Rosboro Glulam Technical Guide - Parr Lumber

1 Box 20, Springfield, OR 97477 Glulam Sales: 1-888-393-2304 Technical Support Hotline: 1-877-457-4139 Fax: 1-541-726-8919 Web: by: Rosboro GlulamTechnical GuideWood is is the earth s natural, energy efficientand renewable building wood is a better use of uses lesswood to make more wood products. That s why usingAPA trademarked I-joists, glued laminated timbers,laminated veneer Lumber , plywood, and oriented strandboard is the right thing to few facts about wood. We re not running out of of theUnited States land base 731 million acres is coveredby forests.

2 About two-thirds of that 731 million acres issuitable for repeated planting and harvesting of only about half of the land suitable for growing timber is open to logging. Most of that harvestableacreage is open to other uses as well, such as camping,hiking, hunting, etc. We re growing more wood every plant more than two billion trees every addition, millions of trees seed naturally. The forestproducts industry, which comprises about 15 percent offorestland ownership, is responsible for 41 percent ofreplanted forest acreage. That works out to more thanone billion trees a year, or about three million treesplanted every day.

3 This high rate of replanting accountsfor the fact that each year, 27 percent more timber isgrown than is harvested. Manufacturing wood products is energy cement and steel, wood products consume onlyfour percent of the energy needed to manufacture allindustrial raw materials. Wood products make up 47percent of those manufactured in the United States. Good news for a healthy every ton ofwood grown, a young forest produces tons of oxy-gen and absorbs tons of carbon It s the right product for the ,THENATURALCHOICE3 THEPOWER OFGLULAMG lued laminated timber ( Glulam ) redefines the possibilitiesfor engineered wood construction.

4 Glulam is an engineeredwood product that optimizes the structural values of arenewable resource-wood. Glulam members are composedof individual pieces of dimension Lumber . The pieces areend-jointed together to produce long lengths that are thenbonded together with adhesives to create the required beamdimensions. Because of their composition, large glulammembers can be manufactured from smaller trees harvestedfrom second and third-generation forests and manufactures Glulam from a variety of speciesincluding Douglas Fir, Larch and Southern Pine. With Glulam , builders and specifiers can continue to enjoy thestrength and versatility of large wood members without rely-ing on the old growth-dependent solid-sawn has greater strength and stiffness than comparabledimensional Lumber .

5 Pound for pound, it s stronger thansteel. That means Glulam beams can span long distanceswith minimal need for intermediate supports. It also meansthat designers and builders have virtually unlimited designflexibility when using Glulam , whether the application ishome construction, a commercial warehouse roof or a highway Technical Guide describes APA EWS trademarkedRosboro Glulam , addresses important design considerations,and includes a Guide of recommended specifications. It alsohighlights just a few of the many applications whereRosboro Glulam is used in today s Box 20, Springfield, OR 97477 Glulam Sales:1-888-393-2304 Technical Support Hotline:1-877-457-4139 Fax:1-541-726-8919 OFCONTENTSA natomy of a Glulam4 Glulam in Residential Applications8 Moisture Effects12 Specification Guidelines 14 Design and Specification Considerations16 Glulam Storage & Handling17 Guidelines for Drilling Holes19 Design Values and Properties Tables20 Minimum Bearing Length Table24 Application Tables.

6 Single-Story Headers25 Application Tables: Floor Beams28 Allowable Beam Tables: BigBeam 30 Allowable Beam Tables: Stock Glulam36 Allowable Beam Tables: Treated Glulam42 BigBeam Wet-Use Design Values44 Solid Sawn Substitution Tables45 Allowable Column Load Tables46 Glossary of Terms49 Technical Support50 ARosboro Glulam is made up of wood laminations, or lams that are bonded together with adhesives. The grainof all laminations runs parallel with the length of the mem-ber. Individual lams typically are 13/8" thick for SouthernPine and 11/2" thick for Douglas Fir and other Westernspecies, although other thicknesses may also be Glulam products typically range in net widthsfrom 31/8" to 83/4" although virtually any member widthcan be custom they are engineered products, glued laminatedtimbers are manufactured to meet a range of design stress-es.

7 Beams are manufactured with the strongest lams on the bottom and top of the beam, where maximum tensionand compression stresses occur. This concept allows the Lumber resource to be used more efficiently by placinghigher grade Lumber in zones that have the maximumstresses, and Lumber with less structural quality in lowerstressed and Unbalanced BeamsRosboro Glulam is manufactured in balanced or unbalanced most critical zone for controlling strength of a glulambending member is the outermost tension unbalanced beams, the quality of Lumber used on thetension side of the beam is higher than the Lumber used onthe corresponding compression side.

8 Allowing a more effi-cient use of the timber resource. Therefore, unbalancedbeams have different bending stresses assigned to the com-pression and tension zones and must be installed accord-ingly. To assure proper installation of unbalanced beams,the top of the beam is clearly stamped with the word TOP . Rosboro Stock Glulam is an example of an unbal-anced beam. Balanced members are symmetrical in Lumber qualityfrom the horizontal centerline, out. Balanced beams areused in applications such as cantilevers or continuousspans, where either the top or bottom of the member maybe stressed in tension due to service loads.

9 They can alsobe used in single span applications, although an unbalancedbeam is more efficient for this use. Rosboro BigBeam is anexample of a balanced Design PropertiesAllowable design properties are a key factor in specifyingglulam. Bending members are typically specified on thebasis of the maximum allowable bending stress of themember. For example, a 24F designation indicates a mem-ber with an allowable bending stress of 2,400 , a 30F designation refers to a member with anallowable bending stress of 3,000 psi. These different stresslevels are achieved by varying the percentages and grade ofhigher quality Lumber in the beam layup.

10 4 Use of different species may also result in different stress designations. To identify whether the Lumber used in thebeam is visually or mechanically graded, the stress combi-nation also includes a second set of designations. Forexample, on an unbalanced 24F layup using visually grad-ed Douglas Fir Lumber , the layup designation is identifiedas a 24F-V4. The V indicates that the layup uses visuallygraded Lumber ( E is used for mechanically graded lum-ber). The number 4 further identifies a specific combina-tion of Lumber used to which a full set of design stressessuch as horizontal shear, E, etc.