cable - a tension member comprised of numerous individual steel wires twisted and wrapped in such a fashion to form a rope of steel; see SUSPENSION BRIDGE

cable band -  a steel casting with clamp bolts which fixes a floor system suspender cable to the catenary cable of a suspension bridge

cable-stayed bridge - a bridge in which the superstructure is directly supported by cables, or stays, passing over or attached to towers located at the main piers

caddisfly - a winged insect closely related to the moth and butterfly whose aquatic larvae seek shelter by digging small shallow holes into submerged timber elements

caisson - a rectangular or cylindrical chamber for keeping water or soft ground from flowing into an excavation

camber - the slightly arched form or convex curvature provided in beams to compensate for dead load deflection, in general, a structure built with perfectly straight lines appears slightly sagged

cantilever - a structural member which has a free end projecting beyond its supporting wall or column; length of span overhanging the support

cantilever abutment - an abutment which resists the lateral thrust of earth pressure through the opposing cantilever action of a vertical stem and horizontal footing

cantilever bridge - a general term applying to a bridge having a superstructure utilizing cantilever design

cantilever span - a superstructure span composed of two cantilever arms, or of a suspended span supported by one or two cantilever arms

cap - the topmost piece of a pier or a pile bent  serving to distribute the loads upon the columns or piles and to hold them in their proper relative positions; see PIER CAP, PILE CAP

capstone - the topmost stone of a masonry pillar, column or other structure requiring the use of a single capping element

carbon steel - steel owing its properties principally to its carbon content; ordinary, unalloyed steel

cast-in-place - the act of placing and curing concrete within formwork to construct a concrete element in its final position

cast iron - relatively pure iron, smelted from iron ore, containing 1.8 to 4.5% free carbon and cast to shape

catch basin - a receptacle, commonly box shaped and fitted with a grilled inlet and a pipe outlet drain, designed to collect the rain water and floating debris from the roadway surface and retain the solid material so that it may be periodically removed

catchment area - see DRAINAGE AREA

catenary - the curve obtained by suspending a uniform rope or cable between two points

cathode - the negatively charged pole of a corrosion cell that accepts electrons and does not corrode

cathodic protection -  a means of preventing metal from corroding; this is done by making the metal a cathode through the use of impressed direct current and by attaching a sacrificial anode

catwalk - a narrow walkway for access to some part of a structure

cellular abutment - an abutment in which the space between wings, breast wall, approach slab, and footings is hollow.   Also known as a vaulted abutment

cement - a powder that hardens when mixed with water; an ingredient used in concrete

cement mortar - a mixture of four parts sand to one part cement with enough water to make it plastic

cement paste -  the plastic combination of cement and water that supplies the cementing action in concrete

center of gravity -  the point at which the entire mass of a body acts; the balancing point of an object 

centroid - that point about which the static moment of all the elements of area is equal to zero

chain drag - a series of short medium weight chains attached to a T-shaped handle; used as a preliminary technique for inspecting a large deck area for delamination

channel - a waterway connecting two bodies of water or containing moving water; a rolled steel member having a C-shaped cross section

channel profile - a cross-section of a channel along its centerline

check - a crack in wood occurring parallel with the grain and through the rings of annual growth

cheek wall - see KNEE WALL

chipping hammer - a welders tool for cleaning slag from steel after welding

chord - a generally horizontal member of a truss

circular arch - an arch in which the intrados surface has a constant radius

clearance -  the unobstructed vertical and horizontal space provided between two objects

clear headway - the vertical clearance beneath a bridge structure available for navigational use

clear span - the unobstructed space or distance between support elements of a bridge or bridge member

clip angle - see CONNECTION ANGLE

closed spandrel arch - a stone or reinforced concrete arch span having spandrel walls to retain the spandrel fill or to support either entirely or in part the floor system of the structure when the spandrel is not filled

coarse aggregate - aggregate which stays on a sieve of 5 mm square opening

coating - a material that provides a continuous film over a surface; a film formed by the material

 coefficient of thermal expansion - the unit strain produced in a material by a change of one degree in temperature

cofferdam - a temporary dam-like structure constructed around an excavation to exclude water; see SHEET PILE COFFERDAM

cold chisel - a fitters chisel used for cold-cutting soft metals when struck with a hammer

column - a general term applying to a vertical member resisting compressive stresses and having, in general, a considerable length in comparison with its transverse dimensions 

compaction -  the process by which a sufficient amount of energy is applied to soil to achieve a specific density

component - a general term reserved to define a bridge deck, superstructure or substructure; subcomponents e.g. floor beams are considered elements 

composite action -  the contribution of a concrete deck to the moment resisting capacity of the superstructure beams 

composite construction - a method of construction where by a concrete deck is mechanically attached to a steel floor system by shear connectors

compression - a type of stress involving pressing together; tends to shorten a member; opposite of tension 

compression failure - buckling, crushing, or collapse caused by compression stress 

