Bridge Terminology: A to Z Glossary for Engineers
January 3, 2023
Bridge terminology can seem bewildering to anyone new to the sector. Like most industries, bridge construction and maintenance can be complex and highly technical – so there are plenty of terms and phrases to familiarize yourself with.
That’s why we’ve put together a glossary of bridge terms in a handy A to Z format. So if you plan to work on bridge construction and maintenance projects in the near future, browse through the listings below, or bookmark this webpage for when you hear a term you don’t understand.
Bridge Terminology Glossary
The elements at the ends of a bridge to provide support.
Accelerated bridge construction (ABC)
A quicker and smarter way to build and install bridges by minimizing the disruption caused by road and waterway closures. Find out more about ABC
Air Working Chamber
A chamber in a caisson into which compressed air is forced to expel the water so that laborers can work at excavating.
Allowable Bearing Pressure
The maximum intensity of pressure on a support allowed by the specifications.
The end part of a cantilever bridge extending from a main pier to an anchor pier.
Used in cantilever bridges to resist the uplift at the end of the anchor arm.
A pile used for attaching anchorage lines.
In a bridge including multiple cantilevers it is the span that separates two cantilever arms of other spans.
The span or spans connecting the abutment with the main span or spans.
Protects the river bank or river bed against scour.
A bridge with curved arches to produce reactions inclined to the vertical.
A rope or cable extending backward from the head of a mast and fastened to some permanent object. E.g. as in a suspension bridge.
A hydraulic machine to cut metallic bars such as rebar into shorter lengths. More about Bar Cutters
A flat-bottomed boat having the capacity to heavy loads when erecting spans by flotation.
A bridge with a span that opens by rotating vertically.
A pontoon bridge, floating and supported by boats or barges.
Batter Pile or Battered Pile
A pile driven at an angle.
A tapered pier with slightly angled sides. Larger at the base than at the top.
A span built with beams.
Above: a beam bridge
The shoes supporting a span. Case study
Any pile carrying a vertical load.
Solid rock beneath sand or silt.
Supporting frame including posts or piles with bracing, caps, and sills.
The lower member of a truss.
A truss in which the lower chord is horizontal and the upper chord joints lie in the arc.
A retaining wall built to sustain a lateral pressure, e.g. earth thrust
The part at the top of a bridge pier or abutment that receives the pedestals or shoes of the superstructure.
A heavy twisted wire rope suspending sections of a suspension bridge.
Uses deck cables connected to one or more vertical towers, or pylons in either a fan or harp configuration
A watertight box or casing used in founding and building structures in water too deep for cofferdams.
A positive, upward curve (deformation) built into a beam due to prestressing.
A structure with at least one portion of which acts as an anchorage for sustaining another portion projecting beyond the supporting pier.
Poured site to create a structural element in its final position.
The curve of a rope or chain hanging freely between two towers.
A suspension bridge using chains instead of cables.
The bridge span over the deepest part of a river most accessible for river traffic.
An enclosure built within a body of water to allow the enclosed area to be pumped out.
A bridge constructed of timbers and steel or iron.
A steel beam with concrete decking above.
National Bridge Inspection Standards (NBIS), condition ratings to describe condition compared to if it were new.
Continuous Beam A beam resting on three or more supports.
A truss extending over three or more supports.
Controlled Lifting Pump
A hydraulic pump used for synchronous lifting with hydraulic cylinders
A small shelf cantilevered out from a beam, wall, or column in order to support a beam or a other load. Sometimes called a tassel or bragger.
A counterweight used on lift bridges, draw bridges, or bascule bridges to stabilizes and provide balance for the bridge lift system.
A truss with both chords curved upward, or both downward making sharp intersections with each other at the ends. The outline resembles a crescent,
Timbers piled cross-wise to form a support for a load.
A drain, pipe or channel for water to pass under a road, railroad or embankment.
Also known as a starling. The projecting ends of a bridge pier. Shaped as to allow water, ice, or other items to strike without damaging the structure.
A pier made of a cylindrical steel shell filled with concrete.
A bridge in which the passing loads are carried directly to the upper portions of the posts.
A bypass to divert water around a structure to allow construction to take place.
A partition wall that carries no load.
A bridge that may be turned to one side, or lifted up, either wholly or in sections, to let boats pass under it.
A pier with two cylindrical piers connected by a solid web.
