Glossary of Terms
Don’t let words fail you—brush up on all the steel industry terms, words and acronyms here
From “A & D” to “Z section,” bookmark this beneficial resource
Terms identified by ( * ) are usually qualified by type of load effect, e.g., nominal tensile strength, available compressive strength, etc.
Terms identified by ( ** ) are usually qualified by type of component, e.g. local web buckling, local flange buckling, etc.
A & D
Abbreviation for ‘Analysis and Design’.
AASHTO
Abbreviation for ‘American Association of State Highway and Transportation Officials’.
A regulatory organization which governs the design and specifications of highway bridges.
Accessories
Structural components related to the design, fabrication and erection of steel joists (bar joists) and Joist Girders including, but not limited to sloped end bearings, extended ends, ceiling extensions, bridging and bridging anchors, headers and bottom chord lateral bracing for Joist Girders.
ADL
Abbreviation for ‘After Dead Load is Applied’.
AEC
Abbreviation for ‘Architecture, Engineering and Construction’.
AECbytes
AEC newsletter – www.aecbytes.com
aecXML
Term for a specific standard format used for BIM electronic data exchange.
Aesthetic
Having the sense of beauty or pleasing to the eye.
AFF
Abbreviation for ‘Above Finish Floor’.
AGA
Abbreviation for ‘American Galvanizers Association’.
AGA is a non-profit association representing the post-fabrication hot-dip galvanizing industry.
AGCA
Abbreviation for ‘Associated General Contractors of America’.
ACG of America is a national trade organization of qualified construction contractors and industry-related companies dedicated to skill, integrity, and responsibility. The AGCA is the voice of the construction industry and is dedicated to improving the quality of construction and protecting the public.
AIA
Abbreviation for ‘American Institute of Architects’.
An organization to unite in fellowship the members of the architectural profession in the United States.
AISC
Abbreviation for ‘American Institute of Steel Construction, Inc.’
Is a non-profit technical specifying and trade organization for the fabricated structural steel industry in the United States. It was founded in 1921 with headquarters located in Chicago. One of their best-known manuals is the Manual of Steel Construction.
AISE
Abbreviation for ‘Association of Iron and Steel Engineers’.
AISE promotes the iron and steel industry through education, networking, and technical events.
AISI
Abbreviation for ‘American Iron and Steel Institute’.
AISI promotes the interests of the iron and steel industry.
Alignment Chart for Columns
A nomograph for estimating the effective length factor, K, of columns in an unbraced frame. Note that the chart is based upon assumptions of idealized conditions, which seldom exist in real structures.
Allowable Strength*
Nominal strength divided by the safety factor.
Amplitude
A measure of floor vibration. It is the magnitude or total distance traveled by each oscillation of the vibration.
Amplification Factor
A multiplier of the value of moment or deflection in the unbraced length of an axially loaded member to reflect secondary values generated by the eccentricity of the load.
Anchor Bolt
A headed or threaded bolt typically complying with ASTM F1554, embedded into concrete and used to anchor columns or other members to a foundation.
Anchor Bolt Plan
A plan view showing the size, location, and projection of all anchor bolts.
Anchorage
The process of fastening a steel joist or joist girder to a masonry, concrete, or steel support by either bolting or welding.
Angle
A hot rolled shape called an Angle with symbol L, which has equal legs or unequal legs.
Angle Unit
A member used as a steel joist substitute, which is intended for use at very short spans (10 feet or less) where open web steel joists are impractical. They are usually used for short spans in skewed bays, over corridors, or for outriggers. It can be made up of two or four angles to form channel sections or box sections. Tube and channel sections are also used. See Joist Substitute.
ANSI
Abbreviation for ‘American National Standards Institute’.
A nonprofit organization, ANSI promotes the use of U.S. standards internationally.
Apex
The highest point on a steel joist or joist girder where the sloped chords meet. See also Peak.
API
Abbreviation for ‘Application Programming Interface’.
A set of rules, protocols, and tools that allow different software applications to communicate and exchange data without direct user interaction.
Applicable Building Code
Building code under which the structure is designed.
Approval Plans
Plans sent by the steel joist manufacturer to the buyer, engineer, architect, contractor or other person for approval. The plans may include a framing plan, elevations, sections, and a material list.
Arched Joist
A special profile steel joist where the top and bottom chords are curved parallel to each other.
ASCE
Abbreviation for ‘American Society of Civil Engineers’.
Founded in 1852, ASCE is the oldest national professional engineering society in the United States. It is dedicated to the advancement of the individual civil engineer and the civil engineering profession through education.
ASD
Abbreviation for ‘Allowable Strength Design’
ASD is a method of proportioning structural components such that the allowable strength equals or exceeds the required strength of the component under the action of the ASD load combinations.
ASD Load Combination
Load combination in the applicable building code intended for allowable strength design.
Aspect Ratio
For any rectangular configuration, the ratio of the lengths of the sides.
ASTM
Abbreviation for ‘American Society for Testing and Materials’.
ASTM has developed over 10,000 technical standards used by industries worldwide.
Atrium
An opening or skylighted lobby through two or more floor levels other than an enclosed stairway, elevator, etc.
AutoCAD
The world’s most popular computer-aided drafting software product for the personal computer in both DOS and windows by Autodesk, Inc. Anything that can be drawn on a drawing board can be drawn by AutoCAD.
Automatic Welding
A welding procedure using a machine to make a weld.
Auxiliary Load
Any dynamic live loads such as cranes, monorails, and material handling systems.
Available Strength*
Design strength or allowable strength as appropriate.
AWI
Abbreviation for ‘American Welding Institute’.
AWI was established in 1984 to bridge the gap between the findings of basic welding research and the needs of the industry.
AWS
Abbreviation for ‘American Welding Society’.
AWS is a non-profit organization whose major goal is to advance the science, technology, and application of welding and related joining disciplines.
Axial Force
A force tending to elongate or shorten a member.
Axial Compression
An axial force causing compression in a member.
Axial Load
A load whose line of action passes through the centroid of the member’s cross-sectional area and is perpendicular to the plane of the section.
Axial Strut Load
A structural member designed to transfer axial tension or compression load only.
Axial Tension
An axial force causing tension in a member.
Backing Bar
A welding aid used to prevent melting through of a joint when preforming, for example, a complete-joint penetration groove weld.
Balcony
An elevated platform or seating space of an assembly room projecting from a wall of a building.
Ballast Roof
A roof that has selected material, such as crushed stone, placed on its surface to hold down the roof from wind forces.
Bar
A square or round piece of solid steel, which is usually 6 inches or less in width.
Bar Joist
Open Web Steel Joist (OWSJ), a lightweight steel truss consisting, in the standard form, of parallel chords and a triangulated web system, proportioned to span between bearing points. Also known as metal joists or steel joists.
Base Metal
The metal to be welded or cut.
Base Plate
A steel plate welded to the base of a column, which distributes the column loads over an area of foundation large enough to prevent crushing of the concrete and usually secured by anchor bolts.
Base Ply
One layer of felt fastened to the metal deck over which a built-up roof is applied.
Batten
A small piece of angle or plate welded to a double angle, web member, or any two parallel components to tie them together and usually located at the middle of the member.
Bay
The distance between the main structural frames or walls of a building.
Beam
A structural member, usually horizontal, whose main function is to carry loads transverse to its longitudinal axis. These loads usually cause bending of the beam member. Some types of beams are simple, continuous, and cantilever.
Beam-Column
A structural member whose main function is to carry loads both parallel and transverse to its longitudinal axis.
Bearing
The distance that the bearing shoe or seat of a steel joist (bar joist) or Joist Girder extends over its masonry, concrete or steel support.
Bearing Plate
The steel plate used for a steel joist (bar joist) or Joist Girder to bear on when it is supported by masonry or concrete supports. The plate is designed by the Specifying Professional to carry the steel joist reaction to the supporting structure.
Bearing Wall
A wall supporting any vertical loads in addition to its own weight.
