Glossary of Metal Building Terms

The following is a list of terms frequently used in the Metal Building Systems Industry:


Accessory– An extra building product

AISI – American Iron and Steel Institute

AISC – American Institute of Steel Construction

AISE – Association of Iron and Steel Engineers

Aluminum Coated Steel – Steel coated with aluminum for corrosion resistance

ANSI – American National Standards Institute

Anchor Bolts – Bolts used to anchor members to a foundation or other support.

Anchor Bolt Plan – Anchor Bolt Plans (a plan view) show the size, location and projection of all anchor bolts for the components of the metal building system, the length and width of the foundation (which may vary from the nominal size of the metal building system) and column reaction (magnitude and direction). The maximum base plate dimensions may also be shown.

Approval Plans – Approval plans may include framing plans, elevations, and sections through the building for approval of the buyer.

ASCE – American Society of Civil Engineers.

Astragal – A closure between the two leaves of a double swing or double slide door to close the junction.

Automatic Welding – A welding procedure utilizing a machine to make a weld.

Auxiliary Loads – All dynamic live loads required by the contract document, such as cranes and material handling systems.

Axial Force – A force tending to elongate and shorten a member.



Base Angle – An angle secured to a wall or foundation used to attach the base of the wall paneling.

Base Plate – A plate attached to the base of a column which rests on a foundation or other support, usually secured by anchor bolts.

Bay – The space between the primary frames measured parallel to the ridge.

Beam – A member, usually horizontal, that is subjected to bending loads. There are three types; simple, continuous and cantilever.

Beam and Column – A structural system consisting of a series of rafter beams supported by columns. Often used as the end frame of a metal building.

Bearing End Frame – See “Beam and Column”.

Bearing Plate – A steel plate that is set on the top of a masonry support on which a beam or purlin can rest.

Bent – The main member of a structural system.

Bill of Materials – A list of items or components used for fabrication, shipping, receiving, and accounting purposes.

Bird Screen – Wire mesh used to prevent birds from entering the building through ventilators and louvers.

Blind Rivet – A small headed pin with expandable shank for joining light gage metal. Typically used to attach flashing, gutter, etc..

BOCA – Building Officials and Code Administrators International, Inc..

Brace Rods, Angles, and Cables – Braces used in roof and walls to transfer loads, such as wind loads, and seismic and crane thrusts to the foundation. (Also often used to plumb buildings but not designed to replace erection cables).

Bracket – A structural support projecting from a wall or column on which to fasten another structural member. Examples are canopy brackets, lean-to-brackets, and crane runway brackets.

Bridge Crane – A load lifting system consisting of a hoist which moves laterally on a beam, girder, or bridge which in turn moves longitudinally on a runway made of beams and rails. Loads can be moved to any point within a rectangle formed by the bridge span and runway length.

Bridging – Structural member used to give weak axis stability to bar joists.

British Thermal Unit (BTU) – That amount of heat required to raise the temperature of one pound (2.2 kg) of water by 1o F (0.56oC.).

Building Code – Regulations established by a recognized agency describing design loads, procedures, and construction details for structures. Usually applying to designated political jurisdiction (city, county, state, etc.).

Building Line – See “Steel Line”.

Built-Up Roofing – A roof covering made of alternating layers of tar and asphaltic materials.

Built-Up Sections – A structural member, usually an “I” section, made from individual flat plates welded together.

Butt Plate – The end plate of a structural member usually used to rest against a like plate of another member in forming a connection. Sometimes called a splice plate or bolted end plate.


“C’’ Section – A member formed from steel sheet in the shape of a block “C”, that may be used either singularly or back to back.

Camber – Curvature of a flexural member in the plane of its web before loading.

Canopy – A projecting beam that is supported and restrained at one end only.

Capillary Action – That action which causes movement of liquids when in contact with two adjacent surfaces such as panel side laps.

Cap Plate – A plate located at the top of a column or end of a beam for capping the exposed end of the member.

Caulk – To seal and make weathertight joints, seams, or voids by filling with a waterproofing compound or material.

Channel-Hot-Rolled – A “C” shaped member formed while in a semi-molten state at the steel mill to a shape having standard dimensions and properties.

Clip – A plate or angle used to fasten two or more members together.

Closure Strip – A resilient strip, formed to the contour of ribbed panels and used to close openings created by metal panels joining other components.

