Glossary
TRANSPORTATION
GLOSSARY
Abutment
An end support for a bridge superstructure. Abutments are categorized as
substructure elements, and are typically constructed of concrete, timber,
steel, or from a combination of these materials.
Aggradation
A general and progressive buildup or raising of the longitudinal profile of the
channel bed as a result of sediment deposition.
Anchor Pile
Used as an alternative to horizontal strutting to help prevent high backwall
abutments from moving inwards. Driven into firm ground and connected to
abutment piles with galvanized steel wires.
Approach Road
A Department term to describe a designated municipal road that connects the
adjacent town, village or summer village to the Provincial Highway System.
Approach Slab
A flat slab that provides a smooth transition from the approach roadway to a
bridge with one end supported on the bridge and floating on the approach fill
on the other.
Backwall
That part of the bridge abutment above the bearing seats, used primarily to
retain approach fill and to provide support for an approach slab and joint
assembly.
Backwall Scab
A vertical timber member behind the backwall sheeting, in line and connected
to the timber piles by means of a steel strap and bolts. The purpose of the
scab is to help prevent the timber abutment cap from rotating.
Backwater
The rise in water level caused by a downstream obstruction or constriction in
a channel.
Batter Pile
A pile driven at an angle inclined to the vertical to provide higher resistance to
lateral loads.
Batter Post
The end portion of a truss that carries the compression forces of the top chord
down to the bearing.
Beam
A structural member whose primary function is to transmit loads to the
support primarily through flexure and shear. A beam may be supported at the
ends and/or at intermediate locations.
Bearing
A structural device that transmits loads (from the superstructure to the
substructure) while facilitating translation and/or rotation. Typically bearings
are either of the sliding or fixed type, and are categorized as superstructure
elements. See also Neoprene.
Bearing Pile
A pile whose purpose is to carry axial load through friction or point bearing.
Frictional support is provided by the soil surrounding the pile, and end bearing
support by the underlying rock or other very firm material.
Bearing Seat
The top surface of a cap or a corbel that receives loads from the bearing.
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Glossary
TRANSPORTATION
Bent
A type of pier consisting of two or more columns or column-like components
that are connected at their top ends by a cap, strut, or other component
holding them in their correct positions.
Beveled End
The end portion of a culvert that is cut or formed to line in a plane inclined to
the vertical. The beveled end extends the invert beyond the barrel, and helps
facilitate a smooth transition between the roadway sideslopes and the natural
banks of the watercourse, etc. A beveled end also improves the hydraulic
characteristics of a culvert.
Box Culvert
A closed invert culvert having a monolithic rectangular (or trapezoidal) crosssectional shape. Box culverts are typically constructed in concrete (either
precast or cast-in-place).
Breast Wall
The portion of a bridge abutment located below the bridge seat and between
the wing walls. Essentially, a breast wall is a component of a high abutment,
and is employed to retain the lower portion of the approach fill to the bridge (a
back wall being used to retain the upper portion of the approach fill).
Bridge Approach
The section of road located within 1 kilometre of each end of a bridge or
culvert.
Bridge Approach
Railing
A roadside guardrail system preceding a bridge structure and attached to the
bridge rail system, intended to prevent a vehicle from impacting the end of the
bridge railing or parapet.
Bridge Apron
An area of protective material laid down on a streambed (or canal bed) to
control local scour around a feature requiring protection. Typically, riprap is
used to provide this protection. See also Riprap.
Bridge Culvert
A structure that is a conduit located below the roadway surface facilitating
passage of streams or other traffic through the roadway. Bridge size culverts
have an equivalent diameter of at least 1500 mm. See also Beveled End,
Concrete End Treatment, CSP, Culvert Barrel, Piping and SPCSP.
Bridge Rail
A safety feature attached to a bridge structure to help prevent errant vehicles
from going over the edge. See also Parapet.
Bridge Structure
Infrastructure grouping that includes bridges (single-span, continuous beam
single or multiple arch, suspension, frame type, bridge size culverts,
watercourse training works and overhead sign structures. See also Major
Bridge and Standard Bridge.
