nineteen wood construction and design Timber Construction Timber Construction Timber Construction

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APPLIED ARCHITECTURAL STRUCTURES: STRUCTURAL

ANNE NICHOLS FALL 2017 leture nineteen wood

all-wood framing systems studs, beams, floor

post & beams trusses omposite onstrution masonry

Leture 19 F2009abn Wood Constrution 2 Timber

shear walls Timber Constrution glulam arhes &

1 APPLIED ARCHITECTURAL STRUCTURES: STRUCTURAL ANALYSIS AND SYSTEMS DR. ANNE NICHOLS FALL 2017 leture nineteen wood onstrution and design Timber Constrution all-wood framing systems studs, beams, floor diaphragms, shearwalls glulam arhes & frames post & beams trusses omposite onstrution masonry shear walls onrete steel Wood Constrution 1 Leture 19 F2009abn Wood Constrution 2 Timber Constrution studs, beams floor diaphragms & shear walls Timber Constrution glulam arhes & frames manufatured or ustom shapes glue laminated bigger members Wood Constrution 3 Wood Constrution 4 1

s floor joists 2x6, 2x8, 2x10, 2x12 typial at

load-bearing masonry walls limited to around 3

2 Timber Constrution post & beam Timber Constrution omposite onstrution trusses Wood Constrution 5 Wood Constrution 6 Timber Constrution by Code light-frame light loads 2x s floor joists 2x6, 2x8, 2x10, 2x12 typial at spaings of 12, 16, 24 normal spans of ft or m plywood spans between joists stud or load-bearing masonry walls limited to around 3 stories fire safety Timber Constrution by Code heavy timber member size rated for fire resistane solid or built-up setions beams spaed 4, 6 or 8 apart or 1, 2 or 2.5 m normal spans of ft or 3-6 m timber olumns or load-bearing masonry walls knee-braing ommon Wood Constrution 7 Wood Constrution 8 2

Timber lightweight : strength ~ like steel strengths vary

growth manufatured wood assembles piees adhesives Wood

Constrution 9 Wood Constrution 10 Wood Properties moisture

shrinkage strength varies some temperature steam volatile

duration higher loads normal duration reep > 10 years

3 Timber lightweight : strength ~ like steel strengths vary by wood type by diretion by flaws size varies by tree growth manufatured wood assembles piees adhesives Wood Properties ell struture and density softwood hardwood Wood Constrution 9 Wood Constrution 10 Wood Properties moisture exhanges with air easily exessive drying auses warping and shrinkage strength varies some temperature steam volatile produts ombustion Wood Properties load duration short duration higher loads normal duration reep > 10 years additional deformation with no additional load Wood Constrution 11 Wood Constrution 12 3

Wood Properties strength allowable design loads are given with respet to diretion of loading wood is weakest in shear parallel to the grain wood is strongest in ompression and tension parallel to

1, 2, & 3 visual mehanial Wood Constrution 13 Wood Constrution 14 Engineered Wood plywood veneers at different orientations glued together split resistant higher and uniform strength limited

4 Wood Properties strength allowable design loads are given with respet to diretion of loading wood is weakest in shear parallel to the grain wood is strongest in ompression and tension parallel to grain Lumber Grading light-framing onstrution standard utility eonomy strutural light-framing selet strutural no. 1, 2, & 3 visual mehanial Wood Constrution 13 Wood Constrution 14 Engineered Wood plywood veneers at different orientations glued together split resistant higher and uniform strength limited shrinkage and swelling used for sheathing, shear walls, diaphragms Engineered Wood glued-laminated timber glulam short piees glued together straight or urved grain diretion parallel higher strength more expensive than sawn timber large members (up to 100 feet!) flexible forms Wood Constrution 15 Wood Constrution 16 4

5 Engineered Wood I setions beams other produts pressed veneer strip panels (Parallam) laminated veneered lumber (LVL) wood fibers Hardieboard: ement & wood Timber Elements stressed-skin elements modular built-up plates typially used for floors or roofs Wood Constrution 17 Wood Constrution 18 Timber Elements built-up box setions built-up beams usually site-fabriated bigger spans Timber Elements trusses long spans versatile ommon in roofs Wood Constrution 19 Wood Constrution 20 5

Timber Elements folded plates and arh panels usually of

laminated timber long spans usually only for roofs Wood

joists girders Approximate Depths lateral braing

6 Timber Elements folded plates and arh panels usually of plywood Timber Elements arhes and lamellas arhes ommonly laminated timber long spans usually only for roofs Wood Constrution 21 Wood Constrution 22 Timber Elements beams joists girders Approximate Depths lateral braing defletion elasti reep Wood Constrution 23 Wood Constrution 24 6

Wood Design National Design Speifiation Amerian Wood Counil ASD & LRFD (ombined 2005) adjustment fators x tabulated stress = allowable stress adjustment fators terms, C with subsript i.

