• Earthquakes and Structures
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• 제7권1호
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• pp.101-117
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• 2014

This paper presents a reliability-based analysis on seismic performance of timber-steel hybrid shear wall systems. Such system is composed of steel moment resisting frame and infill wood frame shear wall. The performance criteria of the hybrid system with respect to different seismic hazard levels were determined through a damage assessment process, and the effectiveness of the infill wood shear walls on improving the seismic performance of the hybrid systems was evaluated. Performance curves were obtained by considering different target non-exceedance probabilities, and design charts were further established as a function of seismic weight. Wall drift responses and shear forces in wood-steel bolted connections were used as performance criteria in establishing the performance curves to illustrate the proposed design procedure. It was found that the presence of the infill wood shear walls significantly reduced the non-performance probabilities of the hybrid wall systems. This study provides performance-based seismic evaluations on the timber-steel hybrid shear walls in support of future applications of such hybrid systems in multi-story buildings.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.283-293
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• 2016

Owing to an increase in the air tightness of recent buildings, the natural ventilation rate was significantly lowered and the removal of accumulated moisture became difficult in these buildings. The hygrothermal performance of these buildings should be carefully considered to provide comfortable indoor environment by removing the moisture condensation risk and the mold growth potential. In this study, hygrothermal performance of two selected wall structures was investigated based on WUFI simulation program. The results displayed that the indoor temperature had impact on the moisture accumulation in the insulation layer for both modeled walls, showing that lower indoor temperature resulted in higher moisture accumulation, especially in the wood frame structure. Also, the yearly moisture accumulation profile exhibited a downward shift throughout the year by adding a vapour retarder with a lower sd-value. In addition, both of the two walls have condensation risk in winter, due to low temperature level. The wood frame structure has a bigger fluctuation and higher condensation risk than the concrete structure.

• Journal of the Korean Wood Science and Technology
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• 제23권3호
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• pp.8-15
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• 1995

This analytical study was carried out to make quality and productivity up in designing the frame-type furniture with semi-rigid joint by understanding the mechanical and structural behavior of the joint and by evaluating the validity of application of the time-saving Finite Element Method to its structural analysis. Slope deflection equation for rigid joint was modified to describe the moment-rotation behavior of semi-rigid joint and the joint stiffness factor(Z) could be calculated to lessen the experimental expense. It was proved that Finite Element Analysis with imaginary elements having equivalent MOE to the semi-rigid joint could be the alternative method for the structural analysis of the frame-type furniture, comparing the internal rotation of the 2-dimensional beam-to-column model with two-pin(wooden dowel) from the finite element method with other available theoretical and experimental rotation value.

• Journal of the Korean Wood Science and Technology
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• 제45권1호
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• pp.28-35
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• 2017

본 연구에서는 접합부가 접착제로 일체화된 강절형 기둥-보 접합 시험편과 슬릿 가공한 보부재에 기둥부재와 일체화된 목질접합물을 삽입하고 핀으로 접합한 시험편을 제작하여 모멘트 저항성능을 검토하였다. 목질접합물은 GFRP로 보강한 적층판을 제작하여 사용하였다. 슬릿 가공된 보부재에 GFRP보강적층판을 삽입하고 핀으로 접합된 기둥-보 시험편들은 완전탄소성 모델 분석으로 산출된 특성치들이 대조군인 강판삽입형 기둥-보 시험편보다 20~80% 낮게 측정 되었다. 기둥부재와 보부재가 접착제로 일체화된 강절형 기둥-보 시험편은 초기잔류변형이 거의 관찰되지 않았으며, 강판 삽입형 접합부보다 38% 향상된 초기강성과 41% 향상된 소성률이 측정되었다.

• Journal of the Korean Wood Science and Technology
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• 제47권3호
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• pp.311-323
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• 2019

The number of newly constructed traditional Korean houses, i.e., Hanoks, and light-frame buildings is increasing. However, related research is limited owing to the lack of awareness regarding safety evaluations. Therefore, this study conducted an outdoor exposure test to accurately evaluate wooden constructions. Spruce, pine, and fir (SPF) material was monitored for a year, wherein the SPF material was artificially dried under 18% moisture content, and its physical properties and color differences were measured once a month. Large differences were observed in the material's weight and moisture content, which are indexes sensitive to daily range and rainfall; however, no significant difference was found for other basic properties in the pre and post test results. Herein, $L^*$, $a^*$, and $b^*$ values represent color differences; these values exhibited a general decrease after the test. Such differences were attributed to the loss of lignin in the wood. The color difference value was high between the months of May and July, when the daily range and rainfall significantly fluctuated. Multiple regression analysis was performed on the $a^*$ value (redness indicator), daily range, rainfall, and ultraviolet index. The results indicated that the daily range influenced redness the most. According to the estimated regression equation, the daily range and redness are positively correlated. Based on the results, the types and influence of independent variables on color difference are expected to change as the wood's duration of outdoor exposure and the amount of data obtained both increase.

