TIMBER DESIGN Data: Type of wood: Bending and Tension(Fb) Shear(Fv) Compression(Fc) Modulus of Elasticity(E) Relative Density(G) Specific Gravity
= = = = = = =
Wn2
Yakal 23.10 MPa 1.72 MPa 15.40 MPa 1.46E+04 MPa 0.74 7.26 kN/m3
θ
Loadings: Wind Pressure Minimum Roof Live Load GI roofing Residential Live Load
= = = = =
0.96 kPa 0.80 kPa 0.15 kPa 2.00 kPa
= = =
0.60 m 3.70 m 0.50 m
Spacing: Purlins Truss Floor Joist
DESIGN OF PURINS Span Height Theta, θ;
= =
5.00 2.50
=
(+) Windward
26.57
Try: 50
x
150
;
I
=
1.41E+07 mm4
Loadings: Live load Roofing Purlin weight WDL+LL
= = = =
0.48 0.09 0.05 0.62
kN/m kN/m kN/m kN/m
Leeward: Pn = -0.5P (WW) Wn1 = Pn(Spacing) (LW) Wn1 = Pn(Spacing) Wn2 = WDL+LL(cosθ)
Load Combinations: Condition 1: DL + LL WDL+LL = 0.56 kN/m Condition 2: DL + LL + WL WDL+LL+WL = 0.32 kN/m
Wind Load: Windward: Pn = 1.3(sinθ - 0.5)P
governs!!
Wnt = WDL+LL(sinθ) WN = Wn1 + Wn2 Wt = Wnt
Moments:
5.59
Mn = Mx = 1/8(WnLx2)
=
1.75 KN-m
Mt = My = 1/12(WnLy2)
=
0.29 KN-m
5.00
Shear: Vx = (1/2)WnLx
=
1.40 kN
Vy = (1/2)WnLy
=
0.35 kN
=
6 Mx 6 My + 2 2 bh b h
Check for Bending: To be safe, Fb > Fact
= Check for Shear: To be safe, Fv > Fvact
13.96
MPa
<
23.10
MPa
safe
<
1.72
MPa
safe
3Vx 3Vy + 2bh 2bh
= =
0.35
MPa
6.64
mm
Check for Deflection: To be safe, Yall > Yact Yact = (5/384)(WLn4/EI) = Yallow = L/360
safe =
Therefore use
10.28
50
X
mm
150 mm thick purlins
DESIGN OF TRUSS
Load carried by the truss:
Try:
3" x 8 " for overall size of truss and me 75 x 200 ; = 5.00E+07 I Windward wind load = 1.62 kN
Loadings: = = = =
Weigth of truss Overall Length of Truss= Weight of Truss = Load carried by the ceiling: Ceiling Load
3.10 0.20 16.55 19.85
kN kN kN kN
0.72 1.45
GI roofing Wt. of Purlins Min. Roof LL
θ
1.62
=
-9.93
44.52 m 4.85 kN 24.70 kN
=
Leeward wind load
0.04 kN/m
8.88 θ
M L
w
N
K
O
J Ceiling load
A
B 1.00
0.25
C 1.25
D
E
1.25
1.25
F 1.25
G 1.25
1.25
10.00 m
Forces Due to DL + LL
9.88 kN 4.94 4.94
4.94
4.94
kN
M
kN
4.94
L
w
kN
kN
N
K 4.94
O
kN J Ceiling load
A
B 1.00
0.25
C 1.25
D 1.25
E 1.25
F 1.25
G 1.25
1.25
10.00 m
Forces Due to Wind Load
1.49 0.29
0.29
0.14
1.03 M
1.78 0.89
1.78
L 0.29
N
0.14
0.89 K
0.29
O
0.14 J
0.14 A
B 1.00
0.25
C 1.25
D 1.25
E 1.25
F 1.25
10.00 m
Support Reactions due to DL + LL
Axial Forces due to DL + LL
G 1.25
1.25
d load
Support Reactions Due to wind load
Axial Forces Due to wind load Summary of Bar Forces Top Chords AJ JK KL LM MN NO OP PI Bottom ChordS AB BC CD DE EF FG GH HI Verticals BJ KC DC
Length 1.40 1.40 1.40 1.40 1.40 1.40 1.40 1.40
DL + LL
WL
4.20 -15.10 -17.40 15.70 15.70 -17.40 -15.10 4.20
0.60 0.60 0.80 1.00 -0.10 0.60 0.70 -2.30
1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25
-4.00 2.00 13.70 15.50 15.50 13.70 2.00 -4.00
4.40 4.00 4.20 4.00 2.10 1.20 2.10 3.00
0.63 1.25 1.88
-19.80 -6.50 -1.80
-0.30 0.00 0.20
ME NF OG HP Diagonals JC KD LE EN OF PG
2.50 1.88 1.25 0.63
3.60 -1.80 -6.50 -19.80
-1.60 -0.80 0.70 0.80
1.40 1.77 2.25 2.25 1.77 1.40
12.60 2.50 -2.00 -2.00 2.50 12.60