(perpendiular to grain) F : ompression stress (parallel to grain) strong E: modulus of elastiity F p : bearing stress (parallel to grain) Wood Constrution 25 Wood Constrution 26 Adjustment Fators

7 Wood Design National Design Speifiation Amerian Wood Counil ASD & LRFD (ombined 2005) adjustment fators x tabulated stress = allowable stress adjustment fators terms, C with subsript i.e, bending: b b b f F F produt of adjustment fators Allowable Stresses design values F b : bending stress F t : tensile stress strong F v : horizontal shear stress weak F : ompression stress (perpendiular to grain) F : ompression stress (parallel to grain) strong E: modulus of elastiity F p : bearing stress (parallel to grain) Wood Constrution 25 Wood Constrution 26 Adjustment Fators terms C D = load duration fator C M = wet servie fator 1.0 dry 19% MC sawn 1.0 dry 16% MC glu-lam C F = size fator visually graded sawn lumber and round timber > 12 depth Adjustment Fators terms C fu = flat use fator not deking C i = inising fator inrease depth for pressure treatment C t = temperature fator lose strength at high temperatures Wood Constrution 27 Wood Constrution 28 Leture 19 F2012abn 7

Adjustment Fators terms C r = repetitive member fator 1.15 for more than 3 joists, < 24 o.

fator beams without full lateral support Load Combinations design loads, take the bigger of (dead loads)/0.

5(DL) for instantaneous defletion Wood Constrution 29 Wood Constrution 30 Defletion Limits relies on Uniform Building Code spes Use LL only DL+LL Roof

8 Adjustment Fators terms C r = repetitive member fator 1.15 for more than 3 joists, < 24 o.., or onneted by load-distributing element C H = shear stress fator splitting C v = volume fator for glulam replaes C F for timber C L = beam stability fator beams without full lateral support Load Combinations design loads, take the bigger of (dead loads)/0.9 (dead loads + any possible ombination of live loads)/c D defletion limits no load fators for stiffer members: T max from LL + 0.5(DL) for instantaneous defletion Wood Constrution 29 Wood Constrution 30 Defletion Limits relies on Uniform Building Code spes Use LL only DL+LL Roof beams: Industrial L/180 L/120 Commerial plaster eiling L/240 L/180 no plaster L/360 L/240 Floor beams: Ordinary Usage L/360 L/240 Wood Beam Design - Glulam find M determine allowable stress Pinus Radiata (man.) basi working stress (MPa) Wood Constrution 31 Wood Constrution 32 8

Wood Beam Design - Glulam alulate S required hoose width and height so that bh 2 /6 > S req d evaluate V, L, T, onsider braing, onnetions Wood Columns slenderness ratio = L/d min = L/d 1 d 1 =

9 Wood Beam Design - Glulam alulate S required hoose width and height so that bh 2 /6 > S req d evaluate V, L, T, onsider braing, onnetions Wood Columns slenderness ratio = L/d min = L/d 1 d 1 = smaller dimension l e /d 50 (max) f P A F where F' is the allowable ompressive strength parallel to the grain Wood Constrution 33 Wood Constrution 34 Allowable Wood Stress F F C C C C C where: F = ompressive strength parallel to grain C D = load duration fator C M = wet servie fator (1.0 dry) C t = temperature fator C F = size fator C p = olumn stability fator D M t F p Strength Fators wood properties and load duration, C D short duration higher loads normal duration > 10 years stability, C p ombination urve - tables F * F C p F C D C p Wood Constrution 35 Wood Constrution 36 9

10 C p Charts Proedure 0.822Emin FE l 2 e d ( = 0.8 sawn, = 0.9 glulam) 1. obtain F find l e /d or assume (l e /d 50) ompute 0.822E F E min l 2 e d E min Emin ( CM )( Ct )( CT )( Ci ) ompute F * F C D find F E /F * and get C p F F C * p Wood Constrution 37 Wood Constrution 38 Proedure 2. selet a setion if P & A known, set stress at limit solve for l e, L, or d min if P & l e known, Eentri Loading Stress Limit in reality, as the olumn flexes, the moment inreases P- effet P find A, or d min 3. ontinue from 2 until F satisfied fa fb ( Magnifiation fator) F F a bx 1.0 Wood Constrution 39 Wood Constrution 40 10

Column with Bending Design interation equation f F 2 fbx 1 f F bx F Ex 1.

sampling and testing Wood Constrution 41 Wood Constrution 42 Constrution Requirements - Wood if not treated

must be treated strutural members must be proteted from exposure to weather and water Constrution

11 Column with Bending Design interation equation f F 2 fbx 1 f F bx F Ex 1.0 () term magnifiation fator for P- F bx allowable bending strength Strutural Supervision review hanges in shop drawings! inspetion of onstrution verify ompliane with plans some materials require more variability of materials sampling and testing Wood Constrution 41 Wood Constrution 42 Constrution Requirements - Wood if not treated height above exposed ground 18 joists, 12 girders in masonry or onrete provide ½ air spae foundation sills must be treated strutural members must be proteted from exposure to weather and water Constrution Requirements - Wood rawl spae ventilation fire stops walls at eiling and floor and every 10 along interonnetions soffits and dropped eilings onealed spaes aess for passage of fire stairways & between floors and roof Wood Constrution 43 Wood Constrution 44 11

nineteen Wood Construction 1 and design APPLIED ARCHITECTURAL STRUCTURES: DR. ANNE NICHOLS FALL 2016 lecture STRUCTURAL ANALYSIS AND SYSTEMS ARCH 631

nineteen Wood Construction 1 and design APPLIED ARCHITECTURAL STRUCTURES: DR. ANNE NICHOLS FALL 2016 lecture STRUCTURAL ANALYSIS AND SYSTEMS ARCH 631 APPLIED ARCHITECTURAL STRUCTURES: STRUCTURAL ANALYSIS AND SYSTEMS DR. ANNE NICHOLS FALL 2016 lecture nineteen wood construction and design Wood Construction 1 Timber Construction all-wood framing systems