Galvanized steel cantilever size for 5 ft extension with 17,000 lb load

[chase t]

TL;DR

Right size and type of Steel for cantilevers

I'm trying to decide what size and type of galvanized steel I need for 2 cantilever extensions. The cantilever is 5 ft. The space between the two cantilever arms is a 17 ft Gap the center 7 ft of the 17 ft Gap we'll need to Bear approximately 17,000 lb spread evenly from the front of the cantilever to the back of the cantilever over 5 ft. I will put support beams across these cantilever arms to support the load evenly

 

[berkeman]

Welcome to PF.

What happens if this system fails? What is being held up by it? What is underneath it?

 

[chase t]

It would be catastrophic. A 3.5' deep 5'x7' pool. Nothing underneath it.

 

[berkeman]

That doesn't sound like something we should be helping you with. What do your site engineer and your insurance agent say about the project?

 

[Baluncore]

What will the cantilevers be attached to?
I would question whether the existing building structure could carry that additional supported load.

 

[Chestermiller]

Let's see you analysis so far, starting with your schematic of the system.

 

[russ_watters]

A 17' span is pretty big too.

This sounds to me like something that's illegal to do without a licensed structural engineer. So I'm locking this, per our rules.