timber final requirement

8/9/2019 Timber Final Requirement

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COMPILATION OF NOTES TIMBERDESIGN

TIMBER DESIGN

Generally refers to the proper evaluation of wood or lu!er eleents su"h as individual

plan#s$ %oist$ !eas$ post or "oluns whi"h in"lude the "onne"tion of eleents to the other

eleents and the foundation$ and the perforan"e of eleents and "onne"tions a#in& up

stru"tural syste'

The desi&n of a ti!er stru"tures re(uires all "oponents of the stru"ture to !e of su)"ient

si*e and stren&th to withstand the for"es to whi"h the stru"ture i&ht !e reasona!ly !e

su!%e"ted durin& its useful life' Proper desi&n also re(uires su)"ient sti+ness in e!ers

and stru"tural syste to prevent deforations asso"iated with reasona!le loads fro

ipairin& the servi"e a!ility of non stru"tural syste or "ausin& the stru"tures to feel or

appear unsafe'

Timber construction Manual (5thedition)

this anual is developed !y AITC to provide state,of,the,art te"hni"al inforation

and re"oendations on en&ineered ti!er "onstru"tions

AITC - Aeri"an Institute of Ti!er Constru"tion

T!es o" Timber#$umber

.' Sa%n $umber- is the produ"t of lu!er ills and is produ"ed fro any spe"ies &lain Sa%n Cut

, The ost !asi" way to "ut lu!er !y sli"in& the lu!er in "ontinuous parallel

otion', This ethod of "uttin& pro"edures di+erent &rain patterns dependin& on the

lo"ation it was "ut on the lo&', It is #nown to shrin# and e/pand ost !e"ause the &rains run left to ri&ht on the

width of the !oard', The illin& is fast with a iniu aount of waste of raw aterial'

'uarter Sa%n Cut, The lu!ers are "ut on the (uarters', The wood &rains of this spe"i0" ethod of "uttin& are ore "onsistent and ti&ht

and when the &rains are ti&hter$ it a#es the aterial sturdier', All the &rains run ore in an up ri&ht dire"tion$ eanin& the wood will not e/pand

and shrin# as u"h$ "opared to the plain sawn "ut', The illin& is ediu fast with a ediu aount of waste of raw aterials

Ri"t sa%n Cut, Alost siilar to the (uarter sawn "ut$ the rift sawn is illed in sli&htly di+erent

an&le', This ethod allows the &rain to sit ore ti&ht to one another', The &rains run verti"ally with the thi"#ness of the !oard$ eanin& it will only

shrin# and e/pand in hei&ht', It is the ost e/pensive illin& te"hni(ue !ut re(uires least aount of

aintenan"e'

. 1 P a & e


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Con"lusion2

, If it is used for renovation of a for rent house$ it would !e ideal to use plain sawn

plan#s for e"onoi" reason', If it is used for the renovation of our own house$ it would !e ideal to use (uarter

sawn plan#s for a little ore (uality aterials', If it re(uires usin& hi&h (uality aterials with very little aintenan"e$ then the

!est aterials would !e rift sawn plan#s' Glued $aminated timber (Gluelam)

, Is a type of stru"tural ti!er produ"t "oposed of several layers of diensioned

ti!er !ounded to&ether with dura!le$ oisture,resistant adhesives' This

aterial is "alled a lainatin& sto"# or lasto"# for short', 3y lainatin& several pie"es of ti!er$ a sin&le lar&e$ stron& stru"tural ti!er is

anufa"tured fro saller pie"es'

, These stru"tural e!ers are used as verti"al "oluns and hori*ontal !eas$ aswell as "urved and ar"hed shapes' Gluela is readily produ"ed in "urved shapes

and its availa!le in ran&e of spe"ies and appearan"e "hara"teristi"s to eet

varied,end use re(uireent' Conne"tions are usually ade with !olts$ dowels and

steel plates', Gluela has u"h lower e!odied ener&y than reinfor"ed "on"rete and steel4

althou&h of "ourse it des entail ore e!odied ener&y than solid ti!er' Can !e

used in u"h lon&er span$ heavier load and "ople/ shapes'