Camber
The difference in elevation of the midspan point and a straight line drawn
between the two ends. When used in the context of culvert construction it is
the adjustment required in the longitudinal profile of the bedding to
compensate for post-construction settlement.
A horizontal beam located below the abutment or pier bearings, and spans
between piles. The purpose of the cap is to distribute the dead and live loads
from the superstructure. The term can also be used to describe the cover
(metal or plastic) used to protect the exposed wood end grain from wetting.
Cap
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Glossary
TRANSPORTATION
Cathodic Protection
An electrical method of preventing corrosion of one steel component by the
sacrificial corrosion of a second component. Operates by electrically
connecting the two structures in the same electrolyte. For bridge applications,
cathodic protection has been used to protect the soil side of metal culverts,
and on bridges to protect the steel reinforcement in concrete decks.
Chords
Top and bottom members of trusses (typically steel angles or channels) that
run the full length of a bridge.
Clear Roadway
Total clear width of the traveled lanes. The distance between the inner faces
of the curbs, measured perpendicular to the center line of the road to the
nearest 0.1 metre. For tapered roadways, the minimum width is used. For
structures with medians, total clear width of all the lanes is used.
Collar
See Concrete End Treatment.
Concrete End
Treatment
A concrete enhancement component attached compositely around the end(s)
of large diameter metal culverts to strengthen the beveled end. Its purpose is
to improve hydraulic performance and aesthetics, and to help resist uplift
forces. A full concrete end treatment is comprised of a cutoff wall, collar, and
headwall. The cutoff wall is a transverse vertical wall located at the end of the
culvert that starts at the invert and extends below the culvert. (A cutoff wall
may also be used at the end of drop structures, spillways, etc.). The collar is a
longitudinal stiffening beam which extends along the length of the bevel. The
headwall is a transverse vertical wall located over the crown (or roof) of the
culvert.
Corbels
A beam spanning between two piles in the direction parallel to the centerline
of the bridge.
Corrosion Analysis
The review of corrosion parameters at a site that will affect the life of a
structure. Generally conducted at a culvert site to determine the estimated
life of a galvanized pipe.
Corrugated Steel
Pipe
Galvanized or aluminized sheet steel which is formed into a pipe by a rolling
process. This popular culvert material is commonly referred to as "CSP." The
current method for production favoured by fabricators is to form helical
corrugations with continuous seams either locked or welded. Pipe can also be
formed with annular seams with riveted seams, but fabricators have now
more or less dropped this practice, probably because of production costs.
Culvert
A curved or rectangular buried conduit for conveyance of water, vehicles,
utilities, or pedestrians. See also Box Culvert and Bridge Culvert.
Culvert Barrel
Curb
The section of a bridge culvert that is circumferentially enclosed.
A raised surface beside a roadway, forming a vertical or sloping face that
delineates the roadway edge and may also channel water. On bridges, the
concrete curb also acts as a safety feature by helping to redirect errant
vehicles.
Cutoff Wall
See Concrete End Treatment.
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Glossary
TRANSPORTATION
Dead Load
The load from material that is supported by the (bridge) structure and is not
subject to movement.
Debris
Material transported by the stream or abandoned bridge materials such as
piling.
Deck
A component of a bridge superstructure (with or without wearing surface) that
carries and distributes wheel loads. See also Wearing Surface.
Deck Joint
A structural discontinuity between two (bridge) components that permits
relative rotation or translation between the two, where at least one of the
components is the deck. Essentially, these joints in the roadway surface are
used to accommodate horizontal movements (or rotations) of the deck that
occur as a result of thermal variations. Standard drawings for typical joints are
available.
Deck Top
The surface on which the wearing surface is bonded. If no wearing surface
exists the deck top is in direct contact with the wheels of the vehicle.
Degradation
A general and progressive lowering of the longitudinal profile of the channel
bed (i.e. streambed of a watercourse) as a result of long-term erosion.
Depth of Scour
The depth of material removed from a streambed by scour, measured below
the original bed. See also Erosion and Scour.
