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Monday, July 27, 2020 | History

1 edition of Bending strength of large Alaskan Sitka spruce and western hemlock log bridge stringers found in the catalog.

Bending strength of large Alaskan Sitka spruce and western hemlock log bridge stringers

Bending strength of large Alaskan Sitka spruce and western hemlock log bridge stringers

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Published by U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory in [Madison, Wis.] .
Written in English

    Subjects:
  • Wooden bridges,
  • Sitka spruce,
  • Western hemlock

  • Edition Notes

    SeriesResearch paper FPL -- 341
    ContributionsForest Products Laboratory (U.S.)
    The Physical Object
    Pagination16 p. :
    Number of Pages16
    ID Numbers
    Open LibraryOL14218031M

      The load capacity of any structural element is dependent on its physical dimensions as well as its material strength. Empirical data support the premise that the bending strength of round wood is greater and less variable than that of the lumber it would yield, besides the fact that the effective section properties of round wood are larger than those of lumber produced from it. When making the species choice using strength and weight, Sitka Spruce is at the top of the list. Actually, if this were the case, all designs would use only carbon fiber. Set the criteria to strength, weight, and cost, Sitka becomes much less attractive. A FEW CHOICES. I went to both Lowes and Home Depot to see what choices I had.

    Sitka spruce, so hardy that it grows farther north than any other conifer, also rates as the "strongman" of soft woods. Indians long ago used its tough root tendrils to sew together their bark canoes. In modern times, Sitka spruce, with reputedly the greatest strength-to-weight ratio of any wood, took to the air. YIELD OF SECOND-GROWTH HEMLOCK-SPRUCE STANDS Ö GROWTH DIFFERENCES OF SPRUCE AND HEMLOCK Western hemlock does not attain the total height of Sitka spruce at maturity. In the young fast-growing stand, however, the pro- portion of hemlock actually has little influence on the average height of dominants.

      Alaska is home to several species, but in all cases Alaska Trees are among the hardiest varieties in order to withstand the harsh environment. The climate is quite diverse, from growing zones 4 and 5 along the southern coast, to the severe cold climate of zone1 found in . Sitka Spruce is also known as Silver Spruce, Pacific Coast Spruce, and Tideland Spruce. Sitka Spruce grows along the Pacific coast of North America from Oregon north to Alaska, prized by musical instrument makers for guitars and pianos. Boat builders also regard it as second to none for the construction of yacht masts, its strength to weight.


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Bending strength of large Alaskan Sitka spruce and western hemlock log bridge stringers Download PDF EPUB FB2

Ultimate strength, a total of 40 large logs, 25 Sitka spruce, and 15 western hemlock, were field-tested in bending. CURRENT METHODS OF DERIVING STRESSES Log stringer bridges are designed by two different methods. One assumes relatively low fiber stresses, but allows full or nearly complete load distribution between stringers.

Gower suggests. Additional Physical Format: Online version: Bending strength of large Alaskan Sitka spruce and western hemlock log bridge stringers. [Madison, Wis.]: U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, Bending strength of large Alaskan Sitka spruce and western hemlock log bridge stringers.

By Forest Products Laboratory (U.S.) Abstract. Cover graphy: p. 3 of of access: Internet Topics: Western hemlock., Author: Forest Products Laboratory (U.S.). Each bridge consisted of 10 Sitka spruce logs. Eight logs were stringers while the other two, placed on top of the two outside stringers, were called brow logs (fig.

During removal and subsequent handling, two logs from the Thorne River Bridge were broken. Thus, 28 logs were available for testing. The eight stringers from each bridge were Cited by: 2. Bending Strength of Large Alaskan Sitka Spruce and Western Hemlock Log Bridge Stringers.

Madison, Wis.: United States Department of Agriculture. Log Stringer Bridges. Log Bridge Construction Handbook. Vancouver: Ferric. Ministry of Forests. Forest Service Bridge Design and Construction Manual. Victoria, BC: Resource Tenures and Engineering Branch.

R.L. Tuomi, R. Bending Strength of Large Alaskan Sitka Spruce and Western Hemlock Log Bridge Stringers. Superposition of the longitudinal stress distributions associated with neighboring knots was used to determine the interaction distances between different knot sizes.

The interaction between two knots was considered significant when the superposition of the stress distribution caused an increase in the longitudinal stress level of ten percent or more. Out of 4, knots measured in 44 Douglas. The table below provides laboratory values for several properties of wood that are associated with wood strength.

