On 22/05/17 10:00, The Natural Philosopher wrote:

You could tie the top section for extra strength.

That is certainly possible.


And put in verticals in other places.

Not possible here as they would become columns to the floor.


The ply skin adds a huge amount of
strength in all other directions

Yes.


However in this case I would pay a structural engineer to sign off any
plans

Then you can sue if it falls down



Possibly metal gussets would be an option - very very strong...