Truss Top Chord Lateral Support 1

[hoshang]

Hi all,
For a Pratt truss, lateral support is provided by a transverse U-frame consisting of the floor beam and truss verticals. What about a Warren truss? It doesn't have verticals.

 

[hoshang]

BAretired said:
The cross braced members would be considered tension only as they appear slender enough to buckle under a compression load.

Can cross brace members be ignored in gravity load analysis if they were to be considered as tension only? If so, the support structure in the foreground would seem like the attached image, isn't it?

 

[BAretired]

X-brace members have zero stress under gravity load, but they cannot be ignored because they are required for stability of the structure (actually only one member is required for stability, but it would have to be capable of resisting both tension and compression).

Under wind load from the left, the solid red member would be in tension. The dashed red member would be in tension for wind from the right.