AMERICAN INSTITUTE OF TIMBER CONSTRUCTION LAMINATED .
AMERICAN INSTITUTE OF TIMBER CONSTRUCTIONGLULAMLAMINATED TIMBER ARCHITECTURE
Glulam: Engineered Strength.Unsurpassed Versatility. Dependable Quality.By combining engineered strength with the warmth andbeauty of wood, structural glued laminated timber (glulam)offers designers a multitude of options for large, open spaceswith minimum number of columns.Structural glued laminated timber is manufactured bybonding assemblies of high-strength, kiln-dried lumber,with waterproof adhesives. Special bonding techniquesallow individual lumber pieces to be joined end-to-endto form long laminations, then face-bonded to formdeep timbers.Glulam is manufactured in both softwood and hardwood species. Popular species include Douglas FirLarch, Southern Pine, and Alaskan Yellow Cedar. Otherspecies are available upon request. AITC 117, DesignSpecifications for Structural Glued Laminated Timber ofSoftwood Species, and AITC 119, Design Specifications forStructural Glued Laminated Timber of Hardwood Species,provide detailed manufacturing and design information.VERSATILEThe laminating process allows timbers to be produced ina variety of shapes from straight beams to graceful,curved arches. This architectural adaptability allows glulam to extend the enduring qualities of wood into applications as varied as individual designers’ imaginations.Common uses in residential construction include ridgebeams, garage door headers, door and window headers,and columns. High strength and stiffness make glulambeams ideal for long-span girders and beams needed forcommercial construction. Glulam arch systems andtrusses further increase the aesthetic and structural possibilities when using laminated timber construction.Only AITC-licensed glulam producersare permitted to use the AITCQuality Marks and Certificates toidentify products conforming toANSI /AITCA190.1.2The size of structural glued laminated timber membersis limited only by transportation and handling constraints. Widths up to 10 3 / 4 inches are manufacturedusing single laminations across the width. Wider sizesare manufactured using two or more laminations acrossthe width of the member. Typical depths range from 5 1 / 2inches up to several feet. Standard sizes are described inStandard AITC 113, Standard for Dimensions of StructuralGlued Laminated Timber.STRONGSpecially graded laminations with high strength andstiffness properties are carefully positioned within timbers to create glulam members with exceptional structural properties. The highest grades of lumber are usedin the areas of greatest stress, with lower grades usedwhere strength is not as critical. This lay-up conceptmakes very efficient use of the lumber resource. In a typical glulam beam, stresses are highest near the top andbottom of the member, so the highest grades are placednear the surfaces, with lower grades placed in the core.The high strength and stiffness of laminated timbersenable glulam beams and arches to span large distanceswithout intermediate columns. This translates to largerrooms and more design flexibility than with traditionaltimber construction.DEPENDABLEStructural glued laminated timbers have been used successfully in the United States for more than 70 years. InEurope, glulam has been used successfully for more than100 years. AITC’s quality program ensures consistent,reliable product performance by inspecting all stages ofproduction for conformance with industry standards.