• Wind and Structures
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• 제27권3호
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• pp.163-173
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• 2018

The design wind pressure for low-rise buildings in the ASCE 7-10 is defined by procedures that are categorized into the Main Wind Force-Resisting System (MWFRS) and the Components and Cladding (C&C). Some of these procedures were originally developed based on steel portal frames of industrial buildings, while the residential structures are a completely different structural system, most of which are designed as low-rise light-frame wood constructions. The purpose of this study is to discuss the rationality (or irrationality) of the extension of the wind loads calculated by the ASCE 7-10 to the light-frame wood residential buildings that represent the most vulnerable structures under extreme wind conditions. To serve this purpose, the same approach as used in the development of Chapter 28 of the ASCE 7-10 that envelops peak responses is adopted in the present study. Database-assisted design (DAD) methodology is used by applying the dynamic wind loads from Louisiana State University (LSU) database on a typical residential building model to assess the applicability of the standard by comparing the induced responses. Rather than the postulated critical member demands on the industrial building such as the bending moments at the knee, the maximum values at the critical points for wood frame buildings under wind loads are used as indicators for the comparison. Then, the critical members are identified through these indicators in terms of the displacement or the uplift force at connections and roof envelope. As a result, some situations for each of the ASCE 7 procedures yielding unconservative wind loads on the typical low-rise residential building are identified.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.304-313
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• 2000

This study presents the behavior of traditional wood structures of national heritage under earthquake loadings. A series of experimental program for four wood frames was performed to investigate characteristics of initial stiffness, behavior after ultimate loads, and hysteretic behaviors. The frames consisted of columns with a lintel by special joint and a bare frame was infilled by a mud wall. A pushover est was aimed to estimate the range of ultimate rotation of connection as a pilot test for cyclic load tests. One of frames infilled by a mud wall showed a larger stiffness than those of bare frames due to a strut action in the diagonal direction. However, the post yielding stiffness of the infilled frame was not increased.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.339-342
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• 2003

According to the results of structural safety analysis, allowable safe snow depth for type B(wood frame with single span) was 25.9cm, and those for type A(wood frame with multi span) and type C and D (steel frame with multi span) were 17.6cm, 25.8cm, and 20.0cm respectively. An experiential example study on meteorological disasters indicated that a strong wind damage was experienced once every 20 years, and a heavy snow damage once every 9.5 years. The most serious disaster was a heavy snow and it was found that a half break or complete collapse of structures were experienced by about 70% of farmhouses.

• Journal of the Korean Wood Science and Technology
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• 제44권3호
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• pp.440-448
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• 2016

본 연구는 WUFI Pro 5.3을 이용하여 한국농어촌공사에서 제시하고 있는 농어촌 표준 목조주택 설계를 기준으로 목조 벽체의 hygrothermal 거동에 대한 평가를 실시하였다. 그 결과, 2010년도에 제시된 벽체보다 2014년도에 개선된 벽체의 Total Water Contents (TWC)가 더 낮게 나타난 것을 확인하였고, 3년간의 평가에서 TWC가 일정하게 유지되는 동적 안정 상태에 도달하였음을 보아 hygrothermal 환경을 적절히 고려하는 개선임을 확인하였다. 또한 농촌지역과 어촌지역을 구분지어 hygrothermal 거동을 평가한 결과, 벽체가 해당지역의 온도보다 상대습도에 큰 영향을 미치는 것을 확인하였다. 또한, 목재 기반 재료의 과도한 수분 함량 문제는 실외마감의 재료를 바꾸는 것으로 어촌지역에도 적용이 가능한 벽체로 개선할 수 있었다. 곰팡이 성장 위험의 경우, 초기 실내 설정온도에서 여름철에 곰팡이가 성장할 가능성이 높은 것으로 나타났으며, 이를 고려하여 여름철 실내 설정온도를 변화시키는 것으로 개선되었다. 이러한 결과를 통해, 건축설계 단계에서 WUFI 프로그램과 같은 hygrothermal 거동 분석 프로그램을 이용하여 건축물의 수분에 대한 문제를 미리 분석하고 이에 맞는 벽체의 개선이 필요하다고 판단된다.

• Journal of the Korean Wood Science and Technology
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• 제45권5호
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• pp.535-543
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• 2017

목구조물 기둥-보 접합물로는 슬릿 가공된 부재에 강판을 삽입한 형상이 통용되고 있다. 본 연구에서는 접합부가 접착된 강절형 문형라멘프레임 및 강판 대용인 목질접합물을 제작하여 절반은 기둥부재에 일체화하고 나머지 절반은 보부재와 핀으로 접합한 반강절형 문형라멘프레임을 제작하였다. 목질 문형라멘프레임들은 강판삽입형 접합부 문형라멘프레임과 수평내력성능을 비교 분석하였다. 수평내력성능은 완전탄소성모델 분석과 구간별 강성변화율 및 단기허용전단내력으로 평가하였다. 실험결과, 강절형 문형라멘프레임의 최대내력이 강판삽입형 접합부 문형라멘프레임 보다 낮게 측정되어 항복 내력은 0.58, 종국내력은 0.48로 산출되었으나, 초기강성과 소성률은 각각 1.35, 1.1 향상된 값이 측정되었다. 반강절형 문형라멘프레임의 완전탄소성모델 분석 결과 최대내력은 강절형 문형라멘프레임보다 낮았으나 파괴 후 인성이 우수하여 종국내력은 1.05~1.07 높은 값이 산출되었다. 강판삽입형 문형라멘프레임은 반복 시험이 진행됨에 따라 강성이 급격히 감소한 반면 접합부가 목질로된 문형라멘프레임들의 강성은 서서히 감소되었다.