Drag strut - do I need it here?
Drag strut - do I need it here?
(OP)
I have attached a sketch to this post. The question is in the sketch and it is about drag struts and whether or not I would need it for this case. Thank you in advance for the help.






RE: Drag strut - do I need it here?
RE: Drag strut - do I need it here?
is this an L-shape room with supports/foundations at 4 pts ?
if the drag brace connects to the long side between 1 and 2, where'll the drag load go ? beam along the wall to 1 and 2 ??
is the drag brace trying to stabilize pt 4 ?
RE: Drag strut - do I need it here?
Load is attracted to stiffness, so if you have a brace along that line then that line is going to be very rigid. Members in line with the brace will want to attract load to the brace whether or not you tell them to. If you wanted to play it safe, figure the load applied to the brace and then distribute that load appropriated over the length of that line and design your members accordingly.
RE: Drag strut - do I need it here?
By saying "...if I design the deck to span between 1 & 2..." I assume you mean you will design your diaphragm to span between 1 & 2 and not the decking itself.
RE: Drag strut - do I need it here?
I would also place one 90 degrees to it at the re-entrant corner too.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Drag strut - do I need it here?
I should have been more descriptive. That is an L-shaped building, and the 'x' represents cross bracing. Also, by 'deck' I really meant diaphragm.
SteelPE, I was thinking the same. Whether or not I design my diaphragm to span between 1 and 2, depending on the 'design depth' of that diaphragm segment, load will still try to make its way to brace 4, because there's stiffness there - and without a drag strut, there may be issues. Is this question often left to the judgement of the engineer or is there any guidance out there?
RE: Drag strut - do I need it here?
RE: Drag strut - do I need it here?
RE: Drag strut - do I need it here?
Thanks for the response. The cross-bracing on the other orthogonal direction were not shown on for clarity (not because they don't exist) - My question is a theoretical one for lateral load applied along one direction (direction parallel to the drag strut.) I should have made a better job stating this in my original post. Thanks.
RE: Drag strut - do I need it here?
Direction of joists doesn't matter.