Initially developed in 1961, AITC certification and quality assurance programs are the best in the industry,ensuring safe, long-lasting, high-quality timber. TheAITC product mark is the Symbol of Quality in engineered timber.AITC’s quality control and inspection system is basedon three elements:1. Licensing of manufacturers. AITC licensesqualified laminators whose personnel proceduresand facilities have complied with the requirementsof ANSI / AITC A190.1.2. Quality control maintenance. Each licenseeagrees to accept responsibility for maintaining aquality control system that is in compliance withANSI / AITC A190.1, other AITC standardsand AITC 200.3. Periodic plant inspection. AITC’s InspectionBureau, a nationwide team of qualified inspectors,conducts frequent, unannounced audits andverification of laminators’ in-plant quality controlsystems, procedures and production.For designers and users, AITC brings together allaspects of the engineered timber industry through standards development and technical support activities.AITC standards are recognized by all major buildingcodes in the United States. Standards and technicalnotes developed by AITC provide guidance to buildingofficials and industry professionals in the design and useof glued laminated timber.COVER: Glulam are a popular choice for the structural systems in recreational spaces.Boathouse, Princeton University.ABOVE (top): Natural light flows through the open glulam system into library’s interiorspaces. Poynter Institute, St. Petersburg, FL. ARCHITECT: Jung/Brannen & Assoc.; STRUCTURALENGINEER: Weidlinger Assoc. Consulting Engineers; CONTRACTOR: Federal Construction Co.ABOVE (bottom): Wood ceilings and beams were selected for acoustical control.Performing Arts Center, North Texas University: Denton, TX. ARCHITECT: KVG Gideon TollArchitects; ENGINEER: Freese and Nichols, Inc.; CONTRACTOR: Huber, Hunt and Nichols, Inc.3
Glulam: Splendid Arches. Custom Designs.Spectacular Structures.The natural beauty of wood is unsurpassed. Exposed structuralglued laminated timber provides structures with a warmth andbeauty unrivaled by other building materials. Glulam membersmay be textured and finished to meet contemporary, traditionalor historic buildings’ appearance requirements.Long, clear spans and majestic soaring arches are noproblem for this versatile structural material. The laminating process used to manufacture glulam enables thecreation of any number of straight, tapered or curvedshapes. Graceful curved arches and beams are favoredfor many ecclesiastical designs. The AITC brochureStructural Glued Laminated Timber in Religious Structuresshowcases several outstanding structures with laminatedtimber framing.Glued laminated timber trusses, beams and arches areused to provide efficient enclosures for expansive areassuch as gymnasiums, educational and recreational facilities, indoor pools, auditoriums and shopping centers.Pressure-treated glulam timbers or timbers manufactured from naturally durable wood species such as AlaskaCedar are well suited for creating beautiful and functional bridges and waterfront structures. Wood’s ability toabsorb impact forces created by traffic and its naturalresistance to chemicals, such as those used for de-icingroadways, make it ideal for these installations. Glulamhas been successfully used for pedestrian, forest, highwayand railway bridges.4APPEARANCE GRADESAppearance grades are assigned to timbers based on therequirements described in AITC 110 Standard AppearanceGrades for Structural Glued Laminated Timber. These designations do not modify design values nor influence thegrades of the lumber used in the laminations, nor changeany other provisions governing the manufacture, use orstructural performance of glued laminated timber. Fourstandard appearance grades are available: Industrial Framing Architectural PremiumIndustrial grade is suitable for installations where theglulam member will not be exposed to view or whenappearance is not a primary concern. Framing grades aresurfaced hit-or-miss to match the widths of conventionalframing and are ideal for concealed window and doorheaders. Architectural grade is recommended for mostinstallations where appearance is important. Premiumgrade should be specified when appearance is of utmostimportance. If a variation in the color or grain of thewood in adjacent laminations is also a consideration,designers may want to specify combinations manufactured from a single species or species group. Special textured surfaces, such as rough sawn, are also availablefrom most manufacturers.
