GLULAM - WALSH INDUSTRIES, LLCwalsh-industries.com/Walsh_Industries_Website/Industry...For every ton of wood grown, a young forest produces 1.07 tons of oxygen and absorbs 1.47 tons

P R O D U C T G U I D E

G L U L A M

ENGINEERED WOOD SYSTEMS

Brochure 7/10/00 11:12 AM Page 1

Wood is good. It is the earth’s natural, energy efficient and renewable building material.

Engineered wood is a better use of wood. It uses less wood to make more wood products.

That’s why using APA trademarked I-joists, glued laminated timbers, laminated veneerlumber, plywood, and oriented strand board is the right thing to do.

A few facts about wood.■ We’re not running out of trees. One-third of the United States land base –731 million acres – is covered by forests. About two-thirds of that 731 million acres issuitable for repeated planting and harvesting of timber. But only about half of the landsuitable for growing timber is open to logging. Most of that harvestable acreage also isopen to other uses, such as camping, hiking, hunting, etc.

■ We’re growing more wood every day. American landowners plant more thantwo billion trees every year. In addition, millions of trees seed naturally. The forestproducts industry, which comprises about 15 percent of forestland ownership, isresponsible for 41 percent of replanted forest acreage. That works out to more than onebillion trees a year, or about three million trees planted every day. This high rate ofreplanting accounts for the fact that each year, 27 percent more timber is grown than is harvested.

■ Manufacturing wood products isenergy efficient. Wood products madeup 47 percent of all industrial rawmaterials manufactured in the UnitedStates, yet consumed only 4 percent ofthe energy needed to manufacture allindustrial raw materials, according to a 1987 study.

■ Good news for a healthy planet. For every ton of wood grown, a young forestproduces 1.07 tons of oxygen and absorbs 1.47 tons of carbon dioxide.

Wood. It’s the right product for the environment.

W O O D , T H E N A T U R A L C H O I C E

Percent of Percent ofMaterial Production Energy Use

Wood 47 4

Steel 23 48

Aluminum 2 8

NOTICE:The recommendations in this data file apply only to glulam that bears theAPA EWS trademark. Only glulam bearing theAPA EWS trademark issubject to the Association’squality auditing program.

B IND

MILL 0000

ANSI A190.1-1992

117-93

EWS 24F-1.8E SP


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CONTENTS

100 Years of Glulam . . . . . . . . .4

Anatomy of a Glulam . . . . . . . . .4

Glulam in NonresidentialApplications . . . . . . . . . . . . . . . .8

Glulam in Residential Applications . . . . . . . . . . . . . . .14

Designing for FireResistance . . . . . . . . . . . . . . . .20

Moisture Effects . . . . . . . . . . . .22

Design and SpecificationConsiderations . . . . . . . . . . . . .25

Glulam Specification Guide . . .26

Storage, Handling and Installation . . . . . . . . . . . .28

Glossary of Terms . . . . . . . . . . .30

About Engineered Wood Systems . . . . . . . . . . . . .31

lued laminated timber (glulam) redefines the possibilities for engineered wood construc-tion. Glulam is an engineered wood productthat optimizes the structural values of a

renewable resource – wood. Glulam members arecomposed of individual pieces of dimension lumber.The pieces are end-jointed together to produce long lengths which are then bonded together withadhesives to create the required beam dimensions.Because of their composition, large glulam memberscan be manufactured from smaller trees harvestedfrom second- and third-growth forests and planta-tions. A variety of species is used. With glulam,builders and specifiers can continue to enjoy thestrength and versatility of large wood members without relying on the old growth-dependent solid-sawn timbers.

Glulam has greater strength and stiffness thancomparable dimensional lumber. Pound for pound,it’s stronger than steel. That means glulam beamscan span long distances with minimal need forintermediate supports. It also means that designersand builders have virtually unlimited design flexibil-ity when using glulam, whether the application ishome construction, a commercial warehouse roof or a highway bridge.

This Engineered Wood Systems brochure describesAPA EWS trademarked glulam, addresses impor-tant design considerations, and includes a guide ofrecommended specifications. It also highlights just a few of the many applications where glulam is used today in construction.

G


Cover photo: Willamette Industries, Inc.


ANATOMY

OF A GLULAM

A glulam is made up of wood lamina-tions, or “lams” that are bonded to-gether with adhesives. The grain of alllaminations runs parallel with the lengthof the member. Individual lams typicallyare 1-3/8 inches thick for southern pineand 1-1/2 inches thick for Westernspecies, although other thicknesses mayalso be used. Glulam products typicallyrange in net widths from 2-1/2 to10-3/4 inches although virtually anymember width can be customproduced.

Because they are engineered products,glued laminated timbers are manufac-tured to meet a range of design stresses.Beams are manufactured with thestrongest lams on the bottom and top ofthe beam, where maximum tension andcompression stresses occur. This con-cept allows the lumber resource to beused more efficiently by placing highergrade lumber in zones that have themaximum stresses, and lumber with less structural quality in lower stressed zones.

Balanced and Unbalanced BeamsGlulam may be manufactured as unbalanced or balanced members.

The most critical zone of a glulam bending member with respect to con-trolling strength is the outermost tensionzone. In unbalanced beams, the qualityof lumber used on the tension side ofthe beam is higher than the lumber usedon the corresponding compression side,allowing a more efficient use of thetimber resource. Therefore, unbalancedbeams have different bending stressesassigned to the compression and tensionzones and must be installed accordingly.

To assure proper installation of unbal-anced beams, the top of the beam isclearly stamped with the word “TOP.”Unbalanced beams are primarilyintended for simple span applications.

Balanced members are symmetrical inlumber quality about the mid-height.Balanced beams are used in applicationssuch as cantilevers or continuous spans,where either the top or bottom of themember may be stressed in tension dueto service loads. They can also be usedin single span applications, although anunbalanced beam is more efficient for this use.

Allowable Design PropertiesAllowable design properties are a keyfactor in specifying glulam. Bendingmembers are typically specified on thebasis of the maximum allowable bend-ing stress of the member. For example, a 24F designation indicates a memberwith an allowable bending stress of2400 psi. Similarly, a 26F designationrefers to a member with an allowablebending stress of 2600 psi. These differ-ent stress levels are achieved by varyingthe percentages and grade of higherquality lumber in the beam layup. Useof different species may also result indifferent stress designations.

To identify whether the lumber used in the beam is visually or mechanicallygraded, the stress combination alsoincludes a second set of designations.For example, for an unbalanced 24Flayup using visually graded Douglas-firlumber, the layup designation is identi-fied as a 24F-V4. The “V” indicates thatthe layup uses visually graded lumber.(“E” is used for mechanically gradedlumber.) The number “4” further identi-fies a specific combination of lumberused to which a full set of design stressessuch as horizontal shear, MOE, etc., are

4

100 Years of GlulamIn terms of current needs to optimize products from a carefullymanaged timber resource, glulamis one of the most resource efficientapproaches to wood building prod-ucts. It is an engineered productmanufactured to meet the mostdemanding structural require-ments. But glued laminated timber is not a new product.

The first patents for glulam were issued in Switzerland and Germany in 1900. A 1906German patent signaled the truebeginning of glued laminatedtimber construction. One of thefirst glulam structures erected inthe U.S. was a research labora-tory at the USDA Forest ProductsLaboratory in Madison,Wisconsin. The structure waserected in 1934 and is still inservice today.

A significant development inthe glulam industry was the introduction of fully water-resistant phenol-resorcinol adhesives in 1942. This allowedglulam to be used in exposedexterior environments withoutconcern of glueline degradation.

The first U.S. manufacturingstandard for glulam wasCommercial Standard CS253-63,which was published by theDepartment of Commerce in1963. The most recent standard is ANSI Standard A190.1-92,which took effect in 1992.


5

TABLE 1

ALLOWABLE STRESSES (in psi)

Combination Fb ten. Fb comp. Fv MOE Fc // Fc⊥ Ft

Unbalanced Layups

24F-1.8E 2400 1600 195 1.8 x 106 1200 500 950

24F-V4/DF 2400 1850 240 1.8 x 106 1650 650 1100

24F-V3/SP 2400 1950 270 1.8 x 106 1700 740 1150

Balanced Layups

24F-V8/DF 2400 2400 240 1.8 x 106 1650 650 1100

24F-V5/SP 2400 2400 270 1.8 x 106 1700 740 1150

assigned. Some of the most commonglulam beam layups with their corre-sponding allowable stresses are shown in Table 1.

