University of Iowa Libraries       Lichtenberger Engineering Library

Glossary of Bridge Terminology



Wagon Bridge: Same as "Highway Bridge."

Wagon-way: That portion of a floor set aside for wagon traffic.

Wakefield Piling: Same as "Sheet Piling." -- A form of piling used to shut out water, generally made of several planks spiked or bolted together, and arranged to secure a tongued and grooved effect when driven close together. Steel shapes are also employed for this purpose.

Wale: A flat piece of timber laid horizontally for bracing upright timbers and for guiding them during driving, as in sheet piling.

Wale-piece: Same as "Wale."

Waling Strip: Same as "Wale."

Walking Crane: Same as "Locomotive Crane." -- A locomotive, or steam engine on wheels, with a crane attached. Used in yard work.

Wall: A structure or slab of small thickness, built in a vertical or nearly vertical plane.

Wall Plate: A steel plate laid on a masonry or a concrete wall to carry the end of a beam and to distribute its load.

Wallower: Same as "Trundle = Lantern Wheel." -- A gear wheel composed of two parallel discs set some distance apart on an axle with round rods parallel to the axle, set at equal intervals around the periphery of the discs. These rods mesh with the teeth of another gear.

Wane: A beveled edge of a board or plank as sawn from an unsquared log.

Wane Tie: A square tie showing part of the original surface of the tree on one or more corners.

Warp: A twist. To twist.

Warren Girder: A latticed triangular girder in which all the triangles are equilateral. Nowadays any triangular girder is spoken of as a Warren Girder.

Warren Truss: A form of triangular truss composed of equilateral triangles. See Fig. 22k.

Fig. 22k

Wash Boring: A boring made by a churn drill by means of which samples of the material penetrated, in granular form, are washed to the surface by a flow of water.

Wash Mill: An apparatus for washing sand, gravel, rock, etc.

Washer: A flat disc or plate, having a central hole, placed under the head or the nut at the end of a bolt, in order to distribute the pressure over the wood or other soft material.

Washout: The destruction or displacement of a bridge, trestle, or embankment due to floods.

Waste: Cotton used for wiping grease from machinery. Excess material from an excavation. To fail to utilize, in an embankment, material taken from a cut.

Water: A colorless liquid chemically defined as H20. The run-off from a drainage basin as carried by the rivers and streams.

Water Cement: Same as "Hydraulic Cement." -- A cement which sets or hardens under water.

Water Column: The water which rises in a vertical tube when the lower end is immersed in a current.

Water Crack: A crack in steel due to the process of quenching it while red hot.

Water Crane: A crane operated by means of hydraulic pressure.

Water Current: A flow of water.

Water Cylinder: The cylinder in a pump by means of which and the moving piston therein water is forced into an exterior main.

Water-hammer: The shock resulting from the sudden stopping of the flow of water in a pipe.

Water Hemp: Same as "Virginia Hemp." -- An inferior species of hemp grown along the rivers in the Eastern United States.

Water Hose: A hose conveying water.

Water Jet: A flow of water, at high velocity, from an orifice or nozzle.

Water Joint: A joint between parts precluding the passage of water.

Water Level: The elevation at which water stands.

Water Line: The intersection of the free surface of a body of water with any plane or object.

Water-mark: A mark or stain left on a bank, tree, or other object by a stream receding from high water.

Water Meter: An apparatus for measuring the quantity of water flowing in a pipe.

Water-power: Power developed from moving water; also applied to any plant used for generating power from moving water.

Water Pressure: The pressure exerted by a column of water when confined.

Water-proof Paint: Any paint not soluble in water.

Water-table: A belt course of masonry, moulding, or other projecting member with a sloping top, so placed as to throw off water from a wall.

Water Tempering: A process of heating hardened steel to draw the temper (lower the degree of hardness) and quenching in water when the desired condition (as indicated by the color) is attained.

Watershed: The line of separation between contiguous drainage areas. The divide. The height-of-land. Often, but incorrectly, used for drainage-area.

Watertight: Closed up to such an extent as to prevent the passage of water.

Waterway: An opening or passage for water. A channel or stream of water as a means of communication. Space available for navigation.

Wattle: To apply wattling to a pile dyke.

Wattling: A screen used in river protection work, composed of long, slender poles, usually willow, passed horizontally and alternately behind and in front of a series of piles forming the dyke.

Ways, or Launching Ways: Supports or tracks set on a slope, down which a caisson slides at the time of launching. Used also for the apparatus by which cars are unloaded on a hill-side.

Weak Iron: White, brittle pig-iron.

Wearing Floor: A floor exposed to the traffic. Usually refers to the upper layer of a double plank floor.

Weather Joint: A masonry joint where the mortar forms an outward sloping surface from the bottom of the upper course to the top of the lower course.

Weathering: The process of seasoning by exposure to the elements.

Web: The portion of a truss or girder between and connecting the flanges, its function being principally to resist shear.

