Structural simulation using a 3D CAD program:

Problem

For various reasons a new awning was needed at my place in 2000:

Loads are primarily snow (assumed to be max 220kg/m2).
intended roof cladding Macrolon SP.

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Iteration #0

A first design was done fairly quickly:

Finite element (FEM) calculations show stresses and displacements under load:

Note that this design results in high stresses and a whooping 35mm dip of the front tip when loaded with 2000N/m2 (roughly 200kg/m2) area force (recommended design snow load). The design features a lateral fix on the right hand edge, where the structure is bolted to the wall twice. Loads in those bolts are quite large. Loads around the cut outs are non optimal as well (those holes will not be stiffened around their edges, as the whole beam is laser-cut and welded, not machine from a monolithic block (after all, this is not an aerospace competition).
However, better get the FEM modelling right, or results are somewhat out of the shape:

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... Iteration 6 ...

Since the beams have a larger cross-section and smaller cut outs, loads look better and bending at the tip is halved. However, lateral loads on the two bolts are still way to high.

Maybe we should re-arrange the vertical beams.

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Semi final (iteration 10)

The horizontal cylinder was moved forward, the vertical beams were designed stronger which reduces bending and thus eliminating any bolts to the wall. Cross section of the horizontal beams was enhanced and hence overall forces and displacements look better:
maximum displacement is 9mm at the tip and 5mm at rear, stresses are well below the (if I've done my homework right) 14x10⁷ N/m2 stress for St37-2 steel.

Note that the larger diameter of the horizontal truss allows additional loads like lifting the diesel engine from a 4wheel drive. Adding the immediate surrounding, the foundations were planned:

The structure had been set up in November 2001 and has survived so far:

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