4x4" Square Tubing Generator Stand

[klamberth27]

TL;DR Summary

I am building a generator stand and have some 4x4" square tubing with .25" wall thickness. Do I need a support in the middle or are the braces at the ends good enough.

Generator weights approximately 1000lbs. I will be removing from the trailer and mounting it to a concrete pad. The reason for the stand is simply because there is a 100 gallon fuel tank that needs to remain under it like it is mounted in the trailer. The spacer/stand is so that the fuel tank can remain below the generator but be mounted to the concrete pad.

Diagram is attached.

 

[Baluncore]

...Do I need a support in the middle or are the braces at the ends good enough...
...Generator weights approximately 1000lbs...

Welcome to PF.
First identify the position of all the mounting points that attach the generator to the trailer chassis.
What are the dimensions of those original chassis mountings on the trailer?
If the generator will be operated on the frame, what will stop the frame falling sideways? and how will the frame be attached to the concrete slab?

Storing that much fuel is a real liability. What are your local rules? Will the fuel tank rest independently on the slab? will the drain be blocked? or the material corrode? What happens when it leaks or spills during filling? Where does the fuel flow?

 

[Dr.D]

Will you build from steel, aluminum, or some other material?

 

[klamberth27]

Will build from Steel .25"

 

[Baluncore]

The generator appears to have two black skids that rest on the trailer. Are those part of the generator or part of the trailer? Will the original skids be used to rest on the new frame?

Is the fuel tank built into the trailer, suspended from or mounted on the trailer, or is it part of, or slung from the generator?

 

[klamberth27]

Correct. The skids are built into the generator cage and will remain. They will be sitting on the new frame. The fuel tank sits just below the Generator and is suspended in the trailer. The plan is to unbolt from the trailer and place under the generator on the concrete slab.

 

[Baluncore]

The fuel tank sits just below the Generator and is suspended in the trailer.

Then the tank should be suspended in the new frame, below the generator, and not in contact with the concrete.
The fabrication of the new frame can be guided by the construction of the original trailer frame. Because it is not mobile, components can be heavier, but it should not be made any lighter. Study the mounting points on the generator support, and the suspension points on the tank.