Cantilevering Rooftop Truss Stability

[gmannix1000]

Hi All,

Question about the stability of a cantilevered truss, if anyone has encountered it before.

I have some rooftop trusses, full storey height, in which a hanger column is supported at it's end - see attached. There is another long truss along the perimeter at the cantilevered edge bracing the tips of the cantilever.

In terms of the bottom chord at the cantilever being in compression for the rest of its cantilevered length - has anyone any advice on the lateral stability of the trusses given they are not tied back in any way to any floor or any core? Right now I'm showing beams at every truss vert, high and lo.

Has anyone come across this issue? Or if anyone has any advice or suggestions?

 

[CANPRO]

In addition to your beams, I would put continuous cross-bracing between trusses on each column line.

 

[MIStructE_IRE]

As above, truss bracing between columns.

You’ll also need wind girders (bracing) on plan, ideally at both chord levels, which are tied back to cores/vertically braced bays.

Other considerations:

1. Vibration
2. Pre-camber necessary?
3. Redundancy within hangers
4. Hanger Connection details! Read about the Hyatt Regency Hotel. Scary stuff showing how a simple change in connection detail led to catastrophic failure.