Bridge components

thumb|Gateway Arch

lowest and supporting layer of a structure

structural element capable of withstanding loads by resisting bending

architectural upright support for a structure or superstructure

thumb|Truss bridge for a single-track railway, converted to pedestrian use and pipeline support. In this example the truss is a group of triangular units supporting the bridge. thumb|Typical detail of a steel truss, which is considered as a revolute joint thumb|Historical detail of a steel truss with an actual revolute joint A truss is an assembly of members such as beams, connected by nodes, that creates a rigid structure.

thumb|upright=1.35|The Battlement|crenellated parapet on a bastion of [[Kyrenia Castle, Cyprus]] A parapet is a barrier that is an upward extension of a wall at the edge of a roof, terrace, balcony, walkway or other structure. The word derives from the Italian parapetto (parare 'to cover/defend' and petto 'chest/breast'). Where extending above a roof, a parapet may simply be the portion of an exterior wall that continues above the edge line of the roof surface, or may be a continuation of a vertical feature beneath the roof such as a fire wall or party wall. Parapets were originally used to de

thumb|A schematic image of three types of cantilever. The top example has a full moment connection (like a horizontal flagpole bolted to the side of a building). The middle example is created by an extension of a simple supported beam (such as the way a Springboard|diving board is anchored and extends over the edge of a swimming pool). The bottom example is created by adding a [[Robin boundary condition to the beam element, which essentially adds an elastic spring to the end board. The top and bottom example may be considered structurally equivalent, depending on the effective stiffness of the

thumb|right|400px|A simple crane

distance between supports of an arch, bridge, etc.

thumb|The superstructure of Kurobe Dam in Japan rests on opposing concrete abutments thumb|Abutment for a large steel arch bridge thumb|Brick abutment supporting disused tramway over the Yass River in [[Yass, New South Wales]] thumb|right|Cream (colour)|Cream-colored concrete abutment gives vertical support to both the small iron rail bridge and earthen fill of the bridge approach embankment at Old Town Station Staten Island Railway - Staten Island, New York

thumb|The superstructure of this cargo ship is at the back and includes a Lifeboat (shipboard)|lifeboat. right|thumb|The cruiseferry Mega Smeralda. The blue and white part of the ship is the superstructure and the yellow part of the ship is the hull.

fence or barrier consisting of one or more horizontal rails and vertical supports

thumb|Ceiling of Hinkle Fieldhouse in [[Indianapolis, Indiana, is constructed of large trusses built of riveted girders]]

architectural element

thumb|right|320px|The trunnions are the protrusions from the side of the barrel that rest on the carriage.

part of a bridge

general term for the members installed between the superstructure and substructure of a bridge

two-dimensional transverse rigid frame (or similar structures such as three-hinged arches)

not at a right angle