Steel construction Glossary

Anchoring: all the means to fix a column or a post to its foundation, direct sealing or bolted rods on the base plate.

Bolt: fastener consisting of a cylindrical metal body with a head at one end and a helical thread at the other, closed with a threaded nut. One can distinguish normal bolts, high resistance bolts and adjusted bolts.

Swaged bolt: rivet which is cold set with a pneumatic or hydraulic pistol; the head is tronconic and the shank is circularly grooved, with a break of carefully sized groove; a ring set by axial expulsion ensures the tightening up to the point where the break of the groove guarantees automatically the correct condition of tension in the shank after installation.

Box-girder: composed of two parallel webs solidarized by flanges high and low.

Cable: bundle of strands (see this word) arranged in helix around a core.

Cast iron: carbon and iron alloy (3 to 4 %) giving a very resistant in compression but breaking and nonductile metal; its transformations are carried out especially by hot moulding (grey pig iron, known as foundry pig iron). The cast iron has a remarkable corrosion resistance and a thermal dilation coefficient very low.

Cellular beam: hot-rolled section whose web is cut out according to polygonal or circular lines; both half profiles are moved of a half-not to reconstitute the beam by welding of the two elements, tooth with tooth or after addition of intercalated plates.

Cladding: cover of facade set up by mechanical fixation. Light facade with single or double skin with integrated insulation.

Cleat: folded flat rib being used to fix a purlin on a principal rafter.

Clinching: method of connection consisting in realizing in a single operation of projection on the metal elements that must be assembled.

Cold chisels: intersections in the form of Saint Andrew's cross placed in a roof truss.

Cold profile: product obtained by using the aptitude for the cold forming of steels (stainless like carbon steel) from 0,1 to 10 mm thickness; the sheet is gradually folded without thickness modification, while passing between a succession of couples of complementary rollers.

Collaborating steel deck: steel deck associated to a concrete slab to establish a composite structure of floor.

Closure: element, metallic or not, of infilling between the roofing and the façade.

Composite construction: metal framing associated to some reinforced concrete, (ex: steel beam and slab in reinforced concrete, steel columns filled with concrete, but also beam or steel post coated with reinforced concrete). Both materials participate in the resumption of the efforts. The composite construction improves the behaviour of frameworks in case of fire.

Connection plate: plate fixed at the ends of the columns or beams in a plan generally perpendicular to the longitudinal axis of the part. Plate at the end of a section whose assembly with that of the following section ensures the mechanical continuity of a column.

Connector: pin welded to a metal beam, intended to insure a mechanical connection with a slab in concrete (longitudinal slide or uprising of the slab), and to constitute a composite construction.

Corrosion: attack and slow destruction of the surface of materials by the action of the chemical agents (especially dissolved salts and acids). On metals, corrosion is an oxidation; it is avoided by preliminary treatment such as electrolytic treatments, galvanization, tinning, chromium plating, etc, or by anti-corrosive coatings and paintings.

Counter: in a trussed roof, element joining the tie beam to the lower chord of a trussed purlin to oppose to their buckling in case of uprising due to the wind.

Curb: part on which the bank of a cover and the waterproofing systems are pressed around a hopper or of a skylight.

Decking: part of a bridge including the cover and the joist framing which supports it directly, other than the lower supports (piles and abutments) or superiors (suspending rods, stay, pylons).

Dished plate: sheet resulting from the work of the metal sheeting on a press, between a matrix and a punch which forms the relief of a print.

Double-skin: component of envelope, used for the façades but also for the covers, comprising an insulation inserted between two metal facings, the interior facing being a ribbed decking, the external facing a cladding.

Dowel: metal rod of square section (10 to 15 mm on side), known as cow rib, being used to arm the masonry filler of the old floors. The pegs are laid out parallel to the beams and rest on bent struts.

Dry construction: this method of construction consists, for the realization of the framing and cladding, in assembling on the construction site industrialized components, using a minimum of concrete in the slabs or even without concrete.

Expanded metal: grate of a single piece, stiff and run-resistant, made by cutting and stamping of a sheet steel; used as fence of safety barrier, grating for footbridge, hanging ceilings, etc.

Fillet: a rounded inside intersection that meets at an angle between two surfaces (the web and the flange of a section for example).

Fire (resistance): normalized fire resistance that consists in placing a certain surface of material in front of an intense heat and in pursuing the test until spontaneous inflammation of the material. The classification which results from it is a function of duration sold before inflammation and takes into account the speed of propagation of the flame (but not emanations of poison gases).