compression flange - the part of a beam which is compressed; due to a bending moment 

concentrated load - a force applied over a small contact area; also known as point load 

concrete - a mixture of aggregate, water, and a binder, usually portland cement, which hardens to a stone-like mass 

concrete beam - a structural member of reinforced concrete 

concrete pile - a pile constructed of reinforced concrete either precast and driven into the ground or cast-in-place in a hole bored into the ground 

condition rating - a judgment of a bridge component condition in comparison to its original as-built condition 

conductor - a metal that is suitable for carrying electric current 

connection angle - a piece of angle serving to connect two elements of a member or two members of a structure; also known as clip angle 

consolidation - the time dependent change in volume of a soil mass under compressive load caused by pore-water slowly escaping from the pores or voids of the soil 

construction joint - a pair of adjacent surfaces in reinforced concrete where concreting was intentionally stopped and continued later 

contaminant - a salt or other element not normally present in the atmosphere which may react with the steel to produce corrosion 

continuous beam -  a general term applied to a beam which spans uninterrupted over one or more intermediate supports 

continuous bridge - a bridge designed to extend without joints over one or more interior supports

continuous spans - spans designed to extend without joints over one or more intermediate supports 

continuous truss - a truss having its chord and web members arranged to continue uninterrupted over one or more intermediate points of support 

continuous weld - a weld extending throughout the entire length of a connection 

contraction - the action of drawing together 

coping - a course of stone laid with a projection beyond the general surface of the masonry below it and forming the topmost portion of a wall; a course of stone capping the curved or V shaped extremity of a pier, providing a transition to the pier head proper, when so used it is commonly termed the "starling coping," "nose coping," the "cutwater coping" or the "pier extension coping" 

corbel - a piece constructed to project from the surface of a wall, column or other portion of a structure to serve as a support for an other member 

core - a cylindrical sample of concrete removed from a bridge component for the purpose of destructive testing 

corrosion - the general disintegration of surface metal through oxidation 

counter - a truss web member which functions only when the span is partially loaded; the dead load of the truss does not stress the counter; see WEB MEMBERS 

counterfort - a bracket-like wall projecting from a retaining wall on the side of the retained material to stabilize it against overturning; a counterfort, as opposed to a buttress, acts entirely in tension 

counterforted abutment  - an abutment which develops resistance to bending moment  in the stem by use of counterforts. This permits the breast wall to be designed as a horizontal beam or slab spanning between counterforts, rather than as a vertical cantilever slab 

counterforted wall - a retraining wall designed with projecting counterforts to provide strength and stability 

counterweight -  a weight which is used to balance the weight of a movable member; in bridge applications counterweights are used to balance a movable span so that it rotates or lifts with minimum resistance. 

couple - two forces that are equal in magnitude, opposite in direction, and parallel with respect to one another 

course - a layer of bricks or stone bedded in mortar 

cover - in reinforced concrete, the clear thickness of concrete between a reinforcing bar and the surface of the concrete; the depth of backfill over the top of  a pipe 

covered bridge - an indefinite term applied to a wooden bridge having its roadway protected by a roof and enclosing sides

cover plate - a plate used in conjunction with flange angles or other structural shapes to provide additional flange section in a beam, column, or similar member 

crack - a break without complete separation of parts; a fissure 

cracking (reflection) - visible cracks in an overlay indicating cracks in the concrete underneath 

crack initiation - the beginning of a crack usually at some submicroscopic defect 

crack propagation -  the growth of a crack due to energy supplied by repeated stress cycles 

creep - an inelastic deformation that increases with time while the stress is constant 

creosote - an oily liquid obtained by the distillation of wood tar and used as a wood preservative 

crib - a structure consisting of a foundation grillage combined with a superimposed framework providing compartments or coffers which are filled with gravel, concrete or other material satisfactory for supporting the structure to be placed thereon 

cribbing - a construction consisting of wooden, metal or reinforced concrete units so assembled as to form an open cellular-like structure for supporting a superimposed load or for resisting horizontal or overturning forces acting against it. 

cribwork - large timber cells which are submerged full of concrete to make an underwater foundation 

cross bracing - transverse bracings between two main longitudinal members;  see DIAPHRAGM, BRACING 

cross girders - girders supported by bearings which supply transverse support for longitudinal beams or girders 

cross section - the shape of an object cut transversely to its length 

cross-sectional area - the area of a cross-section 

crown -  the highest point along the internal surface of the transverse cross section of a pipe or arch; also known as soffit or vortex 

crown of roadway - the vertical dimension describing the total amount the surface is convexed or raised from gutter to centerline; this is sometimes termed the cross fall of roadway 

culvert - a drainage structure beneath an embankment 

curb - a short barrier paralleling the side limit of the roadway to guide the movement of vehicle wheels and safeguard constructions and pedestrian traffic existing outside the roadway limit from collision with vehicles and their loads