Ah, such nice, clear diagrams. It seems that pappou taught you well, indeed. Keep it up with including the materials like that; it's helpful for texturing.
In the moon-style bridges overview, I see that there is a curved step...what bothers me about that is that near the bottom of the step the grade is very steep...In real life that would be a tripping hazard.
I like the look of the iron bamboo railings; I think they might look good on the moon bridges?