Bending Moment
The condition in the analysis of the internal stresses across the cross section of a member when it is subjected to forces that cause it to bend.
Bending Stress
Is zero at the neutral axis and assumed to increase linearly to a maximum at the outer fibers of the section. Formula in the elastic range: Bending stress (in psi)=(M * c)/I, where ‘M’ is the bending moment at the section in inch-lbs, ‘I’ is the moment of inertia of the section in inches^4, and ‘c’ is the distance from the neutral axis to the point at which the stress is desired in inches.
Bent
The plane of beam or joist girder members, which support loads and the columns which support these members.
Bevel Cut
A single cut made at an angle to the member length. See Miter Cut.
BG-Type Joist Girder
A type of joist girder where steel joists are located at all panel points at which vertical webs and diagonal webs intersect the top chord.
Biaxial Bending
Bending of a structural member at two perpendicular axes at the same time.
Bifurcation
The phenomenon whereby a perfectly straight member may either assume a deflected position, deflect, then twist out of plane, or may remain in an undeflected configuration.
Bill of Lading
A list that gives each part or mark number, quantity, length of material, total weight, or other description of each piece of material that is shipped to a jobsite. The receiver compares each item on this list to what is on the truck and signs the statement. See also Shipping List.
Bills of Material
A list of items or components used for fabrication and accounting purposes. See Cut-List.
BIM
Abbreviation for ‘Building Information Modeling’.
BIM ADDENDUM
Current model of contractual language.
BIM Master or Model Manager
Whoever contractually has control of the 3-D model, the gatekeeper and possibly manager of the server.
BIM Handbook
500-page guide published 2008 by John Wiley & Sons.
BioEdge
A sustainable steel product offering by Steel Dynamics, highlighted by use of electric arc furnaces, renewable energy, and renewable biocarbon as an alternative to use of anthracite in the steel production process.
Blasting
A method of cleaning or of roughening a surface by a forceable stream of sharp angular abrasive.
Blueprint
Also called a blue line, a blueprint is a copy of an architectural or other drawing made by a special machine usually on white paper with blue lines and text.
While this reproduction method of prints is no longer common, the word “Blueprint” is still utilized interchangeably with “plan set” or “construction drawing set.”
BOCA
A minimum model regulatory code for the protection of public health, safety, welfare, and property by regulating and controlling the design, construction, quality of materials, use, occupancy, location, and maintenance of all buildings and structures within a jurisdiction. The last printing of BOCA was in 1999, and it is no longer in current adoption or use. However, many of its design principles were carried over into the current IBC code. (See IBC.)
Bolted Splice
The connection between two structural members joined at their ends by bolting to form a single, longer member.
Bond Beam
The top course of block of a masonry wall filled with concrete and reinforcing steel and used to support roof loads.
Bottom Bearing
A bearing condition, where the steel joist or joist girder bears on its bottom chord and not at an underslung condition.
Bottom Chord
The bottom members of a steel joist or joist girder.
Bottom Chord Extension (BCX)
The extended part of a joist bottom chord from the first bottom chord panel pointing towards the end of the steel joist (bar joist).
Bottom Chord Strut
A bottom chord of a steel joist or joist girder designed to transfer an axial tension or compression load.
Boundary Condition
An idealization to model how a structure is attached to its “external” points of support, for example, pin, fixed, roller, or shear release.
Bow String Joist
A special profile steel joist where the top chord is curved and the bottom chord is straight or level.
Bow’s Notation
Used in a graphical analysis of a steel joist or joist girder. It is a notation for denoting truss joints, members, loads, and forces. Capital letters are placed in the spaces between truss members and between forces. Each member and load is then designated by the letters on opposite sides of it.
BPM
Abbreviation for ‘Building Product Manufacturer’.
Braced Frame
A frame that resists lateral loads using diagonal bracing, K-braces, or other system of bracing.
Bracket
A structural support attached to a column or wall on which to fasten another structural member.
Bridge Crane
A lifting system which has a hoist that moves laterally on a beam or other member, which then in turn moves longitudinally on a runway made of beams and rails.
