Other
long span structures employ networks of interconnected grids. These
include grids, |
spaceframe lattices, and vaults. These "space" structures have
considerable width as well |
as
length. They are designed to support external loads applied
perpendicular to their |
plane.
This is in contrast to relatively narrower, long span structures such as
bridges, that |
are designed
to support loads applied parallel to their plane. |
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 |
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 |
Fig. 223 - Loaded planes |
|
◄ a) parallel to plane |
b) perpendicular to plane ► |
(demonstration models) |
click image to enlarge |
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Grids |
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Grids,
or tessellations, are planar structures created from the intersection of
regularly |
spaced
parallel members that form a repeating pattern of polygons. Grids
can be broadly |
classified by the number of differently oriented parallel lines that
intersect to form the grid |
pattern.
Fig. 224 a), below shows a two-way pattern in which
the members run parallel to |
the
boundary of the grid (i.e. lines oriented 0o and 90o).
Figure b) is an identical two-way |
grid but
the lines run diagonal to the boundary (i.e. 45o and 135o).
Figure c) is a three-way, |
grid
with lines parallel to 90o, 150o, and 210o.
Variations of these grids can be created by |
the
systematic elimination of some of the members to form more open grids.
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 |
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 |
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a) two-way grid |
b) two-way grid |
c ) three-way grid |
0o and 90o |
45o and 135o |
90o, 150o, and 210o |
. |
Fig. 224 - Two-way and three-way grid
patterns (visualization
models) |
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Exercise: Draw or model other types of two-, three-, or ?-way
grids you can imagine. |
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Back
to Knowhere |
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Page 132
- Building stability - Grids |
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