Abutment
Earth-retaining structures supporting the superstructure at the beginning and end of the structure.

Admixture
A material other than portland cement, aggregates, or water which is added to a concrete hatch prior to or during mixing (e.g., sand, clay, fly ash, hydrated lime).

Air Entrainment
The process of adding air to concrete in order to increase durability while causing only a small decrease in strength. Used in bridge decks to offer resistance to thermal forces.

Anchorage
A tie embedded in concrete, rock, or other fixed material (e.g., an anchor for a post tensioning tendon).

Approach
Section of roadway immediately before and after the structure.

Approach Slab
Used to describe an approach with a reinforced concrete slab. An approach slab is used to prevent settlement of the approach pavement.

Arch
A curved structure which transfers vertical loads through inclined reactions to its end supports.

As-Built Plans
Plans issued after the construction of a structure reflecting any and all field changes made to the final design plans.

Axle Load
The total load on a truck axle. For most design vehicles this is twice the wheel load.

Backwall
The principal retaining component of an abutment.

Base Metal
The existing steel material to which another member is welded using an electrode.

Batch
Total weight of cement and aggregates which produces a given amount of concrete.

Batter Pile
A pile which is inclined (e.g., 1 horizontal on 3 vertical) in order to resist large lateral loads.

Beam
A horizontal member supporting vertical loads (e.g., pier cap beam, primary member).

Bearing
Mechanical system which transmits vertical loads from the superstructure to the substructure.

Bearing Plate
A steel plate which is used to transmit loads from the superstructure to the substructure.

Bedrock
Underlying layer of rock on top of which rest various other layers of soil.

Benchmark
A point with a known elevation and coordinates from which other survey points are referenced.

Bent
A basic structural configuration consisting of a rigid frame with two vertical supports connected by a horizontal member.

Bitumen
The petroleum-based cementing component used in asphaltic binders.

Bleeding
The flow of mixing water from within recently placed concrete.

Bolster
In reinforced concrete, a support used for horizontal steel. Also known as a chair.

Boring
A soil sample taken by drilling a hole in the ground and retrieving a portion for testing.

Box Culvert
A culvert made out of a reinforced concrete box structure.

Box Girder
A superstructure design which utilizes a box-shaped trunk providing good torsional rigidity. See also Torsional Rigidity.

Brace
A structural member which is placed diagonally in order to provide stiffness to a frame.

Butt Joint
The joint between two pieces of metal in the same plane which have been bolted or welded together.

Cable Stayed Bridge
A bridge in which the deck is suspended by straight, diagonal cables.

Camber
The arching or bending of a beam upward to compensate for the dead load deflections that occur when a load (such as the bridge deck) is placed on it.

Cap Beam
The top beam in a bent which ties together the supporting columns or piles.

Cast-in-Place
Refers to concrete which is poured and cured in its final location in the field.

Causeway
An elevated roadway used to cross long expanses of water, swamps, or wetlands.

Chamfer
A notched or angled edge or corner typically formed in concrete at a 45 degree angle.

Chloride
Component in deicing agents which has adverse effects on concrete and steel bridge elements.

Chord
Longitudinal members located at either the top or bottom plane of a truss.

Clearance
Used to indicate the distance between two elements (e.g., vertical clearance is the distance between the bottom of the superstructure and the top of the underpass surface).

Cofferdam
A watertight sheeted pit used for construction of foundations at locations where the ground level is below water.

Cold Joint
Joint between old or hardened concrete and new concrete.

Composite Construction
Type of design where the bridge deck works together with primary members in resisting loads.

Compression Seal Joint
A joint assembly typically consisting of an extruded neoprene elastic seal squeezed into a joint opening.

Concentrated Load
A point load at a specific location.

Connection Plate
A steel plate which connects two elements (e.g., a connection plate which joins a diaphragm to a girder).

Construction Joint
Apoint where two concrete pours meet (e.g., the face between an abutment backwall and footing).

Continuous Span
A span with primary members extending across a pier uninterrupted.

Core
A cylindrical specimen taken from either concrete, rock, or timber elements which is used to determine the condition of the element.

Corrugated
A material (usually metal) with alternating ridges and valleys used for elements such as guard railing.

Coupon
A portion of steel taken from an element used to determine the condition of the element.

Cover
The distance between the exposed surface of a concrete element and the topmost surface of the reinforcing steel.

Cross Frame
Steel elements, comprised of crossing, steel angles, which are placed in an "X” configuration to act as diaphragms.