Diaphragm
A transverse flexural component connecting adjacent longitudinal flexural
components.
Dowel
A relatively short length of round metal bar (sometimes referred to as a pin)
used to interconnect or attach two components in a manner to minimize (or
limit) movement and displacement.
Drift
Debris, typically trees, woody material, and other trash, which may be
transported by a flowing stream. A major flood event can result in large
accumulations of drift occurring at bridge sites on "drift-prone" streams.
Drift Pin
A steel pin used (in bridge construction) to connect wood members.
Erosion
The general and continuous removal of material from stream banks and bed
by the action of flowing water.
Fish Baffles
An obstruction located in the water flow to slow the velocities to within
acceptable limits for the successful passage of fish.
Flange
The wider horizontal sections of a bridge girder found at the top and bottom of
the web.
Flex Beam
A galvanized metal guardrail that has a "W" shaped cross-section.
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Glossary
TRANSPORTATION
Floor Beam
A transverse beam spanning between longitudinal girders, trusses or arches.
Typically this beam carries a bridge deck and/or stringers and is connected to
the main load carrying members.
Freeboard
The vertical distance between the level of the water surface normally
corresponding to the design flow and a selected reference point such as the
bottom of the superstructure, the top of the culvert crown, or the top of the
berm.
Girder
A main structural bridge component whose primary function is to resist loads
in flexure and shear. Generally, this term is used for fabricated sections.
Typically this component supports the bridge deck, floor beams and/or
stringers. See also Flange.
Grade Separation
A crossing of two highways, or a highway and a railroad, at different levels.
Guidebank
An extension of the bridge headslope or dyke (more or less parallel to a
stream) that is designed to direct the stream flow through the area of the
bridge opening. Typically the purpose of the guide bank is to help protect a
bridge abutment and/or road from erosion.
Hanger
Slender (vertical) bridge member that carries load in tension.
Hazard Marker
Warning signs at a bridge approach, used to delineate the end of the curb
and bridgerail. Yellow board with black diagonal lines sloping towards the
road.
Headwall
A transverse wall at the end of a culvert. See also Concrete End Treatment.
Height of Cover
Vertical distance between the roadway surface and the crown of a culvert.
Height of Fill
Vertical distance between the roadway surface and the centerline invert of a
culvert.
Horizontal Alignment
The configuration of a road or roadway as seen in plan, consisting of
tangents, lengths of circular curve, and lengths of spiral or transition curves.
Live Load
A load imposed by vehicles, pedestrians, equipment, wind, ice or components
that are subject to movement.
Local Scour
Scour in a channel or on a floodplain that is localized at a pier, abutment, or
other obstruction to flow.
Low Level Crossing
Bridge crossing at which it is considered acceptable for flood waters to flow
over the roadway. Use of roadway is lost for short periods of time during
these flood events.
A bridge that does not fit the standard bridge category due to the length and
height requirements for the bridge or other site conditions. Truss bridges,
steel girder bridges and longer span concrete bridges are examples. See also
Standard Bridge.
Major Bridge
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Glossary
TRANSPORTATION
Neoprene
A synthetic rubber that is used in bridge bearings and joints. It is available in
various grades to accommodate design requirements. It is a durable material,
resistant to oil, water and ultraviolet light.
Parapet
A reinforced concrete wall along the edge of a bridge deck that acts as a
bridgerail system.
Pier
A substructure element used to transfer superstructure loads from the spans
it supports to the foundation. See also Bent, Pier Cap, Pier Shaft and Pile
Bent.
Pier Cap
The top element of a bridge pier, located between the bearing and the shaft
or columns. See also Cap.
Pier Shaft
The vertical element of a bridge pier that extends from the bottom of the cap
down to the footing or foundation piling.
Pile
A relatively slender deep foundation unit, wholly or partly embedded in the
ground, that is installed by driving, drilling, auguring, jetting, or otherwise and
that derives its capacity from the surrounding soil and/or from the soil or rock
strata below its tip. See also Batter Pile and Bearing Pile.
Pile Bent
A single line of free-standing piles, suitably braced and connected to form a
pier. See also Bent.
