Effects of knot area ratio on the bending properties of cross-laminated timber made from Korean pine

AbstractThe effect of knot clusters on the bending properties of Korean pine (Pinus koraiensis) cross-laminated timber (CLT) was analyzed to increase the utilization of low-quality lumber. The laminae used to manufacture the CLT were classified into five groups, four major layer groups, and one minor layer group, by mechanical grade and knot area ratio (KAR) of the lamina. Out-of-plane bending tests were conducted on CLT made from each layer group. The modulus of elasticity (MOE) of the manufactured CLT was closely correlated with the MOE of each individual major axis lamina. In the case of the modulus of rupture (MOR) of the CLT, the KAR of the laminae used in the major axis layer was more significantly affected than the MOE. The main finding is that the lower fifth percentile MOR value of the CLT specimens with large knots (KAR > 0.5) was higher than the acceptable reference value of E3 grade CLT (ANSI/APA PRG 320) made from a similar lamina grade. Therefore, the use of low-quality lumber to manufacture CLT can be expanded under the condition of limitation of the greater KAR.

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Preliminary evaluation for quality of dimension lumber in four common softwoods in Mongolia

Journal of Wood Science ◽

10.1186/s10086-020-01919-7 ◽

2020 ◽

Vol 66 (1) ◽

Author(s):

Murzabyek Sarkhad ◽

Futoshi Ishiguri ◽

Ikumi Nezu ◽

Bayasaa Tumenjargal ◽

Yusuke Takahashi ◽

...

Keyword(s):

Pinus Sylvestris ◽

Modulus Of Rupture ◽

Preliminary Evaluation ◽

Pinus Sibirica ◽

Bending Properties ◽

Picea Obovata ◽

Dimension Lumber ◽

Commercial Species ◽

Characteristic Values

Abstract The quality of dimension lumber (2 by 4 lumber) was preliminarily investigated in four common Mongolian softwoods: Pinus sylvestris L., Pinus sibirica Du Tour, Picea obovata Ledeb., and Larix sibirica Ledeb. to produce high quality dimension lumber for structural use. In total 61, 39, 67, and 37 pieces of lumber were prepared for Pinus sylvestris, Pinus sibirica, Picea obovata, and L. sibirica, respectively. The lumber was visually graded and then tested in static bending to obtain the 5% lower tolerance limits at 75% confidence level (f0.05) of the modulus of elasticity (MOE) and the modulus of rupture (MOR). In addition, the effects of sawing patterns on bending properties were also analyzed. The f0.05 of the MOE and MOR were 4.75 GPa and 15.6 MPa, 3.39 GPa and 11.0 MPa, 3.78 GPa and 11.7 MPa, and 6.07 GPa and 22.3 MPa for Pinus sylvestris, Pinus sibirica, Picea obovata, and L. sibirica, respectively. These results suggested that with a few exceptions, characteristic values of MOR in the four common Mongolian softwoods resembled those in similar commercial species already used. In visual grading, over 80% of total lumber was assigned to select structural and No. 1 grades in Pinus sylvestris and Pinus sibirica, whereas approximately 40% of total lumber in L. sibirica was No. 3 and out of grades. Sawing patterns affected bending properties in Pinus sylvestris and L. sibirica, but did not affect Pinus sibirica and Picea obovata. Dynamic Young's modulus was significantly correlated with bending properties of dimension lumber for the four species. Based on the results, it was concluded that dimension lumber for structural use can be produced from the four common Mongolian softwoods.

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Experimental study on bending properties of cross-laminated timber-bamboo composites

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.124313 ◽

2021 ◽

Vol 300 ◽

pp. 124313

Author(s):

Weiqun Dong ◽

Zhiqiang Wang ◽

Jianhui Zhou ◽

Meng Gong

Keyword(s):

Experimental Study ◽

Bending Properties ◽

Cross Laminated Timber

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Bending Properties of Cross Laminated Timber (CLT) with a 45° Alternating Layer Configuration

BioResources ◽

10.15376/biores.11.2.4633-4644 ◽

2016 ◽

Vol 11 (2) ◽

Cited By ~ 8

Author(s):

Dietrich Buck ◽

Xiaodong (Alice) Wang ◽

Olle Hagman ◽

Anders Gustafsson

Keyword(s):

Bending Properties ◽

Cross Laminated Timber

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Tree-ring-based spring precipitation reconstruction in the Sikhote-Alin' Mountain range

Climate of the Past ◽

10.5194/cp-17-951-2021 ◽

2021 ◽

Vol 17 (2) ◽

pp. 951-967

Author(s):

Olga Ukhvatkina ◽

Alexander Omelko ◽

Dmitriy Kislov ◽

Alexander Zhmerenetsky ◽

Tatyana Epifanova ◽

...

