• International Journal of High-Rise Buildings
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• v.9 no.3
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• pp.261-271
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• 2020

The 2020 National Building Code of Canada (NBC) and the 2021 International Building Code (IBC) both include Tall Wood Buildings (TWB) and are hailed as documents responsible for the proliferation of Mass Timber construction. Mass Timber construction is critical to reducing the carbon footprint of the construction industry; a sector acknowledged as being one of the greatest contributors of global annual CO₂ emissions. Origine, a 13-storey multi-residential building erected in 2017 in a previously unsuitable site, is currently the tallest all-wood building in North America. This article describes the challenges overcome by the designers and client as they engaged with code officials, building authorities, and fire-service representatives to demonstrate the life-safety performance of this innovative building. It also traces the development of the "Guide for Mass Timber Buildings of up to 12 Storeys" published in Quebec and how it has enabled other significant Tall Wood projects across North America.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.45-54
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• 2003

The density and strength of wood is affected by degradations and defects, such as voids and knots. Old wooden structures such as traditional cultural properties have been deteriorated by these types of defects. They were evaluated by a visual observation that is difficult to evaluate the inner deterioration in structures. In this study, three nondestructive testing techniques were investigated to detect the wooden structural members. Ultrasonic stress wave tests, drilling resistance tests and visual inspections were used to examine the structural wood members. Patterns of Resistograph using by drilling resistance tests could indicate the features of internal wood such as voids, knots, decay, fungi, and so on. The technique just like as ultrasonic stress wave tests, however, difficult to detect exactly area where small amounts of internal deterioration in logs are. In spite of results of ultrasonic stress wave test, the internal deterioration of wooden structural members could be evaluated by the relationship between ultrasonic stress wave tests and drilling resistance tests.

• Journal of the Korean Wood Science and Technology
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• v.24 no.3
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• pp.65-71
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• 1996

In the design of wood structures, the consideration of the dynamic load effect has been increased. Generally, damping ratio is presented as the method of considering dynamic load effect. So, the relationship between joint type and damping ratio was investigated. It has been known that the joint extremely damp the dynamic load in wood structures. Static test was performed to determine the effects of nail size and friction area on joint strength and stiffness. Joint strength and stiffness were increased with nail size. However, the static properties of joint was not affected by friction area. Cyclic test was performed to determine the effects of nail size, friction area and load magnitude on damping ratio, Damping ratio was affected by all factors. Increasing the width of the bottom plate was suggested as the most adequate method to increase the damping ratio without the reduction of the static properties of the structures.

• Wind and Structures
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• v.13 no.3
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• pp.221-234
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• 2010

In light-frame wood construction, missing roof-sheathing fasteners can be a relatively common occurrence. This type of construction makes up the vast majority of the residential building stock in North America and thus their performance in high winds, including hurricanes, is of concern due to their sheer number. Construction quality issues are common in these types of structures primarily because the majority are conventionally constructed and unlike steel and reinforced concrete structures, inspection is minimal except in certain areas of the country. The concept of performance-based wind engineering (PBWE), a relatively new paradigm, relies on the assumption that building performance under wind loads can be accurately modeled. However, the discrepancy between what is designed (and modeled) and what is built (the as-built) may make application of PBWE to light-frame wood buildings quite difficult. It can be concluded from this study that construction quality must be controlled for realistic application of PBWE to light-frame wood buildings.

• Journal of the Korean Wood Science and Technology
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• v.26 no.3
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• pp.9-15
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• 1998

The strength and stiffness of structures would be weakened by thermal degradation of wood members which are exposed to a variety of heat including a fire. For this reason, thermal degraded wood members can't pertinently support the load. However, it is easy to repair or rehabilitate wood structures. So, the degraded wood members which can't support the load can be replaced with new members. For the sake of this advantage, there is a need for nondestructive evaluation(NDE) technique, which is very effective to assess wood members in service. In this paper, it was considered whether the stress wave method is adequate to estimate static bending MOE of thermal degraded wood. As the result, the relationship between static bending MOE and MOEsw in elevated temperature was found out significant. Therefore, the application of stress wave method for estimating static bending MOE of thermal degraded zzwood would be possible. However, it is thought that further research for the effects of exposure temperature, time, and thermal degradation on the relationship between static bending MOEb and MOEsw would be needed.

