WOOD PRODUCTS COUNCIL WEBINAR February 18, 2011 “The Products Council” is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reportdtted to AIA/CES for AIA memb ers. C er tificat es of C ompl eti on f or Connection Solutions for both AIA members and non-AIA members are available upon request. Wood Framed Structures This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Tom Williamson, P.E. Consulting Engineer Questions related to specific materials, methods, and services will be Retired Vice President, APA addressed at the conclusion of this presentation.

Learning Objectives Copyright Materials #1 To familiarize designers with the wide variety of connectors This presentation is protected by US and available for wood framed structures and how they can be International Copyright laws. Reproduction, used most effectively to meet a specific design need. dis tr ibu tion, disp lay an d use o f the presen ta tion #2 To acquaint designers with how design properties are without written permission of the speaker is established for wood connectors and what adjustment factors prohibited. must be applied to ensure the proper performance of these connectors. #3 To provide design professionals with an overview of wood © The Wood Products Council 2010 connection techniques to help ensure efficient, durable and structurally sound connections #4 To use design examples to illustrate these principles and to acquaint designers with additional resources available to assist them in wood connection design and detailing. Outline Mechanical Connectors

•Fastener types Common Type Fasteners •Fastener design values . Nails . Staples •Connection design basics . Wood Screws . Lag screws •Wood connection design . BltBolts philosophy •EiEnvironment tlfftal effects - moitisture •Examples •Additional information

Mechanical Connectors Light Frame Commercial Buildings

Nails are generally used when loads are light. They are used for light-frame construction, diaphragms, and shear walls. Screws may be more satisfactory than nails under vibration or Staples can be used in place of withdraw al loads since they hav e nails, but equivalent capacities less tendency to work loose need to be confirmed Mechanical Connectors Timber Rivets

. Timber Rivets . Hot-Dipped Galvanized . Fixed-shank cross-section . Fixed head dimension . Vary only in length . NDS provides design Other types: values . Timber rivets . Used in Canada for . Split rings . Shear plates several decades . Metal plates . Added to 2005 NDS . Wood . . Pre-engineered . DFL hangers . SP

Specialized Connectors National Design Specification

. Split Ring . Wood-to-wood . Require special tooling of wood prior to job site . Shear Plates . Wood-to-wood or wood-to-dissimilar materials (concrete or steel) . Both have successful long history . Glulam or PSL . NDS provides design values All-Wood Fasteners System Air Force Trestle Project

Wood bolts (()laminated ) in all-wood structure . Long History > 100 years . Wood dowels and pegs . Difficult to obtain published design values . Uses automated CNC 50 feet

technology 1 . Timber ’s Guild - www.tfguild.org

Pre-Engineered Connectors Pre-Engineered Connectors

Joist and beam hangers

. Top and face mount . Product specific . Use correct nails . Fill all holes . Ensure proper fastener penetration Pre-Engineered Hold-Downs Pre-Engineered Connectors Allow ing for Shr in kage Hold-down hardware

. Proprietary devices are av ailable to address potential shrinkage problems in multi-story buildings . Need to verify code compliance with manufacturer

Small Diameter Fasteners Small Diameter Fasteners

Lots of Types Nails and .box nomenclature .common nail . Short . Box nail .ring shank . Ring nail .sinker, cooler, … . Common nail Lots of Pennyweights . Sinker . Power-driven .2d, 4d, 6d, 8d, 10d, … . Roofing . Etc. Nail Nomenclature Specifying Nails

There is no control over nail nomenclature! In ASTM F 1667 both pennyweight and type define a size Manufacturers can and will call fasteners anyygthing that they want. Avoid problems by specifying pennyweight, tditdlthtype, diameter and length

10d is not a clear specification! . Ex: 10d common : 0. 148” x 3”

Small Diameter Fasteners Nail Comparison

CifComparison of common, b bdikilox and sinker nails Nails and nomenclature Type Pennyweight Length Diameter . Short Box 10d 3” .128 . Box nail Sinker 10d 2‐7/8” .120 . Ring nail Common 10d 3” .148 . Common nail . Sinker Assume 1-1/2” side member thickness . Power-driven Diameter Lateral Load Common Box Sinker . Roofing for DF . Etc. .148 118 lbs 10d 20d 16d Power Driven Nailed Connections Power Driven Nailed Connections Often Used in Shear Walls and Diaphragms Often Use d in Shear Wa lls an d Diap hragms Nail installation APA Prescriptive Recommendations for overdriven nails provided in APA Technical Topic TT-012A Overdriving reduces performance If < 20% fasteners overdriven by <1/8”, then they may be ignored.