Cross Section
A section taken transverse to an element's centerline (e.g., a roadway cross section, deck cross section, etc.).

Crown
The high point on a road which may or may not be located on the road centerline.

Curb
A raised element used to denote the edge of pavement. Curbs can be made of concrete, granite, or other material.

Curved Girder
A girder which is curved in the horizontal plane to accommodate the overpass horizontal alignment.

Dead Man
An object buried with an anchor. See also Anchorage.

Dead Load
The aggregate weight of all permanent, nonmoving superstructure elements resting on the substructure.

Deck
The physical extension of the roadway across the obstruction to be bridged. The deck transfers vehicle loads to the supporting superstructure primary members.

Deck Joint
A gap between two spans, or the approach and a span, which allows for some rotation and/or translation.

Deflection
The vertical displacement of a member subjected to loading.

Deformed Bar
A reinforcing bar with raised rib-shaped surface deformations that enhance the bond between steel bar and concrete.

Diagonal
A member placed at an angle to provide stiffness.

Diaphragm
A non-load bearing member which is attached between stringers acting to stiffen primary members and help distribute vertical loads.

Drainage
The removal of storm water runoff from the bridge and site.

Drop Hammer
A piece of metal acting as a hammer in a pile driver.

Dowel
A reinforcing bar embedded in two concrete sections which transfers stresses and holds the sections together.

Duct
The void in a prestressed concrete girder in which the prestressing tendon is placed.

Elastomeric Pad
A pad made of a synthetic rubber which compresses under loads and is used in bearings. See also Bearing and Neoprene.

Electrode
A material which, when combined with the base metal, helps form the weld between two pieces of metal. See also Base Metal.

Elevation
A vertical distance from an arbitrary reference (datum). Also used to denote a view along the length of an element (e.g., a view of the bridge from abutment to abutment).

Embankment
A raised area of fill surrounding a structural component (e.g., abutment).

Epoxy-Coated Reinforcing
Reinforcing steel with a protective coating placed to prevent corrosion.

Falsework
A temporary support structure made of steel or wood. Typically used for formwork or erection of a structural member.

Fill
A term used to define a region where additional earth is needed to raise the elevation of a constructed project, as in cut and fill.

Flange
The top and bottom horizontal component in an "I" girder cross section or top horizontal component in a "T” girder cross section.

Flexural Rigidity
The ability of a beam to resist bending.

Flood Plain
A region of land adjacent to a water channel which is susceptible to flooding.

Floor Beam
A transverse member supporting longitudinal primary members.

Footing
The base to a column or wall which transfers loads from the substructure to the subsoil.

Form
A temporary structure which acts as a mold for a concrete element until the element has the required strength to support itself.

Formwork
An entire system of forms, supports, and related elements.

Fracture Critical
A member whose failure due to fracture could result in the failure of the entire structure.

Framing Plan
A plan view of the bridge used to show the layout, geometry, and properties of superstructure primary and secondary members.

Friction Pile
A pile which derives its principal support from shear resistance between the pile and surrounding earth.

Ganged Forms
Reusable forms which are prefabricated and assembled to make a complete unit.

Geometries
Concerning the layout, orientation, and spatial properties of an element, group of elements, or component.

Girder
Commonly used to refer to a primary member placed along the longitudinal axis of a bridge. Used interchangeably with the term stringer.

Group Loading
Combinations of loads and forces (e.g., dead load with live load, wind, stream flow pressure, etc.) that a structure must be able to withstand.

Grout
A cement-based filler material used to fill in voids, cracks, cavities, and other openings in concrete elements. Usually a thin mix of cement, water, and sometimes sand.

Grouting
The process of filling cracks and voids with grout.

Gusset Plate
A steel plate used to connect steel members to each other (e.g., as in a cross frame assembly).

Hairline Cracks
Extremely fine cracks which are formed on the surface of new concrete. Typically occurs at high temperatures which causes a rapid loss of moisture.

Haunched Girder
A member whose cross-sectional depth varies from support to support.

Heave
The upward movement of soil which can be caused by moisture, excavation, pile driving, etc.

I-Girder
A girder whose cross section resembles the letter "I".

Impact
A factor used to describe the dynamic effect of a vehicle moving across a bridge.

Jacket
A surrounding encasement of an element such as a pier column or pile which can be made of concrete, fabric, or other material.

Jacking
The lifting of an element or group of elements using hydraulic or other types of jacks and, if needed, a temporary support system.

Joint
See Cold Joint and Deck Joint.

