Civil Engineering Dictionary

Updated: Mar 28, 2020

Absolute Temperature: The temperature reckoned from the absolute zero temperature. Absolute velocity: The vector sum of the velocity of a fluid parcel relative to the earth and the velocity of the parcel due to the earth's rotation; the east-west component is the only one affected. Absolute Viscosity: Term used interchangeably with viscosity to distinguish it from kinematic viscosity and/or commercial viscosity; occasionally, dynamic viscosity. Absolute zero temperature: Temperature measured from absolute zero (-459.67°F, or -273.16°C). Absorbent: A material which, due to an affinity for certain substances, extracts one or more such substances from a liquid or gaseous medium with which it contacts and which changes physically or chemically, or both, during the process. Calcium chloride is an example of a solid absorbent, while solutions of lithium chloride,lithium bromide, and ethylene glycols are liquid absorbents. Absorber : That part of the low side of an absorption system, used for absorbing vapor refrigerant. Absorption: Act or process of absorbing. Abutment : A concrete support wall constructed at both ends of a bridge or an arch, in order to resist the horizontal force from the bridge or the arch, support the ends of the bridge span and to prevent the bank from sliding under Acid rain: rainwater carrying acidic atmospheric pollutants (nitrous or sulfuric oxides) Acid Rain: Atmospheric precipitation with a pH below 5.6 to 5.7. Burning of fossil fuels for heat and power is the major factor in the generation of oxides of nitrogen and sulfur, which are converted into nitric and sulfuric acids washed down in the rain. Acid rain : Atmospheric precipitation with an pH below 5.6 to 5.7. Acre: Unit of land area in the Imperial system; 4840 square yards, or the equivalent of a rectangular field one chain wide and one furlong long, approximately 4047 square metres or 0.4047 hectares. Activation Energy: The energy required for initiating a metallurgical reaction—for example, plastic flow, diffusion, chemical reaction. The activation energy may be calculated from the slope of the line obtained by plotting the natural log of the reaction rate versus the reciprocal of the absolute temperature. Active earth pressure : The horizontal push from earth onto a wall. The active earth force from sand on to a free retaining wall is equivalent to that from a fluid of density 0.25 to 0.30 times that of the sand. The force from sand on to a fixed retaining wall is very much more. Adhesion: The property of a lubricant that causes it to cling or adhere to a solid surface. Adiabatic: Occurring with no addition or loss of heat from the system under consideration. Adiabatic change : A change in the volume, pressure, or temperature of a gas, occurring without a gain of heat or loss of heat. Adiabatic compression: Compressing a gas without removing or adding heat. Adiabatic cooling : A method in which paramagnetic salts are pre-cooled, and then demagnetized, thereby producing further cooling. Admixture or additive : A substance other than aggregate, cement or water, added in small quantities to the concrete mix to alter its properties or those of the hard concrete. The most important admixtures for concrete are accelerators, air-entraining agents, plasticizers and retarders. Admixtures: Materials added to mortar or concrete to achieve particular modifications to the normal properties of the basic material. Adsorbent: A material which has the ability to cause molecules of gases, liquids or solids to adhere to its internal surfaces without changing the adsorbent physically or chemically. In water treatment, a synthetic resin possessing the ability to attract and to hold charged particles. Adsorption: Assimilation of gas, vapor, or dissolved matter by the surface of a solid or liquid. Aeration: Making contact between air and a liquid by spraying liquid into the air or by agitating the liquid to promote absorption of air. Also act of fluffing molding sand. Aeration: Air trapped in the hydraulic fluid. Excessive aeration causes the fluid to appear milky and components to operate erratically. Aerobic: A condition in which free or dissolved oxygen is present in water. Aggregate: A mixture of sand and stone and a major component of concrete. Aggregate: The stones and sand (coarse and fine aggregate respectively) used as a filler in concrete, asphalt etc. Aggregate: sand, gravel etcmixed with cement to form concrete. Air brick: Ventilation built into brickwork to provide ventilation through the wall. Air-entrained concrete : A concrete used for constructing roads. It has about 5% air and is therefore less dense than ordinary good concrete, but it has excellent freeze-thaw resistance. The strength loss is roughly 5% for each 1% air entrained. Air entrained concrete produced by adding an admixture to concrete or cement, which drags small bubbles of air (Smaller than 1 mm in diameter) into the concrete mix. The bubbles increase the workability and allowing both sand and water contents to be reduced. Air-Hardening Steel: A steel containing sufficient