Renewable Resource,Sustainable ProductsOnly one primary building materialcomes from a renewable resource: wood.As it grows, it cleans the air and waterand provides habitat, scenic beauty andopportunities for recreation. As a goodenvironmental steward, the forestproducts industry employs sustainableforestry practices and efficiently usesharvested material. Virtually 100% ofevery log harvested, all under county,state and/or federal forestland management regulations, is utilized.Of the structural building materials, ithas the lowest energy requirements forits manufacture, significantly reducingthe use of fossil fuels and environmentalpollution compared to other materials.As part of a structure, wood’s naturalinsulating properties (many times higherthan steel or concrete) reduce the energyrequired to heat and cool the structurefor its lifetime. Wood is reusable, easilyrecycled, and 100% biodegradable, andunlike the resources for other structuralmaterials, the resource for wood volumehas been increasing in U.S. net reservessince 1952, with growth exceedingharvest in the U.S. by more than 30%.Just like its parent material, glulamenjoys all of these natural benefits.In addition to the great environmentalbenefits associated with wood, glulamtimbers extend the available woodresource by using high-grade materialonly where it is needed in the lay-up.Glulam technology uses small dimensionlumber to make large structural timbers,utilizing logs from second and thirdgrowth forests and timber plantations.ABOVE (top): St. Anastasia Catholic Church: St. Augustine, FL. ARCHITECT: Richard L. San Giovanni;ENGINEER: C. Louis Structural Engineers; CONTRACTOR: Hall Construction Company, Inc.Sustainable products from a renewable resource.ABOVE (bottom): North Syracuse Baptist Church: Syracuse, NY. ARCHITECT: RSA Architects;CONTRACTOR: Butterfield Construction.5
ABOVE (top): Exploration Place: Wichita, KS. ARCHITECT: Moshe Safdie & Associates with Schaeffer, Johnson, Cox, Frey; STRUCTURAL ENGINEER: Dudley Williams &Associates; CONTRACTOR: Dondlinger & Sons Construction.ABOVE (bottom left): Originally designed in steel, the structural system for this winery in Sacramento, CA was switched to 48-ft. glulam because of productavailability, reduced cost, a 20% faster installation time, and because the winery’s humidity and fermentation fumes would not corrode the wood system.DESIGN & ENGINEERING: Summit Engineering, Inc.ABOVE (bottom right): Residence: Aurora, OR. Laminated timbers permit large rooms with minimal columns, while providing the warmth of wood for livingor work environments. ARCHITECT: Jack Smith F.A.I.A.; ENGINEER: Bouiss & Associates; CONTRACTOR: Busic Construction Company.6
Installations In &Around WaterExperience shows that wood is one of themost suitable materials for constructionin and around water. Wood is resilientenough to resist battering by the oceanand docking ships, and it is naturallyresistant to the destructiveness of saltwater. It doesn’t rust or spall; it is notaffected by corrosion.Where wood is fully exposed to weather,or where protection from the elements isinsufficient to ensure a moisture contentof less than 20% in the glulam, pressuretreatment with preservatives or theuse of heartwood of a naturally durablespecies is required. Buildings housingwet processes, or where wood is in directcontact with the ground or water alsorequire similar protection. AITC 109,Preservative Treatment of StructuralGlued Laminated Timber provides specificrecommendations for treated glulam.New covered bridge with laminated trusses. ENGINEER: USDA Forest Service.Golf Course Bridge.Michigan arch bridge. ENGINEER: Northwest Design Group, Inc.7
Glulam: Readily Available. Cost Effective.Easily Installed.Frequently used for spans over 100' with no intermediate postsor columns, glulam construction is visually and structurallyadaptable, generally reduces the overall cost of a project, andindividual glulam are easily modified and installed on site——no special crews are required.READILY AVAILABLEEASILY INSTALLEDAITC manufacturing plants are located throughout theUnited States. Straight beams in common sizes are massproduced and readily available at most building materialand lumber distribution centers. Custom timbers maybe obtained directly from laminating plants or a localrepresentative, and can be cut-to-length and pre-fabricated in the laminating plant to arrive at the job siteready for immediate installation.Smaller glulam members are easily maneuveredmanually. Larger timbers and custom configurations canbe installed with mobile construction equipment.Conventional hand and power tools are used for modifications and connections.COST EFFECTIVEThe beauty of exposed glulam construction does notrequire the added expense of false ceilings to concealstructural framework. Accurate manufacturing reducesthe need for on-site fabrication, minimizing waste andlabor costs during installation. Equally important, glulam timbers are readily adapted to design changes andminor adjustments during construction. Because glulammay be easily modified in the field to fit existing