Engineered Wood Systems Technical Note EWS Y117, Allowable Properties for APA EWS Glulam provides designstresses for all glulam produced by EWS members.

Axis OrientationGlulam beams are typically installedwith the wide face of the laminationsperpendicular to the applied load, asshown in Figure 1. These are commonlyreferred to as horizontally laminatedmembers. If this same member isrotated 90 degrees such that the load isapplied parallel to the wide face of thelaminations, it is considered to be avertically laminated member. Glulammembers have different tabulated stressproperties depending on whether themember is used in a horizontal or verti-cal orientation. For more information,refer to the Engineered Wood SystemsTechnical Note EWS Y117, AllowableProperties for APA EWS Glulam.

FIGURE 1

BEAM CROSS SECTION

y

y

xx

SizesGlulam is available in both custom andstock sizes. Stock beams are manufac-tured in commonly used dimensions, and cut to length when the beams areordered from a distributor or dealer.Typical stock beam widths include:3-1/8", 3-1/2", 5-1/8", 5-1/2", and 6-3/4",which meet the requirements for mostresidential construction applications.

Where long spans, unusually heavyloads, or other circumstances controldesign, custom members are typicallyspecified. Custom members are avail-able in virtually any size and shape that may be required to meet the design conditions.

Some of the common custom shapesthat are available include curved beams,pitched and curved beams, radial archesand tudor arches.


Appearance ClassificationGlulam is available in a range of appear-ances, all looking different but havingthe same structural characteristics for agiven strength grade. Glulam appear-ance classifications are:

Framing. This classification is intendedonly for use in concealed applications.Beams with this appearance classifica-tion are provided in widths designed tofit flush with 2x4 and 2x6 wall framing.

Industrial. Used for concealed applica-tions or where appearance is not ofprimary importance.

Architectural. The appearance of choicein applications where members areexposed to view, because they have asmooth, attractive finish. Stock beamsare often supplied with this appearanceso they may be exposed to view in thefinished structure.

Premium. Available only as a customorder where finished appearance is ofprimary importance.

All appearance classifications permitnatural growth characteristics withvarying degrees of open voids permit-ted. Voids are filled as required by theappearance grade specified using insertsand wood fillers. The appearance classi-fication is not related to lumber layuprequirements and thus does not affectdesign values for the beam.

Section Properties and CapacitiesWhen selecting a glulam member, thebuilder, designer, or specifier must use a member with the required sectionproperties to satisfy the load carryingrequirements. Different load capacities

into a fabricated member (see Figure 2)which is opposite in direction and mag-nitude to the calculated deflectionwhich will occur under gravity loads.

The glulam industry recommends thatroof beams be cambered for 1-1/2 timesthe calculated dead load deflection. Thiswill generally be sufficient to assure thatthe beam will not exhibit a sag over aperiod of many years of loading, as mayoccur with non-cambered wood prod-ucts. To achieve a level profile it is rec-ommended that floor beams be onlycambered for 1.0 times the calculateddead load deflection.

Camber for glulam beams is specified aseither “inches of camber” or as a radiusof curvature that is to be used in themanufacturing process. Commonlyused curvature radii for commercialapplications are 1600 and 2000 feetalthough any camber may be specified.

are possible for different stress levelcombinations of glulam. Tables givingthe load carrying capacities for glulamare included in the Engineered WoodSystems Data File: Glued Laminated BeamDesign Tables, Form EWS S475. Thesebeam capacities are based on loadingperpendicular to the wide faces of thelaminations; that is, bending about the x-x axis of the beam as shown inFigure 1.

CamberOne of the most important design considerations for wood framing isdeflection. For longer spans, deflectionis often the controlling design factor.While any wood bending member canbe designed to minimize deflection,glulam is the only engineered woodproduct that can be easily cambered toreduce the aesthetic effect of in-servicedeflections. Camber is curvature built

6

Glulam beam being tested at the APA Research Center.


7

Most residential applications requirevery little or no camber which, in turn,makes glulam the ideal choice. Stockbeams are typically supplied with arelatively flat camber radius of 3,500 feetas shown in Table 2 or zero camber.Thus, they have just the right camber forresidential construction. If, however,more camber is required, such as for along span roof beam, custom beams areavailable through manufacturers to meetthe most exacting specifications.

For additional information on camberingglulam beams, refer to Engineered WoodSystems Technical Note: Glulam BeamCamber, Form EWS S550, which pro-vides a camber table for various beamspans and radii of curvature.

Trademarks and AcceptancesGlulam beams manufactured byEngineered Wood Systems members are certified with the APA EWS trade-mark. The mark (as shown) signifiesthat the manufacturer is committed to arigorous program of quality verificationand testing and that products are manufactured in conformance withANSI Standard A190.1-92, American National Standard for Structural Glued Laminated Timber.

Typical information included in anAPA EWS trademark is shown on thesample trademark. This information mayvary depending on whether the memberis supplied as a custom or stock product.

The APA EWS trademark is recognizedby all major model building codes forthe certification of glued laminatedtimber produced by Engineered WoodSystems members.

(1) Indicates structural use: B-Simple span bending member. C-Compression member. T-Tensionmember. CB-Continuous or cantilevered span bending member.

(2) Mill number.

(3) Identification of ANSI Standard A190.1, Structural Glued Laminated Timber. ANSI A190.1 is theAmerican National Standard for glulam beams.

(4) Applicable laminating specification.

(5) Western woods (see note 6).

(6) Structural grade designation. The APA EWS 24F-1.8E designation is a glulam grade commonlyused in residential applications. Combining a group of six layup combinations made with Douglas-fir-Larch, Spruce-Pine-Fir, southern pine, and/or Hem fir, this grade provides strength (allowable bendingstress of 2,400 psi and allowable shear stress of 195 psi) and stiffness (modulus of elasticity of 1.8 x106 psi) needed for typical residential applications, while greatly simplifying the design specification.

(7) Designation of appearance grade. INDUSTRIAL, ARCHITECTURAL, PREMIUM, or FRAMING.

B IND

MILL 0000 ANSI A190.1-1992

117-93EWS 24F-1.8E WW

1

7

2

3

564

TABLE 2

CAMBER FOR 3500-FOOT RADIUS

Span in feet: 10 12 14 16 18 20 22 24 26 28Camber in inches: .04 .06 .08 .11 .14 .17 .21 .25 .29 .34

L = Span (ft.)

Cambered beam

∆ = Camber (in.)

R = Radius of curvature (ft.)

FIGURE 2

BEAM CAMBER PARAMETERS


8

GLULAM IN

NONRESIDENTIAL

APPLICATIONS

Visible beauty, hidden strengthGlulam has a reputation for being usedin striking applications such as vaultedceilings and other designs with soaringopen spaces. In churches, schools,restaurants, and other commercialbuildings, glulam is often specified forits beauty as well as its strength. Forgood reason. Glulam has the classicnatural wood appearance that holds a timeless appeal.

Aesthetics aside, there are many otherapplications where the strength anddurability of glulam beams make themthe ideal structural choice. Typical usesrange from simple purlins, ridge beams,floor beams and cantilevered beams tocomplete commercial roof systems. Insome instances, warehouse and distrib-ution centers with roof areas exceeding1 million square feet have been con-structed using glulam framing. In largeopen spaces, glulam beams can spanmore than 100 ft.

One of the greatest advantages of glulam is that it can be manufactured ina wide range of shapes, sizes, and con-figurations. In addition to straight pris-matic sections, beams can also beproduced in a variety of tapered configu-rations such as single tapered, doubletapered and off-centered ridges. Curvedshapes range from a simple curvedbeam to a pitched and tapered curvedbeam to a complex arch configuration.

Bridges represent a growing market forglulam in pedestrian and light vehicularapplications for stream and roadwaycrossings. Glulam is also used in sec-ondary highway bridge designs rangingfrom straight girders to soaring arches.And, the railroads are finding glulam tobe a viable structural product for use in their heavily loaded bridge structures.

In all of these uses, the strength andstiffness of glulam give builders anddesigners more design versatility thanthey have with other structural prod-ucts. And, these advantages come at acost that is competitive with other structural systems.

Spans using glulam arches are virtuallyunlimited. For example, in reticulatedglulam framed dome structures, archesspan more than 500 feet.