carbon and other alloying elements to harden fully during cooling in air or other gaseous mediums from a temperature above its transformation range. The term should be restricted to steels that are capable of being hardened by cooling in air in fairly large sections, about 2 inches or more in diameter. Air-Lift Hammer: A type of gravity drop hammer where the ram is raised for each stroke by an air cylinder. Because length of stroke can be controlled, ram velocity and thus energy delivered to the workpiece can be varied. Alloy: A substance that has metallic properties and is comprised of two or more chemical elements, of which at least one is a metal. Alloy Cast Iron: Highly alloyed cast irons containing more than 3% alloy content. Alloy cast irons may be a type of white iron, gray iron or ductile iron. Alloy Steel: A steel in which a deliberate addition of one or more alloying elements, e.g. Mn, Ni, Cr, Mo, etc. has been made during steelmaking to enhance the properties of the steel. The amounts of each element that must be present in steel before it is classified as an alloy steel are given in Table 1 in EN 10020:2000. At low levels of addition, the steels may be classified as low alloy. The same standard classifies steels which do not meet the minimum requirements as 'non-alloy' steels. Altimeter: An instrument used to measure the height above a reference point, such as ground or sea level. Alumina: Aluminum oxide produced fron bauxite by a complicated chemical process. It is a material that looks like granulated sugar. Alumina is an intermediate step in the production of aluminum from bauxite, and is also a valuable chemical on its own. Aluminum: killed steel steel treated with aluminum as an oxidizing agent in order to reduce the oxygen content to such a level that no reaction occurs between carbon and oxygen during solidification. Amalgam: A dental alloy produced by combining mercury with alloy particles of silver, tin, copper and sometimes zinc. Ammeter: An instrument for measuring the magnitude of electric current flow. Amplitude: A measure of floor vibration. It is the magnitude or total distance traveled by each oscillation of the vibration. Amplitude: The maximum instantaneous value of alternating current or voltage. It can be in either a positive or negative direction. The greatest distance through which an oscillating body moves from the mid point. Anchor Bolt: An anchor bolt is a specialized bolt used to attach items to hard surfaces such as concrete, asphalt, brick or stone. Anchor bolts are made up of a threaded end that is turned into the surface of interest and a washer and nut used to carry the load on the bolt. Anchor bolts come in many shapes, sizes, and materials depending on the application and the load requirements. Anchorage: The process of fastening a joist or joist girder to a masonry, concrete, or steel support by either bolting or welding. Anion: A negatively charged ion that migrates through the electrolyte toward the anode under the influence of a potential gradient.(see Cation) (see Ion) Anode: 1. The electrode of an electrolyte cell at which oxidation occurs. Electrons flow away from the anode in the external circuit. It is usually at the electrode that corrosion occurs and metal ions enter solution. 2. The positive (electron-deficient) electrode in an electrochemical circuit. Contrast with cathode. Anode: In electrolysis or electrochemical corrosion, a site where metal goes into solution as a cation leaving behind an equivalent of electrons to be transferred to the opposite electron, called the cathode. Anolyte: The electrolyte adjacent to the anode in an electrolytic cell. Antioxidant: An additive to retard oxygen-related deterioration, especially oxidation of lubricants.. (see Inhibitor) Aperature: In an extrusion die, the shaped opening through which the heat-softened metal is forced and which gives the extruded product its cross-sectional shape. Also called the “orifice”. Apex: The highest point of a gable. Apron: Device that the molten slag flows across on its way from the spout to the doughnut. It is cooled by water spray. Aqueduct : a bridge or channel for conveying water, usually over long distances Argon: Argon is a chemical element with symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble or inert gas. Argon is the third most common gas in the Earth's atmosphere, at 0.93% (9,300 ppm). Artesion well : A spring which water flows naturally out of the earth's surface due to pressure placed on the water by an impervious overburden and hydro-static head. ASTM: American Standard of Testing and Materials Axial Impellers: An axial impeller is the rotating component in an axial flow pump. Also known as the rotor, the impeller contains multiple blades to convert the mechanical energy of the shaft into fluid acceleration and pressure rise as the fluid moves through the pump. Backfill: The replacement of excavated earth into a trench around or against a basement /crawl space foundationwall. Backhoe: a rubber tired vehicle with loader bucket in front and small excavator bucket at back. Balcony: A platform, enclosed by a railing