If > 20% fasteners overdriven by >1/8”, then a dd 1 additi onal f ast ener f or every 2 overd ri ven.

Or: . re-analitbdthiklyze capacity based on average thickness of panel measured from the bottom of the nail head . example: 5/8” panel with fasteners overdriven by 1/8” = capacity of 1/2” panel . adjust nailing schedule accordingly

LaageScewrge Screw T ype F asteesasteners Bolted Connections

Lag Screws or Lag Bolts Bolts . 1/2”, 5/8”, 3/4”, 7/8”, 1” inch . Typically used diameters as an alternative . Diameters of >1” not permitted to bolts by the NDS since they can initiate high tension-ppperp . Turned into pre - stresses on the bolt hole that drilled holes can induce splitting of the . Lead holes are wood a function of sp. . Pre-drilled holes 1/32” to 1/16” gr. of wood larger than diameter used . CitkitCommon mistake is not allowing room for installation Bolted Connections Bolted Connections

Bolts may have more slip than others due to over drilled holes which other fasteners such as screws do not require

Bolted Screw

Partially Concealed Kerf Plate Bolted Truss Connections BltdCBolted Connec tions

Align fasteners concentrically with forces –avoid eccentricities Long Span Arches Moment Splice with M oment Spli S lice

Lag screws Bolts

Steel plates plus mechanical fasteners top/bottom transfer axial tension and compression forces Chicago Bears pressure pltlates t ransf er thrust Practice Facility shear plates transfer shear

Design/Specification Options Engineered Connection Design

Prescriptive Engineered Must evaluate and provide for: . Follows a recipe . NDS & NER-272 . forces present . IBC, IRC, ESR reports . Published design values and tables . Accounts for performance . environmental effects . Based on predetermined of different materials design values, . Nominal values . material effects joint configuration, . Adjjppustments applied for end materials used, etc use conditions . aesthetics . Ex: IBC tables for shear walls or diaphragms Basic Theory: Engineered Design Basic Theory: Engineered Design

. Nominal design val ues determined based Values published for: on equations provided in the NDS . Nominal design values published in Nails tables in the NDS or in other references Wood Screws . Published nominal design values based Lag Screws on assumed end-use conditions Bolts . Normal load duration (10 year) Shear Plates . Dry condition of use Split Rings . And others Timber Rivets

Other References for Mechanical Fastener Interchangeability Fasteners ICC Reports . NER-272 ISANTA NER-272 or ESR-1539 International , Nail and Association . Provide “conversion” tables for prescriptive . ESR-1539 requirements International Staple, For example, if model code requires 8d commons at NilNail and dT Tool 6” oc, then wh at f ast ener t ype and spaci ng i s Association ISANTA “equivalent” . Has values for engineered designs for staples anditfthd a variety of other power-didriven f ast eners . Available from International Staple, Nail and Tool Association (ISANTA) www.isanta.org . NDS does not have design values for staples Basic Theory: Engineered Design Lateral Connection Strength , Z

Lateral connection For d owel t ype f ast eners: nail s, spik es, strength, Z, based on bolts, lag screws and wood screws yield model and . LtLateral ll load dd desi gn val ues are cal cul ltdbated by yi ildeld- depends on: limit equations – Yield Model . Crushing (bearing) . Withdrawal design capacity calculated from strength of wood empirical (test-based) equations Z Sppg,p,lit rings, shear plates, dowels, drift . Size of wood pieces . Fastener size and pins, and timber rivets etc. strength . Lateral and withdrawal design values from empirically based tables . Plus applicable end use adjustment factors