Glulam trusses also take many shapesincluding simple pitched trusses, com-plicated scissors configurations and longspan bowstring trusses with curvedupper chords. When designed as spaceframes, glulam truss systems can creategreat clear spans for auditoriums, gym-nasiums, and other applications requiring large open floor areas.

When manufactured with waterproofadhesives, glulam products can be fullyexposed to the environment providedthey are properly pressure-preservativetreated. Exposed applications includeutility poles and crossarms, marinas,docks and other waterfront structuresand bridges.

Two lane highway bridge in Colorado using glulam radial arches.


9

The Disney ICE rink in Anaheim, California features glulam arches curved to a 75-foot radius to form the ice center’s roof system.

Glulam cantilevered frame for curling rink, Calgary, Canada. REI, an outdoor sports equipment retailer, used glulam columns andbeams in its Minneapolis, Minnesota store.


10

Lincoln School in Spreckles, California is home for the local county library where AlaskaYellow Cedar and Douglas-fir glulam members add light and warmth.


11

Curved beams define the building design in the Steinbeck Center,Salinas, California.

Panelized wood roof with open web glulam trusses and beams.

Glulam pedestrian and light vehicular golf course bridge under construction in Orlando, Florida.


12

Glulam arches support the roof of the Chicago Bears practice facilityin Lake Forest, Illinois.

Glulam tower for Nebraska Power and Light transmission line. This 236,000-square-foot potash storage building in Portland, Oregon features APA EWS glulam arches.


13

Glulam truss highway bridge, Hiroshima, Japan.

Panelized wood roof system featuring glulam beams and purlin trusses in the PepsiCo Distribution Center, Hayward, California.


14

GLULAM IN

RESIDENTIAL

APPLICATIONS

In residential construction, APA EWStrademarked glulam beams are oftenchosen for their beauty in exposeddesigns such as rafters in vaulted ceilingsor long clear-span ridge beams. They’realso ideal for hidden structural applica-tions, such as floor beams and headers.No other product combines the strengthand natural beauty of wood like glulam,and nothing provides builders anddesigners with the design flexibilitydemanded by today’s homeowner.

Stock Beams and Custom BeamsFor most residential applications, stockbeams are the product of choice. Stockbeams, readily available from distributorsthroughout North America, are manufac-tured in widths of 3-1/8, 3-1/2, 5-1/8,5-1/2 and 6-3/4 inches with depthsranging from 9 to 36 inches. Often stockbeams are supplied as an architecturalappearance classification making themsuitable for exposed applications.

Custom glulam beams are also readilyavailable in most market areas and areused when a larger cross-section, longerlength, curved shape, or differentappearance classification is needed.Examples of curved custom applicationsinclude curved fascia members andarches over clear span areas such as greatrooms and interior pool enclosures.

Floor BeamsThe superior strength of glulam allowslonger clear spans than solid-sawn lum-ber. Because glulam is manufacturedfrom kiln-dried lumber, shrinkage and

warping are minimized. In addition,glulam beams have excellent fastener-holding capability, which means a firmsubfloor with minimal nail popping or squeaks.

In the photo above, the depth of thegluam matches the depth of the I-joistsit is supporting. This is called an I-joistcompatible glulam or IJC beam. IJCbeams are supplied in depths of 9-1/2",11-7/8", 14" and 16" to match thedepths of I-joists used in residentialconstruction. This allows ceilings to beframed flush with no need for extrafurring out.

In the application shown at top right, aglulam supports the second floor I-joistframing. The glulam beam was chosenfor its size, strength and availability.

A two-car garage is directly below theupper story room and the glulam beam

I-joist compatible glulam beams are supplied in depths of 9-1/2", 11-7/8", 14", and 16".

allows a long clear span with no inter-mediate supports. Eliminating the needfor a post in the middle of the garagemeans there’s more room to open andclose car doors and maneuver vehicles.

Conventional solid-sawn timbers orother structural framing members wouldnot have been able to span the neces-sary distance without additional sup-ports. A glulam was the ideal solution. Itmet the design needs and was availablefor timely, cost-effective delivery.

Ridge and Rafter BeamsThe open, airy designs and high ceilingscommon in residential constructiontoday make glulam the perfect choice for ridge beam applications as shown at right. They can span long distancesand carry virtually any design load.Sloping glulam rafter beams are theperfect complement to ridge beams in exposed applications.


15

Glulam beam supports second floor I-joist construction.

No other material combines the strength and natural beauty of woodlike glulam.

Glulam ridge beams complement the spacious, open designscommon in modern residential construction.


16

Long, curved custom glulam beams form the distinctive shape of thisocean view home in Malibu, California.

Glulam garage door header extends over adjacent narrow shear wall.(See Figure 4 for details.)

Glulam headers support framing in this two-story home.


17

Garage Door HeadersGlulam headers can easily span distanceslong enough to allow garage door open-ings for two or three cars. And becausethey are cut to length when you buythem, you pay only for the length youneed – nothing is wasted. A commonwidth of glulam garage door header is3-1/2 inches, which fits conventional2x4 wall construction. For 2x6 wallconstruction, a 5-1/2-inch-wide glulamprovides the perfect fit. Beams withwidths of 3-1/8" and 5-1/8" are alsoused for these applications.

Full-length glulam headers at an end-wall provide an excellent nailingsurface for structural wood panels,which help tie the beam to wall framingmembers on either side of the garagedoor opening to improve bracing. Thisconstruction methods adds rigidity andimproves resistance to wind and earth-quake loads by effectively creating anarrow shear wall as shown in Figure 4.

ColumnsGlulam columns are straight and dimensionally true, making framing aneasy task. Because glulam columns areavailable in long lengths, the membersdon’t have to be spliced together, as isoften necessary with sawn lumber. And,glulam columns can be exposed to viewas a unique architectural feature of theframing system.

FIGURE 4

BRACED WALL DETAIL FOR GARAGE DOOR OPENING IN ONE-STORY BUILDINGCheck local building code requirements or contact APA for additional information.

16" min.

2x top plate

Glulam header

Nail sheathing to header (grid pattern)

APA Rated Sheathing

Approved steel hold-downs

Anchor bolts

Approved steel strap ties

2x studs – nail sheathing to all plates and studs

2x plates – nail sheathing to each plate

Continuous reinforced concrete stem wall and footing (or slab edge)

FIGURE 3

GLULAM GARAGE DOOR HEADERS – DESIGN EXAMPLE

The 16-foot 3-inch beam span in this figure supports roof trusses on a 28-foot-widehouse with 2-foot overhangs, under a 15 psf design dead load and 25 psf design snowload. According to the data in Tables 3A and 3B (Pages 18-19), four different sizes ofglulam beams could be selected: 3-1/8 by 15 inches, 3-1/2 by 13-1/2 inches, 5-1/8 by12 inches and 5-1/2 by 12 inches, all suitable to carry the required design loads withthe final choice being based on localavailability, cost and designerpreference.

2'

2'

Glulam Header

16'-3"

Clear opening

28'Span of supported

roof framing


18

TABLE 3A

APA EWS 24F-1.8E GRADE GLULAM GARAGE DOOR HEADERS FOR SINGLE-STORY APPLICATIONSRough Door Opening = 9 ft 3 in. (Beam depths based on 1-1/2" laminations.)