or balustrade, projecting from the face of either an inside or outside wall of a building (e.g. a gallery in a theatre). Ball Mill: A method of obtaining a high luster on small parts by rotating them in a wooden-lined barrel with water, burnishing soap and stainless steel shot. Ballast: Framed walls (generally over 10' tall) that run the entire vertical length from the floor sill plate to the roof. This is done to eliminate the need for a gable end truss. Barge board: Horizontal beam rafter that supports shorter rafters. Barometer: To check the atmospheric pressure a device is used called barometer Barrel (Drum): The sequence of abrupt changes in magnetic induction occurring when the magnetizing force acting on a ferromagnetic specimen is varied. Base Plate: A type of mounting where the hoist is mounted to the top side of a horizontal supporting surface. Bat : A half-brick. Batching: Amount or quantity of core or mold sand or other material prepared at one time. Batching Plants: A batching plant is an installation of equipment for mixing bulk components. It typically refers to a remote installation set up for the purpose of mixing concrete on site. Bearing : (1) The supporting section of a beam length or area. (2) The compressive stress between a beam and its support (bearing pressure), particularly on foundations. (3) The horizontal angle turned between a datum direction such as true north and a given line. Bearing Guides: A bearing guide is a mechanical device used to provide a smooth, controlled surface to guide the movement of another component such as a tool bit. The guide is often a set of concentric cylindrical shells with ball or roller element bearings between the two surfaces. An example of a bearing guide is the small guide often used with router bits in woodworking. Bearing Load: A compressive load supported by a member, usually a tube or collar, along a line where contact is made with a pin, rivet, axle, or shaft. Bearing Test: The shear load on a mechanical joint (such as a pinned or riveted joint) divided by the effective bearing area. The effective bearing area of a riveted joint, for example, is the sum of the diameters of all rivets times the thickness of the loaded member. Bench mark: an elevation reference point. Bernoulli equation : Is an Energy equation for two points along the bottom of an open channel experiencing uniform flow. Bernoulli's Theorem: The simplest aromatic hydrocarbon (C6H6) used in petrochemical processes and as a solvent. It must be used with caution because of its toxicity. For safety considerations, laboratories have substituted other solvents like toluene in its place. Blacking Hole: Irregular shaped surface cavities in a casting containing carbonaceous matter. Caused by spilling off of the blacking from the mold surface. Blasting: A method of cleaning or of roughening a surface by a forceable stream of sharp angular abrasive. Bleeding: The tendency of a liquid component to separate from a liquid-solid or liquid-semisolid mixture, as oil may separate from a grease. Blister: High-carbon steel produced by carburizing wrought iron. The bar, originally smooth, is covered with small blisters when removed from the cementation (carburizing) furnace. Boiler: Tubes which form part of the heating surface of a boiler, as distinct from superheater tubes. The tubes may contain water and be surrounded by the furnace gases as in a water tube boiler, or they may act as flues and be surrounded by water as in smoke tube boiler. Boom: The lower or bottom horizontal member of a truss. Bore: The angle above or below the horizontal axis of the base boom section. Boulder: pieces of rock larger than 200mm Boulders: rocks larger than 30 an (12 inches) in diameter Box culvert: culvert of rectangular cross section, commonly of precast concrete. Box gutter: A timber gutter lined with lead or some other waterproof material. (Fr. chèneau (m) encaissé). Brace: A member, usually a diagonal, which resists lateral loads and/or movements of a structure. Bracing : metal that is attached to a fabrication prior to galvanizing in order to provide support so that the steel does not change shape during heating and cooling; can be temporary or permanent Brick: Building unit of a regular size usually made of baked clay. Can also becalcium silicate or concrete. The standard size of metric bricks in the UK is 65 x 102.5 x 215mm, designed to be used with a 10mm mortar joint. The equivalent theoretical size of imperial bricks, used with a 3/8inch joint, is 2 5/8 x 4 3/16 x 8 5/8 inches. Clay bricks are of course of great antiquity as evidenced by archaeology and the bible. Brick guard: Steel mesh panel used on scaffolding to make sure that loose bricks cannot fall off the scaffold. Brick ledge: The metal angle iron that brick rests on, especially above a window, door, or other opening. Brick lintel: Trim used around an exterior door jamb that siding butts to. Brick mold: A small, corrugated metal strip @ 1 X 68 long nailed to wall sheeting or studs. They are inserted into the grout mortar joint of the veneer brick, and holds the veneer wall to the sheeted wall behind