• International Journal of High-Rise Buildings
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• v.10 no.4
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• pp.311-321
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• 2021

Perception of the public to structural fires is very important because there are only a number of tall timber buildings constructed in the world. People are hesitating to accept tall timber buildings, so it is essential to ensure the first generation of tall timber buildings to a very high standard, especially fire safety. Right now, there are no specific design standards or regulations for fire design of tall timber buildings in Europe. Even though heavy timber members have better fire resistance than steel components, many conditions still need to be verified before considering the use of timber materials, e.g. fire spread, post-fire collapse, etc. This research numerically explores the structural behaviours of a tall Glulam building when one of its internal Glulam (Glued laminated timber) columns fails after sustaining a full 120-min standard fire and is removed from the established finite element building model created in SAP2000. The numerical results demonstrate that the failure and removal of the selected internal Glulam column may lead to the local failure of the adjacent CLT (Cross laminated timber) floor slabs, but will not lead to large disproportionate damage and collapse of the whole building. Here, the building is assumed to be located in Glasgow, Scotland, UK.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.49-52
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• 2008

Structural Wood is developed by purpose to make efficient use of wood resources. The biggest advantage of structural wood is stable as strength is high than wood product that is used by structure in existing. Order manufacture according to design details is available. It Is used to main structure elements to large spatial structure. Structure wood kind utilizes Glulam, prefabricated wood I-joists and laminated veneer lumber(LVL) and so on. Structural Design and construction of Open-air Stage Roof Structure is described in the presented paper. Architectural roof materials is used to PVF/PFLT membrane. Column and diagonal members is used to steel members(SS400), and Cantilever beam is used to Glulam assembled with different Grade laminations(10S-28B).

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.90-95
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• 2004

Pitch pine (Pinus rigida) has been planted in Korean forests for several decades, primarily for erosion control and use as a fuel supply. To enhance its value, and especially potential use as lamina for structural glued laminated timber (glulam), log quality and lumber yield of pitch pine were evaluated in this study. Trees from pure pitch pine stands with an average diameter at breast height of 32 cm were felled and bucked into 3.6m long 15 cm minimum butt-end diameter logs. Over 80% of the logs were classified to No.2 or No.3 visual grade group. Upon sawing total lumber yield was 55.2%, 39.9% for structural glulam lamina, 7.2% for louver, and 8.1% for miscellaneous use. The final lumber yield for manufacturing structural glulam, after cross-cutting to eliminate knots and finger jointing, was only 15.3%. To enhance this manufacturing yield requires that the rate of knot-included lumber used as lamina be raised. However arrangement of the knot-included lamina, whose mechanical properties need to be accurately evaluated, must be optimized to minimize any reduction to the structural glulam strength. The log quality and lumber yield of pitch pine evaluated in this study are expected to facilitate proper planning for wood product manufacture in the Korean lumbering and glulam industrial field, which has not previously dealt with this species.

• Journal of the Korean Wood Science and Technology
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• v.51 no.2
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• pp.81-97
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• 2023

The aim of this study were to evaluate tannin resorcinol formaldehyde (TRF) for the preparation of cross-laminated timbers (CLTs) made from fast-growing tree species and to analyze the physical and mechanical properties of CLTs. TRF copolymer resin was prepared by using the bark extracts of Swietenia mahagoni (L.) Jacq. It was observed that the TRF adhesive possessed less solid content (23.59%), high viscosity (11.35 poise), and high pH values (10.0) compared to the standard phenol resorcinol formaldehyde. The TRF adhesive was applied to produce CLTs with the addition of 15% tapioca and flour as an extender. The six-layered CLTs were produced from sengon (Falcataria moluccana Miq.), jabon [Anthocephalus cadamba (Roxb) Miq.], coconut (Cocos nucifera L.), and the combination of coconut-jabon and coconut-sengon wood. The analysis of variance revealed that the layer composition of CLT significantly affected the physical and mechanical properties of the beam. While the modulus of rupture met the standard, the moisture content and modulus of elasticity values did not fulfill JAS 1152-2007. All of the CLTs produced in this study demonstrated low formaldehyde emission, ranging from 0.001 mg/L to 0.003 mg/L, thereby satisfying the JAS 1152 for structural glue laminated timber.

