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I have an issue with a post that’s deflecting a little bit too much. Picture a 10 foot HSS c-channel section, used vertically as a post. Web/flange 4.5 x 1.75 @ 3/16 thick.

Clients (friends) insisted on using same metal profile for all members of a patio cover, which works great except on that post which is the only one not braced at the top.

Now I’m trying to think of ways to add stiffness to the post, as a last resort before switching the post to 4x4 tubing (major pain)

How can I add stiffness to the post, short of adding a brace?

I thought of:

1 Bolting on another channel back to back, 2 x 0.5’’ bolts every 2 feet?

2 Welding a plate on the open face of the c-channel?

3 a 3/4’’ threaded rod going through the whole section, with plates at each end clamping the whole post in tension, would that add any stiffness?

I welcome your opinions.

cannotcompute
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1 Answers1

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The best way is to add another HSS c channel back to back because this way you are quadrupling the I in the weak axis. Just make sure the bolts are tight.

If the bolts are not tight fusing the two channels as one, you get at least something more than 2*I.

kamran
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