0.30 -0.30 -0.60 2.50 1.30 -1.00
Design of Truss Members Stresses Top Chord -17.40 Bottom chord 15.50 Vertical -19.80 / -0.30 Diagonal 12.60 / 0.30
Length 1.40 1.25 1.25 2.25
DESIGN OF TOP CHORD Try: 3" 75 P L L/d
mm
= =
-17.40 1400
=
18.67
X X
;
mm
I =
5.00E+07
kN mm
π E K = 4 6 fc
=
8" 200
.5
9.87
since L/d>K and L/d>11
it is long column
To be safe: Fc >= fc
Fc =
Fc = fc = =
π2 E 2
L 36 d
11.49 P/A 1.16 MPa
Therefore use
< 11.49 75
x
ok, SAFE
200 mm for TOP CHORD
mm4
DESIGN OF BOTTOM CHORD Try: 3" 75 P L L/d
mm
= =
15.50 1250
=
16.67
X X
;
mm
I =
5.00E+07
mm4
kN mm
π E K = 4 6 fc
=
8" 200
.5
9.87
since L/d>K and L/d>11
it is long column
To be safe: Fc >= fc Fc =
Fc = Fc =
π2 E 2
L 36 d
14.41
1.03 MPa
Therefore use
< 14.41 75
x
ok, SAFE
200 mm for BOTTOM CHORD
DESIGN OF VERTICALS Try: 3" 75 P L L/d
mm
= =
-19.80 1250
=
16.67
π E K = 4 6 fc
=
X X / mm
8" 200
mm
;
-0.30 kN
.5
9.87
since L/d>K and L/d>11 To be safe: Fc >= fc
it is long column
I =
5.00E+07
mm4
Fc =
π2 E 2
L 36 d
Fc = fc = =
14.41 P/A 1.32 MPa
Therefore use
< 14.41 75
x
ok, SAFE
200 mm for VERTICALS
Check for Stress Reversals: Fb
>= ft
Fb
=
ft =
To be safe:
23.10 MPa P (3 / 5) Ag
=
0.03
Since Fb > Ft, Use
<
75
x
23.10
SAFE
200 mm for VERTICALS
DESIGN OF DIAGONALS Try: 3" 75 P L L/d
X X
mm
= =
12.60 2250
=
30.00
/ mm
π E K = 4 6 fc
=
8" 200
;
mm
I =
5.00E+07
mm4
0.30 kN
.5
9.87
since L/d>K and L/d>11
it is long column
To be safe: Fc >= fc
Fc =
π2 E 2
L 36 d
Fc = fc = =
4.45 P/A 0.84 MPa
Therefore use
< 75
Check for Stress Reversals: Fb
>= ft
Fb
=
ft =
To be safe:
23.10 MPa P (3 / 5) Ag
4.45 x
ok, SAFE
200 mm for DIAGONALS MEMBERS
ft =
P
=
(3 / 5) Ag
Since Fb > Ft, Use
0.03
75
<
x
23.10
SAFE
200 mm for DIAGONALS MEMBERS
DESIGN OF POST
At Truss supports
DL + LL
WL
DL + LL + WL
-23.69 -23.69
-0.19 4.66
-23.88 -19.03
A B At Girder Supports
-17.27 USE, P = Try:
-17.27
95.52 8" 200
mm
96.39 X X
Length of column Weight of Column 4Pgirder L/d
0.00
Interior Post Carries 4 Girder 4P = 95.52
=
= PTotal
8" 200 = =
3.00 0.87 kN
=
96.39 kN
15.00
π E K = 4 6 fc
=
mm
;
I =
Load Transmitted by the 4 Girder together w/ post weight….Center post
.5
9.87
since L/d > K and L/d > 11 it is long column To be safe: Fc > =fc Fc =
Fc =
π2 E 2
L 36 d
17.79
1.33E+08
mm4
fc = =
P/A 2.41 MPa
Therefore use
< 17.79 200
x
ok, SAFE
200 mm for POST
DESIGN OF FASTENERS AND CONNECTORS
FOR TOP AND BOTTOM CHORD Determine the portion of the trus with largest P
3
P =
"
x
8
"
3
"
x
19.50 kN
k Diameter of Nail
P =1.25 KD 3 / 2
= = = = =
### 0.32 in 8.13 mm 0.008 m 0.17
115.75
8
"
DESIGN OF T&G Residential Live Load Specific Gravity Modulus of Elasticity
Wnt
= = =
2.00 kPa 7.26 kN/m3 1.46E+04 MPa
Try: 25
X
100
; I
=
2.08E+06 mm4
0.10
0.10
WDL+LL 0.025
T&G
T&G
FJ
0.50 Loadings: Dead Load (Weight of T&G) = Area X S.g. Live Load (Residential LL) WDL+LL (-) Leeward
MMAX = (1/8)WL2 VMAX = wL/2 Check for Bending: To be safe, Fb > Fact Fact = 6Mmax/bh2
= 0.16 MPa Since Fact is less than Fallowable, it is safe
=
0.08 kN/m
=
-0.48 kN/m
