A bridge deck or road bed is the roadway, or the pedestrian walkway, surface of a bridge. It is not to be confused with any deck of a ship. The deck may be of concrete, wood which in turn may be covered with asphalt concrete or other pavement. The concrete deck may be an integral part of the bridge structure (T-beam or double tee structure) or it may be supported with I-beams or steel girders(floor beams). The deck may also be of wood, or open steelgrating.
Look up bridge deck in Wiktionary, the free dictionary.