Yield Equations (Based on Mode) NDS DOWEL YIELD EQUATIONS

MODE I bearing Mechanics dominated yield based: of wood fibers MODE II 4 modes pivoting of fastener with 6 equations localized crushing of wood fibers NDS DOWEL YIELD EQUATIONS Withdrawal Connection Strength

Withdrawal MODE III Connection Strength fastener yield in Depends On: bending at one plastic hinge and bearing dominated . Depth of yield of wood fibers penetration MODE IV in main member fastener yield in bending at two . Wood density plastic hinges and bearing dominated . FtFastener size and yield of wood fibers type . Plus applicable end use adjustment factors

Typical Tabulated Results Connection Design Nominal connection strengths are tabulated in pages of tables in the NDS The NDS has design provisions and tabulated and other reference books nominal values for Thickness commonldly used connect ors Steel for wood framed structures side Main Bolt G = 0.50 G = 0.43 member DlFiLhDouglas-- HFiHem-Fir Allowable = nominal x plate st, diameter t Z, lb Z, lb adjustment factors m, in in D, in Zll, lb  Zll, lb  21/22-1/2 1/4 1/2 1510 790 1410 640 Adjustment factors account 5/8 2190 880 1880 700 for a wide range of different 3/4 2630 980 2250 770 end use conditions 7/8 3060 1050 2630 830 1 3500 1130 3000 900 Yield Equation Input Parameters Equivalent Specific Gravity (G) Specific Gravity fNilLtlVliLVLfor Nail Lateral Values in LVL

For composite products such as SCL (LVL , PSL , LSL and OSL) use an equivalent specific gravity, as determined by the manufacturer based on tests

Connections With Dowel Bearing Strength of Wood Structural Panels WdSttlPldNilWood Structural Panel and Nails

Wood Structural Specific Gravity, G Dowel Bearing

Panel Strength, Fe Structural I, 0.5 4650 psi Other grades (()a) 0420.42 3350 psi Oriented Strand All grades 0.5 4650 psi (a) Use G = 0.42 when species of the plies is not known. When species of the plies is known, specific gravity listed for the actual species and the corresppgonding dowel bearing ggy strength may be used, ,or the weig ghted average may be used for mixed species. Angle to Grain Adjustments Adjustment Factors HkiHankinson F ormul a C - Load duration D Calculate wood bearing strength , Fe, at any angle to grain (for large fasteners: bolts, lag screws, etc) CM - Wet Service Not necessary for nails or wood screws Ct - Temperature

Cg - Group action Fe Fe Fe  CD - GtGeometry, appli lidhied when spacing 2 2   F sin   F cos  and end or edge distances are less Fe e e F than opti mal e Fell Ctn - Toe-nail factor

Fe ϴ - Angle of grain adjustment

Geometry Factor , CΔ Multiple-Bolt Tension Connection

Minimum Spacing, End, & Edge Distances Determine the adjusted ASD capacity of the multiple-bolt double shear tension Parallel and perpendicular to grain connection at th e end of th e 24F -V4 Doug las-Fir glllulam When D < ¼”, C = 1.0 Given: ∆ (2) ¼” thick A36 steel side plates 5 1/8 x 12 GLB When D > ¼” and if end distance OR sppgqacing < required (6) 1” Φ A307 bolts GLB dry (initial & in -service) then C∆ factor applied to all fasteners Seismic Tension Load Temperature normal

2 steel pl’s 5 1/8 x 12 glulam (1/4”x6”) 8” 4” 4”

T T ”” ”” ”” 3 6 3 6”

1”Φ blbolts typ. 1”Φ bolts typ. Multiple-Bolt Tension Connection Wet Service Factors, CM

Find Geometry Factor, CΔ . Bolts Check spacing and end/edge distance requirements: Saturated . Lag screws

End distancemin = 7D = 7(1”) = 7 in < 8 in OK . Wood screws (for CΔ = 1.0 parallel tension member table 11.5.1B) 19% MC cc spacing between bolts in a row, s, = 4D = 4(1”) = 4 in < 4 in OK fabrication MC (for CΔ = 1.0 table 11.5.1C) Spacing between rows = 1.5D (table 11.5.1D) in-service MC =1.5(1” ) = 1.5 in. < 3 in OK Dry

Edge distance = 1.5D (for lm/D = 5.125/1) = 5.125 < 6 table 11.5.1A) = 1.5(1”) = 1.5 in < 1.5 OK CM 1.0 0.7 0.4 Lateral Load 101.0 070.7 101.0 Withdrawal Load (lag & wood screws only) CΔ = 1.0 since all NDS base dimensions are met or exceeded

Mechanical Connections Group Action Factor, Cg

Group action factor, Cg

. Equation calculation or use NDS tables . Applicable for split ring connectors, shear plate connectors or dowel -type fasteners with D ≥ ¼” and < 1” located in a row or group Calculated Group Action Factor, Cg Tabulated Group Action Factor, Cg

. Assume As/Am =0.5 and enter column 1 of the table

. Assume As = 16 and enter table between 12 and 20 . Assume 10 fasteners in a row - read across to column for 10 fasteners

. Interpolate Cg = 0.65

Local Stresses in Fastener Groups Local Stresses in Fastener Group

NDS 10 . 1. 2 Closely spaced fasteners can lead to Stresses in Members at brittle failure and CtiConnections lower capacity “Local stresses in connections using Additional wood failure mechanisms multiple fasteners shall be checked need to be considered in design as in accordance with principles of covered in Appendix E of the NDS engineering mechanics. One method (this is in addition to yiildeld equations, for determining these stresses is geometry factor and group action factor) provided in Appendix E.” Local Stresses in Fastener Groups Local Stresses in Fastener Groups

Appendix E: NDS Equations Appendix E: NDS Equations

Local Stresses in Fastener Groups Toe Nail Factor , Ctn

Properly spaced fasteners Toe nail installation • Correct toe nail . Increased ductility installation is important . Higher capacity • 5/6 reduction for lateral . Spread out the • 2/3 reduction for fasteners! withdrawa l “Air Nail ” Factor, Cair Glued Connections

Adhesi ves use bdbased on applicati on .Manufactured components

Cair= 0000.00 .GfGlued floor construction .In-service repair

Adhesives must be carefully chosen to suit expected end use conditions as some adhesives are sensitive to changing environmental conditions (temperature and moisture)

Glued Connections Glued Connections

.Gluing is not recommended for Glued floor bonding wall or roof consttitruction sheathing to • Minimize squeaks due to reduced • Increases stiffness ductilit y concerns due to T-beam .Difficult to maintain action b ut no l oad the quality of the increases taken application in the field .Prohibited in high seismic zones Design Example Field Repair with Epoxy Bolted Splice Joint Check Epoxy can be used for Determine the size, some in-service repair number, and placement of bolts and rehabilitation needdttded to transf er a situations 7500 lb. load (dead load pp)lus snow load) through the McGraw-Hill “Wood shown. Engineering and Wood is seasoned No . Construction Handbook” 1 Douglas-fir (MC < 19%), which will has a chapter on epoxy remaidin dry i n servi ce repair (MC < 19%).

Design Example Design Example Bolted Splice Joint Check Bolted Splice Joint Check

DtDeterm ine s ize of wood memb ers: Determine size and number of bolts required: . Try 5/8-in. bolts . Assume a nominal 2 × 8isused8 is used . Z (nominal) = 1310 lb. per bolt (Table 11F of NDS) . CD = 1.15 (Snow Load Table 2.3.2)

. Z’ ( all owabl e) = Z × CD × CM 2 . A (required) = P/Ft = 7500/(675 × 1.15 × 1.2*) = 8.05 in. Z’ = 1310 × 1.15 × 1.0 = 1506 lb. *1.2 is the size factor for tension (Table 4a of NDS Supplement) . Number required = 7500/1506 = 4.98

. Try 2 × 8, A = 10 . 87 5 in.2 for bot h ma in me mbe r a nd . Try 6 - 5/8 in . bolts , two rows of (3) bolts side plates Design Example Design Example Bolted Splice Joint Check Bolted Splice Joint Check Group action factor:

DtDeterm ine group ac tion f act or: . Enter table for As/Am = 0.5 2 Am =15= 1.5 × 725=10875in7.25 = 10.875 in. . Enter table for As between 5 and 12 2 As = 2 × 10.875 = 21.75 in. . Enter table for 3 fasteners in a row

Per footnote 1 of Table 10.3.6A of NDS . Interpolate Cg = 0.95

If As/Am > 1 use Am/As = 10.875/21.75 = 0.5 Q = 1506 × 0.95 × 6 = andAd use Am ilin place of fA As 8584 lb. > 7500 lb. OK

Basic Concepts of Wood Shear Wall Performance CtiBhiConnections Behavior Wall performance driven by fasteners . Strength . Ductility

Edge‐Tear

Nail-Head NilNail pull‐througPull-h Through Connection Hysteretic Response of Walls Failures with 4" Perimeter Nail Spacing

8000

4000 bs) ll ( 0 Load

ral ‐4000 ee

Lat 7/16” control Nailhead ‐8000 Reinforced Edge tear pull‐ ‐6 ‐4 ‐2 0 2 4 6 through Horizontal Displacement (in)

Wall Allowable Loads Wall Allowable Loads

Peak load Vall = 8630/2.5 = 3450 lb First‐cycle envelope • Computed per ICC -ES Acceptance Criteria for = 8630 lb Prefabricated Wood Shear Walls (AC130) 4 in nail spacing ad • Based on first-cycle envelope of cyclic response oo

Vall = Δm = 2.38 in • Minimum safety factor of 2.5 assumed ateral L

LL 3570 lb

• Allowable load is computed as minimum of:

1) Vall = Vmax/SF Δm/(1.4*0.7R) = 0.44 in 2 4 6

2) Load corresponding to ∆s/1.4, where ∆s = drift Horizontal Displacement (in) limit Wood’ s Orthotropic Nature Compression Parallel to Grain

Wood cells are analogous to a bundle of straws (where the straws represent ) . Very strong parallel t o grai n . Relatively weak perpendicular to grain . No published design values Since wood is very strong for tension perpendicular to in compression parallel to grain grain – preferable way of making wood connections

Compression Perpendicular to Grain Connecting Wood

While wood is weaker in Wood compressive strength is compression perp to a key consideration but all wood grain, it is still an excellent way to transfer products are not equal bearing stresses . Sawn wood . Glulam . OSB . Plywood . Structural Composite (SCL) Compression Values Compression Parallel to Grain

2x12 Sawn Lumber

Species Grade Compression Compression Parallel Perpendicular DF #1 1500 625 SP #1 1600 565 SPF #1/#2 1150 425 Engineered Wood Products Product Grade Compression Compression Parallel Perpendicular Glulam 24F‐1.8E 1600 560 LVL 26F‐1.7E 2350 450/750 LSL 24F‐1.6E 2150 490/825

Tension Values Tension Connections

2x12 Sawn Lumber

Species Grade Compression Tension Fc/Ft Parallel Parallel DF #1 1500 675 2.2 SP #1 1600 675 2.4 SPF #1/#2 1150 450 2.5

Engineered Wood Products

Product2 Grade Compression Tension Fc/Ft Parallel Parallel Glulam 24F‐1.8E 1600 1100 1.5 LVL 26F‐1.7E 2350 1700 1.4 LSL 24F‐1.6E 2150 1350 1.6 Material Properties of Wood Staggered Nailing

Sppglitting occurs parallel to grain Framing

Wood Structural Panel Staggering Nail

1/8" Gap Between Panels

Staggering a line of Splitting will not nails parallel to wood occur perpendicular to grain, no matter grain minimizes how close nails are splitting Nailing not staggered Nailing staggered

Staggered Nailing Basic Concepts of Wood Connections

Causes of tension perpendicular to grain in wood connectors .Staggered nailing in 1. large diameter fasteners 2. notching tightly nailed shear 3. hanging loads wall helppps prevent 4. restraint by connector detail splitting of framing members and allows higher loads to be transferred Notching Beam to Concrete

Problem Solution Tension perpendicular Notched beam bearing to grain . Tension perpendicular to