conditions, renovation projects are also simplified.Standard connection details reduce mistakes and allowfor rapid installation. AITC 104 Typical ConstructionDetails provides additional guidance for detailing glulamtimbers. The availability of long lengths eliminates theneed for splices and reduces construction times. Off-sitefabrication of custom laminated timbers further reducesinstallation time.The laminating process and use of kiln-dried lumber tomanufacture glued laminated timbers minimize wood’snatural propensity to check, twist, warp and shrink inservice. Installations remain dimensionally stable andbeautiful over time, virtually eliminating the need forexpensive repairs and call backs.Inventory readily available from local distributors for prompt delivery.Typical uses include: Complete structural systems Ridge beams Garage door headers Door and window headers Long-span girders8
Connection DetailsABOVE (top): 30,000 sq. ft. residence: Newport Beach, CA. ARCHITECT: Brian Jeannete & Associates; StructuralENGINEER: Omnispan Corporation; CONTRACTOR: Buwalda Construction.Cantilever connection.Beam hangers.Garage door header.Truss connection.Beam hangers.Installing a residentialridge beam.Field cuttinga stock beam.Beam intersectionconnection.Installing a glulamtimber truss withmobile equipment.Saw-textured beamsare available frommost manufacturers.Custom fabricationfor assembly withpower tools.Massive glulam timbers,spanning 115 feet, arebeing installed hereto provide structure &decorative framing forthe Unified PhysicalEducation & SportsComplex in Coronado,CA. SHWC Architectsreported, “steel couldnot have provided thedramatic design focusachieved with theexposed laminatedtrusses.”ABOVE (bottom): “We specify glulam for window and door headers and for ridge beams. It costs less than thealternatives for these applications and is faster to install.“ Hess Builders Inc.9
Fire PerformanceBuildings constructed with large structural timbers have excellentfire-resistive qualities. U.S. model building codes recognizethis and provide guidelines for ensuring fire resistant timberstructures. Two distinct approaches are included in the codes:Heavy Timber Construction and Fire Resistive Construction.HEAVY TIMBER CONSTRUCTIONHeavy Timber Construction has long been recognizedby the model building codes as fire resistant. To meetthe requirements of Heavy Timber Construction, limitations are placed on the minimum size, including depthand thickness, of all load-carrying wood members.Other requirements include the avoidance of concealedspaces under floors and roofs and the use of approvedconstruction details. Minimum sizes for laminated timbers meeting the requirements of Heavy TimberConstruction are contained in the building codes and inAITC 113 Standard for Dimensions of Structural GluedLaminated Timber.The performance of Heavy Timber Construction underfire conditions is markedly superior to most unprotected“non-combustible” construction. Unprotected metalslose strength quickly and collapse suddenly underextreme heat. Steel weakens dramatically as its temperature climbs above 450 Fahrenheit, retaining only 10%of its strength at about 1380 F. The average buildingfire temperatures range from 1290 F to 1650 F.In contrast, wood retains a significantly higher percentage of its original strength for a longer period of time,losing strength only as material is lost through surfacecharring. Fire fighting is safer due to elimination of concealed spaces and the inherent structural integrity oflarge glued laminated timbers. Additional information iscontained in AITC’s Superior Fire Resistance brochure.ABOVE (top): Typical glulam beam following a fire test. The outer surface ofthe beam has charred, while the inner areas remain unburned. The charredouter material acts as an insulator during fire, reducing the rate at which theinner material will burn.ABOVE (bottom): Glulam framing was selected over steel for the ParhumpLibrary in Nevada because, as noted by architects/engineers, Leo A DalyAssociates, “the need to fire-proof steel trusses made them cost prohibitive.”The exposed glulam trusses also avoid the expense of suspended ceilings tocover overhead framework. CONTRACTOR: B&H Corporation.10