Bridging
In general, a member connected to a steel joist (bar joist) to brace it from lateral movement. See also Diagonal Bridging and Horizontal Bridging.
Bridging Anchor
An angle or bent plate attached to a wall where the bridging will be attached or anchored, either by welding or bolting. The ends of all bridging lines terminating at walls or beams shall be anchored thereto.
Bridging Clip
A small piece of angle or plate with a hole or slot that is welded to the top and bottom chord angles so that bridging may be attached.
Bridging Diagram
A diagram of the profile of a steel joist used to show the number and location of the rows of bridging.
Brittle Fracture
The tearing or splitting of a member with little or no prior ductile deformation.
BTU
Abbreviation for ‘British Thermal Unit’.
The amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
Buckling
Limit state of sudden change in the geometry of a structure or any of its elements under a critical loading condition.
Buckling Load
The load at which a straight member, under compression, transfers to a deflected position.
Buckling Strength
Nominal strength for buckling or instability limit states.
Building
Any structure used for support or for shelter.
Building Code
Regulations established by a recognized agency describing design loads, procedures, quality of materials, and construction details for buildings for the protection of the public. (See IBC.)
Building Designer
A registered architect or registered engineer who is responsible for the design of a structure. See Specifying Professional.
Building Official
The officer or other authority, which has the duty of administration and enforcement of a building code.
BuildingSmart
Trademarked NIBS effort to standardize and coordinate the business sector’s effort in IFC.
Built-Up Roof
A type of roof composed of two or more layers of alternating felt, tar and asphalt.
Built-Up Section
A structural member made up from individual flat plates welded together or any structural metal elements that are welded or bolted together.
Butt Plate
The end plate of a structural member usually used to rest or butt against a like plate of another member in forming a connection.
Buyer
The entity that has agreed to purchase material from the manufacturer and has also agreed to the terms of sale.
C Shapes
A hot rolled shape called an American Standard Channel with symbol C.
“C” Section
A structural member cold-formed from sheet steel in the shape of a block “C” which can be used by itself or back to back with another C Section.
CAD
Abbreviation for Computer-Aided Drafting.
Calipers
A mechanical instrument usually having a pair of pivoted legs adjustable to any distance and used to measure thickness, distances between surfaces, and any internal or external diameter which is inaccessible with a scale.
Camber
An upward curvature of the chords of a steel joist (bar joist) or Joist Girder induced during shop fabrication. Note this is in addition to the pitch of the top chord.
Canopy
A roof structure that projects or stands alone from the main building structure.
Cant Strip
A metal decking accessory which is a short piece of gage steel used at 45 degrees where a wall or parapet meets the end of deck.
Canted Seat
A seat that is sloped perpendicular to the member, which most steel joist manufacturers do not do. Usually, the steel contractor furnishes a bent plate shim to provide level bearing for the joist seat.
Cantilever
The part of a member that extends freely over a support, which is not supported at its end.
Cap Plate
A steel plate welded to the top of a column, which a steel joist, joist girder, or other structural member can bear on.
Catwalk
Suspended structural framing used to provide access to and between areas below a roof and above a floor.
CD
Construction Drawings or documents
Ceiling Extension
A bottom chord extension except that only one angle of the steel joist (bar joist) bottom chord is extended from the first bottom chord panel point towards the end of the steel joist.
Centerline Span (or Center-to-Center)
A theoretical span definition, which is the distance between the actual centerlines of a beam, column, steel joist, or joist girder.
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.
Certified Welder
A welder who has been certified by a competent experienced welding inspector or a recognized testing facility in the field of welding. The welder must be certified to make certain welds under qualified procedures. The welder must be qualified for each position, type of weld, electrode, and thickness of base metal that is to be welded in the shop or field. (See AWS.)
Change Order
A written document which modifies the plans, specifications, or price of a construction contract.
Channel
A hot rolled structural shape that looks like “[“. There are American Standard Channels designated by (C) and Miscellaneous Channels designated by (MC).
