2182 D - Timber Framing Code

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2182 D - Timber Framing Code Wall Bracing
Class Exercise 1
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• Reference Material
• Class Exercise 1 Roofing Wall Framing
  notes.
• Floor Plan from Exercise 1.
• AS 1684 .2 (2006) Non Cyclonic Code.

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(No Transcript)
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Refer to page 112 Section 8 AS 1684.2
8.3.1 General
Bracing shall be designed and provided for each
storey of the house and for the subfloor, where
required, in accordance with the following
procedure (a) Determine the wind classification
(b) Determine the wind pressure (c) Determine
area of elevation (d) Calculate racking force
N3
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Refer to page 112 Section 8 AS 1684.2
8.3.2 Wind pressure on the building
Wind pressures on the surfaces of the building
depend on the wind classification, width of
building and roof pitch. Tables 8.1 to 8.5 give
pressures depending on these variables. (AS
1684.2, pages 116 124) Pressures are given for
single storey and upper storey of two storeys for
both long and short sides of the building, and
lower storey of two storeys or subfloor for both
long and short sides of the building.
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Refer to page 112 Section 8 AS 1684.2
8.3.3 Area of elevation
The wind direction used shall be that resulting
in the greatest load for the length and width of
the building, respectively. As wind can blow
from any direction, the elevation used shall be
that for the worst direction.
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14.640
7.570
300
2.100m
2.700m
N3
Using the Plan previous information from Roof
and Wall framing Calculations fill in the above
information
(7.570 2) 0.150 3.635 3.635 tan 30
2.098 Rise 2.100m
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Wind Direction 2
Wind Direction 1
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Calculate the area of elevation for Wind
Direction 1
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Refer to page 116 Section 8 AS 1684.2
8.3.4 Racking force The total racking force for
each storey or level of the building shall be the
product of the projected area of elevation of the
building multiplied by the lateral wind pressure
determined from Tables 8.1 to 8.5. The racking
force shall be calculated for both directions
(long and short sides) of the building.
Table 8.2 is used for determining the pressure on
single or upper storey elevations where the wind
direction is at 90O to a ridge and for wind
speeds N1, N2, N3 N4.
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8.3.4 Racking force The total racking force, in
kN, shall be calculated as follows Projected
area of elevation (m2) X Lateral wind pressure
(kPa) Total racking force
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Wind Direction 1
Wind Speed / N3
Roof Pitch 300
Building Width
Pressure / kPa 1.1
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8.3.4 Racking force The total racking force, in
kN, shall be calculated as follows Projected
area of elevation (42.6m2) X Lateral wind
pressure (1.1kPa) Total racking
force (46.9kN) Wind Direction 1
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Side elevation (Wind direction
1) Area m2 Wind Pressure kPa
(table 8.2 p 118) Total Racking
Force KN Nominal Bracing KN Bracing
Required KN
42.6
1.1
46.9
Fill in known information (Area, Pressure, Raking
Force)
Calculate Nominal Bracing
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Refer to page 140 Section 8 AS 1684.2
8.3.6.2  Nominal wall bracing Nominal wall
bracing is wall framing lined with sheet
materials such as plywood, plasterboard, fibre
cement or hardboard, or the like, with the wall
frames nominally fixed to the floor and the roof
or ceiling frame. The maximum amount that can be
resisted by nominal wall bracing is 50 of the
total racking forces determined from Clause
8.3.4 . Nominal wall bracing shall be evenly
distributed throughout the building. If this is
not the case, the contribution of nominal bracing
shall be ignored. The minimum length of nominal
bracing walls shall be 450 mm.
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8.3.6.2  Nominal wall bracing (Cont.) The
bracing capacity of nominal bracing is scheduled
in Table 8.17.
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Calculate all single sided (Gyprock lined) walls
for Nominal Bracing
16.380 x 0.45kN/m 7.4kN
2 x (7.570 0.480) (2 x 1.100) 16.380m
Now Calculate double or Two Sided (Gyprock Lined)
Walls
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Two Sided walls for Nominal Bracing
(4 x 2.500) (1 x 2.400) (1 x 3.500) (2 x
0.500) 16.900m
16.900 x 0.75kN/m 12.7kN
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26.9
Fill in Nominal Bracing total of Single Two
Sided walls
7.371 12.675 20.046 kN
Check that nominal bracing is 50 or less than
total racking force
Bracing required Total Racking Force Nominal
Bracing.
46.9 20 26.9kN of Bracing Required.
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Refer to page 148 Section 8 AS 1684.2
8.3.6.6 Location and distribution of
bracing Bracing shall be approximately evenly
distributed and shall be provided in both
directions (see Figure 8.5). Bracing shall
initially be placed in external walls and where
possible at the corners of the building.
Figure 8.5 Location of Bracing
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Select Bracing Bracing Type G Method B (p
144) Method B 6.0 KN/m x 1.2m (sheet width)
1 Sheet 7.2KN Therefore 4 x 7.2 28.8
KN Reference, 8.3.6.6 Location and distribution
of bracing
Check bracing required to amount of G type
bracing.