Keyword(s):

Climate Variability ◽

Tree Ring ◽

Southern Oscillation ◽

Russian Far East ◽

Pinus Koraiensis ◽

Mountain Range ◽

Korean Pine ◽

Sikhote Alin ◽

The Impact ◽

Standard Tree

Abstract. Climate reconstructions provide important insight into past climate variability and help us to understand the large-scale climate drivers and impact of climate change. However, our knowledge about long-term year-to-year climate variability is still limited due to the lack of high-resolution reconstructions. Here, we present the first precipitation reconstructions based on tree rings from Pinus koraiensis (Korean pine) from three sites placed along a latitudinal (330 km) gradient in the Sikhote-Alin' mountains in the Russian Far East. The tree-ring width chronologies were built using standard tree-ring procedures. We reconstructed the April–June precipitation for the southern Sikhote-Alin' (SSA), March–June precipitation for the central Sikhote-Alin' (CSA) and March–July precipitation for the northwestern Sikhote-Alin' (NSA) over the years 1602 to 2013, 1804 to 2009 and 1858 to 2013, respectively. We found that an important limiting factor for Korean pine growth was precipitation within the period when the air current coming from the continent during the cold period is replaced with the impact of the wet ocean air current. We identified that common wet years for SSA, CSA and NSA occurred in 1805, 1853, 1877, 1903, 1906, 1927, 1983 and 2009 and common dry years occurred in 1821, 1869, 1919, 1949 and 2003. Our reconstructions have 3-, 15- and 60-year periods, which suggests the influence of the El Niño–Southern Oscillation and Pacific Decadal Oscillation on the region's climate and relevant processes. Despite the impact of various global processes, the main contribution to precipitation formation in the study area is still made by the Pacific Ocean, which determines their amount and periodicity.

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The temperature and length for the release of primary and induction of secondary physiological dormancy in Korean pine (Pinus koraiensis Sieb. et Zucc.) seeds

New Forests ◽

10.1007/s11056-019-09750-9 ◽

2019 ◽

Vol 51 (4) ◽

pp. 657-669 ◽

Cited By ~ 1

Author(s):

Y. Song ◽

J. J. Zhu ◽

Q. L. Yan

Keyword(s):

Pinus Koraiensis ◽

Korean Pine ◽

Physiological Dormancy

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Height-diameter relationship for Pinus koraiensis in Mengjiagang Forest Farm of Northeast China using nonlinear regressions and artificial neural network models

Journal of Forest Science ◽

10.17221/5/2019-jfs ◽

2019 ◽

Vol 65 (No. 4) ◽

pp. 134-143 ◽

Cited By ~ 1

Author(s):

Tuan Nguyen Thanh ◽

Tai Dinh Tien ◽

Hai Long Shen

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Northeast China ◽

Tree Height ◽

Pinus Koraiensis ◽

Accurate Estimation ◽

Korean Pine ◽

Ann Models ◽

Artificial Neural ◽

Forest Farm

Korean pine (Pinus koraiensis Sieb. et Zucc.) is one of the highly commercial woody species in Northeast China. In this study, six nonlinear equations and artificial neural network (ANN) models were employed to model and validate height-diameter (H-DBH) relationship in three different stand densities of one Korean pine plantation. Data were collected in 12 plots in a 43-year-old even-aged stand of P. koraiensis in Mengjiagang Forest Farm, China. The data were randomly split into two datasets for model development (9 plots) and for model validation (3 plots). All candidate models showed a good perfomance in explaining H-DBH relationship with error estimation of tree height ranging from 0.61 to 1.52 m. Especially, ANN models could reduce the root mean square error (RMSE) by the highest 40%, compared with Power function for the density level of 600 trees. In general, our results showed that ANN models were superior to other six nonlinear models. The H-DBH relationship appeared to differ between stand density levels, thus it is necessary to establish H-DBH models for specific stand densities to provide more accurate estimation of tree height.

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Fire Resistance of Cross-Laminated Timber Panels Loaded Out of Plane

Journal of Structural Engineering ◽

10.1061/(asce)st.1943-541x.0000787 ◽

2013 ◽

Vol 139 (12) ◽

pp. 04013018 ◽

Cited By ~ 18

Author(s):

Massimo Fragiacomo ◽

Agnese Menis ◽

Isaia Clemente ◽

Giovanna Bochicchio ◽

Ario Ceccotti

Keyword(s):

Fire Resistance ◽

Cross Laminated Timber ◽

Out Of Plane

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Research on the Bending Properties of the Bamboo-Wood Container Flooring

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.744.366 ◽

2013 ◽

Vol 744 ◽

pp. 366-369

Author(s):

Juan Wei ◽

Dan Zeng ◽

Ming Jie Guan

Keyword(s):

Modulus Of Elasticity ◽

Bending Strength ◽

Accelerated Aging ◽

Modulus Of Rupture ◽

Bending Properties ◽

Before And After ◽

Aging Performance

In this paper, the bending properties of bamboo-wood container flooring and bamboo curtain-OSB container flooring were tested and the six-cycle artificial accelerated aging method of ASTM D1037 was conducted to evaluate the aging performance of two kinds of bamboo-wood container floorings. The modulus of rupture (MOR) and modulus of elasticity (MOE) were tested in the longitudinal and transverse directions before and after aging. The results showed that both the bending strength and MOE decreased after aging. The retention ratios of MOR of the bamboo-wood container flooring and bamboo curtain-OSB container flooring were respectively 43.5%, 72.0%, and the retention ratios of MOE were 54.6%, 76.3%. In general, the effect of aging on the bamboo-wood container flooring was larger than that on the bamboo curtain-OSB container flooring.

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