Tablier (pont)

A deck is the surface of a bridge. A structural element of its superstructure, it may be constructed of concrete, steel, open grating, or wood. Sometimes the deck is covered by a railroad bed and track, asphalt concrete, or other form of pavement for ease of vehicle crossing. A 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. When a bridge deck is installed in a through truss, it is sometimes called a floor system. A suspended bridge deck will be suspended from the main structural elements on a suspension or arch bridge. On some bridges, such as a tied-arch or a cable-stayed, the deck is a primary structural element, carrying tension or compression to support the span. A deck bridge is one in which the deck itself is the main structural element, itself carrying the roadway. Contrast to a truss bridge which may carry a deck on the top chords or bottom chords of a structural truss. Structural engineers have several principal categories of bridge decks, for the purposes of analytic techniques. A beam deck is one where the deck and any supporting structure act together as a single beam. A grid deck uses beams and diaphragms as the supporting structure. The supporting system of a grid deck is analyzed using a grillage analysis. A slab deck is one where the deck is analyzed as a plate. If the slab has a stiffness that is different in two directions (at right angles), then the deck is known and analyzed as an orthotropic deck. A beam and slab deck is one where the beams may deflect somewhat independently, and any transverse forces are carried in the deck. A cellular deck is one where a number of thin slabs and webs will enclose cells within the deck. A boxgirder deck is one where the deck forms the top of the box girder during analysis. A railway bridge with its track and ties supported on load carrying elements of the superstructure (floor beams, stringers or girders) is called an open deck.