it. Bridge: The crane movement in a direction parallel to the crane runway. Bull dozer: tracked vehicle with front mounted blade. Bulldozer: The microstructure of malleable or ductile cast iron when graphite nodules are surrounded by a ferrite layer in a pearlitic matrix. Bumper (Buffer): (1) A semirefined alloy containing sufficient precious metal to make recovery profitable. (2) Refined gold or silver, uncoined. Bumping: An energy absorbing device for reducing impact when a moving crane or trolley reaches the end of its permitted travel, or when two moving cranes or trolleys come into contact. Cable : SHIELDEDSpecial cable used with equipment that generates a low voltage output. Used to minimize the effects of frequency noise on the output signal. Caisson: An overhang. Where one floor extends beyond and over a foundation wall. For example at a fireplace location or bay window cantilever. Normally, not extending over 2 feet. Calcination: (1) A copper or copper alloy casting rectangular in cross section, used for rolling into sheet or strip. (2) A coalesced mass of unpressed metal powder. Canopy: A projecting member that is supported at one end only. Cantilever: Foundation void material used in unusually expansive soils conditions. This void is trapezoid shaped and has vertical sides of 6 and 4 respectively. Cantilever footing : A combined footing that supports an exterior wall or exterior columns. Capillary: The name given to the thin tube attached to the bulb which transmits the bulb pressure changes to the controller or indicator. The cross sectional area of the capillary is extremely small compared to the cross section of the bulb so that the capillary, which is usually outside of the controlled fluid, will introduce the smallest possible error in the signal being transmitted from the bulb. Capillary Action: These are cargo vessel size categories. Capesize refers to dry bulk carriers that are too big to pass through the Suez or Panama canals. Consequently, they have to go round the Southern tip of Africa (Cape of Good Hope) or South America (Cape Horn). They are usually around 80,000-160,000 deadweight tons but can be larger, and typical cargoes are iron ore and coal. Needless to say, they require deep berths or trans-shipment facilities on arrival. Panamax cargo ships are the largest that can go through the Panama Canal, and are usually about 65,000 dwt. Handymax vessels typically carry dry bulk cargoes like steel, are in the 35,000-60,000 dwt range, and are equipped with on-board cranes. Casing: (1) A flexible material used to seal a gap between two surfaces e.g. between pieces of siding or the corners in tub walls. (2) To fill a joint with mastic or asphalt plastic cement to prevent leaks. Cast iron : a generic term for a large family of cast ferrous alloys Cast-Iron: The process of using gas tungsten arc welding (GTAW), plasma welding, laser welding, or electron beam welding to apply weld heat to melt the edges of the material and allow them to flow together to form a joint. Catalyst: Catalysis is the increase in the rate of a chemical reaction of two or more reactants due to the participation of an additional substance called a catalyst.Unlike other reagents in the chemical reaction, a catalyst is not consumed by the reaction. Cation: The electrolyte adjacent to the cathode of an electrolytic cell. Cavitation: The process of filling the empty space by a solid object. Cavity: Progressive loss of original material from a solid surface due to continuing exposure to cavitation from a solid surface due to continuing exposure to cavitation. Ceiling: Height above ground or water level of the base of the lowest layer of cloud, below 20,000 feet, covering more than half of the sky. Service ceiling also means an aircraft’s DENSITY ALTITUDE at which its maximum rate of climb is lower or equal to 100 feet per minute. The absolute celing is the highest altitude at which the aircraft can maintain level flight. Cement: A man-made or machine-made clay tile used to finish a floor or wall. Generally used in bathtub and shower enclosures and on counter tops. Cement mortar : Mortar usually composed of four parts sand to one of cement, with a suitable amount of water. Centrifugal: type of pump that flings water outwards and into an exit pipe. Centroid: The point in a member at the intersection of two perpendicular axes so located that the moments of the areas on opposite sides of an axis about that axis is zero. Chain: Surveyors' unit of length in the Imperial system. Gunter's chain, named after its inventor,comprises 22 yards or 66 feet, approximately 20.117 metres. Gunter's chain is useful for deriving areas in acres. The lesser-known Engineer's chain, 100 feet long, was used for measuring lineardistances,along roads for example. Chainage: linear distance. Chainage : A length (Usually 100 feet) measured by chain or steel tape. Chamfer: To take off the edge or arise of any material to a small depth at an angle of about 45°. Check Valve: This is two way valve in the shape of T. use to flow the fluids in one direction and at same time flow is closed for other direction