• Structural Engineering and Mechanics
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• 제16권4호
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• pp.391-404
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• 2003

Local reinforcement in dowel type timber joints is essential to improve ductility, to increase load carrying capacity and to reduce the risk of brittle failure, especially in the case of using solid dowel. In many types of reinforcing materials available today, DVW (densified veneer wood) has been demonstrated to be the most advantages in terms of compatibility, embedding performance and ductility. Preliminary studies show that using appropriately sized DVW discs bonded into the timber interfaces may be an effective way to reinforce the connection. In this paper, non-linear 3-dimensional finite element models, incorporating orthotropic and non-linear material behaviour, have been developed to simulate structural performance of the timber joints locally reinforced by DVW discs. Different contact algorithms were applied to simulate contact conditions in the joints. The models were validated by the corresponding structural tests. Correlation between the experimental results and the finite element simulations is reasonably good. Using validated finite element models, parametric studies were undertaken to investigate effects of the DVW disc sizes and the end distances on shear stresses and normal stresses in a possible failure plane in the joint.

• Journal of the Korean Wood Science and Technology
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• 제41권2호
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• pp.123-133
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• 2013

This paper presents experimental and numerical tests on a recently developed timber column concealed base joint. This joint was designed to replace the wood-wood connection found in the post-and-beam structure of Hanok, the traditional Korean timber house. The use of metallic connectors provides an increased ductility and energy dissipation for a better performance under reversed loading, especially seismic. In this study, we investigate the performance of the joint under pseudo-static reversed cyclic moment loading through the study of its ductility and energy dissipation. We first perform experimental tests. Results show that the failure occurs in the metallic connector itself because of stress concentrations, while no brittle fracture of wood occur. Subsequent numerical simulations using a refined finite element model confirm these conclusions. Then, using a practical modification of the joint configuration with limited visual impact, we improve the ductility and energy dissipation of the joint while retaining a same level of rotational strength as the originally designed configuration. We conclude that the joint has a satisfying behavior under reversed moment loading for use in earthquake resistant timber structure in low to moderate seismicity areas like Korea.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.23-24
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• 2023

In this study, an easily recyclable separable glued-laminated timber (GLT)-steel beam was developed, and a structural design method was presented. The GLT and steel were mechanically composited using self-tapping screws. The GLT-steel beam was designed to fail in the compression of GLT. The bending moment and load-carrying capacity of the GLT-steel beam were predicted based on composite beam theory and compared with experimental test data. As a result, the GLT-steel beam exhibited ductile behavior, and compression failure of GLT was observed. The screw connection showed no damage while the steel plate was extended. The load-carrying capacity of GLT after failure was similar to the load resistance predicted by the compressive strength of GLT and the tensile strength of steel. This indicates that the ductile behavior of the GLT-steel beam can be safely designed by the tensile strength (yield) of steel.

• Journal of the Korean Wood Science and Technology
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• 제52권4호
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• pp.375-382
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• 2024

The study focuses on evaluating the bending creep performance of laminated veneer lumber (LVL) formwork in timber concrete composite (TCC) structures. Timber-framed construction is highlighted for its environmental benefits and seismic resistance, but limitations such as poor tensile strength and brittle failure in bending hinder its use in high-rise buildings. Wood-concrete hybrid structures, particularly those using reinforced concrete slabs with TCC floors, emerge as a potential solution. The research aims to understand the time-dependent behavior of TCC components, considering factors like wood and concrete shrinkage and connection creep. The experiment was conducted in western Japan on the TCC floor designed for use in the Kama-city Inatsuki-higashi compulsory education school. The LVL formwork, measuring 9,000 mm by 900 mm, and concrete is loaded onto it for testing. The creep test periods are examined using concrete loading. It employs a comprehensive creep analysis, adhering to Japanese standards, involving deflection measurements and regression analysis to estimate the creep coefficient. Results indicate substantial deformation after shoring removal, suggesting potential reinforcement needs. The study recommends extending test periods for improved accuracy and recognizing regional climate impacts. Overall, the research provides valuable insights into the potential of LVL formwork in TCC structures, emphasizing safety considerations and paving the way for further experimentation under varied conditions to validate structural integrity.

• 건축역사연구
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• 제15권4호
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• pp.75-86
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• 2006

Korea is closed to China in the geographical position and is related to China as two countries have developed similar culture, art, and social systems. Architecture is a kind of culture and has advanced in the wooden architecture with a considerable change. The study investigated a phylogenetic relationship between two countries based on characteristics of architectural universality. With comparison and analysis on the common feature and difference of the beam and structure in the wooden architecture from the Koryo and Zhejiang Province(China), the systemicity of the wooden architecture was examined. The beam is a part of timber which is consist of the wooden structure frame and also a crucial subject to understand a development process of the wooden architecture.

• 한국공간구조학회논문집
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• 제19권1호
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• pp.65-73
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• 2019

This paper assesses the structural performance (force-slip response, slip modulus, and failure modes) of a CLT-concrete composite by conducting fifteen push-out test specimens. In addition, non-linear 3D finite element analysis was also developed to simulate the load-slip behavior of the CLT-concrete specimens under shear load. All 15 test specimens simulating the effect of concrete thickness, connection angle and penetration depth with four different shear connector types were built and tested to evaluate the flexural performance. Experimental results show that the maximum shear capacity for the composite action is obtained when the fixing angle is $90^{\circ}$ and the penetration depth of 95mm for SC normal screw was used to achieve ductile failure compared to other shear connectors.

