Rafter Stability

GET BACK ONTO THE CIVIL ENGINEER AND REFER TO THIS INDIVIDUAL'S DESIGN.

And don't SHOUT while doing it.

How rude.

No one here can help you. There is no information that is useful.

Good advice, and quality construction costs money.

It does not come from an anonymous forum half way around the world with no idea of the existing structure.

Hire a competent civil engineer, pay him a good retainer and follow his advice.

As someone with no formal mechanical engineer training all I can offer is my opinion.

It's my understanding that a vertical tubular column is ideal for off center loading which is what you seem to have.

Given that your roof was self-supporting with no vertical columns is an achievement in itself.

Even with the height of the column which seems to be more than 7 meters? The arrangement in your drawing is capable supporting a pretty impressive load.

I would make sure the connection points are made appropriately.

Check some online calculators with your exact length and specifications for additional peace of mind.

There are also other forum's. Where these questions are discussed without fear of death and legal retribution because after all it's on you or whomever is in charge? �� I mean you are working with a reputable engineer correct?

Please be fully aware that I really don't know what I'm talking about. every word I say should be considered dangerous and irrational. You must insert all possible and relevant disclaimers here.

Have fun making your polymers!

There might be a business opportunity here.

Ha! I think you're right.

The Applied Science of Informally Educated Opinions-

It's worked well for me and billions of others for thousands of years

-Happy Thanksgiving

I'd consider beefier gussets