The lateral pressure exerted by a bank of earth when supported by a retaining wall or an abutment.
Elastomeric Bridge Bearing
A bearing type commonly used on modern bridges. Designed to compress under a vertical load, while allowing for horizontal rotation and lateral shear movement.
Emerson's Foundation Pump
A pump adapted for pumping water out cofferdams to allow work to take place.
A formula expressing the resistance of long columns to buckling.
A support at the end of a span to allow expansion and contraction of the bridge.
A group of steel cylinders in a box or suitable frame beneath the shoe of a bridge span to allow for movement during temperature changes and loading.
The scaffold or temporary supports used when erecting a structure..
A pile used at wharfs, or in front important structures to protect them from sudden blows by vessels.
A pier sunk to a great depth in a soft, or semi-fluid soil relying on the principle of flotation for stability.
A support system for freshly poured concrete - including the mold and all supporting bracing/ components.
An excavation in which a foundation is placed.
Baskets of galvanized steel wire holding rocks together to reduce erosion of embankments.
A corrugated reinforced concrete pile.
A bridge constructed from lattice girders.
A structural steel column composed of eight angle-irons riveted together in pairs.
A metal plate used to connect the structural members of a truss.
The enlarged part of a beam near its supported ends.
The wall at the head or main part of an abutment.
A slang expression used by bridge workers for almost any item for example when it lacks a specific name. e.g. thingumbob, thingamajig.
A formula to calculate wind-pressure on surfaces facing the wind.
Used to lift and position heavy loads from above in here traditional cranes will not fit. See more
A device for lifting heavy weights or exerting great force by means of liquid pressure.
Used in groups to lift heavy loads such as bridge decks for bearing maintenance. Also known informally as a ram or jack.
Used to supply hydraulic flow (oil) to activate hydraulic lifting equipment.
A rolled structural shape with a cross-section shaped like the letter "I."
The point where an arch rests on a wall or column, or the upper part of a pier from which an arch springs.
Jack Up System
A multi-point lifting system, typically includes four jack-up units positioned under each corner of a load.
A low, reinforced concrete wall wider at the base, tapering vertically to near mid-height, then continuing straight up to its top.
A crane having a swinging boom.
The main pile in a group of piles.
A truss having several web systems
A beam placed as a guide for other beams.
A bridge resting on legs instead of masonry abutments.
A type of movable bridge that travels in a vertical plane. Also known as a hoist bridge.
The greatest load a structure is allowed to carry as stated in the specifications. A safety load.
A perforated metal sheet for reinforcing concrete.
A form of reinforced concrete using wire netting.
A cofferdam constructed of timber, hinged at one corner and joined on the diagonal corner so it can be opened after the pier is built and moved away to another pier site.
Nest (of rollers)
A group of rollers, arranged in a frame or box to support a bridge shoe.
The end of a pier. See also "Starling." The projecting end of a bridge-pier, shaped to allow ice, drift, etc., to strike it without injury.
An arch in which the axis is not perpendicular to the central plane of the structure.
A process of sinking piers by excavating with a dredge through an open crib.
A beam or joist projecting from a structure. Used to support a load at its end.
A bow-string truss with the upper chord joints in a parabola.
Parapet or Parapet Wall
A low wall or barrier placed on top of an abutment to stop the earth from encroaching on the end of the span.
Prefabricated Bridge Elements and Systems
A footing for a tower post. A bridge shoe.
A steel or iron casting upon which the bridge-shoe rests. Also a stone block to support a column.
A block of stone or concrete placed on top of a footing to carry a loaded column.
A pile formed by driving a steel shell into the ground, putting in small quantities of concrete, and hammering down to force the concrete into the earth beyond the point of the shell, therefore increasing the bearing area.
A strut connecting and bracing two pedestals.
Same as "Dead Load." The weight of all the parts of a bridge.
A vertical support structure used to hold up a bridge. Typically made of wood, concrete, or steel.
Also called ‘bent’. Typically bents with one column are called piers. Used to transmit the loads from a bridge superstructure to the foundation.
A machine for sinking or driving piles.
A foundation formed in soft soil by driving a group of piles to a depth to give the required bearing capacity to carry the load.
The pier supporting a bridge’s swing span upon which it turns.
Application of tensile forces to the steel tendons after the segments are in place. These forces allow the span to carry the desired loads.
A girder fabricated off-site from cement that uses reinforced steel and post-tensioning cables.