Cold Forming – The process of using press brakes or rolling mills to shape steel into desired cross sections at room temperature.

Collateral Load – All additional dead loads required by the contract documents other than the weight of the metal building system, such as sprinklers, mechanical and electrical systems, and ceilings.

Column – A main member used in a vertical position on a building to transfer loads from main roof beams, trusses, or rafters to the foundation.

Component – A part of a metal building system.

Continuity – The terminology given to a structural system denoting the transfer of loads and stresses from member to member as if there were no connections.

Contract Documents – The documents which define the responsibilities of the parties involved in the sale, supply, and erection of a metal building system. Such documents normally consist of a contract and specification. Plans may be included.

Corner Post – An end wall column located at the corner of the building.

Covering – The exterior metal roof and wall paneling of a metal building system.

Crane – A machine designed to move materials by means of a hoist.

Crane Rail – A track supporting and guiding the wheels of a bridge crane of trolley system.

Crane Runway Beam – The member that supports a crane rail and is supported by columns or rafters depending on the type of crane system. On underhung bridge cranes, runway beam also acts as crane rail.

Curb – A raised edge on a concrete floor slab or skylight.

Curtain Wall – Perimeter wall panels which carry only their own weight and wind load.



Damper – A baffle used to open or close the throat of ventilators.

Dead Load – The weight of the metal building system construction, such as roof, framing, and covering members.

Deflection – The displacement of a structural member or system under load.

Design Loads – The loads expressly specified in the contract documents which the metal building system is designed to safely resist.

Diagonal Bracing – See “Brace Rods”.

Diaphragm Action – The resistance to racking generally offered by the panels, fasteners, and members to which they are attached.

“Dogleg” – An extension of an end post that is welded onto the outside flange of the column.

Door Guide – An angle or channel guide used to stabilize or keep plumb a sliding or rolling door during its operation.

Downspout – A conduit used to carry water from the gutter of a building.

Drift Pin – A tapered pin used during erection to align holes in steel members to be connected by bolting.


Eave – The line along the side wall formed by the intersection of the planes of the roof and wall.

Eave Gutter – See “Gutter”.

Eave Height – The vertical dimension from finished floor to the eave.

Eave Strut – A structural member located at the eave of a building which supports roof and wall paneling.

Elastic Design – A design concept utilizing the proportional behavior of materials when all stresses are limited to specified allowable values.

End Bay – The bays adjacent to the end walls of a building. Usually the distance from the end wall to the first interior primary frame measured parallel to the ridge.

End Frame – A frame located at the end wall of a building which supports the loads from a portion of the end bay.

End Post – See “End Wall Column”.

End Wall – An exterior wall which is perpendicular to the ridge of the building.

End Wall Column – A vertical member located at the end wall of a building which supports the girts. In beam and column end frames, end wall columns also support the beam.

End Wall Overhang – The projection of the roof past the end wall.

Erection – The on-site assembling of fabricated components to form a complete structure.

Erection Plan – See “Framing Plans”.

Expansion Joint – A break or space in construction to allow for thermal expansion and contraction of the materials used in the structure.

Exterior Framed – A wall framing system where the girts are mounted on the outside of the columns.



Fabrication – The manufacturing process performed in a plant to convert raw material into finished metal building components. The main operations are cold forming, cutting, punching, welding, cleaning, and painting.

Facade – Architectural treatment given to the front or any exterior surface of a building.

Fascia – A decorative trim or panel projecting from the face of a wall.

Field – The “job site”, “building site’, or general marketing area.

Filler Strip – See “Closure”.

Film Laminating Coil – Coil metal that has a corrosion resistant film laminated to it prior to the forming operation.

Fixed Base – A column base that is designed to resist rotation as well as horizontal or vertical movement.

Flange – The projecting edge of a structural member.

Flange Brace – A bracing member used to provide lateral support to the flange of a beam, girder, or column.

Flashing – A sheet metal closure which functions primarily to provide weather tightness in a structure and secondarily to enhance appearance.

Flush Frames – A wall framing system where the outside flange of the girts and the columns are flush.

Footing – A pad or mat, usually of concrete, located under a column, wall, or other structural member, that is used to distribute the loads from that member into the supporting soil.

Foundation – The substructure which supports a building or other structure.

Frame – Primary structural member (columns and rafters) which support the secondary framing.

Framed Openings – Jambs, headers, and flashing which surround an opening in the wall of a metal building.

