|
Design Principle for Purlins Selection Tables
The purlins selction table are derived in accordance
to BS 5950 Part: 1987 "Code of Practice for design
of Cold Formed Sections."
The tables primarily enable structural engineers and
designers to quickly select the type of purlins
selection which shall meet the strength and
deflection requirements based on the following
predetermined design parameters commonly applied as
follows.
|
1 |
Dead
Load: |
0.15 kN/2 (inclusive of Duroklip 0.65 mm
T.C.T @7.04 kg/m2
50 mm thick insulation wool @ 32kg/m2
1 layer double-sided aluminum foil
1 layer chicken mesh
|
|
2 |
Live
Load: |
0.25 kN/m2 (Malaysian Building By-law Clause
63) |
|
3 |
Wind
Load (uplift): |
0.50 kN/m2 |
|
4 |
Basic
Wind speed: |
32 m/s |
|
5 |
Roof
Pitch: |
Less than or equal to 30 degrees |
|
6 |
Most
severe inward load
combination: |
1.4 D.L + 1.6 LL |
|
7 |
Most
severe outward load
combination: |
1.0 D.L + 1.4 W.L |
|
8 |
Deflection
limit due to
unfactored
dead load: |
L/250 |
|
9 |
Deflection
limit due to
combined
unfactored + live
load: |
L/150 |
|
10 |
Deflection
limit due to
unfactored
live load: |
L/180 |
|
11 |
Design strength Py is to be taken as minimum
yield strength of 450 n/mm2 or 350 n/mm2,
whichever the steel grade is being used. (BS
5950 Part 5: 1987)
|
|
