Example 3:  [two-way rectangle (REC) outer grid staggered over small square (SS) grid]

.

barrel_vault.jpg

spaceframe_cylinder.jpg

spaceframe_cylinder.jpg

click image to enlarge

a)  barrel vault

b)  cylinder

c) unit cell

RT (purple), ST (green)

M = 17    J = 8

Fig. 282 - Arched spaceframes - 3  (demonstration models)

17 < 3 ( 8 ) - 6,  needs + 1 M

 

Example 4:  [two-way rectangle (REC) outer grid over two-way small square (SS) grid]

.

barrel_vault.jpg

spaceframe_cylinder.jpg

spaceframe_cylinder.jpg

click image to enlarge

a) barrel vault

b) cylinder

c) unit cell

ST (blue), RT (purple), IT (red)

M = 17    J = 8

Fig. 283 - Arched spaceframes - 4  (demonstration models)

17 < 3 ( 8 ) - 6,  needs + 1 M

 

Hyperboloid cylinders

.

Thus far we have been concerned with how to stabilize spaceframes.  However, intriguing

structures can also be created by intentionally destabilizing lattices.  For example, the

rhombohedral unit cell of the Tri-1 lattice can be modified slightly by removing one of its

struts as shown on the next page (Fig. 285).  The spaceframe built from it can be flexed

into the model of a curved structure called a hyperboloid cylinder.

.

hyperboloid_cylinder.jpg

Fig. 284 - Hyperboloid cylinder

hyperboloid_cylinder.jpg

◄ flexing in

overhead view ►

(built from all LT or ST)

(demonstration model)

click image to enlarge

.

The contour of this model depends on the way that it is flexed.  Flexing it so that the grid

with the missing struts faces inwards results in the narrow diameter hyperboloid above.

.

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Page 151 - Building stability - Hyperboloid cylinders

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