Piping
A movement of water through the soil around a structure that may cause the
loss of fine particles. Piping around a culvert is usually the result of
inadequate clay seals and/or a blockage of the culvert causing a hydraulic
head at the upstream end. If left unchecked, piping will most likely lead to
severe structural problems with the culvert, and ultimately to its failure.
Precast Prestressed
Concrete Girders
Factory manufactured precast concrete girders strengthened with highstrength steel strand under tension. This tension force keeps concrete in a
constant state of compression. Prestressed girders are designed not to crack.
Precast Reinforced
Concrete Girders
Factory manufactured precast reinforced concrete girders (sometimes
referred to as precast girders). These girders employ reinforcing bars to
handle the tension stresses that develop when the girder is in use. It is part of
the design assumption that a certain amount of micro-cracking will occur
when the girder is in service. See also Reinforced Concrete and
Reinforcement.
Reinforced Concrete
Structural concrete containing no less than the minimum amounts of
prestressing tendons or nonprestressed reinforcement.
See also
Reinforcement.
Reinforcement
Reinforcing bars and/or prestressing steel.
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Glossary
TRANSPORTATION
Remaining Life
A subjective estimate of how long an infrastructure component (road, bridge
or appurtenance) should remain in service without including the effects of
possible rehabilitation. This estimate is based on factors such as structural
and loading conditions, horizontal and vertical alignments, traffic volumes,
age, etc.
Riprap
A hard durable material that is used to provide protection from erosion and/or
scour due to moving water. For bridge applications, material such as rock or
concrete, may be placed along streambanks, headslopes, inlet and outlet of
culverts, etc. For road applications, materials such as sandbags or small
rocks may be placed in ditches and drainage structures, etc. See also
Guidebank and Spur.
Scaling
Deterioration of the concrete surface. Under certain conditions the hardened
sand/cement paste with forms the smooth surface layer of the concrete
breaks down over time, and falls away in 'scaly patches'. Typically the depth
of the patches is not deep, but generally the coarse aggregate of the interior
is exposed.
Scour
Erosion of a streambed by the action of flowing water. Typically erosion at
bridge sites tends to be localized, and is the result of the increase in the
velocity of the water which occurs at constrictions of or obstruction in the
watercourse i.e. reduction of the waterway opening, piers, raised footings etc.
See also Erosion and Local Scour.
Shear
The force on a component (or element) which tends to deform (or fail) it by
sliding the constituent fibres (or molecules) over one another. The application
of this force results in internal stresses (shear stresses) developing. All solid
materials have an inherent strength to resist these forces. This resistance is
referred to as its shear resistance. When the shear stresses due to the
applied force are greater than the shear resistance, the material ruptures, and
shear failure is said to have occurred.
Shear Key
A preformed hollow in the side of a precast component filled with grout or a
system of match-cast depressions and protrusions in the face of segments
that is intended to provide shear continuity between components.
Sheathing
See Sheeting.
Sheeting
Timber planks (sometimes called sheathing) spiked and bolted to pier or
backwall piles and cap to form a wall. Used as an alternative to sway bracing
on piers and to retain road fill on abutment backwalls.
Shotcrete
Sprayed in place concrete – more commonly used for repairs at bridges and
culverts.
Sight Distance
From any given point, the unobstructed distance a driver can see, usually
along the roadway ahead.
Sign Structure
A permanent structure designed and constructed to support a large traffic
sign or combination of signs overhead of an existing roadway. A sign
structure is classified as a Bridge.
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Glossary
TRANSPORTATION
Siltation
Deposition of solid particles (sand, silt, small rocks, etc.) by flowing water.
Siltation occurs in areas where the velocity of water slows down (i.e. the
inside of a stream bend, an increase in stream width, behind a dam etc.).
Skew Angle
Angle between the axis of support relative to a line normal to the longitudinal
axis of the bridge (i.e. a 0º skew denotes a rectangular or square bridge).
The complement of the acute angle between two centerlines which cross.