• 한국건축시공학회지
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• 제22권2호
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• pp.149-160
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• 2022

본 연구에서는 국내에서 생산되는 목재와 접착제를 활용한 Glued-in rod 접합부의 인발성능을 평가하고자 접착제의 종류, 철근의 매입깊이 및 매입방향을 고려한 인발성능 실험연구를 수행하였다. 실험결과, 액상형 접착제 사용 실험체가 더 우수한 인발성능을 보여주었으며, 철근의 매입깊이가 길어질수록 철근의 항복을 먼저 유도하여 높은 최대 인발하중을 보여주었다. 인발성능 실험결과를 통하여 철근의 항복강도보다 접착제의 부착강도를 더 강하게 설계하는 것이 유리한 Glued-in rod 접합부 설계식을 제안하였으며, 접착제의 부착강도의 시공오차를 고려한 보정계수 0.75 또한 제안하였다.

• Steel and Composite Structures
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• 제43권4호
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• pp.511-522
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• 2022

An experimental investigation to study the behaviour of connections between cold-formed steel (CFS) joist and plywood structural panel is presented in this paper. Material testing on CFS and plywood was carried out to assess their mechanical properties and behaviour. Push-out tests were conducted to determine the slip modulus and failure modes of three different shear connection types. The employed shear connectors in the study were; size 14 (6mm diameter) self-drilling screw, M12 coach screw, and M12 nut and bolt. The effective bending stiffness of composite cold-formed steel and plywood T-beam assembly is calculated based on the slip modulus values computed from push-out tests. The effective bending stiffness was increased by 25.5%, 18% and 30.2% for self-drilling screw, coach screw, nut and bolt, respectively, over the stiffness of cold-formed steel joist alone. This finding suggests the potential to enhance the structural performance of composite cold-formed steel and timber flooring system by mobilisation of composite action present between timber sheathing and CFS joist.

• Journal of the Korean Wood Science and Technology
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• 제45권6호
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• pp.728-736
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• 2017

In this study, the bending behavior of cross-laminated timber (CLT) connected by nails were investigated. Especially, the load-carrying capacity of the nail-jointed CLT under out-of-plane bending was predicted by the lateral resistance of the used nails. Three-layer nail-jointed CLT specimens and a nail connection were manufactured by 30 mm (thickness) ${\times}$ 100 mm (width) domestic species (Pinus koraiensis) laminas and Ø$3.15{\times}82mm$ nails using a nail-gun. Shear test for evaluating the nail lateral resistance and bending test for evaluating the load-carrying capacity of the nail-jointed CLT under out-of-plane bending were carried out. As a result, two lateral resistance of the used nail, the 5% fastener offset value and the maximum value, were 913 N and 1,534 N, respectively. The predicted load-carrying capacity of the nail-jointed CLT by the 5% offset nail lateral resistance was similar to the yield points on the actual load-displacement curve of the nail-jointed CLT specimens. Meanwhile, the nail-jointed CLT specimens were not failed until the tension failure of the bottom laminas occurred beyond the maximum lateral resistance of the nails. Thus, the measured maximum load carrying capacities of the nail-jointed CLT specimens, approximately 12,865 N, were higher than the predicted values, 7,986 N, by the maximum nail lateral resistance. This indicates that the predicted load-carrying capacity can be used for designing a structural unit such as floor, wall and roof able to support vertical loads in a viewpoint of predicting the actual capacities more safely.

• Journal of the Korean Wood Science and Technology
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• 제39권1호
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• pp.53-59
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• 2011

시험 시편은 1개의 횡목과 2개의 종목이 직결나사못 2개로 연결된 접합부(Type-A)와 2개의 횡목과 2개의 종목이 4개의 직결나사못으로 연결된 접합부(Type-B)를 제작하였다. Type-B를 보강하기 위하여 횡목간의 연결부를 끝면거리 5D로 반턱이음하여 2개의 직결나사를 사용한 접합부(Type-C), 끝면거리 10D로 반턱이음한 접합부(Type-C1)와 끝면거리 10D, 직결나사 3개를 사용한 접합부(Type-C2)를 제작하였다. 압축형 전단 내력 시험결과 Type-B의 내력을 기준으로 Type-B를 보완한 Type-C는 약 30% 감소하였고, Type-C에서 끝면거리를 증가시킨 Type-C1은 Type-B와 비슷한 내력을 보였으며, Type-C1에서 직결나사못의 개수를 3개로 증가시킨 Type-C2는 Type-C1과 비교하여 1.28배 내력을 나타냈다. 기존 정각재를 이용한 옹벽의 접합부 중 긴 횡목과 짧은 횡목이 2개의 종목과 연결되는 접합부는 내력이 저하되기 때문에 이를 대체하기 위하여 실험을 실시하였다. 따라서 Type-B를 Type-C2로 대체한다면 옹벽 시공시 직결나사못에 의한 목재의 할렬, 파단과 시공시간이 줄어들고 접합 내력이 증가할 것으로 기대된다.