Framing – The skeleton parts of a building which provide structural support and stability.

Framing Plans – Roof and wall framing (erection) plans that identify individual components and accessories furnished by the manufacturer in sufficient detail to permit proper erection of the metal building system.



Gable – The triangular portion of the end wall located above the elevation of the eave.

Gable Roof – A ridged roof that terminates in gables.

Galvanized – Steel coated with zinc for corrosion resistance.

Girder – A main horizontal or near horizontal structural member that supports vertical loads. It may consist of several pieces.

Girt – A horizontal structural member that is attached to side wall or end wall columns and supports paneling.

Glaze of Glazing – The process of installing glass in windows and doors.

Grade – The term used when referring to the ground elevation around a building.

Grade Beam – A concrete beam around the perimeter of a building.

Ground Snow Load – The load from snow that has accumulated on the ground.  The actual load applied to the roof design is generally reduced to 70% of the Ground Snow Load.  This is done because some of the snow blows off the roof instead of accumulating.  (See Roof Snow Load)

Grout – A mixture of cement, sand, and water used to fill cracks and cavities. Sometimes used under vase plates or leveling plates to obtain uniform bearing surfaces. Not normally used in conjunction with metal building systems.

Gusset Plate – A steel plate used to reinforce or connect structural elements.

Gutter – A gage metal member at an eave, valley, or parapet designed to carry water from the roof to downspouts or drains.



“H” Section – A steel member with a “H” cross section.

Hairpin – U-shaped reinforcing steel used to transfer anchor bolt shear (due to column thrust) to concrete floor mass.

Haunch – The deepened portion of a column or rafter designed to accommodate the higher bending moments at such points. (Usually occurs at the connection of column and rafter).

Haunch Brace – A diagonal brace from the intersection of the column and rafter section of the rigid frame to the eave to prevent lateral buckling of the haunch.

Header – The horizontal framing member located at the top of a framed opening.

High Strength Bolts – Any bolt made from steel having a tensile strength in excess of 100,000 pounds per square inch (690 MPa).

High Strength Steel – Structural steel having a yield stress in excess of 36,000 pounds per square inch (250 MPa).

Hinged Base – See “Pin Connection”.

Hip Roof – A roof which rises by inclined planes from all four sides of a building. The line where two adjacent sloping sides of a roof meet is called the Hip.

Hoist – A mechanical lifting device usually attached to a trolley which travels along a bridge, monorail, or jib crane. May be chain or electric operated.

Hot-Rolled Shapes – Steel sections (angles, channels, S-shaped, W-shapes, etc.) which are formed by rolling mills while the steel is in a semi-molten state.



ICBO – International Conference of Building Officials.

Ice Dam – A buildup of ice which forms a dam on the roof covering along the eave of the building.

Impact Load – A dynamic load resulting from the motion of machinery, elevators, craneways, vehicles, and other similar moving forces. See “Auxiliary Loads”

Impact Wrench – A pneumatic device used to tighten nuts on bolts.

Insulation – Any material used in building construction to reduce heat transfer.

Intermediate Bay – The distance between two primary frames within a building, other than end frames.

Internal Pressure – Pressure inside a building which is a function of wind velocity and number and location of openings.


Jack Beam – A beam used to support another beam, rafter, or truss and eliminate a column support.

Jack Truss – A truss used to support another beam, rafter, or truss and eliminate a column support.

Jamb – The vertical framing members located at the sides of an opening.

Jib Crane – A cantilevered boom or horizontal beam with hoist and trolley. This lifting machine may pick up loads in all or part of a circle around the column to which it is attached.

Jig – A device used to hold pieces of material in a certain position during fabrication.

Joist – A beam used for supporting floor or roof.


Kick-Out (Elbow) – (Turn-Out) – An extension attached to the bottom of a downspout to direct water away from a wall.

Kip – A unit of measure equal to 1,000 pounds (4.4KN).

Knee Brace – A diagonal brace designed to resist horizontal loads usually from wind or moving equipment.


Lean-To – A structure such as a shed, having only one slope and depending upon another structure for partial support.

Leveling Plate – A steel plate used on top of a foundation or other support on which a structural column can rest.

Liner Panel – A metal panel attached to the inside flange of the girts.

Lip – A flange stiffener.

Live Load – See “Roof Live Load”

Longitudinal – The direction parallel to the ridge.

Louver – An opening provided with fixed or movable, slanted fins to allow flow of air.