Key
A notched or raised protrusion of concrete located on one face of a construction joint which fits into a recess on the other face.

Lateral
A member which is placed roughly perpendicular to a primary member.

Lane Loading
A hypothetical design loading used to simulate a train of trucks moving across a bridge.

Lateral Bracing
Bracing located at either the top flange or bottom flange of a stringer to prevent lateral deformation induced by forces normal to the bridge centerline (e.g., wind).

Live Load
A temporary, moving load such as vehicular traffic.

Load Rating
A value indicating the load capacity of a bridge.

Longitudinal
Used to describe the axis of a bridge which proceeds from abutment to abutment

Negative Moment
Bending moment which causes tension in the top fiber and compression in the bottom fiber of a beam.

Neoprene
A popular material for seal-type expansion joints made of polychloroprene.

Orthotropic Deck
A steel deck which is stiffened both longitudinally and transversely using open or closed ribs and floor beams, respectively.

Overlay
See Wearing Surface.

Parapet
A concrete barrier. Typically refers to a barrier placed on the outside face of the bridge deck over the fascia girder.

Pier
Structures which support the superstructure at intermediate points between end supports (abutments).

Pier Cap
See Cap Beam.

Pile
A member with a small cross-sectional area (in comparison to its length) used to provide adequate support for a column or wall resting on soil which is too weak or compressible to support the structure using a spread footer.

Plan
Used to denote a view of an element, component, or the site from a viewpoint directly above the object looking down.

Plan and Profile
A drawing which presents both the roadway plan view along with its profile on the same sheet and at equal horizontal scales. See also Profile.

Plate Girder
A girder with an "I" cross section composed of steel plate elements which are connected together by welds, bolts, or rivets.

Positive Moment
A bending moment which induces compression in the top fiber of a beam and tension in the bottom fiber.

Posttensioned Girder
A prestressed concrete girder where the prestressing force is applied to the reinforcing tendons after the concrete has cured.

Precast
A concrete element which has been formed and cured prior to placement in the field.

Preliminary Design
An initial design which outlines the major scope of work to be done in a project.

Prestressed Girder
A concrete girder which utilizes steel tendons that have a tensile force placed on them, thereby increasing internal compression and reducing or eliminating stresses due to tension once the beam is loaded.

Pretensioned Girder
A prestressed concrete girder where the prestressing force is applied to the reinforcing tendons before the concrete has been poured.

Primary Member
A load-bearing member which distributes loads longitudinally and is principally designed to resist flexure.

Profile
A graphical depiction of the vertical alignment of a roadway.

Railing
Traffic barrier system made of longitudinal rails attached to vertical posts. Also known as guard railing and guide railing.

Rebar
Shortened name for reinforcing steel.

Redundancy
The presence of multiple load paths so that, if a structural member fails, another element or group of elements can sustain the load. See also Fracture Critical.

Reinforced Earth
The registered trademark name for a type of earth retaining structure that utilizes galvanized steel strips placed in granular backfill and connected to interlocking concrete facing units.

Residual Camber
Camber which results from a prestressing force minus a girder's dead load deflection. See also Camber.

Residual Stress
Stress locked into a member after it has been formed to its final shape.

Resurfacing
The overlay of wearing surface material on top of an existing approach and/or deck overlay to create a more uniform and smooth riding surface.

Rib
A longitudinal stiffener used in orthotropic decks.

Rip Rap
Broken rock placed around piers and abutments to prevent erosion and scour.

Rivet
A cylindrical metal fastener which is used to connect multiple pieces of metal.

Rolled Beam
A steel girder which is formed by hot-rolling.

Screed
A long section of metal or wood which is dragged across freshly placed concrete to both smooth the surface and consolidate the concrete.

Seal
A closure material. Typically used in reference to deck joints and made out of neoprene. Used in strip seal and compression seal assemblies.

Secondary Member
Bracing between primary members designed to resist cross-sectional deformation of the superstructure frame and help distribute part of the vertical load between stringers.

Section
Used to denote a view of an element taken in section (i.e., a slice of an element or component at a given location).

Seismic
Relating to earthquakes as in seismic forces.

Settlement
The movement of foundations or footings due to deformations and/or changes in soil properties.

Shear Connector
Devices used in composite construction which extend from the top flange of a girder and are embedded in the concrete slab, allowing the slab and girder to act as a unit.

Shear Stud
A common form of shear connector which is bolt-shaped and attached to the top flange of a girder with an automatic welding stud gun.

Shim
A thin metal plate placed under bearing assemblies usually to adjust bridge seat elevation discrepancies.

