• Journal of the Korean Wood Science and Technology
• /
• v.33 no.2 s.130
• /
• pp.8-16
• /
• 2005

In an effort to encourage the development of value added engineered applications for small diameter round timber, research is being conducted to develop and verify design guidelines for connections with specific application to round timbers. The objective of this research is to provide potential users with a number of viable connection options applicable in the fabrication of engineered, round wood structural components and systems. Target uses include trusses, built up flange beams and space frames. This paper presents information on a mortised steel plate connection fabricated using powder driven nails in 6 cm diameter Japanese Larch. The design load for PDN connections are around 1.3 kN per nail with strip and 0.8 kN per nail without stripe. The design model for PDN connectors could be chosen by the number of nails. If the number of nails are more than the critical number between nail bearing and wood failure, the wood failure model could be the way to design the structure safely. The wood failure model needs to be studied more but the model could be the tensile and cleavage mixed failure model.

• Earthquakes and Structures
• /
• v.25 no.5
• /
• pp.307-323
• /
• 2023

This study compares two prominent design provisions, National Design Specification (NDS) and Eurocode 5, on load-carrying capacity calculations and failure analysis for mortise-tenon joints. Design procedures of double-shear connection from both provisions were used to calculate load-carrying capacity of mortise-tenon joints with eight different bolt sizes. From this calculation, the result was validated using finite element analysis and failure criteria models. Although both provisions share similar failure modes, their distinct calculation methods significantly influence the design load-carrying capacity values. Notably, Eurocode 5 predicts a 6% higher design load-carrying capacity for mortise-tenon joints with varying bolt diameters under horizontal loads and 14% higher under vertical loads compared to NDS. However, the results from failure criteria models indicate that NDS closely aligns with the actual load-carrying capacity. This indicates that Eurocode 5 presents a less conservative design and potentially requires fewer fasteners in the final timber connection design. This evaluation initiates the potential for the development of a wider range of timber connections, including mortise-tenon joints with wooden pegs.

• Journal of the Korean Wood Science and Technology
• /
• v.42 no.1
• /
• pp.1-12
• /
• 2014

This study carried out life cycle assessment for evaluating environmental impacts of timber Arch-Truss bridge by using domestic Pinus rigida Miller glued-laminated timber throughout life cycle such as extraction, manufacturing, transportation, construction, use, dismantlement, transportation of waste, disposal and recycling. The life cycle GHG (GreenHouse Gas) emissions of the target bridge are 192.56 ton $CO_2$ eq. in 50 years. Especially, the life cycle GHG emissions of concrete used in the target bridge are 82.84 ton $CO_2$ eq. which accounts for 53.02% of the GWP (Global Warming Potential) in extraction and manufacturing stages. The target bridge is constructed of $116.57m^3$ of domestic Pinus rigida Miller glued-laminated timber and used timber has stored 104.72 ton $CO_2$. If an effect of carbon storage in timber is applied to the total GHG emissions of the target bridge, the GHG emissions can be reduced by 54.38%. In the case of substitution effect, if domestic Pinus rigida Miller glued-laminated timber replaces steel manufactures used in other bridge which has the same structure and life span as the target bridge, the GHG emissions in extraction and manufacturing stages can be reduced by 10.26% to 23.91%.

• Journal of the Korean Wood Science and Technology
• /
• v.47 no.4
• /
• pp.533-542
• /
• 2019

As energy costs increase, more people has become interested on energy efficiency and savings in residential buildings. The two main subjects related to energy in residential buildings are insulation and condensation. There are two approaches to prevent condensation; increasing air tightness and maintaining the temperature inside of the wall structure over the dew point, which is in turn related to insulation. Even though the Korean government has highlighted the importance of energy efficiency for residential housings, and in spite of the customers' demands, the timber construction industry is still using conventional light-frame construction without even trying to improve energy efficiency. In this study, various types and combinations of wall structures were tested under cold outdoor and warm indoor temperatures to analyse the temperature gradients and to determine the possible sites of condensation in the wall structures. In addition to the experimental tests, three theoretical models were developed and their estimations of temperature change through the wall structure were compared with the actual measurements to evaluate accuracy of the models. The results of the three models agree relatively well with the experimental values, indicating that they can be used to estimate temperature changes in wall structures. The theoretical analysis of different insulation layers' combinations show that condensation may occur within the mid-layer in the conventional light-frame wall structures for any combination of inner-, mid-, and outer-layers of insulation. Therefore, it can be concluded that the addition of an inner and outer insulation layer or increasing the thickness of insulation may not be adequate to prevent condensation in the wall structure without preventing penetration of warm moist air into the wall structure.