Gluela 5 6 wei&ht of Steel 5 7 wei&ht of Con"rete

Gluela 8 9 ties Stren&th of Steel

: 1 P a & e


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Sim!le Beam

is a e!er that is supported only at its ends ; siple or pinned end "onditions< and

resist loads a"ross a sin&le span' The !ea ends are allowed to rotate freely'

Desi*n shall satis" the three conditions+

.' 3endin& Stress:' Shear Stress parallel to the &rain=' >e?e"tion@' 3earin& Stress

= 1 P a & e


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Bendin* Stress ,ormula

fb=mc

I

fb=m

s 4s=

I

c

Shearin* Stress

fv=VQ

I b

'

Q=a y

- Deri.e "b and ". "or Rectan*ularSection

a Bendin* Stress

fb=mc

I 5m

s

I=bd

3

12

c=

d

2

s=bd

3

d

2

=bd

2

6

fb=m

s=

m

bd2

6

fb=6m

bd2

b Shearin* Stress

fv=VQ

I b'

Q=a y A=bd

(b d2 )( d4 )

Q=bd

2

8 b '=b

fv=V

(bd

2

8

)( bd3

12) (b )

@ 1 P a & e


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V

2

db

3

=3

2 (V

db )=32 (V

A)=1.5V

A

fv=1.5V

A

/0ERE+

"b5 e/tree 0!er !endin& stress

m 5 applied !endin& oent

I 5 area oent of inertia w respe"t tothe NA

c 5 distan"e fro the NA to the e/tree0!er

s5 se"tion odulus

".5 hori*ontal shear stress ;shear parallelto &rainL 5 ;D.


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"t' HT 5 H>LJ HLL J H3

"u' 5 ='B J '=B J ':.

"v' 5 .='9 #N

"w'

a) Com!ute M and S ("b> m#s)

"/' 5WTL

2

8

"y' 5(13.06 )(3.662)

8

"*' 5 :.'D #N,

da' I 5b d

3

12 5( .130 )( .305)

3

12 5 ='D / .,@ @

d!' C 5.305

2 5 '.B:B

d"' S 5I

C 53.07x 10

4

.1525 5 :'. / .,=

dd' f!521.87(106)

2.01x103

x109 5 .' MPa

de' or use

df' f!56m

b d2 5

6 (21.87x106)

(130)(305)2 5 .'B MPa

d&' Note+Cvor CL will !e used only for the estiate or sele"tion of "ross,se"tion

dh' Ti!er Constru"tion Manual BthEdition ;AITC -9 (%et ser.ice "actor (.isuall *raded timber 5in


10/59


dl &58T Cv5 ;

130.18

b

304.8

d

6.4

L

1

x

8 .' 1olume ,actor

d' 5 ;

130.18

130

304.8

305

6.4

4.88

1

x

8 .'

dn' 5 .'9 8 .' use Cv5 .'

do' CC 5 .,: ;

t

r

2Cur.ature ,actor ( "or cur.e member onl and use

CC > - i" not a cur.e)

d! &3 T36 Ci>979 Incisin* ,actor

d(' T, ='9 Ct > -9

dr ,2b> -7(-)(-)(-)(-)(979)(-) > -6 44M&a

ds " b ,2b

dt' .'MPa 8 .D'@@ MPa SafeKKK

du'

b) Com!ute Shearin* Stress (".>VQ

I b ' )

. 1 P a & e


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dv' Note2 the !ea has a !earin& at the support$ the "ode re(uires the shear for"e to

"he"# ay e/"lude he distri!uted load applied within d of the end'

dw' R5WTL

2 513.06 (3.66)

2 5 :=' #N

d/'

dy'15 , WT(d) 5 :=', ;.='9


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er' LL55w L

2

384EI 5

3.6642

5(9.35)

5 '@

es'et' >eadload >e?e"tion

eu' >L5 LL;WDL+WB

W< 5

'@;3.5+0.21

9.35 < 5 ='==

e.

e% ,rom T 38 ! TCMAITCe/' e"oended >e?e"tion Criteria

ey' Coer"ial Q Institutional Liveload 5L

360 53660

360 5 .'.D R'@

SafeKKKe*'

fa' App!"d#ad p$s D" ad#ad=

L

240=

3660

240=15.25mm

f!'

