Exercises for timber Framing Design
For our exercises we use
3 timber framed buildings Plan E, Plan A and
All roof framing members
All wall framing members inclusive bracing and
all floor framing members.
There are two parts for each exercise:
Part A - design of all coupled roof members
Part B - coupled roof members overlay
Plan E will be use to demonstrate the required procedure to fill in the information in the handouts. In no more than 8 Weeks you should have completed the selection of all members for house Pan E. Students then work themselves through the next plan A and later plan C. The lecturer will answer any student's question regarding the member selection or the appropriate rules of the standard. Students how have completed some rows in the roof frame table can check their figures with the lecturer. If students haven't done any work at all correct figures will not be provided.
What to do first?
Roof Construction: -coupled Roof - Steel roof sheeting 0.50mm think and battens, Roof Pitch 26°
For coupled & non-coupled roof refer to 2.7.4 Roofs; the steel roof sheeting is given to find the mass of roof materials refer to Table B1.1 & B1.2
Wind Classification: N2
The maximum design gust wind speed is given in Table 1.1. If given in m/s refer to column 2 permissible stress method
Eaves Width: 400mm
Usually given as horizontal dimension. Remember the overhang is measured in the roof plane
(i.e. 400/cos 26°)
Ceiling Lining: 10mm plasterboard
According to Table B1.2 - 7.5 kg/mē. Note the max ceiling mass is 12 kg/mē.
Roof Frame Timber Type: seasoned, stress grade F.5
Use N1/N2 Supplement 1
Roof Battens Spacing: 900mm maximum
Use Table 32 of N1/N2 Supplement 1
Rafters Spacing: 900mm maximum
Needed as input in Table 29 of N1/N2 Supplement 1
Ceiling Frame timber Seasoned, stress grade F.5
Use N1/N2 Supplement 1
Ceiling Joist Spacing: 450mm maximum, NO overbattens
Needed as input in Table 21 or 22 of N1/N2 Supplement 1
Strutted ridge and underpurlins
Indicates rafter is supported at 3 points (wall, underpurlin and ridge). That means rafter span is continuous. Place underpurlin always at midspan.
Beams Combined strutting/hanging) timber type: seasoned, stress grade MGP 12
Combined counter/strutting) OR
Strutting ) HYSPAN LVL
Wall Height 2400mm (Refer also to specification Wall framing)
Needed as input in Table 7, 8, 11, 12 & 13 of N1/N2 Supplement 1
The next step is to fill
in the required information.
TIMBER ROOF FRAMING
COUPLE ROOF - ROOF FRAME
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