Chipping: A small groove ground back of the cutting edge on the top of a cutting tool to keep the chips short. Civil engineer : an engineer who plans, designs, and supervises the construction of facilities essential to modern life Civil engineering works: Works comprising a structure other than a building and its associated site works such as a dam, bridge, road etc or an operation such as dredging, dewatering, soil stabilisation Cladding: Any material used to face a building or structure. Clay: grains of rock less than 0.001mm. Coagulation: Is the process whereby finely divided particles of turbidity and color, capable of remaining in suspension indefinitely, are combined by chemical means into masses sufficiently large to effect rapid settling. Coarse aggregate : (1) For concrete: aggregate which retained on the No. 4 sieve (4.76 mm). (2) For bituminous material: aggregate which retained on a sieve of 3 mm square opening Coarse Grain: Steel melted without aluminum or other grain refiner additions. Coffer : a sunken panel in a ceiling Cofferdam : a temporary dam built to divert a river around a construction site so the dam can be built on dry ground Cohesion: The property of a substance that causes it to resist being pulled apart by mechanical means. Cohesion of soil : The stickiness of clay or silt. It is the shear strength of clay, which generally equals about half its unconfined compressive strength. Collar beam: Preformed flange placed over a vent pipe to seal the roofing above the vent pipe opening. Also called a vent sleeve. Collimator: A device for confining the elements of a beam of radiation within an assigned solid angle. Colloid: A suspension of extremely small particles (5-5,000 angstroms) in a liquid; the particles do not settle and are not easily separated by filtration. Colloids are considered ionized particulates immune to agglomeration. Greases are colloidal systems with thickeners dispersed in lubricating oil. Colloidal: A state of suspension in a liquid medium in which extremely small particles are suspended and dispersed but not dissolved. Colorimeters: A colorimeter is a chemical measuring device used to determine the amount of solute dissolved in a solution. The colorimeter determines the concentration of the solution based on the wavelengths of light that are pass through the solution to a photoresistor that measures the light. Colorimeters make use of optical filters that can be adjusted to the wavelengths of light that pass through the solution of interest. Compaction: (1) The act of forcing particulate or granular material together (consolidation) under pressure or impact to yield a relatively dense mass or formed object. (2) In powder metallurgy, the preparation of a compact or object produced by the compression of a powder, generally while confined in a die, with or without the inclusion of lubricants, binders and so forth. With or without the concurrent applications of heat. Compasses: An instrument for drawing arcs and circles. Not to be confused, incidentally, with a compass (in the singular) which is a magnetic instrument for finding North. Compression, adiabatic: Is compressing a gas without removing or adding heat. Compressive Strength: The maximum compressive stress that a material is capable of developing, based on original area of cross-section. In the case of a material which fails in compression by a shattering fracture, the compressive strength has a very definite value. In the case of materials which do not fail in compression by a shattering fracture, the value obtained for compressive strength is an arbitrary value depending upon the degree of distortion that is regarded as indicating complete failure of the material. Compressor : The pump which provides the pressure differential to cause fluid to flow and in the pumping process increases pressure of the refrigerant to the high side condition. The compressor is the separation between low side and high side. Computer aided design (cad): The type of computer program with which technical drawings are prepared. The market leader is AutoCAD but there are others. Concrete: Beads or drops of water (and frequently frost in extremely cold weather) that accumulate on the inside of the exterior covering of a building. Use of louvers or attic ventilators will reduce moisture condensation in attics. A vapor barrier under the gypsum lath or dry wall on exposed walls will reduce condensation. Concrete: An artifical stone-like substance obtained by mixing large and small stones and sand with cement and enough water to permit fullhydration and make the mix workable. Concrete (like the stone minerals from which it is made) is strong in compression but weak intension. Roman concrete was based, not on Portland cement, but on a 'pozzolanic' mix, made from volcanic ash and incorporating ground-up bricks and tiles. (Fr. beton, m). Concrete pump: A machine for transporting concrete down a delivery pipe. May be truck mounted or static. Condenser : An apparatus used to transfer heat from a hot gas, simultaneously reducing that gas to a liquid. Conduction: The rate at which heat is transmitted through