Flexural tests of large glued-laminated beams made from visually graded hem-fir lumber

  • 11 Pages
  • 3.37 MB
  • English
Forest Research Laboratory, School of Forestry, Oregon State University , Corvallis, Or
Laminated wood -- Evaluation., Laminated wood -- Tes
Statementby James W. Johnson.
SeriesResearch paper / Forest research laboratory. Oregon state university -- no. 18., Paper (Oregon State University. Forest Research Laboratory) -- 876., Research paper (Oregon State University. Forest Research Laboratory) -- 18.
ContributionsOregon State University. Forest Research Laboratory.
The Physical Object
Pagination11 p. :
ID Numbers
Open LibraryOL17719925M

Flexural Tests of Large Glued-Laminated Beams Made from Visually Graded Hem-Fir Lumber James W. Johnson INTRODUCTION The objectives of this study were to design large glued-laminated beams fabricated from visually graded hem-fir lumber, test the beams in static bending, and measure their performance.

Fifteen large glued-laminated beams made from visually graded hem-fir lumber were designed, fabricated, and tested to failure in static bending. When tested, the beams had an average moisture content of percent.

The beams were 40 feet long, 5 1/8 inches wide and 24 inches : James W. Johnson. of the two different grades of lumber in the beams. Clear straight-grained wood was used in the beams in the areas that are shaded in figure 1. Because of the difficulty in obtaining large quan-tities of the very high quality clear lumber, “L1” grade material was used in the remainder of the beams.

visual grades (20). As the inner laminations of glued-laminated timber beams are subjected to relatively low bending and axial stresses, a significant amount of coarse-grain material could possibly be used for these inner laminations.

Description Flexural tests of large glued-laminated beams made from visually graded hem-fir lumber FB2

Development of combinations of glued-laminated timber utilizing coarse-grain southern pine lumber would result. combining visual grades of two widely different species and the evaluation of these criteria by tests of large beams.

A total of 20 large beams made with Douglas-fir outer laminations and lodgepole pine inner laminations are included. These beams represent three proposed levels of design such that gross inconsistencies in con­.

These beams are 24FE or combination #50 SYP. Width: /4”, /4”, /8”, 9” Industrial Grade in Depths from /8”, to /4” Lengths: up to 48’ Meets AWPA C Standards for Preservative of Glued Laminated Timbers; Uniform lay-up with zero camber; ½ the costs compared to other treated, engineered wood products.

planks. Grade rules for other sizes, such as nominal 5-in. (standard mm) or larger structural timbers may vary between rules-writing agencies or species. The National Grading Rule establishes the lumber classifica-tions and grade names for visually stress-graded dimension lumber (Table 6–2) and also provides for the grading of.

Properties for Visually Graded Dimension Lumber from In-Grade Tests of Full-Size Specimens). Reference design values for visually graded timbers, decking, and some species and grades of dimension lumber are based on pro - visions of ASTM Standard D () (Establishing Structural Grades and Related Allowable Properties for Visually.

Lumber Design Values. Design values provided herein are for Western softwood species manufactured and shipped by mills in the 12 contiguous Western states and Alaska.

Except as otherwise noted, the values are computed in accordance with ASTM standards based on clear-wood tests or on tests of full-size pieces in specific grades. Maximum Allowable Fiberstress. Design Values for Visually Graded Timbers 5" X 5" and Larger See NDS for a description of design value adjustment factors.

What is Flexural Test on Concrete. Flexural test evaluates the tensile strength of concrete indirectly. It tests the ability of unreinforced concrete beam or slab to withstand failure in bending. The results of flexural test on concrete expressed as a modulus of rupture which denotes as (MR) in MPa or psi.

Download Flexural tests of large glued-laminated beams made from visually graded hem-fir lumber FB2

Flexural testing is a simple vend test involving no end tabs but, unfortunately, the test conditions do vary widely with the chosen test method, so results must be treated with caution, although the test is useful as a quality control procedure.

There are three relevant standards – ASTM D M, BSI Methodand CRAG – and all of them cover a three-point test procedure (Fig. Many data have been obtained from flexural tests of laminated beams mm or less in depth, however, similar data on large beams are limited.

Only a few beams over mm deep have been tested. The strength of three structural grade douglas-fir beams, mm deep, tested by the laboratory in were lower than were predicted by the then current.


Details Flexural tests of large glued-laminated beams made from visually graded hem-fir lumber FB2

The grade yields of Hem-Fir (N) (Tsuga heterophylla and Abies amabilis) laminas were compared for visual and machine grades based on the Japanese Agricultural Standard (JAS) for glued laminated main objective of this study was to assess technical and material benefits when a glued laminated timber is manufactured using machine-graded laminas rather than visually graded.