f"' .B':B R ..'DSafeKKK

fd'

fe' Che"# ratios of a"tual values to allowa!le values2+'

f&'

fh' 3endin&2

fb

fb1 5

10.88

17.44 5'9: 8 .' GD

0'f%'

f#' Shear2

fv

fv1 5

0.75

2.40 5'=. 8 .' GD

?'f'

.: 1 P a & e


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fn' >e?e"tion;LL< 5

L/360

58.40

10.17 5'= 8 .' GD

fo'fp'

f(' >e?e"tion ;>L< 511.70

15.25 5'DD% .' GD

fr'fs'ft'fu'

fv'fw'f/'fy'f*'&a'&!'&"'&d'&e'&f'&&'&h'

&i'

*: IN1ESTIGATIN , SIM&$E BEAM

*; E


14/59


&t' 5Afv

1.5 5

(125)(375)(1.75)(103)

1.5 5B@'9n&u'

!' S!an $ o" Beam ("b>,b?e"tionhy'

h*' max= 5w

4

384EI

ia' I=bd

3

12=

(180) (240)3

12=207.36x 106 mm

i!' max= 5w

4

384EI=

5 (8 ) (103 )(3500 )4

384 (6480 )(207.36x106mm )=11.63mm

ic IN1ESTIGATIN # DESIGN , SIM&$E BEAM (%ith o.erhan* at ends)

id EFeterine the value of V at the end supports so that the shear stress in the !ea is

as sall as possi!le'!' >eterine the in shear stress if d 5 : and ! 5 9 "' >eterine the value of depth d for a a/' ?e/ural stress of 'B MPa with the sae

width !'

if'

i&'

ih'

ii'

i%'

i#'

il'

i'

in' SOLXTION

a' alue of V for in shear stress

io' /

1+/

2=4 (3.5)

where/

1=/

2

ip' 2/

1=14

.9 1 P a & e


17/59


i(' /1=

14

2=7 )(

ir' Assue shear in4Vm!0=

7

2 5 ='B #N

is' Vm!0=/1Wx

it' 3.5=714 (x )

iu' V5 'DB iv'!' Miniu Shear Stress

iw' fv=

VQ

I b'=

1 .5V

A =

1.5 (3500 )(200 ) (60) 5 '@@ MPa

i/'

"' >epth d at a/iu !endin& stresss

iy' fb=

6m

bd2 m=2x

2=1 .53)( m

i*' d2=

6m

bf b=

6 (1 .53)(106 )8 .5 (60 )

=18 1000

%a' d=1800=134mm

:b (Sim!le Beam %ith su!!ort !ro.ided b "ramin*)

:c E5 .'

%l' CM5 .'

.D 1 P a & e


18/59


%' C5 .'

%n' CC5 .'

%o' Ci5 '

%p' Ct5 .'

%('

%r' Solution2 ;Lu,une/pe"ted len&thesi&nn' 5 :9'= ;.5. B@: =='== =

/' .B / B@ S>5D : ' =

y' .9 / BDB S>5 .9 999'9D =

*' . / 9@B S>5.: @ DB' =

:. 1 P a & e


22/59


na'

n!' A< Try .9 / BDB

n"' f

b

=*

,=

150(10)6

8816666.67=17.01*+a

nd' 3< olue Fa"tor

ne' Cv=( 130.18160 )1

10 ( 304.8575)1

10 (6.4018)1

10=0.8291

nf' C< 3ea Sta!ility Fa"tor

n&' L$=18m7.5m=10.50m

nh'L$

d=

10500

575=18.26

ni' For Sin&le Span 3ea ;Xniforly distri!uted andL$

d 27

n%'

n#' Xse Le 5 .'9=Lu J =d

nl' 5 .'9= ;. B< J = ;BDB Load Co!ination

r*' DL+75 [+L/+(WLEL1.4 )]

sa' DLd"ad#ad

s!' !v" #ad

s"' L/r##f !v"#ad

sd' WLw!0d#ad

se' EL"art48$a)" #ad

sf'

