Joo-Saeng Park

Moment-Carrying Capacity of Dovetailed Mortise and Tenon Joints with or without Beam Shoulder

This study aimed to evaluate the influence of beam shoulder on the moment-carrying capacity of traditional post-beam joints, dovetailed mortise, and tenon joints. The specimens were manufactured by a computer numerical controlled (CNC) cutting machine with Japanese larch six-ply glulams (glued laminated timber), and moment-carrying capacity was investigated by static loading tests. The results of the tests indicated that the moment resistance, joint stiffness, and failure modes were different with or without beam shoulder. The results also indicated that all joints types underwent significant deformation without breaking and maintained after the yield point. The failure mode, which included post splitting, shear failure of mortise branches, or embedment failure of tenon, was dependent on the presence of the beam shoulder. The results indicated that the beam shoulder significantly affected the performance of the post-beam joint. It was concluded that the beam shoulder reinforced the dovetailed mortise and ...

Bending Strength of Korean Softwood Species for 120×180 mm Structural Members

The goal of this study is to investigate bending properties of domestic timber. Three representative struc- tural timber from Larix kaempferi, Pinus koraiensis, and Pinus densiflora, in the northeastern South Korea were selected. Visual grading for the timber was conducted based on KFRI notification 2009-01 and the bending strength for the timber was evaluated based on ASTM D 198 bending. The high percentage of grade 1 and 2 for Larix kaempferi shows that the KFRI notification was optimized for this species. The bending strength distributions from Pinus koraiensis and Pinus densiflora were very similar. It could be possible to specify the allowable bending properties of these two Specification using a united species group similar to spruce-pine-fir. Lastly, the bending strength of 120 × 180 mm structural members was higher than both existing values in KBC 2009 and design values for timber of imported species described in the NDS. Thus, 120 mm thick domestic softwoods could replace the commercial imported species and the KBC should be modified to provide design values for both timber and dimensional lumber, re- spectively, like NDS.

Analysis of Factors Affecting the Hygroscopic Performance of Thermally Treated Pinus koraiensis Wood

A high airtightness is required for the residential spaces constructed recently to save cooling and heating energy through improving insulation performance. Because the chances to release steam formed by human activity in building and inflow of water vapor in outdoor air to residential space are reduced, the natural humidity control performance of interior materials has become more important. In this study, hygroscopic performance of thermo-physically treated wood (Pinus koraiensis) was estimated. At various relative humidity condition, the water vapor adsorption and desorption rates of wooden materials were measured as well as equilibrium moisture content. Effects of roughness and surface microstructure as physical factors and functional groups as chemical factors on the hygroscopicity were analyzed. It is expected that the results from this study and further study of measuring moisture generation in residential spaces could contribute to install a system for evaluating the hygrothermal performance of wooden building.

[This article has been retracted] Fire Performance of Laminated Veneer Lumber (LVL) with Glued-in Steel Rod Connections

[This article has been retracted] This article describes an investigation into the fire performance of laminated veneer lumber (LVL) made from radiata pine, with glued-in steel rod connections. To determine charring rates, cone calorimeter tests are carried out on samples of LVL with a number of grain orientations, each for a range of constant heat flux exposures. Full-size load-bearing fire resistance tests are carried out on large cross section LVL beams (with no connections) in a 3 × 4m2 full-size furnace, following the ISO 834 curve. Charring rates are found to be similar to solid wood or glulam. To determine connection performance, an experimental investigation is carried out on the axial tensile strength of connections that utilized a threaded steel rod bonded into the timber using two epoxy resins and a composite adhesive. Some specimens are tested at a constant elevated temperature while similar specimens are tested in fire conditions under constant load. The three adhesives give different connection strengths at ambient temperatures and show different strength losses at elevated temperatures. Design recommendations are given in this article.

Effect of End-coating Around Pith of Heavy Timbers of Red Pine and Korean Pine on High-temperature and Low-humidity Drying Characteristics*

This study was performed to identify the effect of end-coating around pith of heavy timbers of Red pine and Korean pine on high temperature and low humidity drying characteristics. Total

Effect of Reserve Air-Drying of Korean Pine Heavy Timbers on High-temperature and Low-humidity Drying Characteristics

The pre-air-drying of Korean pine before the high-temperature and low-humidity drying was shown to be effective in uniform moisture content distribution and prevention of surface check. Our results suggest that initial moisture content of the timber also plays important role in high-temperature and low-humidity drying method. The pre-air-drying also helps in the reduction of surface checks in Korean pine when compared to the Korean pine dried by only high-temperature and low-humidity. End-coating was not effective in the prevention of twist, shrinkage, case hardening and internal checks. The pre-air-drying reduces the internal tension stresses which occur during high-temperature and low-humidity drying thus decreasing case hardening and also preventing internal checks. The pre-air-drying decreases the moisture content and causes shrinkage which leads to increased twist in the Korean pine.

Improvement of Energy Efficiency in Wood Frame House with Energy Efficient Methods

본 연구는 목조주택의 건물에너지 성능을 평가하고 개선하기 위해 수행되었다. 목조주택의 에너지 요구량을 산정하기 위하여 CE3 (Construction Energy Efficiency Evaluation) 웹기반 소프트웨어를 사용하였고 그 결과 대상 주택의 연간 난방에너지 요구량은 바닥면적 1

Cyclic Behavior of Timber Column Concealed Base Joint

m^2

Combustion Characteristics of Bamboo Charcoal Boards

당 160 kWh로 계산되었다. 난방에너지 요구량을 줄이기 위해 다음 4가지의 에너지 절감방법을 채택하였다; a) 건물형태의 단순화, b) 창호면적의 축소, c) 고성능 창호의 적용, d) 폐열회수환기장치의 적용. 열관류율 1

Moment Resistance Performance of Each Joint for Post-Beam Frame Structure

W/m^2{\cdot}K