railing - a fence-like construction built at the outermost edge of the roadway or the sidewalk portion of a bridge to protect pedestrians and vehicles; see HANDRAIL  

rake - an angle of inclination of a surface in relation to a vertical plane; also known as batter 

ramp - an inclined traffic-way leading from one elevation to another 

range of stress - the algebraic difference between the minimum and maximum stresses in a member  

reaction - the resistance of a support against the pressure of a loaded member 

rebar - see REINFORCING BAR 

redundancy - a structural condition where there are more elements of support than are necessary for stability 

redundant member - a member in a bridge which renders it a statically indeterminate structure; the structure would be stable without the redundant member whose primary purpose is to reduce the stresses carried by the determinate structure 

reinforced concrete - concrete with steel reinforcing bars bonded within it to supply increased tensile strength and durability 

reinforced concrete pipe -  a concrete pipe designed with reinforcing bars to increase its surcharge carrying capability 

reinforcement - rods or mesh embedded in concrete to strengthen it 

reinforcing bar - a steel bar, plain or with a deformed surface, which bonds to the concrete and supplies tensile strength to the concrete

resistivity of soil - an electrical measurement in ohm-cm, that estimates the corrosion activity potential of a given soil 

retaining wall - a structure designed to restrain and hold back a mass of earth 

retractile draw bridge  - a bridge with a superstructure designed to move horizontally either longitudinally or diagonally from "closed" to "open" position, the portion acting in cantilever being counterweighted by that supported on rollers; also known as traverse draw bridge 

rib - curved structural member supporting a curved shape or panel 

rigger - an individual who erects and maintains scaffolding or other inspection access equipment 

rigid frame - a structural frame in which the members are connected together without hinges 

rigid frame bridge - a bridge with moment resistant connections between the superstructure and the substructure to produce an integral, elastic structure 

rigid frame pier - a pier with two or more columns and a horizontal beam on top constructed monolithically to act like a frame 

rip-rap - gabions, stones, blocks of concrete or other protective covering material of like nature deposited upon river and stream beds and banks, lake, tidal or other shores to prevent erosion and scour by water flow, wave or other movement 

rivet - a metal fastener used in pre-1970 construction; made with a rounded preformed head at one end and installed hot into a predrilled or punched hole; the other end was hammered into a similar shaped head thereby clamping the adjoining parts together 

riveted joint - a joint in which the assembled members are fastened by rivets

roadway - the portion of the road intended for the use of vehicular traffic 

roadway shoulder area - the area immediately adjoining the roadway, used to accommodate stopped vehicles in emergencies 

rocker bearing - a bridge support which accommodates expansion and contraction of the superstructure through a rocking action 

rocker bent - a bent hinged or otherwise articulated at one or both ends to provide the longitudinal movements resulting from temperature changes and superimposed loads 

rolled shape - forms of rolled steel having "I", "H", "Z" or other cross sectional shapes 

rolled-steel section - any hot-rolled steel section including wide flange shapes, channels, angles, etc. 

roller - a steel cylinder intended to provide longitudinal movements by rolling contact