26.9kN Required 28.8kN given in type G.
4 Type G sheets will meet the requirements.
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(G)
Bracing Type G Table 8.18 page 144 AS 1684.2
- 2006
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Mark Plan with Bracing Sheets to support Wind
Direction 1
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Refer to page 148 Section 8 AS 1684.2
8.3.6.6 Location and distribution of
bracing Bracing shall be approximately evenly
distributed and shall be provided in both
directions (see Figure 8.5). Bracing shall
initially be placed in external walls and where
possible at the corners of the building.
Figure 8.5 Location of Bracing
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Refer page 150 of 1684.2 (2006)
Wind Speed
Ceiling Width
Roof Pitch
Spacing of Bracing
Calculate spacing of Bracing for Wind Direction 2
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Braces are too far apart. We must place
intermediate braces lt 6.1m apart
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Braces are too far apart. We must place
intermediate braces lt 6.1m apart
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Wind Direction 2
Repeat for Wind Direction 2
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Calculate the area of elevation for Wind
Direction 2
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Refer page 122 of 1684.2 (2006)
Wind Direction 2
Wind Speed
Roof Pitch
Building Width
Pressure / kPa 1.2kPa
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8.3.4 Racking force The total racking force, in
kN, shall be calculated as follows Projected
area of elevation (18.1m2) X Lateral wind
pressure (1.2kPa) Total racking
force (21.7kN) Wind Direction 2
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End elevation (Wind direction
2) Area m2 Wind Pressure kPa
(table 8.4 p 122) Total Racking
Force KN Nominal Bracing KN Bracing
Required KN
18.1
1.2
21.7
Fill in known information (Area, Pressure, Raking
Force)
Calculate Nominal Bracing
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Wind Direction 2
Calculate all single sided (Gyprock lined) walls
for Nominal Bracing
2 x (14.640 0.480) 28.320m
28.320 openings nominal S/S length
Refer to window schedule for window sizes
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Window Schedule
Window W x H W9 Bedroom
1 1.800 1.550 W1 Bedroom 2 1.200
1.550 W8 Bedroom 3 1.200
1.550 W2 Bath WC 1.800 0.900 W3
Laundry 1.350 0.900 W4 Kitchen
1.650 0.900 W5 Dining 1.200
1.550 W6 Living 1.850 1.650 W7
Family 1.850 1.650 D2 Entry 1.350
2.060 D1 Kitchen 0.900 2.060
Total length of opening widths 16.150
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Wind Direction 2
28.320 openings nominal S/S length
12.170 x 0.45kN/m 5.477kN
28.320 16.150 12.170m
Now Calculate double or Two Sided (Gyprock Lined)
Walls
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Wind Direction 2
Two Sided walls for Nominal Bracing
(11.510 4.300) 5 doors _at_ 0.900 15.810
4.500 11.310m
11.310 x 0.75kN/m 8.483kN
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10.85
10.85
Fill in Nominal Bracing total of Single Two
Sided walls
5.477 8.483 13.960 kN
Check that nominal bracing is 50 or less than
total raking force
Nominal Bracing is over 50 - Therefore Total
raking force is to be halved 21.7 2 10.85 kN
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Refer to page 148 Section 8 AS 1684.2
8.3.6.6 Location and distribution of
bracing Bracing shall be approximately evenly
distributed and shall be provided in both
directions (see Figure 8.5). Bracing shall
initially be placed in external walls and where
possible at the corners of the building.
Figure 8.5 Location of Bracing
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Refer page 150 of 1684.2 (2006)
Wind Speed
Ceiling Width
Roof Pitch
Spacing of Bracing
Calculate spacing of Bracing for Wind Direction 2
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Select Bracing Bracing Type G Method B (p
144) Method B 6.0 KN/m x 1.2m (sheet width)
1 Sheet 7.2KN - Therefore 2 x 7.2 14.4 kN
14.4 kN Meets the racking force requirement, but
does not meet the requirements of clauses 8.3.6.6
8.3.6.7, Therefore those requirements need to
be met.
Braces need to start at the corners and no
further apart than 6.700m maximum Spacings to
Wind Direction 2
Mark braces on floor plan.
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Bracing for Wind Direction 2 complete.
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Select Bracing Bracing Type G Method B (p
144) Method B 6.0 KN/m x 1.2m (sheet width)
1 Sheet 7.2KN - Therefore 2 x 7.2 14.4 kN
Refer to8.3.6.5 pg 148 panel length 600 equals
strength of 900 Divided by two. i.e. .9 x 6Kn/m
5.4 / 22.7
(3 x 2.7) (.9 x 6kN) 7.2 20.7
Braces need to start at the corners and no
further apart than 6.700m maximum Spacings to
Wind Direction 2
Mark braces on floor plan.
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Bracing for Wind Direction 2 complete.
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Exercise 1 Completed