Shore
An inclined supporting member for fomwork and the enclosed concrete. See also Form.

Shoulder
The section of roadway on either side of the travel lane.

Shrinkage
The natural (i.e., not load-related) change in volume of concrete. This change in volume is typically decreasing (shrinking) and caused by moisture loss when drying.

Simple Span
A span in which primary members begin and end at supports. See also Continuous Span.

Site
The bridge and area surrounding the structure which either affects the bridge or is affected by the bridge.

Skew
The angle between a line projected orthogonally or radially from the overpass alignment and the centerline of bearings.

Slipform
Forms which are moved in a regulated fashion along a concrete element. The form is moved as the section it leaves has reached sufficient strength.

Slump
A measurement used to define the workability of concrete which is taken by determining the loss in height of wet concrete after a coneshaped mold is removed. The smaller the slump, the stiffer the mix.

Sole Plate
The top steel plate of a bearing which is attached to the bottom flange of a stringer.

Spalling
The breaking away of surface concrete from an element.

Splice
The joining of two elements through a connection device (e.g., two steel girders joined by a plate bolted to each).

Spread Footing
A footing which supports a single column.

Staged Construction
Construction that occurs in phases, usually to permit the flow of traffic through a construction site.

Stay-in-Place Forms
Forms, usually present at the underside of a deck slab, which remain in place after the deck has cured. Also known as permanent forms.

Stiffener
Aplate welded to a steel beam web to enhance section properties of the beam. Intermediate stiffeners are welded vertically and longitudinal stiffeners along the length of the beam.

Stirrup
A U-shaped reinforcing bar used to resist diagonal tension.

Strand
A twisted group of wires.

Strengthening
A method employed to enhance the capacity of a structural member (e.g., posttensioning truss members).

Stringer
See Girder.

Strut
The transverse (i.e., non diagonal) member in a lateral bracing system (also known as lateral struts).

Substructure
Structural components and all constituent elements designed to support the superstructure and overpass roadway.

Superelevation
A banking of the roadway cross section.

Superimposed Dead Load
Permanent loads that are placed on a structure after the concrete has hardened (e.g., bridge railing, sidewalks, etc.)

Superstructure
Structural components and all constituent elements of a bridge above the supports.

Suspension Bridge
A bridge in which the roadway is suspended from two or more cables hanging from tower structures.

T-Girder
A girder whose cross section resembles the letter "T".

Tendon
A steel strand stretching along the length of an element used in concrete prestressing.

Tip
The bottom end of a pile.

Torsional Rigidity
The ability of a beam to resist torsion (i.e., twisting about the longitudinal axis).

Transverse
Used to describe the axis of a bridge which lies perpendicular or radial to the centerline of the structure.

Tremie
A pipe or funnel, used for placing concrete in water whose top and bottom are open, allowing for concrete to be poured into it.

Trestle
Usually used in reference to timber structures consisting of a set of stringers resting on a pile or frame bent.

Truck Loading
A hypothetical design loading used to simulate a single truck on a bridge.

Truss
A set of members arranged vertically in a triangular fashion to form an integrated load-bearing unit.

Uniform Load
A load distributed uniformly over the length of an element.

Uplift
A combination of loads which causes the superstructure to lift up off the substructure.

Vertical
Used to describe the axis of a bridge which proceeds upward, perpendicular to the underpass surface.

Vertical Clearance
The minimum distance between the structure and the underpass.

Voided Slab
A bridge which uses a concrete slab with voids introduced to decrease the overall weight of the superstructure.

Water Cement Ratio
The ratio between water and cement which controls the strength of concrete.

Waterproofing Membrane
A protective sheet placed between a wearing surface and concrete deck to shield the concrete deck from water and corrosive chemicals which could cause delamination and spalling.

Wearing Surface
A layer of asphalt or concrete based material placed on top of the bridge deck to protect the deck and substructure from traffic and chemicals and provide for a smooth riding surface.

Web
The vertical component in an “I” or “T” girder cross section.

Weep Hole
A hole in a concrete element (e.g., abutment backwall) used to drain the element.

Weep Tube
A tube made of PVC or other material which is embedded in a concrete element (e.g., deck, abutment) and extends past the surface to drain the element.

Wheel Load
The load due to one wheel in a design vehicle. Two wheel loads typically comprise a single axle load.

Wingwall
A side wall to an abutment backwall designed to assist in the confining of earth behind the abutment.

Yield Point
The stress at which a material begins to yield.