Web Members: The parts or sections forming the web of a truss.

Web Plate: The plate forming the web of a girder.

Web Splice: A splice joining two web plates.

Web Stiffener: An angle riveted to the web of a beam to distribute a load or to prevent buckling.

Web Stress: Any stress in a web member of a truss.

Webbing: The members or parts making up the web.

Wedge: A solid having two inclined faces.

Wedge Bearing Draw: A swing span in which the live load, or a portion thereof, is carried by wedges under the chords of the trusses.

Weep-hole: A hole in a wall for draining the water that tends to accumulate at the back.

Weeping Pipe: A pipe embedded in the masonry to carry off quickly the water from the top or back of a pier or abutment. A pipe inserted in a wall or in any construction for the purpose of drawing off water that otherwise would accumulate.

Weir: A dam which discharges water over its top or crest.

Weld: To unit two pieces of metal by heating the ends until they become soft and then hammering them together. The part of the piece thus united.

Weld Iron: A term suggested for wrought iron, but seldom used.

Weld Steel: Steel capable of being welded.

Welded Heads: Heads first worked into the desired shape and then welded on the bars.

Welded Joint: The union of metallic pieces by welding.

Welding: The act or process of making a weld.

Welding Hammer: A hammer used in welding metals.

Well: A vertical opening or shaft in a crib or caisson for removing materials or for the passage of workmen.

Welt: Same as "Butt Joint." -- A joint in which the ends of the pieces are square and press against each other.

Wet Blow-out: A process of blowing material from the working chamber of a caisson by wetting it, and placing it at the mouth of the discharge pipe. [See also "Wet Suction."]

Wet Dock: A dock where vessels are placed to load and unload.

Wet Process: A method in the manufacture of cement in which the ingredients are mixed together with an ample amount of water, then dried, burned into clinkers, and ground.

Wet Puddling: The present process of puddling, in which the furnace is first charged with fluxing cinder or "hammer slag" (oxide of iron) and then with gray iron. Afterward the charge is heated so that the iron and the flux form a pasty mass, which is then stirred with puddling bars.

Wet Rot: A decay affecting timber, caused by alternate wetting and drying.

Wet Suction: A process of discharging material from the working chamber of a caisson by wetting it and placing it at the mouth of a discharge pipe through which it is blown by the pressure of the air.

Weyrauch's Formula: A formula proposed by Weyrauch to determine the allowable unit stress when the member is subjected to a reversal of stress. It is no longer used in good American bridge engineering practice.

Wharf: A structure or a level place along the bank of a waterway, upon which vessels lying alongside can discharge their cargoes.

Whatman's Paper: A trade name for a well-known brand of drawing paper manufactured by the Whatman Turkey Mills.

Wheel: A circular framework or a solid disc capable of revolving about its centre.

Wheel Base: The space occupied by a group of wheels sustaining a load.

Wheel Carriage: The frame or box holding the bearing wheels of a draw-span.

Wheel Chain: A chain constructed so as to run over a chain wheel.

Wheel Concentration: The amount of load carried and delivered by one wheel.

Wheel Flange: The lip or projection on the face of a wheel acting as a guide or restraint.

Wheel Frame: A framework supporting a wheel or wheels.

Wheel Friction: Same as "Rolling Friction." -- The resistance offered by a surface to another surface rolling over it.

Wheel Guard: A timber or iron placed on the side of the roadway of a bridge to prevent the wheel hubs from striking the truss or the hand railing.

Wheel Loads: Loads on the different wheels of a locomotive. Also a system of wheel loadings.

Wheel Tread: See "Tread."

Wheel Wrench: A wrench having a wheel-shaped handle.

Wheelbarrow: A small hand vehicle for transporting materials, consisting of a bed or box resting on two handles, supported by a wheel at one end and the operator's hands at the other.

Whetstone: A stone for sharpening tools by rubbing.

Whin: An early form of windlass for hoisting.

Whipple Truss: A double intersection Pratt truss. See Fig. 22z.

Fig. 22z

Whiskey Jack: A hydraulic jack in which spirits are used instead of water.

White Lead: A mixture of the carbonate and the hydrated oxides of lead. Used as pigment for paint.

White Lime: A solution or preparation of lime used for white-washing.

White Metal: An alloy similar to Babbitt metal, but containing more antimony and copper.

White Pine: A variety of pine tree of small size and soft wood. It has a short needle-like leaf.

White Wash: Same as "White Lime.'

Wick Packing: Any packing put up in the form of wicks.

Wide Cross-cut Saw: A cross-cut saw with a long, wide blade having a handle on each end so that it can be operated by two men.

Wild Steel: Steel that spits and flies in the ladle, usually caused by overoxidization of the metal.

Williot Diagram: A graphical method for determining the deflections of a framed structure. See Chapter XII.

Winch: Same as "Windlass."

