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Glossary of Bridge Terminology



V-Thread: A thread having a cross-section like an inverted letter V.

Vacuum Process: An abandoned process for sinking piers. Its essential feature was the intermittent loading of the caisson by suddenly withdrawing the air from the working chamber, leaving the outside atmospheric pressure unbalanced, and thereby giving a downward impulse to the caisson. See "Trautwine" for details.

Valley: A re-entrant angle formed by the intersection of two parts of a roof.

Valve: A device for closing the passageway in a pipe, duct, or conduit.

Van Dyke Print: A print made on Van Dyke brown-print paper; same as "Negative Print."

Vanadium Steel: An alloy steel containing a small percentage of vanadium which has the effect of raising the elastic limit and ultimate strength of the metal, mainly by purification.

Vanishing Point: A point in perspective drawing where parallel lines appear to intersect the ground line or horizon.

Varnish: A solution of certain gums or resins in alcohol or linseed oil; used by painters to produce a hard, transparent coat or surface.

Vehicle: An oil or other medium used by painters for carrying the pigment of a paint. Any apparatus for carrying loads.

Velocity: The rate of motion.

Vent or Vent-hole: An outlet or passage for fluids.

Vent-hole: Same as "Vent."

Vermiculated: Tortuous or sinuous like a worm.

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

Vernier: A small movable scale running parallel to a fixed scale and graduated so that n + 1 or n - 1 parts on the vernier are equal to n parts of the primary scale.

Vernier Caliper: A steel caliper with a vernier attachment which reads to thousandths of an inch.

Vernier Plate: The revolving plate on a transit to which are attached the verniers.

Vertex: The highest point, crown, or apex.

Vertical: Upright, plumb, perpendicular to the horizon. Also an upright member in a truss.

Vertical Bracing: Wind bracing lying in a vertical plane, such as sway bracing

Vertical Clearance: The vertical or overhead space allowed for the passage of any vehicle or craft, measured above the roadway or the water level.

Vertical Curve: A curve in a vertical plane, usually a parabola, connecting two grade tangents of a roadway or railroad.

Vertical Lift Bridge: A bridge having a span that hoists vertically.

Vertical Line: Any line which is perpendicular to a horizontal plane.

Vertical Strut: A vertical compression member.

Viaduct: An extended bridge of many spans, mainly over dry ground. Usually consists of alternate towers and open spaces or bays.

Vibration: A movement back and forth. A form or mode of motion in which the moving particle occupies successive positions in recurrence.

Vibration Rod: A tension diagonal for vertical or portal sway-bracing used in light highway bridges. Such bracing is far inferior to rigid sway-bracing.

Vibratory Stress: A stress caused by vibration.

Vicat Needle: A small definitely weighted needle having a point of a definite, prescribed area; used in testing the activity of cement. A small rod, one millimeter in diameter, mounted in a frame and bearing a weight of three hundred grams; used for testing the activity of cement.

Virginia Hemp: An inferior species of hemp grown along the rivers in the Eastern United States.

Virtual Moment: A term applied to the product of a force by its virtual velocity.

Virtual Velocity: An arbitrary, infinitesimal displacement of the point of application of a force resolved into the line of action of the said force. The term is a misnomer, for it has nothing whatsoever to do with velocity.

Vise: An appliance or tool for gripping and holding an object, consisting of two jaws and a screw with a handle for forcing the jaws together.

Vitrifaction, or Vitrification: The act of vitrifying.

Vitrified Brick: A glazed brick, made by fusing a silicious compound.

Vitrify: To convert into glass by the application of heat.

Voids: The spaces between the particles of a substance or of a mixture; used in connection with sand, broken stone, or gravel for concrete.

Volatile Thinner: All that liquid portion of a paint, water excepted, which is volatilized in a current of steam at atmospheric pressure.

Voltmeter: An electrical instrument for measuring a drop in voltage or the difference in potential between two points in a circuit.

Volume: The space occupied by an object.

Volumenometer: An apparatus for measuring the volume of a solid body by determining the quantity of fluid which it displaces.

Volumetric Modulus of Elasticity: The ratio of the unit stress, applied on the three principal axes, to the relative change in volume. It generally equals two-thirds of the lineal modulus.

Vortex: A whirlpool or eddy in a fluid.

Voussoir: A stone or block in the shape of a truncated wedge which forms part of an arch ring.

Vug: A cavity in a casting.

Vulcanize: To treat with sulphur by mixing and heating. Applies to India-rubber. To treat wood by a certain patented cooking process which is now defunct.

Vulcanized Fibre: A vegetable fibre saturated and coated with a metallic chloride giving the material toughness and strength.