a material. Conductivity: The rate at which heat is transmitted through a material. Conductor: Substance or body capable of transmitting electricity or heat. Cone: The conical part of an oxyfuel gas flame next to the orifice of the tip. Cone Angle: The angle that the cutter axis makes with the direction along which the blades are moved for adjustment, as in adjustable-blade reamers where the base of the blade slides on a conical surface. Consolidation : The gradual, slow compression of a cohesive soil due to weight acting on it, which occurs as water, or water and air are driven out of the voids in the soil. Consolidation only occurs with clays or other soils of low permeability, it is not the same as compaction, which is a mechanical, immediate process and only occurs in soils with at least some sand. Construction: The process of assembling materials and erecting a structure. The medium in which a building is built (eg wood, steel or masonry). Consumption: Measures the physical use of steel by end-users. Steel consumption estimates, unlike steel demand figures, account for changes in inventories. Apparent Supply — Derived demand for steel using AISI reported steel mill shipments plus Census Bureau reported imports, less Census Bureau reported exports. Domestic market share percentages are based on this figure, which does not take into account any changes in inventory. Contact Corrosion: When two disimiliar metals are in contact without a protective barrier between them and they are in the presence of liquid, an electrolytic cell is created. The degree of corrosion is dependent on the area in contact and the electro-potential voltage of the metals concerned. The less noble of the metals is liable to be attacked, i.e., zinc will act as a protector of steel in sea water whereas copper or brass would attack the steel in the same environment. Contact Fatigue: Cracking and subsequent pitting of a surface subjected to alternating Hertzian stresses such as those produced under rolling contact or combined rolling and sliding. The phenomenon of contact fatigue is encountered most often in rolling-element bearings or in gears, where the surface stresses are high due to the concentrated loads and are repeated many times during normal operation. Continuous beam : A beam extending over several spans in the same straight line. Contour: an imaginary line linking points of equal elevation. Contour: The outling of an object. Contour line: A line drawn on a site plan joining points of the same elevation. Contour Machining: Machining of irregular surfaces such as those generated in tracer turning, tracer boring and tracer milling. Convex: The curved surface of a cylinder as a sphere when viewed from the outside. Conveyor: A mechanical apparatus for carrying or transporting materials from place to place. Types include apron, belt, chain, gravity, roller, monorail, overhead, pneumatic, vibrating, etc. Conveyor: A mechanical apparatus for carrying or transporting materials from place to place. Types include apron, belt, chain, gravity, roller, monorail, overhead, pneumatic, vibrating, etc. Coping: The process of removing certain sections of a structural steel member to allow easier fitup to the supporting structural member. Corbel: A strip of formed sheet metal placed on outside corners of drywall before applying drywall 'mud'. Corrosion: Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents. Corrosion Fatigue: Fatigue accelerated by simultaneous attack from a corrosive environment. Corrosion : the chemical or electrochemical reaction between a material and its environment that produces a deterioration of the material and its properties; zinc chemically reacts with elements in the atmosphere, thereby sacrificially corroding to prevent underlying steel corrosion Counterfort: A foundation wall section that strengthens (and generally perpendicular to) a long section of foundation wall Crane: Lifting device which can be fixed or mobile. Crane Service, Heavy: Service that involves operating at 85 to 100% of rated load or in excess of 10 lift cycles/hour as a regular specified procedure. Crane, Cantilever Gantry: A gantry or semigantry crane in which the bridge girders or trusses extend transversely beyond the crane runway on one or both sides. Crawling: A coating defect consisting of a lack of adhesion to, or dewetting of, the substrate while the coating or ink is wet. The cause is due to a difference in surface tension of the coating and substrate. Crawling is also known as cissing and dewetting. Creep: A time-dependent deformation of a structural member under a sustained constant load. Crib: Network of cast iron used to support the cope when no cope flask is used. Curl: Appears as a relatively uniform curvature or sweep along the length of coiled metal. Curtain wall: A non-load bearing exterior wall which carries only its own weight and wind load. Cutting Torch (Arc): A device used in air carbon arc cutting, gas tungsten arc cutting and plasma arc cutting to control the position of the electrode, to transfer current and to control the flow of gases. Cutting Torch (Oxyfuel Gas): A