Superstructure Cross Section

Value	Description	Photo Example
Beam and Slab (Composite)	A beam-slab composite is a construction technique that combines a concrete slab with a steel beam to create a strong and stiff structure. The technique takes advantage of the strengths of both materials, with concrete being strong in compression and steel being strong in tension.
Beam and Slab (Non Composite)	The precast beams are placed on the supporting piers or abutments, usually on rubber bearings which are maintenance free. An in-situ reinforced concrete deck slab is then cast on permanent shuttering which spans between the beams.
Beam Deck	A beam deck typically involves a combination of beams and a deck that work together to support the loads from traffic and transfer them to the bridge supports.  Beams can be made of steel, concrete, or a combination of both (composite beams).
Box Girder	A girder that forms an enclosed tube with multiple walls.
Slab	Slab bridges are flat concrete beams with twisted or roughened reinforcing steel rods concentrated in the lower portion and at either end of the slab, where tensile forces and sheer are the greatest.
Truss, Deck	A bridge which carries its deck and traffic entirely on top of the truss structure.
Truss, Through	This bridge involves portal frames which increases their span capability. In doing so, the vertical clearance above the bridge's roadway sets the truss height.
Units with Slab	A superstructure cross section with a slab typically involves a combination of beams (or girders) and an embedded concrete slab.
Units without Slab	A superstructure cross section without a slab typically involves the primary load-carrying elements, such as beams or girders, and other structural components that provide stability and support.
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[Supporting Notes to further explain any exceptions or special situations or to help provide further clarity]