Rectangular spaceframe lattices

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Rectangular spaceframe lattices are comprised of two rectangular grid layers that are

staggered relative to each other.  Diagonal struts connect the hubs of each layer thereby

triangulating the web.  One variation of this spaceframe, called Rec-2, is identical to the

one that can be sliced out of the octet truss parallel to the 110 plane.

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staggered_rec_grids.gif

◄  Fig.  265 - Staggered

rec-2_spaceframe

rectangular grids

 

Fig. 266 - Rec-2 spaceframe

(green) sliced out of

the octet truss ►

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Rec-2 spaceframe:  (two-way rectangular outer grid staggered over two-way

                                rectangular inner grid)

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The Rec-2 spaceframe is similar in structure to Square-2 except for the rectangular pattern

of its grids.

rec-2_spaceframe.jpg

rec-2_spaceframe.jpg

rec-2_spaceframe.gif

click image to enlarge

a) outer grid

b) inner grid

c) strut diagram

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Fig. 267 - Rec-2 spaceframe  [demonstration model built from RT (red) and ST (blue)*

* can also be built with LT and IT to increase depth
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Like Square-2, the unit cell of Rec-2 is inherently unstable.  Therefore the framework lacks
torsional stability.  Adequate perimeter support must be provided.  It is useful for vertical
glazing frameworks subject to inward and outward acting wind loads that are of equal

magnitude.

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Fig. 268 - Stability analysis

M = 11     J = 6

of Rec-2 unit cell

11 < 3 ( 6 ) - 6

RT (red), ST (blue)

unstable, need +1 M

(demonstration model)

click image to enlarge

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Page 147 - Building stability - Rectangular spaceframes

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