A type of pre-cast concrete girder in which compressive stresses are introduced in a fabrication facility. These allow the member to carry larger loads than conventional reinforcement.
The main truss that supports smaller trusses.
A vertical structure marking the entrance to a bridge.
A load that is not in motion.
The hammer of a pile driver. Also another name for a hydraulic cylinder.
Platforms built on the side of a trestle or bridge so that personnel can get out of the way of approaching trains.
Concrete in which steel bars are inserted to strengthen it.
'Rebar' - A bar or rod placed in concrete constructions to increase their resistance, especially to bending and shear.
The process of covering an embankment with stones.
An extra and external portion of a body giving it additional strength and stiffness
A bridge support that accommodates expansion and contraction of the superstructure through a rocking action.
A single roller or a group of rollers to allow longitudinal movement/expansion of a structure.
An iron or steel box holding rollers for a bridge shoe.
A portion projecting beyond the general line of the structure.
A temporary bearing made with confined sand for lowering the object that is temporarily supported. The sand is released to lower the load.
Generally refers to sub-diagonals and suspenders of trusses
A way to erect a span without falsework by cantilevering from adjacent spans
A wheel with a grooved face for carrying a rope or cable.
A form of piling used to shut out water. Made of planks spiked or bolted together in a tongued and grooved effect.
A temporary bridge taking the place of the main bridge while construction is completed on the main bridge.
The pin in a shoe which receives the load from a span or a column.
A ton of two thousand pounds. (in the US). 907.19 kg
A beam with its ends free and resting on two supports.
A bridge where the spans are not perpendicular to the piers, abutments, road, or river beneath.
A system using hydraulic push-pull cylinders, traveling over a pre-constructed track.
The most common type of bridge. Used in where the span does not need to be long.
The distance between two supports holding up a structure.
The roughly triangular piece formed by an arch.
Self-Propelled Modular Transporter used to move sections of a bridge into position
A ‘cutwater’, the projecting end of a bridge-pier, shaped to allow ice, drift, etc to strike it without damage to the structure.
One of the larger vertical posts supporting a railing.
Same as "Dead Load." The weight of all the parts of a bridge.
Stiffened Suspension Bridge
A suspension bridge with stiffening trusses.
Lifting equipment that includes a bundle of steel cables guided through a hydraulic cylinder.
Consists of all of the parts that support the superstructure such as the abutments, piers, footings, and piling.
The portion of a bridge above the piers, pedestals, and abutments. The part of a structure which receives the live load directly.
A roadway suspended from chain or wire cables. Usually hung between huge towers and securely attached to abutments.
Tension members of a suspension bridge hanging from the main cable to support the deck.
Synchronous Hoist System
A below-the-hook sling adjuster used with cranes for accurate positioning.
A reinforced concrete beam or a rolled structural shape with a cross-section like a letter "T."
Steel strands used for post-tensioning.
The state or condition of a component being stretched.
A pile in place loaded with a known weight for testing the bearing capacity of the soil.
A 'bowstring bridge' using features seen in both a suspension bridge and an arched bridge.
The upper member of a truss, usually resisting compression.
The moment of a force or a system of forces tending to produce rotation.
A bridge composed of bents or towers carrying the deck. Can be either timber or metal.
A very strong type of bridge constructed with metal girders.
Tubular Arch Bridge
A bridge in which the primary supporting members are arched tubes.
A straight abutment with additions of two wing walls at right angles to the face.
A crossing where one of the roads or tracks is below the other.
The unwanted tendency of a structure to rise from its supports due to special loading conditions
Stress due to an uplift action, as that from the end lifting machinery in a swing span.
Vertical Lift Bridge
A bridge having a span that hoists vertically.
An extended bridge of many spans, mainly over dry ground.
The highest point, crown, or apex.
The destruction or displacement of a bridge or embankment due to floods.
A cement that sets or hardens under water.
Ways, or Launching Ways
Supports or tracks set on a slope, down which a caisson slides at the time of launching.
The top layer of material on a roadway
Bracing, taking up the stresses caused by the wind.
An abutment similar to a U-abutment except that the two wings make angles with the face of from thirty to forty-five degrees.
One of the side walls of an abutment extending outward from the head wall to hold back the slope of an embankment.
The excavation for a foundation.
Any system of bracing in which the diagonals intersect.
The point, or intensity of stress, at which the rate of stretch begins to increase rapidly.