Span of supported roof trusses (ft)

22 24 26 28 30 32 34 36

Non-Snow Load 3-1/8 x 7-1/2 3-1/8 x 7-1/2 3-1/8 x 7-1/2 3-1/8 x 7-1/2 3-1/8 x 7-1/2 3-1/8 x 9 3-1/8 x 9 3-1/8 x 9(125%) 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 7-1/215 psf Dead 5-1/8 x 6 5-1/8 x 6 5-1/8 x 6 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/220 psf Live 5-1/2 x 6 5-1/2 x 6 5-1/2 x 6 5-1/2 x 6 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2

Snow Load 3-1/8 x 7-1/2 3-1/8 x 9 3-1/8 x 9 3-1/8 x 9 3-1/8 x 9 3-1/8 x 9 3-1/8 x 9 3-1/8 x 10-1/2(115%) 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 9 3-1/2 x 9 3-1/2 x 9 3-1/2 x 915 psf Dead 5-1/8 x 6 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/225 psf Live 5-1/2 x 6 5-1/2 x 6 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2

Snow Load 3-1/8 x 9 3-1/8 x 9 3-1/8 x 9 3-1/8 x 9 3-1/8 x 9 3-1/8 x 10-1/2 3-1/8 x 10-1/2 3-1/8 x 10-1/2(115%) 3-1/2 x 7-1/2 3-1/2 x 7-1/2 3-1/2 x 9 3-1/2 x 9 3-1/2 x 9 3-1/2 x 9 3-1/2 x 9 3-1/2 x 915 psf Dead 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/230 psf Live 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2

Snow Load 3-1/8 x 9 3-1/8 x 9 3-1/8 x 10-1/2 3-1/8 x 10-1/2 3-1/8 x 10-1/2 3-1/8 x 10-1/2 3-1/8 x 10-1/2 3-1/8 x 12(115%) 3-1/2 x 9 3-1/2 x 9 3-1/2 x 9 3-1/2 x 9 3-1/2 x 10-1/2 3-1/2 x 10-1/2 3-1/2 x 10-1/2 3-1/2 x 10-1/215 psf Dead 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 7-1/2 5-1/8 x 9 5-1/8 x 9 5-1/8 x 9 5-1/8 x 940 psf Live 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 7-1/2 5-1/2 x 9 5-1/2 x 9

Rough Door Opening = 16 ft 3 in. (Beam depths based on 1-1/2" laminations.)


22 24 26 28 30 32 34 36

Non-Snow Load 3-1/8 x 12 3-1/8 x 12 3-1/8 x 13-1/2 3-1/8 x 13-1/2 3-1/8 x 13-1/2 3-1/8 x 13-1/2 3-1/8 x 15 3-1/8 x 15(125%) 3-1/2 x 12 3-1/2 x 12 3-1/2 x 12 3-1/2 x 12 3-1/2 x 13-1/2 3-1/2 x 13-1/2 3-1/2 x 13-1/2 3-1/2 x 13-1/215 psf Dead 5-1/8 x 10-1/2 5-1/8 x 10-1/2 5-1/8 x 10-1/2 5-1/8 x 12 5-1/8 x 12 5-1/8 x 12 5-1/8 x 12 5-1/8 x 1220 psf Live 5-1/2 x 10-1/2 5-1/2 x 10-1/2 5-1/2 x 10-1/2 5-1/2 x 10-1/2 5-1/2 x 10-1/2 5-1/2 x 12 5-1/2 x 12 5-1/2 x 12

Snow Load 3-1/8 x 13-1/2 3-1/8 x 13-1/2 3-1/8 x 15 3-1/8 x 15 3-1/8 x 15 3-1/8 x 15 3-1/8 x 16-1/2 3-1/8 x 16-1/2(115%) 3-1/2 x 12 3-1/2 x 13-1/2 3-1/2 x 13-1/2 3-1/2 x 13-1/2 3-1/2 x 13-1/2 3-1/2 x 15 3-1/2 x 15 3-1/2 x 1515 psf Dead 5-1/8 x 10-1/2 5-1/8 x 12 5-1/8 x 12 5-1/8 x 12 5-1/8 x 12 5-1/8 x 12 5-1/8 x 12 5-1/8 x 13-1/225 psf Live 5-1/2 x 10-1/2 5-1/2 x 10-1/2 5-1/2 x 10-1/2 5-1/2 x 12 5-1/2 x 12 5-1/2 x 12 5-1/2 x 12 5-1/2 x 12

Snow Load 3-1/8 x 13-1/2 3-1/8 x 15 3-1/8 x 15 3-1/8 x 15 3-1/8 x 16-1/2 3-1/8 x 16-1/2 3-1/8 x 16-1/2 3-1/8 x 18(115%) 3-1/2 x 13-1/2 3-1/2 x 13-1/2 3-1/2 x 13-1/2 3-1/2 x 15 3-1/2 x 15 3-1/2 x 15 3-1/2 x 15 3-1/2 x 16-1/215 psf Dead 5-1/8 x 12 5-1/8 x 12 5-1/8 x 12 5-1/8 x 12 5-1/8 x 12 5-1/8 x 13-1/2 5-1/8 x 13-1/2 5-1/8 x 13-1/230 psf Live 5-1/2 x 10-1/2 5-1/2 x 12 5-1/2 x 12 5-1/2 x 12 5-1/2 x 12 5-1/2 x 12 5-1/2 x 12 5-1/2 x 13-1/2

Snow Load 3-1/8 x 15 3-1/8 x 16-1/2 3-1/8 x 16-1/2 3-1/8 x 16-1/2 3-1/8 x 18 3-1/8 x 18 3-1/8 x 18 3-1/8 x 19-1/2(115%) 3-1/2 x 15 3-1/2 x 15 3-1/2 x 15 3-1/2 x 16-1/2 3-1/2 x 16-1/2 3-1/2 x 16-1/2 3-1/2 x 18 3-1/2 x 1815 psf Dead 5-1/8 x 12 5-1/8 x 12 5-1/8 x 13-1/2 5-1/8 x 13-1/2 5-1/8 x 13-1/2 5-1/8 x 13-1/2 5-1/8 x 15 5-1/8 x 1540 psf Live 5-1/2 x 12 5-1/2 x 12 5-1/2 x 12 5-1/2 x 13-1/2 5-1/2 x 13-1/2 5-1/2 x 13-1/2 5-1/2 x 13-1/2 5-1/2 x 15

Notes:

(1) This table is for preliminary design use only. Final design should include a complete analysis, including bearing stresses and lateral stability.

(2) Service condition = dry.

(3) Maximum deflection under live load = span/240.

(4) Maximum deflection under total load = span/180.

(5) Maximum 2-ft roof truss overhangs.

(6) Beam weight = 36 pcf.

(7) Assumes a maximum bearing length of 4-1/2 inches.

(8) Design properties at normal load duration and dry service conditions Fb = 2,400 psi, Fv = 195 psi, Ex = 1.8 x 106 psi.

(9) Beam widths of 3 and 5 inches may be substituted for 3-1/8 and 5-1/8 inches, respectively, at the same tabulated depth.


19

TABLE 3B

APA EWS 24F-1.8E GRADE GLULAM GARAGE DOOR HEADERS FOR SINGLE-STORY APPLICATIONSRough Door Opening = 9 ft 3 in. (Beam depths based on 1-3/8" laminations.)


22 24 26 28 30 32 34 36

Non-Snow Load 3-1/8 x 6-7/8 3-1/8 x 8-1/4 3-1/8 x 8-1/4 3-1/8 x 8-1/4 3-1/8 x 8-1/4 3-1/8 x 8-1/4 3-1/8 x 8-1/4 3-1/8 x 8-1/4(125%) 3-1/2 x 6-7/8 3-1/2 x 6-7/8 3-1/2 x 6-7/8 3-1/2 x 6-7/8 3-1/2 x 8-1/4 3-1/2 x 8-1/4 3-1/2 x 8-1/4 3-1/2 x 8-1/415 psf Dead 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/820 psf Live 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8

Snow Load 3-1/8 x 8-1/4 3-1/8 x 8-1/4 3-1/8 x 8-1/4 3-1/8 x 8-1/4 3-1/8 x 9-5/8 3-1/8 x 9-5/8 3-1/8 x 9-5/8 3-1/8 x 9-5/8(115%) 3-1/2 x 6-7/8 3-1/2 x 8-1/4 3-1/2 x 8-1/4 3-1/2 x 8-1/4 3-1/2 x 8-1/4 3-1/2 x 8-1/4 3-1/2 x 8-1/4 3-1/2 x 9-5/815 psf Dead 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 8-1/425 psf Live 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8


Snow Load 3-1/8 x 9-5/8 3-1/8 x 9-5/8 3-1/8 x 9-5/8 3-1/8 x 9-5/8 3-1/8 x 11 3-1/8 x 11 3-1/8 x 11 3-1/8 x 11(115%) 3-1/2 x 8-1/4 3-1/2 x 8-1/4 3-1/2 x 9-5/8 3-1/2 x 9-5/8 3-1/2 x 9-5/8 3-1/2 x 9-5/8 3-1/2 x 9-5/8 3-1/2 x 1115 psf Dead 5-1/8 x 6-7/8 5-1/8 x 6-7/8 5-1/8 x 8-1/4 5-1/8 x 8-1/4 5-1/8 x 8-1/4 5-1/8 x 8-1/4 5-1/8 x 8-1/4 5-1/8 x 8-1/440 psf Live 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 6-7/8 5-1/2 x 8-1/4 5-1/2 x 8-1/4 5-1/2 x 8-1/4 5-1/2 x 8-1/4 5-1/2 x 8-1/4

Rough Door Opening = 16 ft 3 in. (Beam depths based on 1-3/8" laminations.)