• Journal of the Korean Wood Science and Technology
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• v.45 no.4
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• pp.409-418
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• 2017

This work attempted to manufacture glued-laminated timber (Glulam) bonded with melamine-urea-formaldehyde (MUF) resin adhesives at various melamine contents from 20% to 50% under high frequency (HF) heating for a very short time. Two preparation methods were employed to prepare MUF resin adhesives with different melamine contents: one-batch method of synthesizing MUF resins in a single batch, and two-batch method of mixing urea-formaldehyde (UF) resin with melamine-formaldehyde (MF) resin that had been synthesized separately. As the melamine content increased, the gelation time and peak temperature of MUF resins decreased. The adhesion performance of plywood showed that the one-batch MUF resin adhesive with 50% melamine content only satisfied the standard requirement of water resistance. Thus, the one-batch MUF resin adhesive with 50% melamine content was applied for bonding wood lamina from four softwood species such as Japanese larch, Korean red pine, Korean pine and Japanese cedar to manufacture Glulam under HF heating. All Glulam samples bonded with the one-batch MUF resin adhesives with 50% melamine content except those from Korean Red Pine satisfied the requirement in water soaking or boiling water delamination test as an exterior grade Glulam. The presence of rosin in Korean Red Pine was believed to be responsible for its poor adhesion. These results showed that the one-batch MUF resin adhesives with 50% melamine content provided acceptable water resistance with exterior grade Glulam manufactured under HF heating.

• Journal of the Korean Wood Science and Technology
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• v.39 no.2
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• pp.163-171
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• 2011

Because Japanese cedar shows lower mechanical performance, glued-laminated timber (glulam) can be a better way to utilize Japanese cedar for structural purpose. However, low yield of higher grade lamination from log makes it difficult to design structural glulam. This study was aimed to increase the yield of higher grade lamination and provide higher efficiency of manufacturing structural lamination by ultrasonic log sorting technology. Logs were sorted by an existing log grading rule regulated by Korea Forest Research Institute (KFRI). It was found that the KFRI log grading rule contributed to finding better logs in viewpoint of the volumetric yield and it can reduce the number of rejected lumber by visual grading. However, it could not identify better logs to produce higher-grade products. To find an appropriate log-sorting-method for structural products, log diameter and ultrasonic time of flight (TOF) for the log were considered as factors to affect mechanical performance of resulting products. However, it was found that influence of log diameter on mechanical performance of resulting products was very small. The TOF showed a possibility to sort logs by mechanical performance of resulting products even though a coefficient of correlation was not strong (R = 0.6). In a case study, the log selection based on the ultrasonic TOF of the log increased the yield of the outermost tension lamination (E8 or better grade, KS F 3021) from 2.6% to 12.5% and reduced LTE5 (lower than E5 grade) lamination from 43.6% to 10.3%, compared with the existing KFRI log grading rule.

• 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.

• Journal of the Korean Wood Science and Technology
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• v.43 no.2
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• pp.156-167
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• 2015

The aim of this study was to determine the physical and mechanical properties of glued laminated timber (glulam) manufactured from small-diameter logs of three wood species, Acacia mangium (mangium), Maesopsis eminii (manii), and Falcataria moluccana (sengon), with densities of 533, 392, and $271kg/m^3$, respectively. Glulam measuring 5 cm by 7 cm by 160 cm in thickness, width, and length, respectively, was made with three to five lamina, or layers, and isocyanate adhesive. The glulams contained either the same wood species for all layers or a combination of mangium face and back layers with a core layer of manii or sengon. Solid wood samples of the same size for all three species were included as a basis for comparison. Physical-mechanical properties and delamination tests of glulam referred to JAS 234:2003. The results showed that the properties of same species glulam did not differ from those of solid wood, with the exception of the shear strength of glulam being lower than that of solid wood. Wood species affected glulam properties, but three- and five-layer glulams were not different except for the modulus of elasticity. All glulams were resistant to delamination by immersion in both cold and boiling water. The glulams that successfully met the JAS standard were three- and five-layer mangium, five-layer manii, and five-layer mangium-manii glulams.

• Journal of the Korean Wood Science and Technology
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• v.32 no.4
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• pp.46-51
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• 2004

The objective of this study was to evaluate the applicability of high temperature drying to pitch pine (Pinus rigida) lumber, especially intended for use as lamina of structural glued laminated timber (glulam), to enhance the efficient utilization and provide added-value to that species. The high temperature schedule and drying procedures utilized were shown to be reasonable for drying glulam lamina due to the occurrence of small moisture gradients, minimal residual drying stress, and low warpage. Through preliminary tests, it was confirmed that residual resin at lamina surfaces did not adversely affect the gluing process. However, quantitative analysis of resin is required for developing a method to constrain the occurrence of pitch trouble with respect to decreasing long-term adhesive and finish durability of glulam in use after manufacturing. The final moisture content of high temperature dried lamina was much lower than target moisture content and discoloration was more severe than anticipated. In a further study, it will be necessary to determine the optimal drying conditions, such as temperature, humidity, drying time, and top load restraint level, which could best control discoloration, warpage, and moisture content of the lamina, while minimizing fuel expense.

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.23-33
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• 2023

It is widely known that the level of fire resistance of wooden structure is determined by a charring rate or charring depth, and these are adopted for fire design. In this study, specimens of domestic larch column with a lamination wooden type were prepared and the fire resistance properties such as the charring depth, load ratio and the specific charring rate suggested by EN Code investigated. Test results showed that as expected, the weakest part was the corner of the column, so that the charring depth of the corner was deeper than the other parts of the column. For the load ratio less than 0.9, it had little effect on the charring depth.