Flange: in a section, part which is perpendicular to the web.

Flashing: thin metal blade protecting from the passage of water through a joint in a roof or façade.

Flocking: method for realization of coatings by application or projection of short textile fibres or specific coating on a surface prepared beforehand to receive protection.

Folding: operation which consists in giving in workshop the form wished to plane sheets of which the thickness seldom exceeds 5 mm. The length of the folding machines is generally 4 to 6 meters.

Footing: part consisted the sills of a post, by which it transmits the stresses to its foundation.

Forged (steel): part obtained by the deformation of the steel, brought up to a temperature where it is rather malleable, by shock or pressure; for certain grades of steel forging is done cold.

Galvanization : fixing on the steel whose surface was prepared beforehand, by electrolysis or immersion in a zinc bath in fusion, of a fine layer of zinc which will preserve it corrosion.

Girder: A horizontal structure member supporting vertical loads by resisting bending. A girder is a larger beam, especially when made of multiple metal plates. The plates are usually riveted or welded together.

Lattice girder: structure of a beam, a post or a truss which web is replaced by a triangulated network of secondary bars.

Welded plate girder: steel girder constituted by sheet steels welded between them, mostly on a bench of automated soldering.

Grade: the grade of steel defines, following a code adapted by use, its characteristics of elasticity and impact strength.

Hinge: system of connection allowing the angular movement of a part with regard to the other one.

Hollow section: hollow body, of round or square section, elaborated from flat products curved and welded on line, used in particular like elements of structure in steel construction.

Hook: threaded rod, fixed on the cladding rails and the posts, fixing a cladding or a cover, using a washer and of a nut.

Iron: resistant and malleable metal (melting point 1 530 °C, density 7,85). It is especially used in the form of alloy or added with carbon to constitute steels and cast iron.

Jack rafter (or hip rafter): part intended to divide into several intermediate ranges the interval between two trusses, to reduce the section of the purlins.

Joint: constructive device allowing to connect, by bolts, rivets, swage bolts or welding, bars or slabs of a part or a structure.

Laminated sheet: metallurgical operation which allows to apply in a permanent film of protection and/or decoration, on a prepainted galvanized sheet.

Lattice girder: structure of a beam, a post or a truss which web is replaced by a triangulated network of secondary bars.

Lightweight façade: façade made up of materials of low mass, such as metal sheets, glass, the panels of wood or fibres, etc.

Metal coating: cover obtained by projection with a pistol of melted metal, by a flame or a plasma, on a support which the surface has to present a certain roughness and a degree of neatness equal to Ds3.

Metal mesh: this naming applies to the realization of metal surfaces from threads generally in stainless steel. One distinguishes three families: welded threads, weaved threads, and spiral (round or flat threads rolled up around axes).

Mill scale: film of iron oxides which forms on the surface of bars or sheet steels during the hot rolling; must be eliminated (by brushing, sand or shot blasting) before the painting.

Panel wall: frame consisted of posts and crossbars and being used as armature to a masonry filling or cladding of bricks.

Passivation: protective treatment of ferrous metals by warmth or cold phosphatation before their stake in painting. The passivants agents are generally solutions of acid phosphates of heavy metals.

Pin: stalk of steel serving as axis for certain joints, or to facilitate the joining during the erection.

Polonceau: qualify a type of truss characterized by its double punch out of V reversed.

Portal frame: system of construction formed by two columns, articulated or restrainted at the foot, vertical or inclined, and connected to the higher part by a horizontal or broken cross-piece whose each fastener with the amount constitutes a restrainted connection. That involves a mutual dependence of the cross-piece and vertical supports with the hyperstatic system.

Projection: projection created on the surface of a sheet by deformation, addition of a filler or machining.

Puddled iron: traditional industrial process (1784) to obtain from iron in a furnace by extensive puddling of cast iron, iron oxide and scorias; the air and the oxide burn the carbon and transform the cast iron. This material resists well to the corrosion, but the soldering is delicate there; the Eiffel Tower is one of the last big constructed works in puddle iron.

Punching: operation of workshop consisting in making in a structural member of the circular or oblong holes with a punching machine.

Restraints: assembly of two elements avoiding any relative rotation between them, the bending moment a restraint element being transmitted completely to the other.

Rolled sections or profiles: sections of profiles of steel obtained by progressive flattening of the metal between cylinders, to reduce the thickness and level the surface.

Row of piles: row of columns generally connected by horizontal and diagonal beams conferring to the row a high rigidity, to serve as support for the vertical loads and for the horizontal or oblique forces.

