Polymorf - Knowhere

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.

Grids

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 0^o and 90^o). Figure b) is an identical two-way

grid but the lines run diagonal to the boundary (i.e. 45^o and 135^o). Figure c) is a three-way,

grid with lines parallel to 90^o, 150^o, and 210^o. Variations of these grids can be created by

the systematic elimination of some of the members to form more open grids.


.
a) two-way grid	b) two-way grid	c ) three-way grid
0^o and 90^o	45^o and 135^o	90^o, 150^o, and 210^o
.
Fig. 224 - Two-way and three-way grid patterns (visualization models)

Exercise: Draw or model other types of two-, three-, or ?-way grids you can imagine.

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Page 132 - Building stability - Grids