4' remember buckling
Post on 08-Nov-2015
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-
Remember of some buckling lengths
a- Diagonal and vertical joined with lower compression chord:
Lout = 1.2 L if one of the 2 ends of the vertical and the diagonal is not
braced.
What braces a point?
(1) Purlin (2) Long. Bracing
(3) Tension in both members meeting at that point
Examples:
Calculate buckling lengths outside plan for lower chord, diagonals and
verticals for the given shapes.
1)
L1 = L2 = L3 = 3a L4 = L5 = 2a
D1 = D2 = 1.2L D3 = D4 = D5 = L (lower point
braced)
V1 = 1.2L V2 = V3 = V4 = V5 = L
2)
L1 = L2 =L3 = 3a L4 = L5 = 2a
D1 = D2 = 1.2L D3 = D4 = D5 = L (lower point
braced)
+ve+ve-ve +ve +ve
+ve-ve +ve +ve-ve
-
V1 = V2 = 1.2L V3 = V4 = V5 = L
3)
LC1 = LC2 = 2a
L1 = L2 =L3 = L4 = 4a
DC1 = DC2 = 1.2L D1 = D2 = 1.2L D3 = D4 =
L
VC1 = L VC2 = 1.2L V1 = V2 =
1.2L V3 = V4 = L
4) L1 = L2 = 2a L3 = L4 = L5 = 3a
D1 = D3 = D4 = 1.2L
D2 = D5 = L V1 = V3 = V4 = 1.2L
V2 = V5 = L
+ve-ve-ve +veLC1 C2L
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