Superstructure
It is any type of support beam or structure.
span
the substructure-gogodude32
Yes, it is like a bridge, but it is generally a natural formation. A causeway is a raised roadway or roadbed or natural bridge, usually over a body of water. A "bridge", in the majority of cases implies a man-made structure.
it protects from tension and compression
The foundational or floating structure supporting the road surface portion of a bridge.
north bridge
No it's not it's a noun.
the above portion of the earth is called the earth's crust
A drawbridge. There are different types of draw bridges. A bridge that lifts the roadbed straight up along two towers is called a lift bridge. One that tilts one side or the other using a cantilever system is called a cantilever bridge. A bridge that pivots the span from its center allowing vessels to pass on either side is called a swing bridge. All these bridges are considered draw bridges.
It is the portion of the character that lies above the midline.
No, typically the underwater portion of an iceberg is not bigger than the portion that is visible above water. Icebergs are known to have a larger portion underwater, but this is due to the difference in density between ice and seawater rather than the underwater portion being larger in size.