22 24 26 28 30 32 34 36

Non-Snow Load 3-1/8 x 12-3/8 3-1/8 x 12-3/8 3-1/8 x 12-3/8 3-1/8 x 13-3/4 3-1/8 x 13-3/4 3-1/8 x 13-3/4 3-1/8 x 13-3/4 3-1/8 x 15-1/8(125%) 3-1/2 x 12-3/8 3-1/2 x 12-3/8 3-1/2 x 12-3/8 3-1/2 x 12-3/8 3-1/2 x 12-3/8 3-1/2 x 12-3/8 3-1/2 x 13-3/4 3-1/2 x 13-3/415 psf Dead 5-1/8 x 11 5-1/8 x 11 5-1/8 x 11 5-1/8 x 11 5-1/8 x 11 5-1/8 x 12-3/8 5-1/8 x 12-3/8 5-1/8 x 12-3/820 psf Live 5-1/2 x 9-5/8 5-1/2 x 11 5-1/2 x 11 5-1/2 x 11 5-1/2 x 11 5-1/2 x 11 5-1/2 x 11 5-1/2 x 12-3/8

Snow Load 3-1/8 x 13-3/4 3-1/8 x 13-3/4 3-1/8 x 13-3/4 3-1/8 x 15-1/8 3-1/8 x 15-1/8 3-1/8 x 15-1/8 3-1/8 x 16-1/2 3-1/8 x 16-1/2(115%) 3-1/2 x 12-3/8 3-1/2 x 12-3/8 3-1/2 x 13-3/4 3-1/2 x 13-3/4 3-1/2 x 13-3/4 3-1/2 x 13-3/4 3-1/2 x 15-1/8 3-1/2 x 15-1/815 psf Dead 5-1/8 x 11 5-1/8 x 11 5-1/8 x 11 5-1/8 x 12-3/8 5-1/8 x 12-3/8 5-1/8 x 12-3/8 5-1/8 x 12-3/8 5-1/8 x 12-3/825 psf Live 5-1/2 x 11 5-1/2 x 11 5-1/2 x 11 5-1/2 x 11 5-1/2 x 11 5-1/2 x 12-3/8 5-1/2 x 12-3/8 5-1/2 x 12-3/8

Snow Load 3-1/8 x 13-3/4 3-1/8 x 15-1/8 3-1/8 x 15-1/8 3-1/8 x 15-1/8 3-1/8 x 16-1/2 3-1/8 x 16-1/2 3-1/8 x 16-1/2 3-1/8 x 17-7/8(115%) 3-1/2 x 13-3/4 3-1/2 x 13-3/4 3-1/2 x 13-3/4 3-1/2 x 13-3/4 3-1/2 x 15-1/8 3-1/2 x 15-1/8 3-1/2 x 15-1/8 3-1/2 x 16-1/215 psf Dead 5-1/8 x 11 5-1/8 x 12-3/8 5-1/8 x 12-3/8 5-1/8 x 12-3/8 5-1/8 x 12-3/8 5-1/8 x 12-3/8 5-1/8 x 13-3/4 5-1/8 x 13-3/430 psf Live 5-1/2 x 11 5-1/2 x 11 5-1/2 x 11 5-1/2 x 12-3/8 5-1/2 x 12-3/8 5-1/2 x 12-3/8 5-1/2 x 12-3/8 5-1/2 x 12-3/8


Notes:

(1) This table is for preliminary design use only. Final design should include a complete analysis, including bearing stresses and lateral stability.

(2) Service condition = dry.

(3) Maximum deflection under live load = span/240.

(4) Maximum deflection under total load = span/180.

(5) Maximum 2-ft roof truss overhangs.

(6) Beam weight = 36 pcf.

(7) Assumes a maximum bearing length of 4-1/2 inches and minimum bearing length of 3 inches.

(8) Design properties at normal load duration and dry service conditions Fb = 2,400 psi, Fv = 195 psi, Ex = 1.8 x 106 psi.

(9) Beam widths of 3 and 5 inches may be substituted for 3-1/8 and 5-1/8 inches, respectively, at the same tabulated depth.


DESIGNING FOR

FIRE RESISTANCE

Fire Performance of Wood ConstructionThe truly fireproof building does notexist. In nearly all buildings, the con-tents are flammable and are the criticalfactor in a fire. The smoke and heatgenerated by the burning contents cancause extensive damage and loss of lifelong before the structural componentsof the building are affected.

The primary objective in any fire-ratedconstruction is protection of human life.The combination of a variety of prod-ucts and construction methods can slowflame spread and make a building firesafe. In addition to the structural materi-als used, the variables involved in creat-ing a fire safe environment include theuse of sprinkler systems, gypsum wall-board, acoustical tiles, and separationwalls. Sprinkler systems may be used toincrease allowable floor areas for mostoccupancies and in some instances,sprinklers may be substituted for one-hour fire-resistive construction in certainsections of a building. Building codesvary widely, so it is important to reviewthe codes for the geographic area inwhich the building is being constructedto determine fire safety requirements.

Glulam Performance in FireGlulam performs very well in the intenseheat of a fire, where temperatures canrange from 1290° F to 1650° F.Unprotected steel members typically

Procedures are also available to determine the minimum glulam size forprojects in which one-hour fire resis-tance of components is required. Tables 4 and 5 on page 21 illustrate this principle for glulam timber.

A structural member’s fire resistance ismeasured by the time it can support itsdesign load during a fire. An exposedbeam or column sized for a minimumone-hour fire resistance will support itsfull design load for at least one hourduring standard fire test conditionswhich simulate an actual fire. Themodel building codes provide amethodology for calculating the mini-mum size of glulam to provide a one-hour fire rating under given designconditions.

It is important to note that to achieve aone-hour fire rating for a glulam, it isnecessary to replace one core laminationwith one tension lamination as illustratedby Figure 5.

As with all other structural framing,specifications of members designed tohave one-hour fire resistance should becarefully checked by a professionalengineer or architect to assure compli-ance with all local building codes.

Fire TreatmentsWhile pressure impregnated fire retardant chemicals are often used toreduce flame spread of some woodproducts, they are not recommended for use with glulams. If a fire retardanttreatment is used, it is the responsibilityof the design professional to determinethe effects of the treatment on the

buckle and twist in such high tempera-tures, causing catastrophic collapse ofboth the roof and supporting walls.

Wood ignites at about 480° F, but char-ring may begin as low as 300° F. Woodtypically chars at a rate of 1/40 inch perminute. Thus, after 30 minutes of fireexposure, only the outer 3/4 inch of theglulam will be damaged. It is importantto note that the adhesives used in themanufacture of a glulam beam burn atthe same rate as the wood and do notaffect the overall fire performance of themember. The char which develops insu-lates the glulam member and henceraises the temperatures it can withstand.Most of the cross section of a largeglulam will remain intact when exposedto fire, and the member will continue tosupport load.

Thus, depending on the severity of thefire and after re-analysis by a qualifieddesign professional, it is often possible tosalvage the glulam members by merelyremoving the fire damaged material andrefinishing the surface of the member.

One-hour Fire ResistanceTo assure a safe structure in the event of a fire, authorities base fire and build-ing code requirements on research andtesting, as well as fire histories. Based on these and other considerations themodel building codes, including theInternational Building Code (IBC),classify Heavy Timber as a specific typeof construction and set minimum sizesfor roof and floor beams to assure fireperformance.

20


TABLE 4

MINIMUM DEPTHS AT WHICH 6-3/4" AND 8-3/4" WIDEBEAMS CAN BE ADAPTED FOR ONE-HOUR FIRE RATINGS

Depth DepthBeam Width 3 Sides Exposed 4 Sides Exposed

(in.) (in.) (in.)

6-3/4 13-1/2 27

8-3/4 7-1/2 13-1/2

strength of the glulam by consulting themanufacturer of the fire retardant treat-ment. Another option for reducing flamespread is to apply an intumescent paintor stain to the surface of the glulamwhich does not affect the structrualintegrity of the member.