Chords
The top and bottom members of a steel joist (bar joist) or Joist Girder. When a chord is comprised of two angles there is usually a gap between the members.
CIS/2
An AISC approved steel industry file format for electronic exchange of data, one of several file formats being considered as “interoperable” for BIM participation, not supported by contractor software.
Cladding
The exterior covering of the structural members of a building.
Clashes
Instances noted by a 3D drawing where two elements occur in the same space and conflict, i.e. ductwork that collides with steel joist (bar joist) members.
Clash Detection
Property built into some but not all 3-D software.
Clash Meetings
Meetings (possibly weekly) by A/E, G.C., subs and others to resolve clashes.
Clear Span
The actual clear distance or opening between supports for a steel joist (bar joist) that is the distance between walls or the distance between the edges of flanges of beams
Clevis
A U-shaped yoke with internal threads in one end, which can be attached to a threaded rod and the other end a connection with a hole used for a pin or bolt attachment.
Clip Angle
A structural angle, which attaches to the side of a wall, column, beam, etc. where a steel joist, joist girder, or other structural member bears.
Closure Strip
A floor deck accessory made of gage metal which is placed over the ends of metal decking so that concrete cannot run out of the flutes of the deck.
Coefficient of (Linear) Expansion
The change in length, per unit, for a change of one degree of temperature.
Cold-Formed Steel Structural Member
Shape manufactured by press-braking blanks sheared from sheets, cut lengths of coils or plates, or by roll forming cold- or hot-rolled coils or sheets; both forming operations being performed at ambient room temperature, that is, without manifest addition of heat such as would be required for hot forming.
Collateral Load
All additional dead loads other than the weight of the building, such as sprinklers, pipes, ceilings, and mechanical or electrical components.
Collocate
Putting employees from different disciplines on the same site to expedite the BIM coordination and clash resolution process. i.e., steel joist (bar joist) draftsman going to the steel detailer’s site.
Column
A main vertical member carrying axial loads, which can be combined with bending and shear, from the main roof beams or girders to the foundation. These structural members carry loads parallel to its longitudinal axis.
Column Curve
A curve that shows the relationship between axial column strength and slenderness ratio.
Compact Section
A steel section whose flanges must be continuously connected to the webs and the width-thickness ratios of its compression element, and cannot exceed the limiting width-thickness ratios designated in the AISC Manual.
Composite Beam
A steel beam and a concrete slab connected, usually by shear stud connectors, so that they act together to resist the load on the beam.
Composite Joist
An open-web steel joist and a concrete slab connected, by shear studs, so that they create a unified load bearing floor system.
Compound Arch Joist
A special profile steel joist where the top and bottom chords are curved but not parallel to each other.
Compound Scissor Joist
A special profile steel joist where the top and bottom chords are double pitched but not parallel with each other.
Compression
A condition caused by the action of squeezing or shortening of a component.
Compression Member
Any member in which the primary stress is longitudinal compression.
Concentrated Load
A single load or force that has such a small contact area as to be negligible compared with the entire surface area of the supporting member and applied at a certain point on the structure.
Connection
Combination of structural elements and joints used to transmit forces between two or more members. See also Splice.
Continuity
The term given to a structural system denoting the transfer of loads and stresses from member to member, as if there were no connections.
Continuous Span
A span that extends over several supports and has more than two points.
Continuous Weld
A weld that extends continuously from one end of a joint to the other.
Contract
A legal document or agreement, enforceable by law, between two or more parties for the doing of something specified, such as the building of a building or furnishing materials.
Contract Documents
Contract drawings, specifications, etc., used to build a structure which define the responsibilities of the parties involved.
Contract Drawings
All the architectural, structural, mechanical, electrical, etc. plans that make up a legal set of contract documents to build a building by.
Conventional Framing
Framing using conventional steel joists, beams, columns, masonry walls, etc. instead of framing used in Metal Building construction.
Coping
The process of removing certain sections of a structural steel member to allow easier fitup to the supporting structural member.
Corbel
Successive courses of masonry projecting from the face of a wall to increase its thickness or to form a shelf or ledge for a structural member to bear on.
