Single layer grids


Strictly speaking, structural single layer grids are comprised of rigidly fixed members.

Examples include the structural framework, or mullion, of glazed curtain walls, false

ceilings, room partitions, etc.  A broader definition includes grids whose members are

connected together with flexible joints such as nets or screens.



Fig. 225 - Structural


single layer grids


◄ a) fixed joints

(glazed curtain wall)


b) flexible joints  ►

(chair seating)

(scale visualization models)


Two or more single layer grids can be stacked on top of each other in a parallel, multi-

layer structure to stiffen the layers against loads applied perpendicular to their plane.  The

layers are joined together by struts, or web elements, that span from the joints, or hubs, of

one layer to the joints of the adjacent layer(s).  The resulting layered structure can be

classified as a double layer grid or a lattice depending on the relative orientation of the

layers to each other.


Double layer grids


If the grid pattern of one layer is superimposed on top of the pattern of the other, adjacent

layer(s) so that the members and joints overlay, or eclipse, each other, the resulting grid

structure is said to be double layered.  Fig. 226 below shows models of double layer grids

formed from a pair of two-way diagonal grids like the one shown in Fig. 224 previously.  In

figure b) the webbing forms oblique angles with the layers so it is called a trussed double

layer grid.  Examples of double layered grids include grates, catwalks, bridge decks, etc.





click image to enlarge

a) double layer grid catwalk

b) truss grid portico


Fig. 226 - Two-way diagonal double layer grids   (scale visualization models)


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Page 133 - Building stability - Single and double layer grids

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