device used for directing the preheating flame produced by the controlled combustion of fuel gases and to direct and control the cutting oxygen. Dado: A groove cut into a board or panel intended to receive the edge of a connecting board or panel. Damp proof course (dpc): A barrier, usually physical, built into masonry to prevent moisture migrating up from the ground or down from above, e.g. chimneys, parapets. Dampproofing: The end of a pipe (the terminal end) that is not attached to anything. Datum: A predetermined level on a site from which all other levels are established. Datum : Any elevation taken as a reference point for levelling. Dead load: The weight of the materials which form a permanent part of the structure, as opposed to imposed load. Decibel: (dB)A decibel is a division of a logarithmic scale for expressing the ratio of two quantities proportional to power or energy. The number of decibels denoting such a ratio is ten times the logarithm of the Deck: A floor or roof covering made out of gage metal attached by welding or mechanical means to joists, beams, purlins, or other structural members and can be galvanized, painted, or unpainted. Deck : (1) A flat roof, a quay, jetty or bridge floor, generally a floor form with no roof over upon which concrete for a slab is placed. (2) Formwork for a level surfaces. Decomposition: breakdown of organic materials Decomposition: Separation of a compound into its chemical elements or components. Deformed Bar: Concrete reinforcing bars in which the surface is provided with lugs or protrusions (called deformations) which inhibit longitudinal movement of the bars relative to the surrounding concrete. The surface deformations are hot formed in the final roll pass by passing the bars between rolls having patterns cut into them so that the surfaces of the bars are forced into the depressions in the rolls to form characteristic deformations. Density index : (relative density): is a measure of the tendency or ability to compact soil during loading. The density index is equal to 1 for a very dense soil; it is equal to 0 for a very loose soil Density Ratio: The ratio of the determined density of a powder compact to the absolute density of metal of the same composition usually expressed as a percentage. Also referred to as percent theoretical density. (see percent theoretical density) Design loads: The loads specified in the contract drawings or specifications which a building is to be designed for. Design pressure : Highest or most severe pressure expected during operation. Sometimes used as the calculated operating pressure plus an allowance for safety. Detergent (Cleansers): Detergents in cleansers are surface-active compounds that lower the surface tension of water or water solutions and impart emulsifying and dispersing properties to them. Dew Point: The dew point of the atmosphere inside the furnace. The higher the negative number, the dryer the furnace. A dry furnace is desired. Dewatering : The removal of groundwater bypumping so as to artificially depress the water table and avoid the difficulties associated with construction below the water table. Diaphragm: Roof panel or decking, metal wall, or floor slab which provides a larger in-plane shear stiffness and strength adequate to transmit horizontal forces to the resisting structural system. Die: A metal block used in forming materials by casting, molding, stamping, threading or extruding. Diffusion: Movement of atoms in solids. Heat provides the energy for atom movement. Dilution : Reducing a concentration of soluble material by adding pure water. Dimensional Tolerance: A range by which a product's width and gauge can deviate from those ordered and still meet the order's requirements. (see Commercial Tolerance) Distillation : Salt removal process from brackish or sea water by boiling and condensation. Diversion: 1. A situation that occurs when a coil/s intended for an order doesn’t meet quality standards or customers specifications and is therefore diverted to meet another customer's specifications. In addition, coils can be diverted to complete another customer's order or for other reasons as necessary. 2. Removing a product from its original order. Diversion: 1.) A situation that occurs when a coil/s intended for an order doesn't meet quality standards or customers specifications and is therefore diverted to meet another customer's specifications. In addition, coils can be diverted to complete another customer's order or for other reasons as necessary. 