• International Journal of High-Rise Buildings
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• v.10 no.4
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• pp.285-297
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• 2021

Fire safety is one of the most significant issues for the design of mid-rise and high-rise timber structures. A large number of experimental tests were conducted during the last three decades to investigate the fire performance of the dowel-type timber connections. Many influenced parameters (e.g. the thickness of the side timber, the load ratio, the fasteners type etc.) were considered in those experiments. Relevant calculated models were proposed by previous researchers to estimate the fire resistance of the connections. In this study, a series of experimental programs of dowel-type connections in fire are collected. Then, empirical formulas proposed by EN 1995-1-2, Fire safety in timber buildings, and previous researchers are presented and analyzed. The accuracy of those formulas is checked by comparisons between the experimental data and estimated results. The collected experimental research and empirical formulas can be used as the reference for the fire design of dowel-type timber connections in the future.

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

• International Journal of High-Rise Buildings
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• v.9 no.2
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• pp.175-185
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• 2020

Currently, few studies have been conducted to comprehend the seismic reliability of post-tensioned (PT) CLT shear wall structures, due to the complexity of this kind of structural system as well as due to lack of a reliable structural model. In this paper, a set of 4-, 8-, 12-, and 16-storey benchmark PT CLT shear wall structures (PT-CLTstrs) were designed using the direct displacement-based design method, and their calibrated structural models were developed. The seismic reliability of each PT-CLTstr was assessed based on the fragility analysis and based on the response surface method (RSM), respectively. The fragility-based reliability index and the RSM-based reliability index were then compared, for each PT-CLTstr and for each seismic hazard level. Results show that the RSM-based reliabilities are slightly less than the fragility-based reliabilities. Overall, both the RSM and the fragility-based reliability method can be used as efficient approaches for assessing the seismic reliabilities of the PT-CLTstrs. For these studied mid- and high-rise benchmark PT-CLTstrs, following their fragility-based reliabilities, the 8-storey PT-CLTstr is subjected to the least seismic vulnerability; while, following their RSM-based reliabilities, the 4-storey PT-CLTstr is subjected to the least seismic vulnerability

• Journal of the Korean Wood Science and Technology
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• v.49 no.4
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• pp.336-359
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• 2021

In this study, hybrid CLT research and development trends were analyzed to improve the low rolling shear strength of CLT, a large wooden panel used in high-rise wooden buildings. Through this, basic data that can be used in research and development directions for localization of CLT were prepared. As a way to improve the low rolling shear strength, the use of hardwood lamina, the change of the lamina arrangement angle, and the use of structural composite materials are mainly used. Rolling shear strength and shear modulus of hardwood lamina are more than twice as high as softwood lamina. It confirmed that hardwoods can be used and unused species can be used. Rolling shear strength 1.5 times, shear modulus 8.3 times, bending stiffness 4.1 times improved according to the change of the layer arrangement angle, and the CLT strength was confirmed by reducing the layer arrangement angle. Structural wood-based materials have been improved by up to 1.35 times MOR, 1.5 times MOE, and 1.59 times rolling shear strength when used as laminas. Block shear strength between the layer materials was also secured by 7.0 N/mm², which is the standard for block shear strength. Through the results of previous studies, it was confirmed that the strength performance was improved when a structural wood based materials having a flexural performance of MOE 7.0 GPa and MOR 40.0 MPa or more was used. This was determined based on the strength of layered materials in structural wood-based materials. The optimal method for improving rolling shear strength is judged to be the most advantageous application of structural wood based materials with strength values according to existing specifications. However, additional research is needed on the orientation of CLT lamina arrangement according to the fiber arrangement of structural wood-based materials, and the block shear strength between lamina materials.