding the use of timbers as large structural members. For the multi-bonding performances of timbers, four types of bonding surfaces were prepared according to the pith position. For the bonding performances of FRP (fiber-reinforced plastic)/steel plate and timber, a total of 11 types of specimens were produced for the selection of the appropriate adhesive. The bonding performances of the produced specimens were evaluated through a water soaking delamination test, a water boiling delamination test, and a block shear strength test. The test results showed that the bonding strength of the bonding surface according to the pith position was highest in the specimen for which the two sections with the pith at the center of the cross-section on timber and between the bonding surfaces (the tangential and radial sections were mixed) were bonded. Furthermore, the specimens for which the section (radial section) with the pith on the bonding surface of the timber was bonded showed a high delamination percentage. The results of the block shear strength test showed that the bonding section did not have a significant effect on the shear strength, and that the measured wood failure percentage was higher than the KS standard value. The PVAc adhesive showed the highest bonding strength between larix timber and GFRP (glass FRP). Furthermore, the epoxy and polyurethane adhesives showed good bonding strength for CFRP (carbon FRP) and structure steel, respectively.

Mechanical Properties of Composite Materials Composed of Structural Steel and Structural Glued Laminated Timber (구조용 강철과 구조용 집성재 복합재료 보의 역학적 성질)

  • Jang, Sangsik;Kim, Yunhui;Jang, Youngik
    • Journal of the Korean Wood Science and Technology
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    • v.37 no.4
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    • pp.300-309
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    • 2009
  • The effective utilization of wood structure is encouraged to preserve natural resources and the global environment. Long-span and large-scale structures are preferred to promote demand for wood. This study attempts to develop new Fire-resistance Composite Material composed of Structural steel and Structural glued laminated timber for long-span and large-scale structures. Prior to take a fire-resistance test, compare properties of bending strength with Composite material composed of Structural steel and Structural glued laminated timber, structural steel and structural provides the stability of the structure, but the structural glued laminated timber has high value elasticity of bending. Using the Composite material will improve structural stability and Eco-friend construction environment.

Composite deck construction for the rehabilitation of motorway bridges

  • Greiner, R.;Ofner, R.;Unterweger, H.
    • Steel and Composite Structures
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    • v.2 no.1
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    • pp.67-84
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    • 2002
  • Traffic decks of steel or composite motorway bridges sometimes provide the opportunity of using the composite action between an existing steel deck and a reinforced concrete plate (RC plate) in the process of rehabilitation, i.e., to increase the load-carrying capacity of the deck for concentrated traffic loads. The steel decks may be orthotropic decks or also unstiffened steel plates, which during the rehabilitation are connected with the RC plate by shear studs, such developing an improved local load distribution by the joint behaviour of the two plate elements. Investigations carried out, both experimentally and numerically, were performed in order to quantitatively assess the combined static behaviour and to qualitatively verify the usability of the structure for dynamic loading. The paper reports on the testing, the numerical simulation as well as the comparison of the results. Conclusions drawn for practical design indicated that the static behaviour of these structures may be very efficient and can also be analysed numerically. Further, the results gave evidence of a highly robust behaviour under fatigue equivalent cyclic traffic loading.

Detecting of the defects of pavement of a road by using infrared thermography (열화상 비파괴 검사법을 이용한 도로포장 결함 검출)

  • Sim, Jun-Gi;Kim, Ki-Hyun
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.6 no.3
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    • pp.69-76
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    • 2015
  • The purpose of this paper is to find an limitation to detect the defect of damaged asphalt pavement structures for infrared thermography. We use heat source of a natural light to detect the defect efficiently. The heat source was applied to the asphalt specimens. Four asphalt specimens were used: one was the asphalt containing depth of 1cm internal timber, two was the asphalt containing depth of 2cm internal void, Three was the asphalt containing depth of 3cm internal timber and four was not the asphalt containing internal timber. It was found that the depth of 3cm internal timber could be detected by this method. In addition, we used the image processing to make the damage zone displayed clear in the image obtained from the thermographic operation.

Experimental Evaluation of Shear Bonding Performance of Wood-Steel Composite Members (목재-강재 합성 부재의 전단 부착 성능에 대한 실험적 평가)

  • Park, Keum-Sung;Lee, Sang-Sup;Kwak, Myong-Keun
    • Journal of the Korean Association for Spatial Structures
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    • v.19 no.4
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    • pp.53-60
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    • 2019
  • In this study, an experimental study was carried out to evaluate the bond shear performance according to the shear connector between the glue-laminated timber and steel interface. Ten block shear specimens were fabricated according to the configuration of the adhesive surface of wood and steel. In addition, four test specimens were produced according to the main variable shape of the wood-concrete shear connector. As a result of the block shear test, the shear strength of the steel-wood adhesive is shown to have a shear performance greater than the wood-wood shear strength. As a result of the push-out test according to the shape of the shear connector, the shear strength increased linearly with the attachment area. The complete composite behavior between the glued-laminated timber and the steel can be secured.

Design and modelling of pre-cast steel-concrete composites for resilient railway track slabs

  • Mirza, Olivia;Kaewunruen, Sakdirat;Kwok, Kenny;Griffin, Dane W.P.
    • Steel and Composite Structures
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    • v.22 no.3
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    • pp.537-565
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    • 2016
  • Australian railway networks possess a large amount of aging timber components and need to replace them in excess of 280 thousands $m^3$ per year. The relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) is responsible for producing greenhouse gas emissions 6 times greater than an equivalent reinforced concrete counterparts. This paper presents an innovative solution for the replacement of aging timber transoms installed on existing railway bridges along with the incorporation of a continuous walkway platform, which is proven to provide environmental, safety and financial benefits. Recent developments for alternative composite materials to replace timber components in railway infrastructure construction and maintenance demonstrate some compatibility issues with track stiffness as well as structural and geometrical track systems. Structural concrete are generally used for new railway bridges where the comparatively thicker and heavier fixed slab track systems can be accommodated. This study firstly demonstrates a novel and resilient alterative by incorporating steel-concrete composite slab theory and combines the capabilities of being precast and modulated, in order to reduce the depth, weight and required installation time relative to conventional concrete direct-fixation track slab systems. Clear benefits of the new steel-concrete composites are the maintainability and constructability, especially for existing railway bridges (or brown fields). Critical considerations in the design and finite element modelling for performance benchmarking of composite structures and their failure modes are highlighted in this paper, altogether with risks, compatibilities and compliances.