Cover Plate
A long plate usually welded to the top or bottom flange of a rolled steel beam or to the bottom chord of a steel joist or joist girder to increase the load carrying capacity of that member.
Coverage
The width of a steel deck sheet, i.e., 30 inches or 36 inches.
Crane
A machine used to move material by means of a hoist; 2) A machine that can usually move and is used to lift heavy materials or to lift members that are to be erected in a structure.
Creep
A time-dependent deformation of a structural member under a sustained constant load.
Cricket
A ridge or drainage diverting roof framing.
Crimped Angle Web
A regular angle whose ends have been ‘crimped’ in the shape of a ‘U’ whose out-to-out distance is usually one inch. The actual crimped portion of the angle is only a few inches on each end and the end is inserted between top or bottom chord members to be welded.
Critical Load
The load at which deflection of a member or structure occurs as determined by stability analysis.
CSI
Abbreviation for ‘Construction Specifications Institute’.
CSI is a non-profit association that brings together AECO professionals to improve construction documentation.
Curb
A raised edge of a concrete floor slab or support for a mechanical unit.
Curtain Wall
A non-load bearing exterior wall, which carries only its own weight and wind load.
Curvature
The rotation per unit length of a member due to bending forces.
Cut-List
A list of components with dimensions used for fabrication and accounting purposes. See Bill of Materials.
Damping
For floor vibrations, it is the rate of decay of amplitude.
DB
Abbreviation for ‘Design-Build’.
A Project Delivery System where, in contrast to “design-bid-build” (or “design-tender”), the design and construction aspects are contracted by a single entity.
DBB
Abbreviation for ‘Design-Bid-Build’.
DD
Abbreviation for ‘Design Drawings’ or documents.
Dead Load
Loads due to the weight of the components making up the structure and that are intended to remain permanently in place.
Deck
A floor or roof covering made out of gage metal attached by welding or mechanical means to steel joists (bar joists), beams, purlins, or other structural members and can be galvanized, painted, or unpainted.
Design Load
Applied load determined in accordance with either LRFD load combinations or ASD load combinations, whichever is applicable.
Deck Type
The specific type of steel deck to be specified, such as Type “B” Wide Rib, Type “F” Intermediate, Type “N” Deep Rib, Type “A” Narrow Rib, Composite, Cellular, etc.
Deflection
The displacement of a structural member or system under load.
Deformation
The act of distorting or changing the shape or dimensions of a structural element or body resulting from forces or stresses.
Depth of Joist
The out-to-out distance from the top of the top chord to the bottom of the bottom chord taken at some reference location, usually at the midspan of the steel joist or joist girder.
Design Documents
The plans, details, sections, specifications, etc. prepared by the building designer.
Design Length
The span of a steel joist or joist girder, minus any bearing setbacks or other adjustments impacting the working point at each end.
Design Loads
The loads specified in the contract drawings or specifications, which a building is to be designed for.
Design Strength*
Resistance factor multiplied by the nominal strength.
Diagonal Bracing
Structural members, which are inclined and are usually carrying axial load which enable a structural frame to behave as a truss to resist horizontal loads.
Diagonal Bridging
Two angles or other structural shapes connected from the top chord of one steel joist (bar joist) to the bottom chord of the next joist to form an ‘X’ shape. These members are almost always connected at their point of intersection.
Diaphragm
Roof, floor or other membrane or bracing system that transfers in-plane forces to the lateral force resistance system.
Diaphragm Action
The resistance to a racking effect or in-plane shear forces offered by roof deck, panels, or other structural members when properly attached to a structural frame.
Double Curvature
When end moments on a structural member produce a bending effect which causes the member to form an S shape or has a reversal in curvature.
Downstanding Leg
The leg of a structural angle, which is projecting down from you when viewing.
Drift
The lateral movement or deflection of a structure.
Drift Index
The ratio of the lateral deflection to the height of the building.
Drift Pin
A tapered pin used during the erection process to align holes in steel members, which are to be connected by bolting.