Snooper
Vehicle equipped with a basket or platform on a hydraulic arm used by bridge
inspectors for gaining access to the underside or overhead areas of a bridge
for inspection.
Spalling
The breaking or bursting of concrete which usually occurs as a result of the
expansion forces that develop when steel reinforcing bars begin to corrode.
Spur
Projections from the stream banks, constructed from fill or timber, designed to
re-direct stream flows and/or retard bank erosion.
Standard Bridge
A bridge constructed according to AI standard drawings (plans). These
bridges are suited for non-complex site conditions and can be put together
very quickly. Timber and short span concrete bridges are examples of
standard bridges. See also Major Bridge.
Steel Plate
Corrugated Steel
Pipe
A corrugated steel culvert constructed from curved plates that are bolted
together on site to form the basic culvert structure. The plates are fabricated
from flat black plate that is corrugated and punched simultaneously, hot dip
galvanized, and finally curved to the required shape. This type of culvert is
commonly referred to as a SPCSP culvert.
Stirrup
Steel reinforcing bars that are incorporated into concrete beams or girders to
provide additional resistance to shear and/or torsion forces. Typically the bars
are bent to form a closed rectangular loop, or interlocking "U's", and are place
vertically in the web of the beam. During construction they are also used to
support the longitudinal reinforcement. In columns, this type of reinforcement
is usually referred to as a link, In this application the links are place
horizontally, and are also used to provide support to the vertical reinforcing
bars during construction.
Streambed
The surface of a natural or modified channel bed. See also Aggradation,
Degradation, Siltation, Erosion, Scour and Depth of Scour.
Stringer
A longitudinal element supporting the deck and spanning between floor
beams.
Stripdeck
Bridge deck wearing surface consisting of timber planking running parallel to
the roadway.
Structural Condition
Rating
Calculated in terms of a percentage for the last routine bridge inspection. It is
the ratio of the sum of the general ratings to the sum of the maximum
possible ratings for the superstructure and substructure only.
Strut
A bridge component that is used to resist compressive forces.
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Glossary
TRANSPORTATION
Subdeck
Usually refers to a layer of timber planks located between the timber wearing
surface (i.e. strip deck) and stringers or beams on a bridge.
Substructure
That part of a bridge, including abutments and piers, that supports the
superstructure.
Sufficiency Rating
A computerized rating generated by BIM to produce a single numerical value
(in percentage) to represent the present condition, level of service, and safety
of a bridge and its approach roads, relative to the acceptable standard of a
new bridge at the same location. Sufficiency rating is not done on sign
structures or watercourse training structures.
Superstructure
That part of a bridge that spans water, roadway, railway or other obstruction
and is supported by the substructure. Typically the superstructure is
comprised of the bearings, girders, deck, bridgerail, etc.
Vertical
A vertical bridge member that connects the top and bottom chords or a truss
at each panel point.
Vertical Alignment
The configuration of a road or roadway, as seen in longitudinal section,
generally consisting of tangents and parabolic curves. Generally referred to
as Highway Profile.
Vertical Clearance
The minimum vertical distance between the finished surface of the road and
the soffit (underside) of a bridge. Typically a sign advising this height (in
metres) is placed on the side of the bridge girder (or other suitable
component) above the location at which the minimum vertical clearance
occurs.
Watercourse
A natural or artificial channel that conveys water continuously or intermittently
through the year. A watercourse can be a river, lake, stream, creek, etc.
Watercourses impact highways relative to bridge structure requirements and
bridge structures impact watercourses relative to environmental aspects. See
also Low Level Crossing and Streambed.
Wearing Surface
Surface in direct contact with the wheels of vehicles. An overlay or sacrificial
layer of a bridge structural deck used to protect the structural deck against
wear, road salts, and environmental effects. The overlay may include
waterproofing.
Wheel Guard
Bridge safety feature. A curb constructed with timber, used to guide or
redirect an errant vehicle. The wheel guard also helps to protect the bridgerail
posts from vehicular damage.
Wingwall
A portion of a bridge abutment located on each
backwall/breastwall and used to retain the approach fill.
side
of
the
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