For more information on fire-rated construction systems and one-hourrated glulams, refer to the APA Design/Construction Guide: Fire-Rated Systems, Form No. W305.

Relative Insurance CostsInstallation costs and insurance rates are important considerations inany building design. It is a commonmisconception that buildings con-structed of concrete, masonry or steelalways have lower insurance rates. Sincemany building codes require sprinklersystems regardless of the building mate-rials used, rates for wood and nonwoodbuildings are often comparable. Evenwhere rates for buildings framed with“combustible materials” are higher,initial construction costs may be lowerfor timber framing and much lower ifthe steel must be one-hour fire pro-tected. Together with long-term savingson interest, lower initial costs can meanoverall savings when wood is selected.

In a study of four occupancy use typesof commercial buildings in Florida,Georgia, Ohio, and Indiana, insurancerates for wood- and steel-framed build-ings were comparable when the buildings were sprinklered.

21

TABLE 5

MINIMUM DEPTHS AT WHICH 8-3/4" AND 10-3/4" COLUMNWIDTHS QUALIFY FOR ONE-HOUR RATING FOR GIVEN ll/D

Column Depth Depthll/d Width 3 Sides Exposed 4 Sides Exposed

Criteria (in.) (in.) (in.)

l/d > 11 10-3/4 10-1/2 13-1/2

l/d ≤ 118-3/4 7-1/2 12

10-3/4 7-1/2 10-1/2

FIGURE 5

SIMPLE SPAN UNBALANCED LAYUP

StandardBeamLayup

One-Hour Rated Beam

Layup

Compressionlam at top

Core lamsin center

Tension lamat bottom

One tensionlam added at bottom

One core lam removedfrom center


MOISTURE EFFECTS

Moisture Control in Wood SystemsWood is a natural, porous materialwhich always contains some degree ofmoisture. Wood moisture content is ameasure of the total weight of moisturein the wood as a percentage of the oven-dried weight of the wood. Wood pro-duction processes generally involvesome drying. At the time of production,glulam beams typically have an averagemoisture content of about 12 percent.As a comparison, the moisture contentof green lumber can range from 20 to 50 percent, with kiln dried lumber at 16 percent.

Once installed, glulam beams in interiorapplications will equilibrate to approxi-mately 8 to 12 percent moisture con-tent. Exact equilibrium moisture contentis primarily a function of interior relativehumidity and temperature. The time ittakes for the moisture content of a woodmember to equilibrate with its environ-ment is a function of size and can besubstantial for large glulam beams.

Model building codes specify minimumrequirements for ventilation of floor androof spaces. These ventilation require-ments can vary depending on whetheror not vapor retarders are used andwhether or not roofs are pitched and to what degree.

Glulam can be protected from surfacemoisture intrusion during transit and theconstruction cycle by the use of protec-tive sealers. Surface sealants, which canbe applied to the top, bottom and sidesof beams, resist dirt and moisture andhelp control checking and grain raising.Use of a penetrating sealant is recom-mended if beams are to be stained orgiven a natural finish. Sealants can be

Checks are often observed near a glueline in a glulam member wheredifferential drying stresses are greatest.This most often occurs near the outer-most glueline where the amount ofsurface exposed by the outermost lami-nation is greatest. Checks are a naturalcharacteristic of wood and are not nor-mally considered to have a detrimentaleffect on the strength of the member.

For additional information on checking and the effects of checking on the strength of glulam, refer toEngineered Wood Systems TechnicalNotes, Checking in Glued LaminatedTimber, Form EWS R465 and Evaluationof Check Size in Glued Laminated Timber Beams, Form EWS R475.

Preservative TreatmentsDecay growth in wood occurs when the wood moisture content exceeds 20 - 25 percent for a prolonged time.Proper detailing and maintenance canhelp control moisture content andprevent decay fungi growth. However,in many applications directly exposed tothe elements, or other high humidityenvironments, this is not possible. Inthese cases, it is necessary to specify the use of an appropriate pressureimpregnated preservative treatment toeliminate decay and insect hazards or tospecify the use of heartwood of a natu-rally durable species such as AlskaYellow Cedar or Western Red Cedar.

Glulam may be treated after gluing andfabrication or the individual laminationsmay be treated prior to gluing, depend-ing on the species of wood used and thetreatment specified. The availability ofpreservative-treated glulam varies fromone geographic area to another, so checkwith your supplier before specifying a particular treatment.

applied to the beams before they leavethe mill or they can be field applied bythe contractor. The application ofsealants must be part of the specificationif they are to be applied at the mill.

Sealants applied to the ends of beamsalso help guard against moisture penetra-tion and excessive end grain checking. Acoat of sealant should be field applied tothe ends of beams if they are trimmed tolength or otherwise field cut.

For more information on moisture control in wood construction, refer to Engineered Wood Systems TechnicalNotes: Controlling Decay in WoodConstruction, Form EWS R495 andMoisture Control in Low Slope Roofs, Form EWS R525.

CheckingA common moisture related phenome-non in wood is checking. Checkingoccurs naturally to wood in service.Checks are openings that occur in thesurface of the wood and follow parallelto the natural grain direction of thepiece. A close visual evaluation of acheck will always reveal torn woodfibers. The cause of checking is shrink-age of the wood fibers as moisture is lostto the surrounding environment. Rapiddrying increases this differential mois-ture content between the inner andouter fibers and increases the chance for checking to occur.

Glulam beams typically exhibit fewerand less severe checks than comparablesize sawn timbers due to their relativelylow moisture content at time of manu-facture. It is often difficult, however, tocontrol the exposure of glulam to theelements during shipping, storage, anderection. Glulam may pick up surfacemoisture during any of these stages of the construction process.

22


When glulam beams are to be preserva-tive-treated after gluing, membersshould be ordered to exact dimensionswith all hole drilling and fabricationdone prior to the treatment process.This will eliminate breaking the treat-ment envelope by post treatment cut-ting and drilling and help insure a longlife for the member. Glulam beams thatare pressure-preservative treated mustbe bonded with wet-use adhesives.

For further information on this subject, refer to Engineered Wood Systems Technical Note, PreservativeTreatment of Glued Laminated Timber, Form EWS S580.

Connection DetailingAs with any structural material, properconnection detailing is essential toassure the structural performance of themember. This is particularly true withglulam since an improperly designedand installed connection detail can lead to a serious failure. The designer must consider the effects of moisture changes in the glulam member, proper positioning of the mechanical fasteners,and the number of fasteners required to carry the loads to develop an adequate connection detail.

Based on many years of experience, theglulam industry has developed typicaldetails for most connection situations.These details illustrate the right andwrong way to make these connectionsand indicate the consequences of anincorrect detail. The details are illus-trated and described in Engineered Wood Systems Technical Note, GlulamConnection Details Form EWS T300.

23

Cantilever hinge connector used in panelized roof application.

Slotted bolt holes permit horizontal movement of pitched and curved glulam beam.


Notching and Drilling of GlulamClosely related to connection details isnotching and drilling of glulam. Sinceglulam timbers are highly engineeredcomponents manufactured from spe-cially selected and positioned lumberlaminations, an improperly cut notch ora hole drilled in the wrong place canseriously affect the load carrying capac-ity of the member. Only holes, notchesand tapered cuts approved by thedesign professional of record anddetailed on shop drawings should bemade in a glulam member.

Field notching, cutting or drilling of aglulam beam, particularly on the tensionside of the member should be avoided.Field conditions may require making acut, notch or hole that was not originallyanticipated. In some instances, these canbe made in areas of the glulam which arenot highly stressed and will thus haveminimal effect on the structural capacityof the member. To address these specificconditions, Engineered Wood Systems has published a Technical Note, FieldNotching and Drilling of Glued LaminatedTimber Beams, Form EWS S560.

24


25

DESIGN AND

SPECIFICATION

CONSIDERATIONS

Beam and Column DesignTo determine the load capacity andrecommended size for a glulam beam,consult the following Engineered WoodSystems publications:

Data File: Glued Laminated Beam Design Tables, Form EWS S475

Data File: Substitution of Glulam Beams for Steel and Solid-Sawn Lumber, Form EWS S570.

Data File: Design of Structural GluedLaminated Timber Columns, Form EWS Y240

As an alternative to using tables such asthose included in the above Data Files,Engineered Wood Systems, in associationwith Eagle Point Software, has devel-oped computer software to aid in thedesign process. This software, WOOD-CAD, consists of two modules. Onemodule is a beam design program andthe other is a column design program.

