• Journal of the Korean Wood Science and Technology
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• v.47 no.5
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• pp.607-616
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• 2019

On account of the lack of education of Brazilian worker, this paper analyzed the characteristics of those professionals working in the production sector of timber houses. A sectoral survey was carried out with respective entrepreneurs to investigate the available professionals (career and contract types), evaluate the demands of skilled workers, and indicate solutions to improve the quality of labor qualification. Similarly, over 65% of sampled producers presented both direct-hired and outsourced workforce. For such contract ways, Civil Engineers and Architects were the main careers. Carpenters, Civil Engineers and Architects experienced on timber were the main sectoral demands. Timber Engineers have good potentials of service for this sector. The creation of courses on timber products can emerge as a key alternative to train people.

• Structural Engineering and Mechanics
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• v.81 no.6
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• pp.737-750
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• 2022

Timber-Concrete Composite construction system consists of combining timber beam or deck and concrete with different connectors. Different fastener types are used in Timber-Concrete Composite systems. In this paper, the effects of two types of fasteners on structural behavior are compared. First, the notches were opened on timber beam, and combined with reinforced concrete slab by fasteners. This system is called as Notched Connection System. Then, timber beam and reinforced concrete slab were combined by new type designed fasteners in another model. This system is called as Notched-Slab Approach. Two laboratory models were constructed and bending tests were performed to examine the fasteners' effectiveness. Bending test results have shown that heavy damage to concrete slab occurs in Notched Connection System applications and the system becomes unusable. However, in Notched-Slab Approach applications, the damage concentrated on the fastener in the metal notch created in the slab, and no damage occurred in the concrete slab. In addition, non-destructive experimental measurements were conducted to determine the dynamic characteristics. To validate the experimental results, initial finite element models of both systems were constituted in ANSYS software using orthotropic material properties, and numerical dynamic characteristics were calculated. Finite element models of Timber-Concrete Composite systems are updated to minimize the differences by manual model updating procedure using some uncertain parameters such as material properties and boundary conditions.

• Smart Structures and Systems
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• v.29 no.4
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• pp.589-598
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• 2022

Timber structures are susceptible to structural damages caused by variations in moisture content (MC), inducing severe durability deterioration and safety issues. Therefore, it is of great significance to detect MC levels in timber structures. Compared to current methods for timber MC detection, which are time-consuming and require bulky equipment deployment, Lead Zirconate Titanate (PZT)-enabled stress wave sensing combined with statistic machine learning classification proposed in this paper show the advantage of the portable device and ease of operation. First, stress wave signals from different MC cases are excited and received by PZT sensors through active sensing. Subsequently, two non-baseline features are extracted from these stress wave signals. Finally, these features are fed to a statistic machine learning classifier (i.e., naïve Bayesian classification) to achieve MC detection of timber structures. Numerical simulations validate the feasibility of PZT-enabled sensing to perceive MC variations. Tests referring to five MC cases are conducted to verify the effectiveness of the proposed method. Results present high accuracy for timber MC detection, showing a great potential to conduct rapid and long-term monitoring of the MC level of timber structures in future field applications.

• Structural Engineering and Mechanics
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• v.74 no.4
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• pp.457-470
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• 2020

The force resisting ability of a connection has direct implications on the overall response of a timber framed structure to various actions, thereby governing the integrity and safety of such constructions. The behavior of timber framed structures has been studied by many researchers by testing full-scale-connections in timber frames so as to establish consistent design provisions on the same. However, much emphasis in this approach has been unidirectional, that has focused on a particular connection configuration, with no research output stressing on the refinement of the existing connection details in order to optimize their performance. In this regard, addition of adhesive to dowelled timber connections is an economically effective technique that has a potential to improve their performance. Therefore, a comparative study to evaluate the performance of various full-scale timber frame Nailed connections (Bridled Tenon, Cross Halved, Dovetail Halved and Mortise Tenon) supplemented by adhesive with respect to Nailed-Only counterparts under tensile loading has been investigated in this paper. The load-deformation values measured have been used to calculate stiffness, load capacity and ductility in both the connection forms (with and without adhesion) which in turn have been compared to other configurations along with the observed failure modes. The observed load capacity of the tested models has also been compared to the design strengths predicted by National Design Specifications (NDS-2018) for timber construction. Additionally, the experimental behavior was validated by developing non-linear finite element models in ABAQUS. All the results showed incorporation of adhesive to be an efficient and an economical technique in significantly enhancing the performance of various timber nailed connections under tensile action. Thus, this research is novel in a sense that it not only explores the tensile behavior of different nailed joint configurations common in timber construction but also stresses on improvising the same in a logical manner hence making it distinctive in its approach.