Note that due to inadequacies of samples, these values may not necessarily represent average SpeciesAverage Specific Gravity, Oven Dry SampleStatic Bending Modulus of Elasticity (E)Impact Bending, Height of Drop Causing FailureCompress.

Parallel to Grain, Max. Comments: Sitka Spruce has an outstanding stiffness-to-weight ratio, and is available in large, straight-grained pieces, lending this timber to a wide range of commercial uses.

Related Species: Black Spruce (Picea mariana) Engelmann Spruce (Picea engelmannii) Norway Spruce (Picea abies) Red Spruce (Picea rubens) White Spruce (Picea glauca. to of the Western Lumber Grading Rulesfor additional information.

Western Woods Douglas Fir-Larch Douglas Fir-South Hem-Fir Spruce-Pine-Fir (South) Western Cedars Douglas Fir— Pseudotsuga menziesii Western Larch—Larix occidentalis Douglas Fir-South— Pseudotsuga menziesii (Grown in AZ, CO, NV,NMand UT) Western Hemlock—Tsuga.

Tuomi RL, Wolfe RW, Moody RC, Muchmore FW () Bending strength of large Alaskan Sitka spruce and Western hemlock log bridge stringers. USDA Forest Service, Forest Products Laboratory, Research Paper FPLp Log bridges are an economical alternative to steel and concrete structures for temporary crossings; however, reduced availability of large logs for stringers and the advancing age of existing log.

strength of Sitka spruce and western hemlock logs. The final result of the study are Native log stringer bridge in southeast Alaska: Span m (92 ft); Capacity Mg (80 tons).

abundance of high-quality Sitka spruce logs, up to m (5 ft) in diameter, was available locally, Little is known about the bending strength or ex­. The performance of glued laminated beams manufactured from machine stress graded norwegian spruce. National cost study of timber bridges KB.

Timber bridges in Central Europe, yesterday, today, tomorrow 27 KB. Hardwoods for Timber Bridges: Field performance m timber bridges: Lynches Woods Park stress-laminated deck bridge 13 MB. Bridge stringers can also provide a valuable resource. When the logging road system was expanding, bridges were built to span creeks by using large old-growth Sitka Spruce trees because of the sheer size in length and girth as well as the immense strength inherent in spruce to support fully loaded log trucks and other massive equipment.

That was Rick Compton's wager about the foot log bridge he and Hoy Gross were finishing out at the MOTHER EARTH NEWS Ecovillage. Douglas fir, honey locust, western larch, swamp chestnut oak. Picea sitchensis ; Lumber, Timber, Softwood. Relatively easy to work with hand tools.

Data is based on small, clear, air-dried samples unless specified. Usual surface texture: Coarse Dimensional changes when dried lumber is subjected to variations. Price is per BDFT. Lengths are not listed due to varying stock, please add to cart to receive an official quote from our sales team.

For USA customers only: As of November we are no longer able to ship softwoods into the United States. Please read the statement under "International Shipping" on this page or contact us for more details on how we can help you.

Alaska Hemlock (only within southeast Alaska) has a dense, even growth ring pattern that averages 26 growth rings per inch with about 25% summer wood. The finished wood is odorless, tasteless, and non-resinous when dried. The mature Alaska Hemlock trees within southeast Alaska grow between 2 to 5 feet in diameter and up to feet in height.

5. The Sitka Spruce tree is a symbol for a female protector and guardian; the Sitka is the “mother tree”. These trees primarily grow in the northern hemisphere, and are plentiful in areas like British Columbia and Alaska. If a pirate forced you to walk a plank, chances are it was a Sitka spruce; most wooden planks came from Sitkas.

Get this from a library! Partial cutting of western hemlock and Sitka spruce in southeast Alaska. [Wilbur A Farr; A S Harris; United States. Department of Agriculture.; Pacific Northwest Forest and Range Experiment Station (Portland, Or.)].Justin S Crotteau, Annelise Rue-Johns, Jeffrey C Barnard, Eight- to ten-year effects of pre-commercial thinning on understory biomass and forage of Sitka spruce/western hemlock stands in southeast Alaska, Canadian Journal of Forest Research, /cjfr, ().Sealaska ownsacres of surface land, and STC is the dominant timber producer in Southeast Alaska.

With over 35 years of experience harvesting logs from our aboriginal forests to world markets, STC is a price leader on the Pacific coast, marketing more than billion board feet of .