Duct
Any tube, pipe or other conduit by which air or fluid is transferred.
Duct Opening
The round or square opening required through the web system of a steel joist or joist girder to allow passage of a duct.
Ductility
The ability of a material to withstand large inelastic deformations, without fracture. Structural steel has considerable ductility.
Ductility Factor
The ratio of the total deformation at maximum load to the elastic-limit deformation.
DWF
Abbreviation for ‘Drawing Web Format’.
DWG
AutoCAD drawing format.
DXF
Abbreviation for ‘Drawing Exchange Formats’.
Dynamic Joist™
3-D BIM digital steel joist design component add-on for Tekla Structures version 16.0 R1.
Dynamic Load
A load that varies with time, which includes repeated loads, seismic loads, and other loads created by rapid movement.
Dynamic Manufacturing
New Millennium’s unique ability to adjust to any steel joist or metal decking project timeline or changing erection site needs, including staged and just-in-time deliveries.
Eave
The line along the sidewall of a building, formed by the intersection of the plane of the roof and the plane of the wall.
Eave Height
The vertical distance from finished floor to the eave.
Eave Strut
A structural member located at the eave of a building, which supports a roof and/or wall panels.
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.
Eccentricity
The distance between a line of action of force and the centroid of the member it is applied to.
Edge
A sustainable steel product offering by Steel Dynamics, highlighted by use of electric arc furnaces and renewable energy in the steel production process.
Edge Angle
1) A structural angle that is connected around the edge of a steel joist extension or other member 2) An angle used around the sides of a floor to contain the concrete when it is being poured which is also called a Pour Stop.
Edge Distance
The distance from the center of a hole to the edge of a connected part.
Edge Strip
The width or region around the edges of a building where uplift values are higher than in the interior of the roof.
Effective Depth
The distance from the centroid of the top chord to the centroid of the bottom chord.
Effective Length
The equivalent length, KL, used in compression formulas. This method estimates the interaction effects of the total frame on a compression member by using K factors to equate the strength of a framed compression member of length L to an equivalent pin-ended member of length KL subject to axial load only.
Effective Length Factor (K)
The ratio between the effective length and the unbraced length of a member measured between center of gravities of the bracing members. K values are given for several idealized conditions in which joint rotation and translation are realized.
Effective Moment of Inertia
The moment of inertia of the cross section of a member that remains elastic when partial plastification takes place. See Moment of Inertia.
Effective Width
The transverse distance indicating the amount of slab that acts in conjunction with the supporting member.
EJ
Abbreviation for ‘Expansion Joint’.
Elastic Analysis
The analysis of a member, which assumes that material deformation disappears on removal of the force that produced it and the material returns to its original state.
Elastic Design
See Allowable Stress Design and Working Stress Design.
Electrode
The device through which current is conducted through to the arc or base metal during the process of welding.
Embedment
A steel member such as a plate, bolt, stud, or bar cast into a concrete structure, which is used to transmit applied loads to the concrete.
End Bay
The bay that is located from the end of a building to the first interior main frame.
End Diagonal or Web
The first web member on either end of a steel joist or joist girder, which begins at the top chord at the seat and ends at the first bottom chord panel point.
End Distance
The horizontal distance from the first top chord panel point at the end of a steel joist to the first bottom chord panel point.
End Lap
The lap at the end of a sheet of steel deck, which bears over the primary support (steel joist or beam).
End Moment
A moment that is generated at one end or both ends of a steel joist, joist girder, or beam due to continuous frame action which can be caused by wind, live load, or dead load moment.
End Panel
The distance from the panel point at the steel joist seat to the first top chord panel point towards the interior.
End Wall
An exterior wall, which is perpendicular to the ridge of the building.
Envelope
A graphical plot indicating the maximum magnitude of an internal force effect, such as flexural stress, shear stress, axial stress, torsional stress, etc. due to a series of load combinations.
EOD
Abbreviation for ‘Edge of Deck’.
EOJ
Abbreviation for ‘Edge of Joist’.
EOS
Abbreviation for ‘Edge of Slab’.