Splitgrain stresses induced and may induce splitting

Beam to Concrete Sawn Lumber Notching

NthdNotched . Outer third of span only . Avoid tension edge Bearing Wall . Alternative to beam notch

WWPA Technical Note A‐11 “Notching and Boring Guide Field Notching and of Glued Possible Reinforcement LiLaminated dTibB Timber Beams fEdNhiGllfor an End Notch in Glulam

Note end notch limitation for glulam

Horizontal Hole Drilling in Glulam Vertical Hole Drilling in Glulam

HiHorizont tlal HlHole Dr illing Strength reduction = 1.5 x hole diameter/beam width

Example: . 6-3/4” net beam width . 1” diameter vertical hole . Reduction = (1.5 x 1/6.75) . Reduction = 0. 22 . Beam has 78% of original strength Hanger to Beam Hanger to Beam

Load suspended from Full wrap Load supported in lower half of beam sling option upper half of beam . Tension perpendicular to Extended plates puts grain is induced wood in compression Split . May cause splits when loaded C C

NA NA NA NA compression T T

Basic Concepts of Wood Connections Basic Concepts of Wood Connections

Load spread over its surface increases redundancy and reduces stress concentrations Mechanical fasteners . Use small fasteners . Use multiple fasteners when possible . Keep scale of fastener relative to size of wood members being connected Basic Concepts of Wood Connections MGP Wood Trusses

Truss plates . Uses multiple small tooth connectors to distribute loads . Design metal plate connections using the latest edition of ANSI/TPI 1

Basic Concepts of Wood Connections Basic Concepts of Wood Connections

A single bolt connecting many members LkLooks can b bdiie deceiving but…wait a minute...

Cg Environmental (Serviceability) Basic Concepts of Wood Connections CidiConsiderations

Wood , lik e o ther mat eri al s, moves i n . Temperature – not a concern varying environments and M.C. changes . HiditdHumidity and moi itsture can cause dimensi onal ch anges. . ambient conditions . contact with concrete or masonry materials . exposed end grain

Moisture Effects Basic Concepts of Wood Connections

Ambient Conditions Gap panels 1/8 ” to allow for dimensional and wood EMC changes due to moisture expansion

USDA Wood Handbook - free download - Forest Products Lab Connection Serviceability Beam to Column

Shrinkage due to Continuous full moisture loss depth side plates . Restrains wood shrinkage . May cause sppglitting

Solid sawn lumber Glued laminated timber

Beam to Column Beam to Beam

Split Beam hangers Smaller discontinuous . Fasteners near top side plates of supported beam . Transmit forces . Restrains wood . Allows wood shrinkage movement due to . May cause

moisture changes Gap splitting under . Not recommended beam Beam to Beam Beam to Beam

Semi-Concealed Beam hangers . Kerf must . Fasteners near accommodate bottom of supported steel and weld beam . Dowel hole may or . Wood shrinkage may not be effect minimized plugged . TtbTop tabs provid e lateral restraint

Beam End Bearing Beam to Wall

Potential problem . Shrinkage of wood due to moisture changes Note bolts high and low. TiTension perp Cracks developing stresses can be itintrod uced Note bearing angle . May cause and slight gap at Beam to Wall Slotted Connections

Solution: . Use bolts near bottom of beam . Allow for shrinkage . Slotted holes are best

Beam to Beam SiSemi-CldKfPlConcealed Kerf Plate Connection Serviceability

Issue: direct water ingress .Water is absorbed most quickly through wood end grain No end caps or flashing used .Can even occur in low rainfall climates resulting in significant checking and potentially decay Connection Serviceability Connection Serviceability

Issue: direct water ingress End caps and flashing Nails or screws Flashing Details used into flashing End cap protects .Re-direct the water flow strip end grain around the connection .Use preservative treated 1” min. w/ turned wood products out ends .UdUse end caps and dflhi flashing Exposed sections of ½” air space members to be .Must allow for air flow and with insect preservative screen drying treated

Open bottom or weep holes

Beam to Concrete Beam to Concrete

Beam on shelf . Prevent contact Sloped Beam with concrete SplitPossible . Not fully using steel bearing split supported plate . EddExposed end . Provide air space grain at end of beam . May result in splitting Connection Techniques Beam to Masonry

