• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.4
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• pp.163-170
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• 2017

The need for eco-friendly building materials such as engineered wood has increased to reduce carbon emissions. Although the range and height of engineered wood buildings are gradually increasing in North America and Europe, engineered wood is mainly used for low-rise residential buildings in Korea. In order to reduce carbon emissions more, therefore, it needs to expand the use of engineered wood by applying it to various buildings with different uses or more stories. With this background, the aim of this study is to investigate the applicability of engineered wood for 9-story office buildings. Since a 9-story building with engineered wood only is not allowed in KBC, an example building has RC ordinary shear walls as the lateral force resisting system while engineered wood is only used for gravity load resisting moment frames. Another example building is also used for comparison where both lateral and gravity load resisting systems are designed by RC. The applicability of engineered wood is investigated by comparing the seismic performance and the amount of carbon emission of both buildings. The result shows that the seismic performance of both buildings was not significantly different while the amount of carbon emission of the engineered wood building was much less then the RC building. Based on this result, engineered wood is sufficiently applicable to 9-story office buildings even though it still needs to pay attention to the shear design of reinforce concrete walls.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.4
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• pp.225-233
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• 2018

One of engineered woods, glued laminated timber (GLT), can provide a constant level of performance and desired strength even if the quality of wood is low. Due to this fact, there is a growing interest in GLT using domestic species and related research has been carried out continuously. In addition, GLT is popularly being applied to the long-span or high-rise structures overseas. However, KBC 2016 does not allow the engineered woods to be used for middle and high-rise buildings by limiting height. Therefore, a proper design procedure and rationale should be clearly presented by the help of performance-based seismic design. With this background, the goal of this study is to establish a specific procedure for design of a 9-story building with RC shear walls and GLT frames according to the performance-based design of KBC 2016. The performance objectives were set according to KBC and the acceptance criteria for each goal were defined. The RC shear walls and GLT frames were designed by concrete and wood structure requirements, respectively. Analytical models were developed to reflect their nonlinear features, and both nonlinear static and dynamic analyses were conducted. Performance evaluation results showed that the shear walls have insufficient shear strength, so they were re-designed. Consequently, it has been confirmed that GLT frames can be applied to a 9-story office building with the assistance of RC shear walls and performance-based seismic design.

• Fire Science and Engineering
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• v.29 no.4
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• pp.67-72
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• 2015

A series of fire tests was conducted to examine the fire characteristics of flaming and smoldering combustion of engineered wood products, which have been widely used for furniture and finishing materials in buildings. The engineered wood products of MDF, plywood, and chipboard were ignited by a radiant cone heater with incident heat flux of $50kW/m^2$. During the fire test, key parameters representing the fire characteristics such as the heat release rate, yield rate of combustion product, and effective heat of combustion were quantified in terms of thickness. The tests show two peak points of HRRPUA due to lateral fire propagation in the initial stage, followed by later fire penetration through the specimen thickness. The mass loss rate of flaming combustion was 5 times higher than that of smoldering combustion, while the CO yield rate of smoldering combustion was 10 times higher than that of flaming combustion. This study can contribute to the understanding of fire behavior of wood combustibles and provide useful data for fire analysis.

• Journal of the Korean Wood Science and Technology
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• v.33 no.2 s.130
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• pp.8-16
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• 2005

In an effort to encourage the development of value added engineered applications for small diameter round timber, research is being conducted to develop and verify design guidelines for connections with specific application to round timbers. The objective of this research is to provide potential users with a number of viable connection options applicable in the fabrication of engineered, round wood structural components and systems. Target uses include trusses, built up flange beams and space frames. This paper presents information on a mortised steel plate connection fabricated using powder driven nails in 6 cm diameter Japanese Larch. The design load for PDN connections are around 1.3 kN per nail with strip and 0.8 kN per nail without stripe. The design model for PDN connectors could be chosen by the number of nails. If the number of nails are more than the critical number between nail bearing and wood failure, the wood failure model could be the way to design the structure safely. The wood failure model needs to be studied more but the model could be the tensile and cleavage mixed failure model.

• Journal of the Korean Wood Science and Technology
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• v.34 no.2
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• pp.37-45
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• 2006

The viscoelastic properties of blends of melamine-formaldehyde (MF) resin and poly(vinyl acetate) (PVAc) for engineered flooring used on the Korean traditional ONDOL house floor heating system were investigated by dynamic mechanical thermal analysis (DMTA). Because MF resin is a thermosetting adhesive, the effect of MF rein was shown across all thermal behaviors. The addition of PVAc reduced the curing temperature. The DMTA thermogram of MF resin showed that the storage modulus (E') increased as the temperature was further increased as a result of the cross-linking induced by the curing reaction of the resin. The storage modulus (E') of MF resin increased both as a function of increasing temperature and with increasing heating rate. From isothermal DMTA results, peak $T_{tan{\delta}}$ values, maximum value of loss modulus (E") and the rigidities (${\Delta}E$) of MF/PVAc blends at room temperature as a function of open time, peak $T_{tan{\delta}}$ and maximum loss modulus (E") values were found to increase with blend MF content. Moreover, the rigidities of the 70:30 and 50:50 MF/PVAc blends were higher than those of the other blends, especially of 100% PVAc or MF. We concluded that blends the MF/PVAc blend ratios correlate during the adhesion process.