Main Frame – A frame located between end walls of a building which supports the loads from a portion of each adjacent bay.

Main Members – The main load carrying members of a structural system including columns, end wall posts, rafters, and other main support members.

Mansard – A tilted fascia system mounted to the wall, outside the steel line, and extending above the roof line to form a decorative fascia appearance and hide the roof line.

Masonry – Anything constructed of material such as bricks, concrete blocks, ceramic blocks, and concrete.

Mastic – Caulking or sealant normally used in sealing roof panel laps.

MBMA – Metal Building Manufacturers Association

Metal Building System – A metal building system consists of a group of coordinated components, including structural members, exterior covering panels, fastening devices and accessories, which have been designed for specific loads, which will work together compatibly and which have been engineered so that they may be mass produced and assembled in various combinations, or in a combination with various collateral materials, to provide an enclosed or partially enclosed structure.

Mezzanine – An intermediate floor placed in any story or room. When the total area of any “mezzanine floor” exceeds 33 1/3 percent of the total floor area in that room, it will be considered as an additional story.

Moment – The tendency of a force to cause rotation about a point or axis.

Moment Connection – A connection designed to transfer moment as well as axial and shear forces between connecting members.

Moment of Inertia – A physical property of a member, which helps define strength and deflection characteristics.

Monolithic Construction – A method of pouring concrete grade beam and floor slab together to form the building foundation without forming and pouring each separately.

Monorail – A single rail support for a material handling system. Normally a standard hot-rolled I-beam.

Multi-Gable Building – Buildings consisting of more than one gable across the width of the building.

Multi-Span Building – Buildings consisting of more than one span across the width of the building. Multiple gable buildings and single gable buildings with interior columns are examples.


NBC – National Building Code

NC – North Carolina Code

Newton – SI unit of measure for force (N).


Overhead Doors – See “Sectional Overhead Doors”


Panels – Gage metal sheets usually with a ribbed configuration and used for roof and wall skin.

Parapet – That portion of the vertical wall of a building which extends above the roof line at the intersection of the wall and roof.

Pascal – SI unit of measure for force per unit area (N/m2).

Peak – The uppermost point of a gable.

Peak Panel – Formed multi-rib panel located at the building peak.

Peak Sign – A sign attached to the peak of the building at the end wall showing the building manufacturer.

Personnel Doors – A door used by personnel for access to and exit from a building.

Piece Mark – A number given to each separate part of the building for erection identification. Also called mark number and part number.

Pig Spout – A sheet metal section designed to direct the flow of water out through the face of the gutter rather than through a downspout.

Pilaster – A reinforced or enlarged portion of a masonry wall to provide support for roof leads or lateral loads on the wall.

Pinned Base – A column base that is designed to resist horizontal and vertical movement, but not rotation.

Pin Connection – A connection designed to transfer axial and shear forces between connection members, but not moments.

Plastic Design – A design concept based on multiplying the actual loads by a suitable load factor and using the yield stress as the maximum stress in any member.

Plastic Panels – See “Translucent Light Panels”

Ponding – The gathering of water at low or irregular areas on a roof.

Pop Rivet – See “Blind Rivet”

Portal Frame – A rigid frame structure so designed that it offers rigidity and stability in its plane. It is used to resist longitudinal loads where diagonal bracing is not permitted. (Also “Wind Bent”).

Post (End Post; Corner Post) – See “End Wall Column”

Pre-Painted Coil – Coil metal which received a paint coating prior to the forming operation.

Press Brake – A machine used in cold forming metal sheet or strip into desired cross sections.

Pre-Stressed Concrete – Concrete in which the reinforcing cables, wires, or rods in the concrete are tensioned before there is load on the member, holding the concrete in compression for greater strength.

Primary Frame – See “Main Frame”

Prismatic Beam – A beam with uniform cross section.

Purlin – A horizontal structural member attached to the primary frames which supports roof panels.

Purlin Extension – See “End Wall Overhang”


Rafter – The main beam supporting the roof system.

Rails (Door) – The horizontal stiffening members of framed and paneled doors.

Rake – The intersection of the plane of the roof and the plane of the gable. (As opposed to end walls meeting hip roofs).

Rake Angle – Angle fastened to purlins at rake for attachment of end wall panels.

Rake Trim – A flashing designed to close the opening between the roof and end wall panels.