• Journal of the Korean Wood Science and Technology
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• v.21 no.1
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• pp.15-20
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• 1993

X-ray diffractograms of the vessel elements and the wood fibers of Quercus variabilis BLUME were recorded and resolved into characteristic reflections of cellulose I. Some differences were observed in the ratio of integrated intensity and crystallinity index between vessel elements and wood fibers. Present results suggest that cellulose crystal structure in the hardwood species was varied with the elements of wood.

• Korean Journal of Agricultural Science
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• v.37 no.3
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• pp.465-469
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• 2010

In order to develop effective recycling technologies of disused railway wood ties, wood properties and residual creosote oil of wood ties were investigated. Among the total 50 wood ties, 32 wood ties were identified as tropical hardwood tree, such as, Keruing (Dipterocarpus spp.), Kempas (Koompassia malaccensis), Kapur (Dryobalanops spp.) Naytoh (Palaquium rostratum), and so on. Disused wood ties showed mostly sound structure without degradation of cell walls by decay fungi. Disused wood ties showed high strengths of bending and compressive parallel to grain because degradation of wood properties was hardly occurred in use under exterior condition. Disused railway wood ties had relatively poor depth of penetration and residual of creosote oil because of refractory wood structures. These results suggest that disused railway wood ties may be useful as recycling wood wastes.

• Interaction and multiscale mechanics
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• v.5 no.3
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• pp.229-265
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• 2012

Hygroexpansion of wood is a known and undesired characteristic in civil engineering. When wood is exposed to changing environmental humidity, it adsorbs or desorbs moisture and warps. The resulting distortions or - at restrained conditions - cracks are a major concern in timber engineering. We herein present a multiscale model for prediction of the macroscopic hygroexpansion behavior of individual pieces of softwood from their microstructure, demonstrated for spruce. By applying poromicromechanics, we establish a link between the swelling pressure, driving the hygroexpansion of wood at the nanoscale, and the resulting macroscopic dimensional changes. The model comprises six homogenization steps, which are performed by means of continuum micromechanics, the unit cell method and laminate theory, all formulated in a poromechanical framework. Model predictions for elastic properties of wood as functions of the moisture content closely approach corresponding experimental data. As for the hygroexpansion behavior, the swelling pressure has to be back-calculated from macroscopic hygroexpansion data. The good reproduction of the anisotropy of wood hygroexpansion, based on only a single scalar calibration parameter, underlines the suitability of the model. The multiscale model constitutes a valuable tool for studying the effect of microstructural features on the macroscopic behavior and for assessing the hygroexpansion behavior at smaller length scales, which are inaccessible to experiments. The model predictions deliver input parameters for the analysis of timber at the structural scale, therewith enabling to optimize the use of timber and to prevent moisture-induced damage or failure.

• Earthquakes and Structures
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• v.7 no.1
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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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• v.47 no.5
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• pp.617-632
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• 2019

This study aimed to investigate the anatomical structure and fiber quality of four lesser-used wood species namely Benuang (O. sumatrana), Duabanga (D. moluccana), Pisang Merah (H. hellwigii), and Terap (A. odoratissimus). This study evaluated its suitability for raw material in pulp and paper manufacturing. The anatomical structure was observed macro- and microscopically. Macroscopic structures were observed directly to the wood samples, while microscopic characteristics were observed through microtome specimens. Fiber dimension was measured through macerated specimens and fiber quality was analyzed following the Rachman and Siagian's method. Results showed that these four timber species have similarity in the indistinct growth ring, diffuse porous in a radial pattern, rounded solitary vessel outline, 1 to 3 cells of ray width, deposits within the rays, fiber length, and cell wall thickness. Differences were found on vessel diameter, vessel grouping, vessel frequency, tyloses existence, type of axial parenchyma, and ray height. Based on fiber length and its derived values, the wood fibers of all species studied are suitable for pulp and paper manufacturing. They belong to the II quality class. The produced pulp and paper would have good quality, especially in tensile, folding, and tear strength. To promote their utilization, silviculture aspect of these four species has to be well understood.