The sign for "bridge" (as in a "raised pathway") uses the non-dominant arm to represent the driving or walking surface of the bridge and the dominant arm to represent the underlying supports of the bridge. The non-dominant hand is (more or less) horizontal. The non-dominant handshape is not overly important. I use a flat hand for my non-dominant handshape but you can use a fist and it still means "bridge."
BRIDGE:
Notes: