Weld 1/8" thick square tube to 1/2" base

Hello all,

I need advice. I am going to build a gazebo of sorts. It will consist of 3x3, 1/8" thick square tube sticks.

I will have shades and the like on it and it could behave like a sail so I want to ensure it is stuck to the ground well.

I plan on pouring square footings and bolting a 1/2" plate to it, which is in turn welded to the stick.

Sooo...1/8" think square tube secured to a 1/2" plate. How to go about it? My first thought was to gouge out a trough where the tube would meet the plate to act as kind of a bevel to fill with the bead. I was also thinking of using some angle iron t construct a plug, if you will, which would be welded to the plate first, the tube fitted over it as in play A into tube hole B, holding the tube off the plate by a 16th or 8th, and filling it all with the bead, thereby welding the tube to the plate as well as the pre-welded bead. (all this is done in the shop, then placed on the footing). Not sure if that is overkill or not. Sounds cool and fun though.

What am I missing? It's going above a spa so i don't want it collapsing in high wind.

Second request. Anyone know of a stupid simple application that lets you sketch out a structure and then based on the loads you tell it it will need to hold, recommend metal stock size?

All advice appreciated.

Thanks

Don Thompson

That is going to be very heavy. Use something like 14 gauge and you'll have plenty. 16 would be fine too. 1/4" plate would be more than enough for that as well, even if you over build it. No need to gouge. Just clean grind your joints to the plate with a hard stone. Aaannndd, by using the lighter gauge (which is plenty of support unless you are talking about 30 feet or something like that) you'll save lots more money.