How to calculate a structure's ultimate load [closed]

Sorry in advance if this question is excessively noobish or seems lazy. I have no engineering background and am unsure where to get started tackling this problem. Links to resources that could put me on the right path would be very much appreciated. I'm not looking for others to do my work for me; I just want to know what sorts of calculations I need to do.

I'm looking to build a cube-shaped structure, roughly 10 ft cubed, for suspending a series of seats (swings, sort of) for people to sit on. I'd planned on building the structure out of 12" aluminum trusses or buying one pre-made. Here's an example of what I might buy or try to build, for visualization.

I'd then loop rope around the horizontal trusses, using the rope to hang "benches"/"swings" from the structure. I'd attach the trusses to plates and use rebar to affix the plates (and the structure) to the underlying ground.

So the question is -- How do I test whether this structure would be sturdy/safe?

• If I'm planning on hanging, let's say, five seats from each horizontal segment, how can I calculate if the trusses would support that sort of vertical force?

• How about the horizontal force caused by someone potentially swinging on one of the seats?

• Horizontal forces caused by wind hitting any tarp (solid or perforated) I use to cover the structure?

If this calculation is too complex/multivariate for an amateur like myself to reliably tackle, is there somewhere I could turn for an engineer's feedback?

• This is quite an involved process. If this is a temporary structure (to be moved around from place to place), then you have a greater issue with the foundations, since they'll need to be designed for multiple soil types. Find yourself a licensed engineer to do these calculations for you (preferably one with experience with this sort of structure). – Wasabi Mar 20 '16 at 22:45
• It sounds like you may be working on an entertainment project - ANSI E1.43 - 2016 which is freely available from PLASA/ESTA may apply or at least be close. It describes the appropriate steps which will involve including someone who has appropriate engineering knowledge and applying extra safety factors to recognize that most equipment is not designed to support humans.. – Ethan48 Mar 21 '16 at 14:28