Recommended moisture adjustment factors for lumber stresses

1982 ◽  
Vol 9 (4) ◽  
pp. 602-610 ◽  
Author(s):  
Borg Madsen
Keyword(s):  
Moisture Content ◽  
Strength Properties ◽  
Bending Stiffness ◽  
Clear Wood ◽  
Full Size ◽  
Allowable Stresses ◽  
Adjustment Factors ◽  
Effect Of Moisture

The present allowable stresses for lumber and the associated adjustment factors stated in Canadian Standard CSA-086 are based upon tests conducted using small clear wood specimens. Recent comprehensive tests in which full-size lumber specimens were used (in-grade testing) showed that the present allowable stresses cannot be confirmed and also that new adjustment factors need to be developed.This paper deals with the effect of moisture content on the strength properties. Tests were conducted and reported dealing with: bending, stiffness, tension, compression parallel to grain, compression perpendicular to grain, and shear. From these tests it was possible to make specific recommendations for a new set of moisture content adjustment factors, to be used in design, that more realistically reflect the behaviour of lumber.

scholarly journals Compression Properties of Small Clear Southern Yellow Pine Specimens Tested across Five Decades

2021 ◽  
Vol 71 (3) ◽  
pp. 240-245
Author(s):  
Rubin Shmulsky ◽  
Frederico José Nistal França ◽  
J. Tedrick Ratcliff ◽  
Benjamin Farber ◽  
C. Adam Senalik ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Moisture Content ◽  
Wood Properties ◽  
Strength Properties ◽  
Raw Material ◽  
Clear Wood ◽  
Compression Properties ◽  
Three Samples ◽  
Yellow Pine ◽  
Southern Yellow Pine

Abstract Southern yellow pine (SYP) is one of the most used softwood species in the world. Most of this raw material come from fast-grown plantation trees. It is of interest to determine if SYP clear wood properties may have changed over the long term, in particular whether such properties may have declined. Herein, specific gravity (SG), ultimate compression strength parallel to grain (UCS‖), and UCS perpendicular to grain (UCS⊥) from three samples were compared: Sample 1 tested in 2014; Sample 2 from molding and millwork producers tested in 2017–2019; and Sample 3 from a study conducted in the mid-1960s. With respect to specific gravity (SG), the wood in Sample 1 was significantly lower than that from Samples 2 and 3. With respect to UCS‖, all three samples were statistically different. Adjusting to 12 percent moisture content had no influence on the mean separation of UCS‖. With respect to UCS⊥, no statistically significant differences were detected among the test data from any of the three samples. However, for the UCS data generated from the SG and moisture content–related model, Sample 2 was higher than Sample 3, and Sample 3 was higher than Sample 1, and these differences were statistically significant. Overall, these findings do not suggest that broad or consistent changes or declines of these wood strength properties have occurred during the past five decades.

Effect of moisture content of raw materials on the viscosity of limestone–marl slurry

1977 ◽  
Vol 27 (1) ◽  
pp. 30-32
Author(s):  
Kaissar M. Hanna ◽  
Ahmed El Gamal
Keyword(s):  
Moisture Content ◽  
Raw Materials ◽  
Effect Of Moisture

Effect of moisture content on the accuracy and economic feasibility of oil–paper insulation prediction model

2020 ◽  
Vol 14 (9) ◽  
pp. 696-703
Author(s):  
Chong Li ◽  
Kai Wu ◽  
Chuanhui Cheng
Keyword(s):  
Moisture Content ◽  
Prediction Model ◽  
Economic Feasibility ◽  
Effect Of Moisture ◽  
Paper Insulation

scholarly journals Effect of Moisture Content on the Processing and Mechanical Properties of a Biodegradable Polyester

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1616
Author(s):  
Vincenzo Titone ◽  
Antonio Correnti ◽  
Francesco Paolo La Mantia
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Moisture Content ◽  
Mechanical Testing ◽  
Hydrolytic Degradation ◽  
Slight Reduction ◽  
Biodegradable Polyester ◽  
Molding Process ◽  
Elongation At Break ◽  
Effect Of Moisture

This work is focused on the influence of moisture content on the processing and mechanical properties of a biodegradable polyester used for applications in injection molding. The pellets of the biodegradable polyester were exposed under different relative humidity conditions at a constant temperature before being compression molded. The compression-molded specimens were again placed under the above conditions before the mechanical testing. With all these samples, it is possible to determine the effect of moisture content on the processing and mechanical properties separately, as well as the combined effect of moisture content on the mechanical properties. The results obtained showed that the amount of absorbed water—both before processing and before mechanical testing—causes an increase in elongation at break and a slight reduction of the elastic modulus and tensile strength. These changes have been associated with possible hydrolytic degradation during the compression molding process and, in particular, with the plasticizing action of the moisture absorbed by the specimens.

Effect of moisture content on the extraction rate of coffee oil from spent coffee grounds using Norflurane as solvent

2021 ◽  
Vol 165 ◽  
pp. 172-179
Author(s):  
Rosa Colucci Cante ◽  
Isidoro Garella ◽  
Marianna Gallo ◽  
Roberto Nigro
Keyword(s):  
Moisture Content ◽  
Extraction Rate ◽  
Spent Coffee Grounds ◽  
Coffee Grounds ◽  
Effect Of Moisture ◽  
Coffee Oil

Structural Changes on Charring Woods of Dichrostachys and Salix from Southern Africa: The Effect of Moisture Content

IAWA Journal ◽  
1986 ◽  
Vol 7 (3) ◽  
pp. 243-250 ◽  
Author(s):  
Juliet Prior ◽  
K. L. Alvin
Keyword(s):  
Moisture Content ◽  
Southern Africa ◽  
Structural Changes ◽  
Initial Increase ◽  
Dichrostachys Cinerea ◽  
Chemical Changes ◽  
Structural Alterations ◽  
Wood Pyrolysis ◽  
Effect Of Moisture ◽  
Physical And Chemical

Air-dried and saturated cubes of fully developed wood of Dichrostachys cinerea (Leguminosae) and Salix subserrata (Salicaceae) were charred for 60 minutes at 400°C. An initial increase in moisture content caused few structural alterations in Salix but in Dichrostachys it resulted in considerable ray distension and massive deformation of non-gelatinous fibres. An attempt is made to correlate these observations with the physical and chemical changes known to occur during wood pyrolysis.

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