Both modules have many unique features. For example, by simply enter-ing the appropriate model building codejurisdiction, all required code live loadsare automatically applied. In addition,by entering the postal zip code for thelocation of the structure being designed,all model building code requirementsfor snow, wind and seismic load designs are applied.

The beam module permits the design of both sawn lumber and glulam beamsand the new APA EWS PRI-400 I-joist

Proper SpecificationIn many residential and light commercial applications, stock glulambeams meet the requirements for thejob. Other residential applications andmany commercial designs require custom members. In either case, themember capacity and size specifiedmust be verified by a design professional.

To properly specify a glulam member,use the Specification Guide onpages 26-27. While all possible designconsiderations cannot be covered by ageneral specification of this type, mostof the common specification concernsare incorporated.

products. I-joist compatible glulambeams can also be sized using this pro-gram. The program enables the user todesign a beam or analyze the structuralcapacity of an existing beam. The pro-gram checks all code-required loadcombinations, which can be 10 or morefor a complicated framing member,many of which are not considered intraditional load/span tables.

The column module also permits theuse of sawn lumber and glulam and cangreatly simplify the design of complexmultiple story columns. In addition todesigning columns for concentricallyapplied loads, the program allows theuser to imput any degree of eccentricity.

For more information on the WOODCAD software, contactEngineered Wood Systems.


GLULAM

SPECIFICATION GUIDE

The following is a guide for preparingspecifications for structural glued lami-nated timber used for bending memberssuch as purlins, beams, or girders or foraxially loaded members such ascolumns or truss chords.

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TABLE 6

SPECIFIC REQUIRED DESIGN STRESSES

Structural UseApplication (Identification Symbol) Design Stress psi

Bending, Fb _____

BendingSimple span member

Member(B)

Horizontal shear, Fv _____loaded

perpendicular Compression (perpendicular to grain), Fc⊥to wide face of Continuous or cantilevered Top lamination _____the lamination span member

Bottom lamination _____(CB)

Modulus of elasticity, E _____

Tension member Tension parallel to grain, Ft _____(T)

Concentric(1) Modulus of elasticity, E _____

AxiallyLoaded

End grain bearing _____MemberCompression member

(C) Compression (parallel to grain), Fc _____

Modulus of elasticity, E _____

(1) For members subjected to combined bending and axial loading, additional design values for all other applicable stresses such as but not limited to Fbx, Fby, Fvx, Fvy must also be specified.

A. General1. Structural glued laminated timbershall be furnished as shown on theplans and in accordance with the following specifications.

2. For custom orders, shop drawings anddetails shall be furnished and approvedbefore fabrication is commenced.

3. The (manufacturer) (seller) (general contractor) shall furnish con-nection steel and hardware for joiningstructural glued laminated timber mem-bers to each other and to their supports,exclusive of anchorage embedded inmasonry or concrete, setting plates, anditems field-welded to structural steel.Steel connections shall be finished withone coat of rust-inhibiting paint.


B. Manufacture1. Materials, Manufacture and QualityAssurance. Structural glued laminatedtimber shall be in conformance withANSI Standard A190.1, AmericanNational Standard for Structural GluedLaminated Timber, or other code-approved design, manufacturing and/or quality assurance procedures.

2. End-Use Application. Structuralglued laminated timber members shallbe manufactured for the following structural uses as applicable:

Simple span bending member – B

Continuous or Cantilevered span bending member – CB

Compression member – C

Tension member – T

3A. Design Values. Structural glued laminated timber shall provide designvalues as shown in the table on page 26for normal load duration and dry-use condition.(1)

3B. Lamination Combination Number. An alternative to specifying the requireddesign stresses is to specify a specificlaminating combination symbol if known.(2)

4. Appearance Classification.Members shall be (framing) (industrial)(architectural) (premium) classificationin accordance with industry recommendations(3).

5. Laminating Adhesives. Adhesivesused in the manufacture of structuralglued laminated timber shall meetrequirements for (wet-use) (dry-use)service conditions.(1)

6. Camber (when applicable). Structuralglued laminated timber (shall) (shallnot) be manufactured with a built-incamber. Camber radius shall be (1600)(2000) (3500) or (other) feet or a specific amount of camber may be specified in inches.

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Footnotes(1) Dry service condition – moisture content of the member will be at or below 16% in service; wetservice condition – moisture content of the member will be above 16% in service. When structuralglued laminated timber members are to be preservative treated, wet-use adhesives must be specified.(2) Laminating combination should be based on design requirements and section capacities pub-lished in Engineered Wood Systems or manufacturer’s brochures. National Evaluation Report 486provides a tabulation of laminating combinations available from EWS member manufacturers.(3) Appearance grades are described as follows.FRAMING. Use in concealed, traditional 2x4 and 2x6 framing applications. These full-width beamseliminate the need for additional furring or framing around the glulam.

Description: Natural lumber growth characteristics may be visible. Faces of members surfaced to a“hit and miss” characteristic.

INDUSTRIAL. Use where appearance is not or primary importance, or where members are notexposed visually.

Description: Natural lumber growth characteristics may be visible. Voids on edges of laminationsare not required to be filled, except voids and knotholes may be filled in some applications.

ARCHITECTURAL. Use where appearance is important.Description: Natural lumber growth characteristics may be visible. Knotholes and voids largerthan 3/4" are filled or repaired with wood inserts or inert fillers. Exposed surfaces are surfacedsmooth and exposed edges (soffit face) are eased.

PREMIUM. Use where highest-quality visual appearance is required.Description: Natural lumber growth characteristics may be visible. All knotholes and voids arefilled or repaired with wood inserts or inert fillers. Exposed surface of wide face lamination haslimit on knot size and no loose knots are permitted. Exposed faces are surfaced smooth, andexposed edges (soffit face) are eased.

(4) When pentachlorophenol in light solvent or waterborne preservative treatments are specified forprotection against decay or insect attack, individual laminations usually are treated prior to manufac-turing structural glued laminated timber members. These treatments are not available from allmanufacturers and the designer should verify availability prior to specification. Note: Waterbornepreservatives are not recommended for glulam manufactured using western species.Where paintable surfaces are required, specify pentachlorophenol in light solvent or a waterbornepreservative. Wood treated with creosote, creosote/coal tar solution or pentachlorophenol in oilshould not be used in contact with materials subject to staining.(5) When structural glued laminated timber with one-hour fire resistance is specified, minimum sizelimitations and additional lamination requirements are applicable. Supporting steel connectors andfasteners also must be protected to achieve a one-hour fire rating. Cover connectors or fasteners withfire-rated (Type X) gypsum wallboard or sheathing, or 1-1/2" wood, to provide the needed protection.(6) Specify a penetrating sealer when the finish will be natural or when a semitransparent stain is tobe used. Primer/sealer coatings have a higher solids content and provide greater moisture protection,and are suitable for use with opaque or solid-color finishes.

7. Preservative Treatment (when applicable). Members shall be pressuretreated in accordance with AmericanWood Preservers Association (AWPA)Standard C28 with (creosote, or cre-osote/coal tar solution) (pentachloro-phenol in oil) (pentachlorophenol inlight solvent) (waterborne) preservativesas required for (soil contact) (aboveground) exposure.(4)

8. Fire Resistance (when applicable).Members shall be sized and manufac-tured for one-hour fire resistance.(5)

9. Protective Sealers and Finishes.Unless otherwise specified, sealer shallbe applied to the ends of all members.Surfaces of members shall be (not

sealed) (sealed with primer/sealer coating) (other).(6)

10. Trademarks. Members shall bemarked with the Engineered WoodSystems APA EWS trademark indicatingconformance with the manufacturing,quality assurance and marking provi-sions of ANSI Standard A190.1

11. Certificates (when applicable). A Certificate of Conformance may beprovided by the (manufacturer) (seller)to indicate conformance with ANSI Standard A190.1.

12. Protection for Shipment. Membersshall be (not wrapped) (load wrapped)(bundle wrapped) (individuallywrapped) with a water-resistant covering for shipment.