Reactions – The resisting forces at the column bases of a frame, holding the frame in equilibrium under a given loading condition.

Reinforcing Steel – The steel placed in concrete to help carry the tension, compression, and shear stresses.

Ridge – Highest point on the roof of the building which describes a horizontal line running the length of the building.

Ridge Cap – A transition of the roofing materials along the ridge of a roof. Sometimes called ridge roll or ridge flashing.

Rigid Connection – See “Moment Connection”

Rigid Frame – A structural frame consisting of members joined together with rigid (or moment) connections so as to render the frame stable with respect to the design loads, without the need for bracing in its plane.

Rolling Doors – Doors that are supported on wheels which run on a track.

Roll-up Doors – See “Rolling Doors”

Roof Covering – The exposed exterior roof skin consisting of panels or sheets.

Roof Live Load – Those loads induced by the use and occupancy of the building, not including wind load, snow load, seismic load or dead load.

Roof Overhang – A roof extension beyond the end wall or side wall of a building.

Roof Pitch – Ratio of rise to total width.

Roof Slope – The angle that a roof surface makes with the horizontal. Usually expressed in units of vertical rise to 12 units of horizontal run.

Roof Snow Load – That load induced by the weight of snow on the roof of the structure.  (See Ground Snow Load)

Ropeseal – See “Sealant”


Sag Member – A tension member used to limit the deflection of a girt or purlin in the deflection of the weak axis.

Sag Rod, Strap, or Angle – See “Sag Member”

Sandwich Panel – A panel assembly used as covering consists of an insulating core material with inner and outer skins.

SBCCI (sometimes SBC) – Southern Building Code Congress International, Inc.

Screeding – The process of striking off the excess concrete to bring the top surface of the concrete to proper finish and elevation.

Sealant – Any material which is used to seal cracks, joints, or laps.

Section Modulus – A physical property of a structural member. It is used to design and basically describes the bending strength of a member.

Sectional Overhead Doors – Doors Constructed in horizontally hinged sections. They are equipped with springs, tracks, counter balancers, and other hardware which roll the sections into an overhead position, clear of the opening.

Seismic Load – The assumed lateral load acting in any horizontal direction on a structural system due to the action of an earthquake.

Self Drilling Screw – A fastener which combines the functions of drilling and tapping. It is used for attaching panels to purlins and girts.

Self Tapping Screw – A fastener which taps its own threads in a pre-drilled hole. It is for attaching panels to purlins and girts and for connecting trim and flashing.

Shear – The force tending to make two contacting parts slide upon each other in opposite directions parallel to their plane of contact.

Shear Diaphragm – See “Diaphragm”

Sheet Notch – A notch or block-out formed along the outside edge of the foundation to provide support for the wall panels and serve as a closure along their bottom edge.

Shim – A piece of steel used to level base plates or square beams.

Shipping List – A list that enumerates by part number or description each piece of material or assembly to be shipped. Also called tally sheet, bill of materials, or packing list.

Shop Primer Paint – The initial coat of primer paint applied in the shop.

Shoulder Bolt – A fastener used to attach wall and roof paneling to the structural frame. It consists of a large diameter shank and a small diameter stud. The shank provides support for the panel rib.

Shot Pin – A device for fastening items by the utilization of a patented device which uses a powdered charge to imbed the item in the concrete and/or steel.

SI – The International symbol for the metric unit used by the United States (Le Systeme International d’ Unites).

Side Lap Fastener – A fastener used to connect panels together at the side lap.

Side Wall – An exterior wall which is parallel to the ridge of the building.

Side Wall Overhang – A projection of the roof past the side wall.

Sill – The bottom horizontal framing member of an opening such as a window or door.

Sill Angle – See “Base Angle”

Simple Span – A term used in structural analysis to describe a support condition for a beam, girt, purlin, etc., which offers no resistance to rotation at the supports.

Single Slope – A sloping roof in one plane. The slope is from one wall to the opposite wall.

Single Span – A building or structural member without intermediate support.

Siphon Break – A small groove to arrest the capillary action of two adjacent surfaces. (Anti-Capillary Groove).

Skylight – A roof accessory to admit light, normally mounted on a curbed framed opening.

Slide Door – A single or double leaf door which opens horizontally by means of overhead trolleys.

Snow Load – See “Roof Snow Load”

Soffit – A metal panel which covers the underside of an overhang or mansard.

