Rectangular spaceframe lattices 
. 
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
Rec2, is identical to the 
one that
can be sliced out of the octet truss parallel to the 110 plane. 
. 

◄ Fig. 265  Staggered 

rectangular grids 

Fig. 266  Rec2 spaceframe 
(green) sliced out of 
the octet truss ► 

. 
Rec2
spaceframe: (twoway rectangular outer grid staggered over
twoway 
rectangular inner grid) 
. 
The
Rec2 spaceframe is similar in structure to Square2 except for the
rectangular pattern 
of its
grids. 



click image to enlarge 
a) outer grid 
b) inner grid 
c) strut diagram 
. 
Fig. 267  Rec2 spaceframe
[demonstration model built from RT (red)
and ST (blue)* 

* can
also be built with LT and IT to increase depth 
. 
Like
Square2, the unit cell of Rec2 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. 
. 



Fig. 268  Stability analysis

M = 11 J = 6 
of Rec2 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 