2) Removing a product from it's original order. Synonymous with Reapplication. Diversion channel : a bypass created to divert water around a dam so that construction can take place Dome : a curved roof enclosing a circular space; a threedimensional arch Door frame: A frame into which a door is fitted. Door head: The upper part of the frame of a door Door jambs: The two vertical members of a door frame. Door leaves: In wide openings, a door may be made up into two or more individual sections or “leaves”,which are hinged together. Dowel: A wood or metal pin used to strengthen a joint by its insertion partly into each of the joined pieces Drainage : the act, process, or mode of becoming emptied or freed of cleaning solutions and/or zinc Draw Peg: A wooden peg used for drawing patterns. Draw Spike: A steel spike used to rap and draw a pattern from the sand; it is driven into the wood of the pattern, as opposed to a Draw Screw, which threaded. Dredge : To dig or excavate under water. Drift: The lateral movement or deflection of a structure. Drop Hammer: A term generally applied to forging hammers in which energy for forging is provided by gravity, steam or compressed air. See also air-lift. Hammer, board hammer, and steam hammer. (see Air-Lift) Drop Hammer Forming: A process for producing shapes by the progressive deformation of sheet metal in matched dies under the repetitive blows of a gravity-drop or power-drop hammer. The process isrestricted to relatively shallow parts and thin sheet from approximately 0.6 to 1.6 mm (0.024 to 0.064 in.). Dry ice : Refrigerating substance made of solid carbon dioxide which changes directly from a solid to a gas (sublimates). Its subliming temperature is -78°C. Dryer: Dries the strip after a rinsing process. Duct: Any tube, pipe or other conduit by which air or fluid is transfered. Ductile: A metal capable of being drawn into wire or thread. Ductility: The ability of a material to deform plastically without fracturing, being measured by elongation or reduction of area in a tensile test, by height of cupping in an Erichsen test or by othermeans. Dumping: Dumping occurs when imported merchandise is sold in, or for export to, the domestic market at less than the normal value of the merchandise, i.e., a price which is less than the price at which identical or similar merchandise is sold in the comparison market, the home market (market of exporting country) or third country market (market used as proxy for home market in cases where home market cannot be used). The normal value of the merchandise cannot be below the cost of production. Dumpy level: An optical levelling instrument Dumpy level: Originally a simple but accurate optical instrument invented in 1832 by English civil engineer William Gravatt. Now applied to any optical levelling instrument used by builders. Dyke : (1) A mound of earth along a river or channel bank to retain floodwater. (2) Large ditch. (3) A tabular-shaped igneous intrusion. Dynamic load: A load that varies with time which includes repeative loads, seismic loads, and other loads created by rapid movement. Dynamite : a blasting explosive, based on nitroglycerin, but much safer to handle than nitroglycerin alone Eccentric: The condition that exists when a load is applied on a line of action that does not pass through the centroid of the body it is applied to. Eddy Currents: A condition caused by an uneven roll surface. It is seen on the edges of a coil, not across the full width of the coil. EDM: Abbreviation for electrical discharge machining. Efflorescence: A white or coloured powder sometimes formed on the surface of masonry by deposit of soluble salts. Effluent: waste liquid from a house, industry, sewagetreatment plant, etc. Ejector: A device mounted in such a way that it removes or assists in removing a formed part from a die. Elastomer: A rubber or rubber-like natural or synthetic material that can be stretched repeatedly and that returns to its approximate original dimensions when the stress is released. Electrical Precipitator: In air pollution control, the use of electrodes in stack emissions emitting high voltage; particles 0.1 micron and smaller can be attached and collected at discharge electrode. Electro Galvanizing: Galvanizing by Electro deposition of zinc on steel Electrode: The device through which current is conducted thru to the arc or base metal during the process of welding. Electrolysis: The separation of a chemical compound into its components by passing an electric current through it. Electrolyte: A dissolved or fused substance capable of conducting an electric current; examples include the molten solution electrolyzed in an aluminum reduction cell, or the acid solution in a wet-cell battery. Electrolytic Galvanized: Cold Rolled or Black Plate to which a coating of zinc is applied by electro deposition; used for applications in which corrosion resistance and paintability is a primary concern. Electromagnetic Radiation: Energy propagated at the speed of light by an electromagnetic field. Electromotive Force: (1) The force that determines the flow of electricity; a difference of electric potential. (2) Electrical potential; voltage. Electrophoresis: Transport of charged colloidal or macromolecular materials in an electric field. Electroplate: The application of a metallic coating on a surface by means of electrolytic action. Electroplating: Electro deposition of a metal or alloy in an adherent form on to a cathodic piece. Elevation: A geometrical drawing of a facade of a building. Embankment : A ridge of earth or rock placed, shaped and compacted to carry a road, railway, canal, etc., or to contain water. Emulsion: Colloidal dispersion of one immiscible liquid in another; the second suspends, but do