Saint-Andrew's cross: bars in the shape of X used for the wind bracings.

Sand-blasting: process of cleaning of the metal surfaces by projection of abrasive grains with definite dimensions; the first rust-proofing coat of paint has to laid within hours which follow.

Sandwich panel: prefabricated panel which settles on purlins as a single skin cladding, constituted by two ribbed sheet steels enclosing an insulation.

Section: hot rolled long product of different sections; term reserved by the steel makers for the girders which sections are I and H. The IPE has flanges of constant thickness, the IPN has flanges of variable thickness, the HEA and the HEB have webs equivalent to their width. The flanges of the HEA are less thick than those of the HEB, at equal height. Other forms of sections are merchant bars and special sections (T, U, L).

Sheet: metal reduced to the state of sheet by hot or cold rolling; considered thin or strong if less or more than 3 mm in thickness, the sheet can be plane, corrugated, ribbed, perforated, undulated or engraved.

Laminated sheet: metallurgical operation which allows to apply in a permanent film of protection and/or decoration, on a prepainted galvanized sheet.

Prepainted sheet: sheet cold rolled, then, after preparation, covered with painting in a continuous process.

Sheet piles: steel ribbed boards, with edges endowed with a rib which allows their joining, to establish, after sinking in the ground, breast walls or waterproof screens.

Spade: abutment welded under a base plate and penetrating into the concrete of foundation to resist to a horizontal effort

Splice connection: part ensuring the connection, alignment and the transmission of certain efforts between two adjacent or consecutive elements of a framework.

Springer: construction formed by jointives or very close girders, interposed between a metal element heavily loaded with its foundation, to distribute regularly the load to transfer to the foundation.

Stability: state in which a construction under the effect of the stresses has to remain; this state has to place the whole building in sufficient safety with regard to the criterion of ruin.

Steel [F: Acier - G : Stahl]: metal alloy containing iron and less than 2 % of carbon, with possibly elements in addition known as alloy elements.

High-yield steel: steel which yield stress is equal or higher than 355 N/mm². Thermomechanical steels, which form part of it present an improved aptitude for welding compared to standardized steels.

Mild steel: carbon rate from 0,15 to 0,20 % which breaking strength is equal to 400 N/mm²(fu). Current steels for construction, stretched in the form of beams, sections, sheets, bars or drawn out of wire of reinforcement or ordinary wire (known as wire).

 

Steel casting: steel obtained by using smelting techniques, which consist in running an alloy of given composition in a mould reproducing the external and interior forms desired.

Steel deck: element of steel decking, roofing or cladding, in thin, galvanized, ribbed sheet by profiling, being able to be of use as support to a coating.

Collaborating steel deck: steel deck associated to a concrete slab to establish a composite structure of floor.

Steel strip: flat product hot or cold rolled-iron product, of a width lower than 600 mm and a thickness from 0,3 to 15 mm.

Strip: metal strip of flat wheel which connects the bars of an approach.

Stripping: pickling a metal surface with an acid.

Support: part of a foundation or a construction on which a girder or a column put back their load: perpendicularly (free support), vertically and horizontally on the same plan (fringed support) or with possibility of flexion (built-in support).

Swaged bolt: rivet which is cold set with a pneumatic or hydraulic pistol; the head is tronconic and the shank is circularly grooved, with a break of carefully sized groove; a ring set by axial expulsion ensures the tightening up to the point where the break of the groove guarantees automatically the correct condition of tension in the shank after installation.

Tie: part of a metal framework always requested by tension stresses efforts.

Truss: generally triangulated beam, which top chord regulates the slope of a roof and which supports purlins.

Vierendeel truss: truss with rectangular panels and rigid joints but no diagonal members in grate containing between its ribs of square days. Those panels facilitate the transverse passage of other beams.

Weathering steel: steel weakly allied to copper-nickel-phosphore, with improved resistance to atmospheric corrosion by forming of a protective and water resistant layer.

Web: central part of a section, a beam, connecting both flanges in a perpendicular plan to these.

Welded plate girder: steel girder constituted by sheet steels welded between them, mostly on a bench of automated soldering.

Welding: A joining process that produces coalescence of materials by heating them to the welding temperature, with or without the application of pressure or by the application of pressure alone, and with or without the use of filler metal.

Wind bracing: wall or vertical bracing ensuring the stability of a framework, being opposed to its deformation, buckling or overturning under the action of the horizontal forces.