I'm not a builder. Not in the slightest. I'm neither good at it, nor do I particularly enjoy it most of the time.
This may not be an ideal gap to span, but I really need a 22-block long, 5-block wide, 12-block tall bridge and nothing I'm doing looks right to me.
The top is of no concern, I'm talking about the supports below it—the general shape from the walking surface down.
Here's a fly in the ointment—and I'm sure all these caveats is going to make getting a reply unlikely—it's actually an underground walkway and there will be another bridge below it. Moreover, it's a viewing area; visibility from the walkway is very important. I really don't think it needs any sort of rails or anything from the walking surface up.
It can't be lit from above, so the real difficulty is the lighting.
Here are some pictures so you can see the area I'm working with.
Current (smooth stone is scaffolding):
(Above) The far wall in the last image will be the map wall, and the map is so large it needs a viewing platform. I can't raise the ceiling (the whole castle is up there), so the map will be lower than eye level here.
The walkway runs north-south. However, the floor at the bottom will be removed and will drop down to bedrock level far below.
There will be an east-west bridge that runs in the center below it at the lower floor's level.
Pretty well, the castle is all stone bricks with cobble floors. Smooth stone and andesite/polished andesite is used here and there.
This is a vanilla survival single player world with no commands.
With all these specifications, it probably going to be difficult to even get a reply, but perhaps the building community can help me out a little. Also, posting in threads like this help me organize my thoughts and helps me break builders block.
Thanks for reading and for your time!