Check for Shear: To be safe, Fv > Fvact Fvact = (3/2)(Vmax/bh)
= =
0.05 kN/m -0.29
=
0.56 kN/m
=
0.28 kN/m
= =
0.61 kN/m 0.28 kN/m
2.50
= 0.03 MPa Since Fvact is less than Fvallowable, it is safe Check for Deflection: To be safe, Yall > Yact = 0.0058 = 1.39 Since Yact is less than Yallowable, it is safe Therefore use 25 mm X 100 mm T&G Yact = (5/384)(WLn4/EI) Yallow = L/360
DESIGN OF STAIRS
Design of Tread: Try: 2" 50 safe
safe
mm
X X
Width of stairs
8" 200 =
Loadings: Weigth of Tread Live Load TOTAL
= = w =
;
mm
1.10 m 1100 m 0.07 kN/m 0.40 kN/m 0.47 kN/m
Analytical Model: w
=
0.47
1.10 m Mmax = =
(1/8)wL2 0.07 kN-m
Vmax = (1/2)wL =
Check for Bending: To be safe, Fb > Fact Fact = 6Mmax/bh2 = Since Fact is less than Fallowable, it is safe
Check for Shear: To be safe, Fv > Fvact
Fvact = (3/2)(Vmax/bh) = Since Fvact is less than Fvallowable, it is s
ll size of truss and members 5.00E+07 mm4
Try: 2" 50
mm
X X
8" 200
;
mm
Considering the longest span of the stairs: No. of Stairs 0.14 / joint 0.29 / joint
18 @
0.20
Load carried by the tread
=
2.70 m
Fx = Fy =
=
9.93
Theta, θ Length of Carriage Weigth of Carriage
=
36.87 = 4.50 m = 0.07 kN/m
4.44 3.60 m Fx = Fy =
0.89 / joint 1.78 / joint
Analytical Model of Loadings:
P
Load by the Tread: H 1.25
I 0.25
1.00
0.38
0.
kN
44
4.94
Length of Carriage
kN 4.94
P
H 1.25
Vmax = Mmax =
=
4.50 m
kN
/m
0.98 kN 4.42 kN-m
I 0.25
1.00
Check for Bending: To be safe, Fb > Fact Fact = 6Mmax/bh2 = Since Fact is less than Fallowable, it is safe
0.89
1.78 0.89
1.78
P
Check for Shear: To be safe, Fv > Fvact
0.89 H 1.25
I 0.25
Fvact = (3/2)(Vmax/bh) = Since Fvact is less than Fvallowable, it is s
1.00
Check for Deflection: To be safe, Yall > Yact = Yact = (5/384)(WLn4/EI) Yallow = L/360 = Since Yact is less than Yallowable, it is saf
Therefore use
50 mm
X
200
DL + LL + WL 4.80 -14.50 -16.60 16.70 15.60 -16.80 -14.40 1.90 0.40 6.00 17.90 19.50 17.60 14.90 4.10 -1.00 -20.10 -6.50 -1.60
2.00 -2.60 -5.80 -19.00 12.90 2.20 -2.60 0.50 3.80 11.60
S MEMBERS
NALS MEMBERS
nterior Post arries 4 Girder 95.52 96.39 kN
Interior Post (carries 4 girders)
P =
19.50 kN
GN OF T&G
DESIG Specific Gravity Modulus of Elasticity Length of joist Joist Spacing Residential Live Load
0.10
0.10
T&G
1.46E+04
Try 50
T&G
= = = = =
X
175
; I
SECTION A-A: T&G
Floor Joist 0.50 m
Loadings: Dead Loads:
= = =
0.02 kN/m 0.20 kN/m 0.22 kN/m
=
0.007 kN-m
=
MPa le, it is safe
0.05 kN
Weight of joist = Specific Gra Load carried by the T&G Live Load: Floor LL WDL+LL
<
MPa < able, it is safe
Fb
23.10
MMAX = (1/8)WL2 VMAX = wL/2 Check for Bending: To be safe, Fb > Fact
Fv
0.0058 mm 1.39 mm le, it is safe m T&G
1.72 Fact = 6Mmax/bh
Since Fact is less than Fallo Check for Shear: To be safe, Fv > Fvact Fvact = (3/2)(Vmax
Since Fvact is less than Fva
N OF STAIRS
I =
3.33E+07
mm4
max = (1/2)wL 0.26 kN
0.21 MPa an Fallowable, it is safe
<
Fb
0.04 MPa < han Fvallowable, it is safe
Fv
23.10
1.72
I =
3.33E+07
mm4
m
0.47
θ
oad by the Tread: θ
0.28
0.47 kN Weight of Carriage: θ 0.