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STORAGE, HANDLING

AND INSTALLATION

APA EWS trademarked glulam beamsmust be stored properly and handledwith care to assure optimum perfor-mance. Beams may be protected withsealants, primers or paper wrap whenthey leave the manufacturing plant.Sealants on the ends of beams helpguard against moisture penetration andchecking. A coat of sealant should beapplied to the ends of any beamstrimmed or otherwise cut in the field.Surface sealants, which can be applied to the top, bottom, and sides of beams,resist dirt and moisture and help controlchecking and grain raising. Use a pene-trating sealant if beams will be stained or given a natural finish.

A primer coat also protects beams from moisture and dirt and provides apaintable surface. Water-resistant wrap-pings are another way to protect beamsfrom exposure to moisture, dirt andscratches during transit, storage anderection. Because sunlight can discolorbeams, opaque wrappings are recom-mended. Beams can be wrapped individ-ually, by the bundle or by the load. If it is necessary to remove portions of thewrapping during the erection sequenceto facilitate making connections, removeall of the wrapping to avoid unevendiscoloration due to exposure to the sun.

Glulam beams are commonly loadedand unloaded with a fork lift. For greaterstability, the sides of the beams, ratherthan the bottoms, should rest on the

In the yard, a well-drained coveredstorage site is recommended. Keepglulam members off the ground withlumber blocking, skids or rack systems.Beams should remain wrapped to pro-tect them from moisture, dirt, sunlight,and scratches. Cut slits in the bottom of the wrapping to allow ventilation and water drainage. At the job site, use similar storage provisions when possible.

One of the advantages of the highstrength to weight ratio of glulam beamsis that in many residential and lightcommercial applications they can beinstalled with forklifts, front-end loadersand other commonly available construc-tion equipment. That eliminates thetime and cost required to have a craneon the job site.

forks. Supporting extremely long beamson their sides, however, can cause themto flex excessively, increasing the risk ofdamage. Use multiple forklifts to liftlong glulam members. If a crane withslings is used to load or unload beams,provide adequate blocking between thecable and the member. Use woodencleats or blocking to protect corners.Only non-marring fabric slings shouldbe used to lift glulams. Using spreaderbars can reduce the likelihood of dam-age when lifting especially long beamswith a crane.

When transporting beams, stack them on lumber blocking or skids when loading them on rail cars ortrucks. Beams can rest on their sides or bottoms. Secure the load with strapsto keep it from shifting. Protect beamcorners with “softeners” when strapping down the load.


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GLOSSARY OF TERMS

Appearance Classification: Defines thesurface finish of the beam. Architecturaland Industrial are the most commonappearance classifications. Premiumappearance beams are available as cus-tom orders. The structural quality ofglulam has no relation to the appearancegrade specified.

Beam: Normally a horizontal or sloping member that is designed to carry vertical loads:

■ Simple Span: A member that is supported at both ends.

■ Continuous: A single member which is supported at more than two bearing locations.

■ Cantilever: A member which has oneor both supports away from the ends;one of which overhangs its support.

Camber: The curvature built into a beam(in a direction opposite to the expecteddeflection) to prevent it from appearingto sag under a loaded condition.

Column: Normally a vertical member that is designed to carry loads from a beam:

■ Concentrically Loaded: When the resultant load acts parallel to the axis of the member and is applied at its centerline.

Header: A beam which is used to support walls and/or floor and roofjoists that run perpendicular to it.

Laminations: Individual pieces of lumber that are glued together end toend for use in the manufacture of gluedlaminated timber. These end-jointedlaminations are then face bondedtogether to create the desired member shape and size.

Lamination Layup: The physicalarrangement of different grades of laminations throughout the depth of a glulam member.

Moisture Content: The amount of water contained in the wood, usuallyexpressed as a percentage of the weight of oven-dry wood.

Purlin: A secondary structural framingmember such as a joist or rafter that isnormally supported by walls or primary beams.

Radius of Curvature: A dimension that is commonly used as a means ofdescribing the camber requirements in a glulam beam.

“Stock” Glulams: Glulams which aremanufactured to common, standarddimensions and characteristics, and keptin inventory by distributors or dealers forimmediate job site delivery. (May be cutto customer-specified lengths.)

■ Eccentrically Loaded: When the resultant load acts parallel to the axis of the member but is applied away from its centerline.

Combination Number: The identification used to describe the type of lamination layup in the glulammember, the associated allowable designstresses, and if the lumber used wasvisually or mechanically graded.

Deflection: The vertical displacementthat occurs when a beam is loaded,generally measured at positions betweensupports or at the end of a cantilever.

Deflection Limit: The maximumamount the beam is permitted to deflectunder load. Different deflection limitsare normally established for live load and total load.

Design Values: Allowable stress valuesas they are established for each glulambeam, described in terms of Bending(Fb ), Horizontal Shear (Fv), Modulus ofElasticity (E) and other stresses.

Equilibrium Moisture Content: Anypiece of wood will give off or take onmoisture from the surrounding atmos-phere until the moisture in the woodcomes to equilibrium with that in theatmosphere. The moisture content ofwood at the point of balance is calledthe equilibrium moisture content and is expressed as a percentage of theweight of the oven-dried wood.

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ABOUT ENGINEERED WOOD SYSTEMS

Engineered Wood Systems, a related corporation of APA – The Engineered WoodAssociation, is an organization dedicated to the promotion of engineered woodsystems. Operating in close cooperation with APA, Engineered Wood Systemsserves manufacturers of engineered wood products, including glued laminatedtimber (glulam). Engineered Wood Systems member manufacturers certify theirproducts with the APA EWS trademark.

This mark of quality is supported by comprehensive services for quality valida-tion, product research, testing, and marketing. More than 65 percent of theglulam beams currently manufactured in North America bear the APA EWStrademark. The mark appears only on beams manufactured by Engineered WoodSystems members and signifies that beams are produced to the requirements ofAmerican National Standards Institute (ANSI) Standard A190.1. This is thenational consensus standard used by all agencies inspecting glulam beams.

For More InformationFor additional information on APA EWS trademarked engineered wood products, contact Engineered Wood Systems, P.O. Box 11700, Tacoma, WA98411-0700, or one of the regional field offices listed on the back cover.

Other publications from APA and EWS:

Data File: Glued Laminated Beam Design Tables, EWS S475

Data File: Substitution of Glulam Beams for Steel and Solid-Sawn Lumber, EWS S570

APA Design/Construction Guide: Residential and Commercial, E30

Source List: Publications Index, EWS S400

Residential Pocket Guide, EWS X445 (Southern Edition) and EWS X450 (Western Edition)



G L U L A MP R O D U C T G U I D E

We have field representatives in most major U.S.cities and in Canada who can help answer ques-tions involving APA and APA EWS trademarkedproducts. For additional assistance in specifying

engineered wood products or systems, get in touchwith your nearest APA regional office. Call or write:

WESTERN REGION7011 So. 19th St. ■ P.O. Box 11700Tacoma, Washington 98411-0700

(253) 565-6600 ■ Fax: (253) 565-7265

EASTERN REGION2130 Barrett Park Drive, Suite 102Kennesaw, Georgia 30144-3681

(770) 427-9371 ■ Fax: (770) 423-1703

U.S. HEADQUARTERS AND INTERNATIONAL MARKETING DIVISION

7011 So. 19th St. ■ P.O. Box 11700Tacoma, Washington 98411-0700

(253) 565-6600 ■ Fax: (253) 565-7265

PRODUCT SUPPORT HELP DESK(253) 620-7400

E-mail Address: [email protected]

(Offices: Antwerp, Belgium; Bournemouth,United Kingdom; Hamburg, Germany; Mexico City,

Mexico; Tokyo, Japan.) For Caribbean/LatinAmerica, contact headquarters in Tacoma.

The product use recommendations in this publica-tion are based on the continuing programs of labo-ratory testing, product research, and comprehensivefield experience of Engineered Wood Systems.However, because EWS has no control over qualityof workmanship or the conditions under which engi-neered wood products are used, it cannot acceptresponsibility for product performance or designs asactually constructed. Because engineered woodproduct performance requirements vary geographi-cally, consult your local architect, engineer ordesign professional to assure compliance withcode, construction, and performance requirements.

Form No. EWS X440A/Revised April 2000/0300

www.apawood.org@Web Address:


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GLULAM - WALSH INDUSTRIES, LLCwalsh-industries.com/Walsh_Industries_Website/Industry...For every ton of wood grown, a young forest produces 1.07 tons of oxygen and absorbs 1.47 tons