So. Fla. – South Florida Code

Soil Pressure – The load per unit area a structure will exert through its foundation on the soil.

Spall – A chip or fragment of concrete which has chipped, weathered, or otherwise broken from the main mass of concrete.

Span – The distance between supports of beams, birders, or trusses.

Splice – A connection in a structural member.

Square – The term used for an area of 100 square feet (9.29 M2).

Stainless Steel – An alloy of steel which contains a high percentage of chromium. Also may contain nickel or copper.

Steel Line – The outside perimeter of structural steel or inside of wall panels.

Stiffener – A member used to strengthen a plate against lateral or local buckling. Usually a flat bar welded perpendicular to the longitudinal axis of the member.

Stiffener Lip – A short extension of material at an angle to the flange of cold formed structural members, which adds strength to the member.

Stiles – The vertical side members of framed and paneled doors.

Stitch Screw – A fastener used to connect panels at the side lap or to connect flashing to the panels.

Stress – A measure of the load on a structural member in terms of forces per unit area (kips per sq. in. ) (Mpa).

Strut – A brace fitted into a frame work which resists axial forces.

Stud -A vertical wall member to which exterior or interior covering or collateral material may be attached. May be either load bearing or non-load bearing.

Suction – A partial vacuum resulting from wind loads on a building which cause a load in the outward direction.


Tapered Member – A built up plate member consisting of flanges welded to a variable depth web.

Temperature Reinforcing – Light weight deformed steel rods or wire mesh placed in concrete to resist possible cracks from thermal expansion or contraction.

Tensile Strength – The longitudinal pulling stress a material can bear without tearing apart.

Thermal Block – A spacer of low thermal conductance material.

Thermal Conductivity, (k) – The rate of heat flow, in BTU’s per hour, through a square foot of material exactly one inch thick whose surfaces have a temperature differential of 1o F.

Thermal Conductance ( C) – The rate of heat flow in BTU’s per hour, through a square foot of material or a combination of material whose surfaces have a temperature differential of 1o F.

Thermal Resistance ( R) – Resistance to heat flow. The reciprocal of conductance. ( C)

Thermal Transmittance (U) – The rate of heat flow per square foot under steady conditions from the air on the warm side of a barrier to the air on the cold side, for 1o F of temperature difference between the two (BTU/Ft2/hr./1oF.

Thrust – The horizontal component of a reaction.

Tie – A structural member that is loaded in tension.

Torque Wrench – A wrench containing an adjustable mechanism for measuring and controlling the amount of torque or turning force to be exerted – often used in tightening nuts and bolts.

Translucent Light Panels – Translucent plastic panels used to admit sunlight.

Transverse – The direction perpendicular to the ridge.

Tributary Area – The area which contributes load to a specific structural component.

Trim – The light gage metal used in the finish of a building, especially around openings and at intersection of surfaces. Often referred to as flashing.

Track – A metal way for wheeled components; specifically one or more lines of ways, with fastenings, ties, etc. for a craneway, monorail, or slide door.

Truss – A structure made up of three or more members, with each member designed to carry a tension or compression force. The entire structure in turn acts as a beam.

Turnout – See “Kickout”

Turn-of-the-Nut-Method – A method for pre-tensioning high strength bolts. The nut is turned from the snug-tight position, corresponding to a few blows of an impact wrench or the full effort of a man using an ordinary spud wrench, the amount of rotation required being a function of the bolt diameter and length.


UBC – Uniform Building Code.

Uplift – Wind load on a building which causes a load in the upward direction. See “Suction”


Valley Gutter – A channel used to carry off water from the “V” of roofs of multi-gabled buildings.

Ventilator – An accessory, usually used on the roof, that allows the air to pass through.


Wainscot – Wall material, used in the lower portion of a wall, that is different from the material in the rest of the wall.

Wall Covering – The exterior wall skin consisting of panels or sheets.

Web – That portion of a structural member between the flanges.

Web Member – A secondary structural member interposed between the top and bottom chords of a truss.

Welded-Up Section – See “Built-Up Section”

Wind Bent – See “Portal Frame”

Wind Column – A vertical member supporting a wall system designed to withstand horizontal wind loads.

Wind Load – The load caused by the wind blowing from any horizontal direction.


“Z” Section – A member cold formed from steel sheet in the shape of a block “Z”.

Zinc-Aluminum Coated – Steel coated with zinc and aluminum for corrosion resistance.