• Journal of the Korean Society of Food Culture
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• v.36 no.5
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• pp.421-429
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• 2021

Local non-timber forest products can be easily accessed by tourists. These also provide opportunities for tourists to experience the local culture. Many local governments are paying constant attention to the development of non-timber forest product brands to revitalize the local economy and increase the profits of local farmers. Although there are many forest products and tourism resources in each region of Korea, there is no local specialized strategy to sell non-timber forest products and promote consumers' purchase intentions. In this study, we aimed to explore the consumers' perceived creating shared value (CSV) and its association with purchasing behavior of non-timber forest products in Jeongeup city, Korea. Data were collected from 1,066 consumers who had purchased non-timber forest products. Purchasing patterns of local specialty products differed depending on consumers' perceived CSV levels. In addition, consumers with higher levels of perceived CSV showed higher awareness and familiarity with Jeongeup city and experienced Jeongeup city's non-timber forest products. Our findings suggest that improving consumer perception towards CSV of non-timber forest products can be used as a marketing strategy for local non-timber forest products to revitalize the local economy.

• Journal of Korean Society of Forest Science
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• v.89 no.1
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• pp.126-134
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• 2000

The purpose of this study is to examine the status of supply-demand and procurement of the timber used for wooden cultural properties. Because people require the high quality pine timber with cultural assurance and public function for cultural properties, it is priced far higher than ordinary construction timber. The timber consumption was estimated at 18 thousand cubic meter in 1998, of which the large sized log(LSL) with the small end diameter over 30cm consisted of 35.5%, equivalent to 6,300 cubic meter. Majority of the timber was supplied from private forest located in Kangwon-do and national forest, accounting for 65.7% and 16.7%, respectively. Recently the supply more and more relied on timber logged in Kangwon-do. Owing to lack of domestic supply of LSL class timber, part of the volume has been substituted by import log. Most of carpenters working on cultural properties thought that supply of LSL timber would hardly meet the increasing demand for uses of wooden cultural properties. Finally, in order to uphold the tradition of wooden cultural properties, it is necessary to establish a forest management plan which aim at producing large size high quality pine timber.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.454-460
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• 2020

The goal of this study was to classify the area of Larix kaempferi forest available for timber production, considering the legal, physical, environmental, and technical constraints, and to optimize the forest resources and the potential of timber production in South Korea for 50 years. The results showed that the area of Larix kaempferi forest available for timber production is limited to 124,000 ha, 48% of the total area. Without further efforts in resource management, sustainable timber production of Larix kaempferi cannot be guaranteed even at the current level of timber supply. To enhance the potential of timber production for this species, two alternatives were considered: a 705-km annual increment of forest roads (alternative 1) and a 1,000-kmannual increment of forest roads (alternative 2) to enlarge forest areas available for timber production. The results showed that alternative 1 is feasiblefor sustainable timber production both at the current level and with a 5% increment of timber supply. However, alternative 1 is not sufficient in the case of a 10% increment of timber supply with a low growing stock, whereas alternative 2 is sufficient. Therefore, an increase in forests roads as well as regeneration efforts are required to improve the timber production potential of Larix kaempferi in South Korea.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.396-403
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• 1999

This experimental study investigates the hysterestic behavior of traditional timber frames subjected to lateral loads. Prototype frames for this study were selected from one of typical national treasures for timber structures in Korea. For simplicity roof structures and braket systems were excluded from specimens and the joint behavior of beam-to-column system were presumed to have crucial effect on their global behavior. The experimental observation showed stiffness degradation and slip after experiencing initial yield and the first cycle at a new larger displacement due to inherent gaps in traditional timber connection and gradual indentation of interfaces, The cyclic behaviors of all specimens were similar to those os modern timber frames with bolt and nail connections. Additional structural members such as an upper beam and clay-filled wall increased the initial stiffness strength and energy dissipation. It is expected that collapse of Korean traditional timber frames under lateral load is mainly caused from P-$\Delta$ effects rather than local member failure.

• Journal of Korean Association for Spatial Structures
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• v.20 no.2
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• pp.39-49
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• 2020

In this study, we will develop a hybrid cross-sectional shape of steel inserted type glued-laminated timber that can improve the strength of structural glued-laminated timber and maximize the ductility by using steel plate with excellent tensile and deformation ability. A total of three specimens were fabricated and the flexural performance test was carried out to evaluate the structural performance of the steel inserted type glued-laminated timber. In order to compare the effect of steel inserted glued-laminated timber, one structural glued-laminated timber test specimen composed of pure wood was manufactured. In addition, in order to evaluate the adhesion performance of the steel inserted, one each of a screw joint test specimen and a polyurethane joint test specimen was prepared. As a result, all the specimens showed the initial crack in the finger joint near the force point. This has been shown to be a cause of crack diffusion and strength degradation. The use of finger joints in the maximum moment section is considered to affect the strength and ductility of the glued-laminated timber beam. Polyurethane-adhesive steel inserted glued-laminated timber showed fully-composite behavior with little horizontal separation between the steel plate and glued-laminated timber until the maximum load was reached. This method has been shown to exhibit sufficient retention bending performance.

• 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.