FIRE RESISTIVE CONSTRUCTIONFire resistance is the amount of time a structural member can support its load before collapsing. The goal offire-resistive construction is to provide adequate fireprotection for occupants to evacuate the building safely.For example, a one-hour rating means a member orassembly should be capable of supporting its full loadwithout collapsing for at least one hour after a fire starts.The standard test for measuring fire resistance is theAmerican Society of Materials and Testing (ASTM) TestMethod E-119. Ratings of assemblies (including beams,walls and floors) are determined by test procedures thatapproximate actual fire conditions.The results of ASTM fire tests for building assemblies,sponsored jointly by the American Forest & PaperAssociation (AF&PA) and the American Institute ofTimber Construction, enable designers to calculate specific fire ratings for glulam members. Calculations arebased on a consideration of member size, degree offire exposure, and loads on the member. Additionally,fire-resistance ratings for glulam beams require lay-upmodifications.AITC Technical Note 7 Calculation of Fire Resistance ofGlued Laminated Timbers and AF&PA Technical Report10 Calculating the Fire Resistance of Exposed Wood Membersprovide detailed design methods and lay-up modifications required for fire-rated glulam construction.RIGHT (top): 172 ft.-span arches, Animal Science Center, Univ. of Arkansas:Little Rock, AR. ARCHITECT: AMR Architect; STRUCTURAL ENGINEER:Engineering Consultants, Inc.; CONTRACTOR: Harrison Davis Construction.RIGHT (middle): Ross High School: East Hampton, Long Island, NY.ARCHITECT: Richard Cook & Associates; CONTRACTOR: Telemar Construction.RIGHT (bottom): 48-foot glulam was specified for this manufacturing plantin Fairfield, CA to simplify insulation and readily obtain product. Waiting forsteel purlins and girders would have caused a 10-week delay and, in addition,the steel roof would have required rigid insulation on top of the roof deck(whereas the timber design called for the easier-to-install batt-typeinsulation). LE Boyd Roof Structures; ATMN Structural Engineers.11
Equivalent Glulam Sectionsfor Sawn Lumber, Steel, LVL and PSLSawn Lumber and Timber Beam Conversions to 24F-1.8E GlulamLUMBER OR TIMBERNOMINAL SIZEthickness xdepth24F- 1.8E DOUGLAS FIR GLULAM SIZES TO SUBSTITUTE FORDOUGLAS FIR LUMBER OR TIMBERS OF GRADE:Select StructuralNo. 1No. 224F- 1.8E SOUTHERN PINE GLULAM SIZES TO SUBSTITUTE FORSOUTHERN PINE LUMBER OR TIMBERS OF GRADE:Select StructuralNo.1No. 23333xxxx81
Structural Glued Laminated Timber in Religious Structures showcases several outstanding structures with laminated timber framing. Glued laminated timber trusses, beams and arches are used to provide efficient enclosures for expansive areas such as gymnasiums, educational and recreational facili-ties, indoor pools, auditoriums and shopping centers.
Timber service life design - Design Guide for Durability 06. Timber-framed Construction - Sacrificial Timber Construction Joint 07. Plywood Box Beam Construction for Detached Housing 08. Stairs, Balustrades and Handrails Class 1 Buildings - Construction 09. Timber Flooring - Design Guide for Installation 10. Timber Windows and Doors 11.
N6 Technical Guide Timber Curtain Wall Timber Curtain Wall Technical Guide N7 Timber Curtain Wall Detail Timber Curtain Wall Corner Detail Curtain Wall CL to CL 34 7/8" [887mm] Glass 33 7/8" [861mm] CL to CL 34 7/8" [887mm] Glass 33 7/8" [861mm] F.S. Timber to Timber 103 11/16" [2634mm] Outside Dimension 111 3/8" [2829mm]
Design Guide for Durability #06 Timber-framed Construction - Sacrifi cial Timber Construction Joint #07 Plywood Box Beam Construction for Detached Housing #08 Stairs, Balustrades and Handrails Class 1 Buildings - Construction #09 Timber Flooring - Design Guide for Installation #10 Timber Windows and Doors #11 Noise Transport Corridor Design Guide
The American Institute of Timber Construction, established in 1952, is a non-profit industry association for the structural glued laminated timber industry. Its members design, manufacture, fabricate, assemble, and erect structural timber systems utilizing both sawn and structural glued laminated timber components.
1 EN 14081 -1:2005 A1:2011 Timber structures Strength graded structural timber with rectangular cross section Part 1: General requirements 2 EN 14080:2013 Timber structures - Glued laminated timber and glued solid timber - Requirements 3 EN 14374:2004 Timber structures - Structural laminated veneer lumber - Requirements
AMERICAN INSTITUTE OF TIMBER CONSTRUCTION (AITC) AITC 111 (2005) Recommended Practice for Protection of Structural Glued Laminated Timber During Transit, Storage and Erection AITC TCM (2012) Timber Construction Manual, 5th Edition ANSI/AITC A190.1 (2007) American National Standard, Structural Glued Laminated Timber
(SANS 10082) What is a Timber . Correct Standard –SANS 10-082 Timber Frame Construction is not an ABT and timber structures must be built to the SABS standard. Correct treatment is critical H 4 Poles (Piles) at 24 years. Correct Timber Treatment HAZARD CLASS SYMBOL H3 H4 H5 END USE APPLICATION
Timber Piling Council The Timber Piling Council provides technical information, and promotes the use of timber piles in the construction industry. The Timber Piling Council is administered by the Southern Pressure Treater’s Association Photograph shows American Airlines Terminal at JFK w