Structural glued laminated timbers are permitted to be made up a single grade of lumber or a combination of grades. Structural glued laminated timber combinations generally utilize higher grade lumber in the outer zones than in the core. Design values for structural glued laminated timbers are established according to the analysis.

1. Introduction. Engineered wood is a composite material alternative to solid wood, consisting of wood and adhesives, and it is available in several varieties; the most commonly used types of structural EWP are: laminated veneer lumber (LVL), glued-laminated timber (glulam), composite I beam, cross-laminated timber (CLT) and parallel strand lumber (PSL).

A volume-effect relationship for use in the de-sign of glued laminated (glulam) timber beams was de­ veloped based on an analysis of the bending strength of more than Douglas-& and Southern. lumber, the layup designation is identified as a 24F-V4. The “V” indicates that the layup uses visually graded lum-ber.

(“E” is used for mechanically graded lumber.) The number “4” further identifies a specific combination of lum-ber used to which a full set of design stresses, such as hori-zontal shear, MOE, etc., are assigned.

To make Hem-fir glulam beams to a new Canadian specification, E-rated and visually graded lumber was arranged by stiffness, after proof loading the outer tension laminations.

Glued Laminated Timber [8]. Wet-use adhesives were used for face bonding of the laminations. APA staff was present during the lumber selection and manufacturing for all test specimens.

In this study, a total of glulam beams, as shown in Table 1, was tested at the APA Research Center in Tacoma, Washington in the as-received indoor. Test results showed that the normalised flexural capacity measured from pre-tensioned lightweight concrete beams with a reinforcing index below 015 was comparable to that of pre-tensioned normal-weight concrete beams with a similar reinforcing index, while that of a pre-tensioned lightweight concrete beam with a reinforcing index of 0 As provided by Gentry [8] study which focus on flexural performances on Glued-Laminated Timbers with FRP shear, there is significant improvement on timber beam shear strength.

The results shows an. ASTM C78 Materials lab at UCF. Choosing a Backup Generator Plus 3 LEGAL House Connection Options - Transfer Switch and More - Duration:.

This video shows the flexural behavior of Reinforced Concrete Beams under three point flexural test. It is part of the laboratory sessions for undergraduate students. with E-rated lumber in 25 percent of the outer laminations (top and bottom) and visually graded lumber in 50 percent of the center laminations; and 2) a wide-width glulam combination with laminations made from nominal 2-by 4- and 2- by 6-inch No.

2 grade lumber laid edge-to-edge having staggered end joints (termed 2 by 4/2 by 6 glulam combination). member without any natural defects. Most lumber is visually graded, although it can also be machine stress-rated or machine evaluated.

Visually graded lumber is graded by an individual who examines the wood member at the mill in accordance with an approved agency’s grading rules. The grader separates wood members into the appropriate grade.

See further informations on What Marine Recruits Go Through In Boot Camp - Earning The Title - Making Marines on Parris Island - Duration: Military Videos Recommended for you. Glulam beams are manufactured by gluing layers of dimensional lumber together.

Parallam beams are manufactured by gluing together aligned wood stands and bonding them using a microwave process. Large, solid sawn lumber timbers, referred to as “heavy timber” are available, but may be expensive to obtain in decay-resistant species if desired.

The grade yields of Hem-Fir (N) (Tsuga heterophylla and Abies amabilis) laminas were compared for visual and machine grades based on the Japanese Agricultural Standard (JAS) for glued laminated. TEXA Test Method for Flexural Strength of Concrete Using Simple Beam with Center-Point Loading 3.

Significance and Use This test method is used to determine the modulus of rupture of specimens prepared and cured in accordance with Practices C31/C31M or C/CM. The strength deter-mined will vary where there are differences in. Flexural Stresses In Beams (Derivation of Bending Stress Equation) General: A beam is a structural member whose length is large compared to its cross sectional area which is loaded and supported in the direction transverse to its axis.

Lateral loads acting on the beam cause the beam to bend or flex, thereby deforming the axis of the.Background. By laminating a number of smaller pieces of lumber, a single large, strong, structural member is manufactured from smaller pieces.

These structural members are used as vertical columns, horizontal beams, and is readily produced in curved shapes and is available in a range of species and appearances.

Connections are usually made with bolts or steel dowels and steel plates.ties (19). Present criteria for predict- single visual grade of lumber, and necessitating objective t). ing the strength of deep beams with without specially graded tension The glued-laminated beams those specially graded tension laminations had only about 85 per- evaluated were of near-minimum laminations are given in FPL (15).