CtidttConnecting wood to concrete Proper Application Note steel bearing . Prevent contact with plate masonry . Bearing plate under beam . Minimum of ½” air gap at end Note gap at end

Beam to Masonry Buried Column Base

Grouted at bearing Floor slblab poured over connection . Moisture can migrate from concrete to wood . Can cause decay . Not recommended Need steel bearing plate and 1/2 ” air gap between wood and masonry Colu mn Base Column Base

Problem installation . No weep holes in closed shoe . Moisture can accumulate . Decay can result Bearing plate Angle brackets . Anchor bolts in . Anchor bolts in bracket bearing plate . Loose bearing plate . Dapped column end

Column Base Arch Base to Support

Problem installation Problem installation . Where’s the steel . Potential for debris plate? and moisture to . Grout substituted accumulate . Moisture can wick . End grain will pick into wood and up moisture potentially lead to decay . Potential for decay Arch Base to Support Arch Base to Support

Problem installation Note flashing on . Untreated glulam top of glulam arches with a closed shoe . No provision such as weep holes to allow moisture to drain . Major decay has occurred Note open shoe allowing water to drain

Arch Base to Support RESOURCES

When installed in 1985 Where to get more information

25 years la ter in 2010 WEBSITES Where to Find Specifics

. American Wood Council - www.awc.org 2005 NDS . APA - www.apawood.org . Canadian Wood Council - www.cwc.ca . Forest Products Laboratory - www.fpl .fs .fed .us . Southern Council - www.southernpine.com . WoodWorks - www.woodworks.org . Wood Truss Council of America – www.woodtruss.com

Where to Find Design Specifics at Where to Find Design Specifics at AWC APA

T300 - Glulam connection details E830 - Screw and plywood connections E825 - BltBolt and pl ywood connecti ons TT-035 - Corrosion resistant fasteners TT-036 - Glued fl oors TT-039 - Nail withdrawal TT-070 - Nail pull through www.apawood.org and enter the Publications store fffor free d ownl ldoads Free Downloads www.awc.org WWPA Free Downloadable AWC Free Online Connections Calculator WWPA Lumber Design Suite . Single and double . Beams and Joists shear connections . Post and Studs . Withdrawal . Bolts, nails, lag . Wood to Wood screws and Shear Connections wood screws. (nails, bolts, wood . Wood-to-Wood screws andld lag . Wood-to-Concrete screws) . Wood-to-Steel www2.wwpa.org/TECHGUIDEPAGES/DesignSoftware/tabid/859 /Default.aspx www.awc.org/calculators/connections/ccstyle.asp

www.APACAD .org www.WoodUniversity . org Other Reference Books Some Take Home Messages

. Transfer loads in comppgression bearing or compression parallel whenever possible . Avoid the use of details that induce tension perpendicul ar-to-graitin stresses i ithn the memb er . Use multiple smaller fasteners when possible . Avoid eccentricity in joint details . Avoid moisture entrapment at connections . Allow for dimensional changes in the wood due to potential in-service moisture cycling . Do not place wood in direct contact with masonry or concrete . Minimize exposure of end grain

Some Take Home Messages OOPS?

. For prescritiiptive connection d esi gn, f oll ow th e . Who has "recipe". Industry publications and the IBC and IRC responsibility for have thorough provisions of what to use when and this connection where. ?? . For engineered connection design, nominal design values are used as the basis . The NDS has thorough . Even tethe best provisions for how to calculate or determine nominal designed design values. connections . For engineered design, the nominal values must be adjusted by applying adjustment factors to account cannot always for the specific end -use conditions and application . survive field . When in doubt consult industry trade associations. modifications Course Evaluations

In order to maintain high-quality learning experiences, please access the evaluation for this course by logging into CES Discovery and clicki ng on the CEltiCourse Evaluation link on th e l eft s ide o f the page. Questions?

This concludes The American Institute of Architects Continuing Education Systems Course

The Wood Prod ucts Co uncil Tom Williamson , P .E . www.woodworks.org T. Williamson – Timber Engineering LLC [email protected]