,!0c"t4!s pr# b"mt4" ar7"st #ad !s t4" r##f !v"#ad w4!c4 !s L/=11.68 (9 )=105.12 )(

s&' ,# :L#ad C#mb!0at!#0;175(L/+WL)

sh' Then ultiply S/ and Sy !y .DBW 5 .'DB

si' ,x=1.75(10090443.69 )=17658276.46 m m3

s%' ,y=1.75 (3293585.53 )=3819482.29mm3

s#' =' Assue a trial se"tion

sl' Try :: / D=B "ross,se"tion

s'

,x=bd

2

6=

220(735 )2

6=19808250 mm3

= 1 P a & e


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sn' ,y=db

2

6=

735 (220)2

6=5929000mm3

so'

sp'

s(' Note2by

dy should !e% .' then use CL

sr' Ix=bd

3

12=

220 (735)2

12=7279531875 mm4

ss' Iy=

db3

12 =

735 (220)3

6 =652190000mm4

st'

su' *DLx=5.84(9)2

8=59.13 )( . m

sv' *L/x=11.68(9)2

8=118.26 ) ( . m

sw' *WLy=17.8(9)2

4=40.05 )( . m

s/'

sy' - 'bx=-bx CD Cv-bx CD CL w4!c4 "v"r #f CvCL c#0tr#s($s"#w"st va$")

s*' CD=1.60w!0d #ad

ta' Copute Cand CLthen "opare use /5.

t!'

t"' Cv=( 130.18220 )1

10 ( 304.8735)1

10 (6.409)1

10=0.8398

=. 1 P a & e


32/59


33/59


to' $s"CL=0.8139


34/59


ue'

u" Desi*n o" &urlins

u* E


35/59


v"' C!=0.80

vd'

ve'

vf'

v&'

vh'

vi'

v%'

v#'

vl'

v'

vn'vo'

vp'

v('

fbx

-'

bx

+ fby

-'

by

%1.0 !0v"st!7at!#0vr'

fbx

- 'bx+

fby

- 'by [1( fbx-bE )2

]%1.0d"s!70!07

vs'

vt' Solution2

vu' L5 '== #N

w"'HLL5 '9DB #N

wd'

we'

wf'

w&'

wh'

wi'

=B 1 P a & e


36/59


w%'

w#'

wl'

w'

wn'wo'

wp'

w('

wr'

ws'

wt'

wu'

wv'

ww' H/5 HtsinCCCCiCtyd' F!/5 .9'BB ;.'< ;'< ;.'< ;'< ;'CCCCiCtyh' F!y5 ..'= ;.'< ;'< ;.'< ;'< ;'L J DBW ;L J HL

a&%' F]!/5 .9'BB ;.'9< ;Cfueterine F]" and E

al"' F]C5 FCC>ald' 5 '. ;.':Beterine the slenderness ratio

alt'

L"

d

alu' .'B

L"

d=

1500

127=11.81


48/59


a!' =' FCE 5 ='.= MPa

a"' @'B FCE5.'= MPa

ad' 9' FCE 5 'D MPa

ae'

af' B' >eterine Colun

Sta!ility fa"tor

a&'

-CE

-

C

ah' .'B 5 .'::B

ai' =' 5 '=9

a%' @'B 5 '.=B

a#' 9' 5 'D9:al'

CD=

1+-CE

-

C

2c (

1+-CE

-

C

2c)

2

1+-CE

-

C

c

a' .'B U C>5 'DB9=

an' =' U C>5':=9

ao' @'B U C>5 '.=.ap' 9' U C>5 'DB

a('

ar' 9' >eterine FCas' FC5F]CC>at' .'B U FC5 D'D@

MPa

au' =' U FC 5 :'

MPa

av' @'B U FC5 .'=B

MPaaw' 9' U FC5 'DD

MPa

a/'

ay'

a*' D' >eterine P

ana' A 5 ;.:D


49/59


aoi'

ao%' M/5W yL

2

8

ao#' M/56.984

(5

)

2

8

aol' M/521.825 )(m

ao' My5W yL

2

8

aon Combined A


50/59


apl' f!.- !endin& stress due to loads applied to the narrow fa"e ;!endin& in stron&dire"tionw"t s"rv!c" fact#r (T3.5p .58 )

atr' Ct=1.0 (W"tdry ) T"mp"rat$r" fact#r (T3.6p .62)

ats'att Ste! Determine ,t and ,2bL and @@$B N for SL,snow load

timber final requirement

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