44
0.06 kN
0.07 kN/m
/m
13.25 MPa an Fallowable, it is safe
Landing is made up of concrete
<
Fb
23.10
0.04
0.15 MPa < han Fvallowable, it is safe
Fv
4.7851 mm 12.50 mm an Yallowable, it is safe
mm for Carriage
1.72
DESIGN OF FLOOR JOIST A
7.26 kN/m3 1.46E+04 MPa 3.60 MPa 0.50 m 2.00 kPa
Specific Gravity Modulus of Elastic Length of Girder Joist Spacing Residential Live L
T&G
FLOOR JOIST
FLOOR JOIST T&G
=
Try
2.23E+07 mm4
FLOOR JOIST
Weight of the girder A 2.08
0.18 0.50 m
0.050
f joist = Specific Gravity X Area of Joist = 0.06 kN/m ried by the T&G = 0.09 kN/m Check for Deflection: To be safe, Yall > Yact = 1.00 kN/m
17.27 At Mid span: 2.08
=
1.15 kN/m
= =
1.87 kN-m 2.08 kN
= 7.74E+00 mm = 10.00 mm Since Yact is less than Yallowable, it is safe Therefore use 50 mm X 175 mm Yact = (5/384)(WLn /EI) Yallow = L/360 4
Floor Joist 17.27
= 6Mmax/bh2
= 7.33 MPa < Fact is less than Fallowable, it is safe
Fb
23.10
Check for Bending To be safe, F Fact = 6Mmax/bh2 Check for Shear: To be safe, Fv >
= (3/2)(Vmax/bh)
= 0.36 MPa < Fvact is less than Fvallowable, it is safe
Fv
1.72
Check for Deflecti To be safe, Y
DESIGN OF GIRDER Specific Gravity Modulus of Elasticity Length of Girder Joist Spacing Residential Live Load
150
X
300
Weight of the girder:
= = = = =
; I
4.16 kN
0.50
=
3.38E+08 mm4
= Area X Specific Gravity =
2.08 kN
7.26 kN/m3 1.46E+04 MPa 4.00 MPa 0.50 2.00 kPa
0.33 kN/m 4.16 kN
0.50
4.16 kN
0.50
4.16 kN
0.50
4.16 kN
0.50
4.16 kN
0.50
4.16 kN
0.50
2.08
0.50
Weight of the girder 0.33 kN/m
4.00 m 17.27
kN
17.27
t Mid span: 2.08
4.16 0.50
4.16 0.50
4.16 0.50
0.33
2.08 0.50
kN/m
Mmax
=
17.93 kN-m
Vmax
=
17.27 kN
2.00 m 17.27
heck for Bending To be safe, Fb > Fact Fact = 6Mmax/bh2
=
7.97 MPa
<
23.10 MPa
SAFE
Check for Shear: To be safe, Fv > Fvact Fvact = (3/2)(Vmax/bh) = 0.58 MPa < Fv Since Fvact is less than Fvallowable, it is safe Check for Deflection: To be safe, Yall > Yact Yallow = L/360 = 11.11 mm Yactual =
1.72
5wl 4 Pa(3L −4a 2 ) PL3 + + 384 EI 24 EI 48 EI
Therefore use
= 150 x
6.90 mm 300 for Girder
<
11.11 mm
SAFE
2.08 kN
17.27
SAFE
kN