Wind Bracing: Bracing which takes up the stresses induced by the wind.

Wind Load: A load on a structure due to the pressure of the wind.

Wind Pressure: The pressure on a surface produced by the wind blowing against it.

Wind Shake: A crack or fissure in a piece of timber occurring during its growth.

Wind Stress: A stress caused by the application of a wind load to the structure.

Wind Truss: A truss to carry a wind load.

Winding Drum: Same as first meaning of "Drum." -- A revolving cylinder around which ropes or belts either travel or are wound.

Windlass: A hoisting machine consisting of an axle mounted in a frame, and turned by a crank, a wheel, or radial bars at the end, and which winds up a rope causing a load to be raised.

Windlass Jack: A jack having on the nut which surrounds its screw a crown wheel operated by a pinion and a crank.

Windward: The direction from which the wind comes.

Windward Chord: The chord of a span on the windward side (the side from which the wind comes).

Windward Truss: The truss next to the wind.

Wing Abutment: An abutment similar to a U-abutment except that the two wings make angles with the face of from thirty to forty-five degrees.

Wing Nut: Same as "Thumb Nut." -- A nut having a flat projection, or wings, so that it can be turned by the thumb and finger.

Wing Wall: One of the side walls of an abutment extending outward from the head wall in order to hold back the slope of an embankment.

Wiper: Same as "Cam." -- An eccentric; a piece fixed upon a revolving shaft in such a manner as to produce a reciprocating motion in a member making contact with it.

Wire Bridge: Same as "Suspension Bridge."

Wire Cable: A cable of heavy wire, or of numerous small wires twisted together.

Wire Cloth: Wire net having a small mesh.

Wire Gauge: A tool for measuring the diameters of wires or the thicknesses of sheet metals, also the system of sizes and numbers for wires and metal sheets.

Wire Iron: A ductile iron from which wires are manufactured.

Wire Joint: A joint between two wires made by twisting their ends together.

Wire Nail: A nail made from wire.

Wire Rope: A rope made of small strands of twisted wire often with a cotton or hemp centre.

Wohler's Laws: A series of laws based on Wohler's experiments on the fatigue of metal. It is now conceded that they do not in any way apply to bridge designing, because they deal solely with metal stressed beyond the elastic limit and are not applicable otherwise.

Wood: The hard, fibrous substance which composes the body of a tree.

Wood Boring Machine: An apparatus, generally run by air, for boring holes in timbers.

Wood Screw: A screw having a tapering shank and either a flat or a rounded head with a slot for turning by means of a screwdriver.

Work: The overcoming of resistance through space as measured by the product of the force and the distance, in its own direction, over which it acts. Also used as a general term for any engineering construction or the operations connected with such construction.

Work Done in Overcoming Friction: The work done by a force in moving against a frictional resistance. Loosely termed "Work of Friction."

Work of Friction: Used loosely for "Work Done in Overcoming Friction."

Work of Resilience: The work done by a deformed elastic body in recovering its normal condition. Theoretically, this is equal to the energy stored in the body during its deformation, providing that the elastic limit of the material has not been passed.

Working Chamber: Same as "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.

Working Drawing: Any drawing showing all the parts and dimensions with other information pertinent to construction, so that whatever is shown can be built without other drawings or instructions.

Working Load: A safe load established by the specifications.

Working Pit: The excavation made for a foundation.

Working Shaft: A passageway in a crib and caisson for workmen.

Working Stress: The allowable stress on any piece as provided in the specifications. Carelessly used for "Working Unit Stress."

Working Unit Stress: The allowable unit stress or intensity on any piece as provided in the specifications.

Workmanlike: In the manner of a skilled workman.

Workmanship: The art or skill of a workman, or the quality of the execution of the work.

Worm: An endless screw on a shaft which meshes into the worm gear.

Worm Gear: A gear wheel having special oblique teeth which mesh with a worm.

Worm Rack:. A rack having oblique teeth on which a worm meshes.

Worm Shaft: The shaft or axle passing through a worm.

Worm Wheel: Same as "Worm Gear."

Worm Work Dressing: Same as "Vermiculated Dressing." -- A type of stonework finish in which veins are made by cutting away portions of the face.

Wrench: A tool for turning nuts, bolts, and pipes, consisting of a bar or handle having jaws to fit the nut, bolt, or pipe.

Wring Fit: A fit between two parts which are so accurately matched that they have to be put together with a twisting motion.

Wrought Iron: In its perfect condition, wrought iron is simply pure iron, but, owing to impurities (to a certain degree) being present, it only approximates to that condition.

Wrought-iron Pipe: Pipe made from rolled iron plates and welded at the joint. Small sizes are butt-welded, while larger sizes are lap-welded.

Wrought Nail: A nail hammered out from a bar.

Wye: A support for the telescope in the engineers' level, having the form of the letter Y. A railroad siding in the form of the letter Y; used for turning locomotives and trains.