Splice Plate Design

You might look at 80/20™ joining plates for a general idea for dimensions. While these are for their aluminum T-slot extrusions, they may give you a starting point for your application.

Will do. Thank you.

By the way, Their T-slot extrusions come in up to 20 ft. lengths with 1.5 X1.5 in. cross sectional modules up to 3 X 6 in.

I actually have our own custom extrusion that I need to use. But it's close enough to rec tube.

I like this design....

Thank you Solar (boy, you been on here a coon's age... several coon's ages.). No, that won't work, but nice design! I've included a couple of images in another comment. It's going to have a canvas attached to it, so no flanges.

Is this going to be used for electrical conductors or air ?

No. It's a structural beam. Will have canvas attached to its full length by way of the C-shaped groove. I'm designing a tent-like structure. This is part of the framework.

This beam will span 40' when I splice two together and support it.

This is what I came up with. Checking for general feasibility.

I will be bolting the other end.

Wondering if I should bolt both ends instead of plug welding one end.

How much weight do you expect the tube to support?Will it be rolled or pulled back to one spot or stay distributed across the entire span?

I would put a support on both sides,at the seam of the splice,if space permits, with whatever method you decide to use;Perhaps a single support with a long support plate at the top with gussets under the support plate.

Look at some of the electrical duct work splices to get a start for some ideas.

I would make a box the size of the inside diameter of the box tubing,same schedule or thicker.Thread it for fine thread bolts,and bolt it together. With 6 bolts each side of the splice

I would make it about 12 inches long,giving 6 inches on each side of the joint.

This would be stronger than the un-spliced tubing.

I am sure this may be overkill,but better than an under-designed method.

Minimal additional weight. The fabric is pretty light weight. Not actual traditional canvas. A caveat though, is that it's something you can break down after use. We test our structures by putting a girl up on top to roll around. Hi tech testing. So, say 100 lbs or so at the weakest point. Other than that, just wind load. It's a pretty big sail. Although, it is horizontal for the most part, with a typical roof slope.

I've also considered making two splices by cutting a 20' in half and putting one 10' on each end of the full 20 footer. Keeping the joints at the 1/4 positions instead of the 1/2.

But with a box splice like you suggest... I suppose that wouldn't really be a weak point. I may go with a full inner box.