• International Journal of High-Rise Buildings
• /
• v.13 no.2
• /
• pp.187-194
• /
• 2024

The 53-meter tall Albizzia Tower is a white, mineral building with a mixed concrete and wood structure. It harmoniously interacts with the high rises of La Confluence. Its base is largely open, in direct relation to the public space. The spaces are mutable, reversible, moldable thanks to a streamlined structure: posts, beams in glued laminated wood, with posts pushed back on the facade to facilitate the layout of office and housing floors, CLT floors with a span of 7 meters.

• Journal of Korean Association for Spatial Structures
• /
• v.23 no.1
• /
• pp.4-7
• /
• 2023

• Journal of the Korean Wood Science and Technology
• /
• v.51 no.3
• /
• pp.197-206
• /
• 2023

A truss is a structure in which the members are connected and arranged such that they are primarily subjected to axial loading. A truss has the advantage that it can be used for a longer span because the structure distributes the applied force to its members well, and the load is transmitted only in the axial direction of the members. Trusses manufactured using timber have more advantages than those made of other materials. In this study, the properties of parallel chord trusses composed of timber chord and steel-web members were evaluated. We constructed truss specimens with various lengths by using upper and lower chords of 2 × 4 inch spruce-pine-fir lumber and steel-web members manufactured by S and P companies. The specimens were tested in accordance with KS F 2150. The test results showed that the load at the deflection limit and the deflection limit itself increased from L/180 to L/360 regardless of the length of the specimens. For specimens of the same length, the load at the deflection limit increased as the height of the parallel timber chord truss specimens increased from 200 to 300 mm. Successive installations of the steel-web members (SST) showed almost 2 times the load at each deflection limit compared to that of SAT specimens (alternate installation of the steel-web members). When comparing the three load-deflection limits in terms of the manufacturer of the steel-web members, the load at each deflection limit for SST specimens was higher than that for PST specimens.

• Journal of the Korean Wood Science and Technology
• /
• v.42 no.2
• /
• pp.193-206
• /
• 2014

Residual performance of old architectural wood which has been damaged was measured using Nondestructive Evaluation (NDE). The wood Pole Tester was used to assess ultrasonic velocity inside wood and drill resistance was determined using an IML-resistograph. For ultrasonic measurements squared timber and circular timber's measurements were separately conducted with 1,300 m/s as the standard ultrasonic velocity. The standard wood samples divided into two parts; a non-sound area (below the standard), and a sound area (above the standard). Furthermore, schematization of wood was compared with results naked eye observation. The drilling resistance test was performed for both length and thickness direction in wood. The internal of the drilling was set at 30 cm (length direction), 5 cm (width direction) and 30cm (thickness direction). A non-sound area was defined as that 1) amplitude is below 20% and 2) carbonization and deterioration are related.

• International Journal of High-Rise Buildings
• /
• v.9 no.3
• /
• pp.221-233
• /
• 2020

Based on past experiences of natural disasters and fires in Japan, it is stipulated by law that fire-resistant buildings larger than a certain size should be unique in the world. Recent interest in global environmental issues has led to the active introduction of wooden buildings also in Japan, and it is expected that wooden buildings will become larger and higher in size. This paper introduces the background of the development of fire-resistant laminated timber with a "Self-Charring-Stop layer", the contents of this development including other related developments, and the application of these technologies. In addition, towards the realization of much larger and higher buildings in the future, the current problems and issues to be solved are set and the necessity of the future technological development is described. Finally, a conceptual model of wooden high-rise building is proposed, which will be able to be constructed in 2025 by the further technological development.

• Steel and Composite Structures
• /
• v.2 no.1
• /
• pp.67-84
• /
• 2002

Traffic decks of steel or composite motorway bridges sometimes provide the opportunity of using the composite action between an existing steel deck and a reinforced concrete plate (RC plate) in the process of rehabilitation, i.e., to increase the load-carrying capacity of the deck for concentrated traffic loads. The steel decks may be orthotropic decks or also unstiffened steel plates, which during the rehabilitation are connected with the RC plate by shear studs, such developing an improved local load distribution by the joint behaviour of the two plate elements. Investigations carried out, both experimentally and numerically, were performed in order to quantitatively assess the combined static behaviour and to qualitatively verify the usability of the structure for dynamic loading. The paper reports on the testing, the numerical simulation as well as the comparison of the results. Conclusions drawn for practical design indicated that the static behaviour of these structures may be very efficient and can also be analysed numerically. Further, the results gave evidence of a highly robust behaviour under fatigue equivalent cyclic traffic loading.