how much load can 6" by 6" by 1/4" wall thickness steel tubing support?

I want to replace 6" X 6" engineered wood beams (hollow core) with 6"X6"X1/4" mild steel square tubing to support the existing deck and roof. the over all
length of each support post is approx. 17 feet vertical. The deck measures 10'X18'. Support brackets will be welded to each post for the joists etc.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dear Russ:
On Wednesday, April 29, 2015 at 1:18:02 PM UTC-7, Russ wrote:

11ga would probably be thick enough.

Euler buckling, if you want to do are real analysis.

Figure between 3x and 10x the wood you are replacing. But you have little in the way of dampening for straight lengths, where wood will internally dampen vibrations. May need some light x-bracing, say 1.5 x 1.5 inch to within a foot or so of each end.
Should last until about the end of time, or until you forget to put drain holes near the bottom to let water (condensation, rainfall, spilled beer) flow out easily.
I am not a structural PE in any state.
David A. Smith
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.