• Journal of the Korean Wood Science and Technology
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• v.45 no.6
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• pp.746-752
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• 2017

Cross-laminated timber (CLT) is a relatively new engineered wood for timber construction. It is a great shear wall material. It was known that the shear performance of the CLT wall depends on the performance of connections. In connection, nail or screw has to be installed with a certain distance from the end of the timber. Current building code specifies the distance on the name of end distance. The end distance was decided as a minimum distance not to make splitting or tearing out in lumber or glued laminated timber. As a relatively new engineered wood, the end distance of CLT connection need to be identified because CLT is cross-wisely glued lumber products like plywood. Different from glued laminated timber or lumber, cross layer of CLT may prevent wood from splitting or tearing-out. As a result, the end distance of CLT was expected to be reduced than glued laminated timber. The shorter end distance may let more versatile connector design possible. In this study, prior to developing novel connection for CLT, the end distance of CLT connection was experimentally investigated to identify the end distance limitation. The experiments showed that the end distance can be reduced from 7D to 6D, in case of the tested CLT combination and screw in this study.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.58-66
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• 2007

The objective of this research was to develop environment-friendly adhesives for face fancy veneer bonding of engineered flooring. Urea-formaldehyde (UF)-tannin and melamine-formaldehyde (MF)/PVAc hybrid resin were used to replace UF resin in the formaldehyde-based resin system in order to reduce formaldehyde and volatile organic compound (VOC) emissions from the adhesives used between plywoods and fancy veneers. Wattle tannin powder (5 wt%) was added to UF resin and PVAc (30 wt%) to MF resin. These adhesive systems showed better bonding than commercial UF resin with a similar level of wood penetration. The initial adhesion strength was sufficient to be maintained within the optimum initial tack range. The standard formaldehyde emission test (desiccator method) and VOC analyzer were used to determine the formaldehyde and VOC emissions from engineered flooring bonded with commercial UF resin, UF-tannin and MF/PVAc hybrid resin. By desiccator method, the formaldehyde emission level of UF resin showed the highest but was reduced by replacing with UF-tannin and MF/PVAc hybrid resin. MF/PVAc hybrid satisfied the $E_1$ grade (below $1.5mg/{\ell}$). VOC emission results by VOC analyzer were similar with the formaldehyde emission results. TVOC emission was in the following order: UF > UF-tannin > MF/PVAc hybrid resin.

• Journal of Korea Foresty Energy
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• v.25 no.2
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• pp.34-41
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• 2006

In this study, new engineered woods, which can be used as structural members, are developed using three different mechanical jointing methods with large elements produced from logs in a high yield. Flitches of relatively large cross-section are produced from small or medium diameter logs, and are joined with steel bolts, wood dowesl and steel lag bolts. Static bending tests are performed for these three types of built-up beams. Built-up beams joined with steel bolts show $514kgf/cm^2$ for MOR and $129,000kgf/cm^2$ for MOE, which are close to those of typical structural glulams. In case that wood dowels and steel lag bolts are used, elements are isolated as load increases and resists the applied load individually. Therefore, built-up beams joined with wood dowels or steel lag bolts show almost half of steel bolts for both MOE and MOR. From the results of this study, it was indicated that bending properties of engineered woods manufactured using mechanical jointing methods with large elements are influenced mainly by jointing performance between each elements.

• International Journal of High-Rise Buildings
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• v.12 no.2
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• pp.137-143
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• 2023

The use of Engineered Wood Systems (EWS), especially mass-timber, as a structural alternative or complement to steel and concrete is gaining interest and acceptance across different sectors of architecture, engineering, and construction, including in high-rise buildings. Focussing on the Australian context, this study examines the levels of adoption and barriers to using timber as a primary structural material in multi-storey buildings. Data collected from semi-structured interviews with stakeholders at the forefront of adoption in structural design, construction, and property development indicates that timber in multi-storey projects in Australia still faces industry-wide challenges. Designers' awareness and attitudes towards timber adoption are generally positive and suitable for flagship projects, including tall buildings, but for enduring and widespread impact, long-term investment in education within and outside the range of stakeholders already committed to promoting timber adoption is needed.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.499-509
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• 2014

Wood filler is a porous and anisotropic material having different size, shape, and aspect ratio. The use of wood fillers such as wood particle, wood flour, and wood pulp in wood plastic composites (WPCs) are growing rapidly because these wood fillers give improved strength and stiffness to WPCs. However, the wood fillers have originally poor compatibility with plastic matrix affecting the mechanical properties of WPCs. Therefore, to improve compatibility between wood and plastic, numbers of physical and chemical treatments were investigated. While the various treatments led to improved performances in WPC industries using petroleum-based plastics, full biodegradation is still issues due to increased environmental concerns. Hence, bio-based plastics such as polylactide and polyhydroxybutyrate having biodegradable characteristics are being applied to WPCs, but relatively expensive prices of existing bio-based plastics prevent further uses. As conventional processing methods, extrusion, injection, and compression moldings have been used in WPC industries, but to apply WPCs to engineered or structural places, new processing methods should be developed. As one system, co-extrusion technique was introduced to WPCs and the co-extruded WPCs having core-shell structures make the extended applications of WPCs possible.