Equations of Equilibrium
The equations relating a state of static equilibrium of a member or structure, when the resultant of all forces and moments are equal to zero. Three equations must be fulfilled simultaneously: Sum of the forces in the X-direction must equal zero, sum of the forces in the Y-direction must equal zero, and the sum of the moments about any point must equal zero for a two dimensional structure.
Equivalent Uniform Load
A uniform load (in plf) derived from the maximum reaction (in lbs) or the maximum moment (in inch-lbs) of a member carrying various loads. Formula: Weq= 2 * max. reaction (in lbs) divided by length (in feet) or Weq=(8 * max. moment) divided by (lenght^2 (in feet) * 12)
Erection
The process of installing steel joists, joist girders, beams, bridging, metal decking, or other structural members in order to construct a structure.
Erection Plan
Floor or roof plans that identify individual marks, components, and accessories furnished by the steel joist manufactures in a detailed manner to permit proper erection of the steel joist and joist girders. See Framing Plan and Placing Plan.
Erector
The entity that is responsible for the safe and proper erection of the materials in accordance with all applicable codes and regulations.
ERP
Abbreviation for ‘Enterprise Resource Planning’ – a computer system.
ETO
Abbreviation for ‘Engineered to Order’.
Expansion Joint
A break in construction or a special design detail to allow for thermal expansion and contraction of the materials of a structure.
EXPRESS
Data modeling language.
Extended End
The extended part of a joist top chord with the seat angles also being extended from the end of the steel joist (bar joist) extension back into the joist and maintaining the standard end bearing depth over the entire length of the extension.
Fabrication
The manufacturing process to convert raw materials into a finished product, by cutting, punching, welding, cleaning, and painting.
Factor of Safety
Is the ratio of the ultimate load for a member divided by the allowable load for a member and must always be greater than unity.
Factored Load
Product of a load factor and the nominal load.
Farside
For steel joists and joist girders, when looking at the member with the tagged end to the left, it is the side that is opposite the side you see first.
Fascia
The flat surface located at the outer end of a roof overhang, or cantilever end, or also a decorative trim or panel which projects from the face of a wall.
Fastener
Term for a connecting device such as a weld, bolt, rivet, etc.
FC
Abbreviation for ‘Field Cut’.
FCI
Abbreviation for ‘Facility Condition Index’.
Metric related to BIM for older pre-existing facilities.
Field
A term used for the jobsite or building site where construction of the project will take place.
Field Weld
A weld performed on-site by a certified welder. Shop welds are generally preferred due to their controlled environment and lower cost.
Filler
A rod, plate, or angle welded between a two-angle web member or between a top or bottom chord panel to tie them together, usually located at the middle of the member. See Tie or Plug.
Finish
In deck terminology, the coating on the steel deck sheet, i.e., galvanized, painted, or unpainted.
Finish Strip
A roof deck accessory made out of gage metal for finishing out runs of steel deck for small areas of coverage where full sheet coverage is impractical.
Fireproofing
The process of coating a structural steel member with a fire retardant material to make the member resistant to fire.
Fire-Resistance
The ability of a steel joist or other structural member to resist a fire due to the type of protection it has, such as membrane protection or spray on protection. There are hundreds of floor-ceiling or roof-ceiling assemblies with their fire-resistance rating given in the Underwriters Laboratory Fire Directory.
Fixed-End Support
A condition where no rotation or horizontal or vertical movement can occur at that end. This type of support has no degrees of freedom. Three reactive forces exist at the rigidly fixed end. See also Rigid Connection.
Flange
A structural bracing member used to provide lateral support to the flange of a beam, the bottom chord or a joist girder, or a column.
Flange Brace
A steel member such as a plate, bolt, stud, or bar cast into a concrete structure, which is used to transmit applied loads to the concrete.
Flashing
Pieces of sheet metal or the like used to cover and protect joints, etc. where a roof comes in contact with a wall or chimney.
Flexible to the Finish
We keep our promises. When you ask for steel joists and metal decking delivered by a certain time, and we say we can do it, it gets done. We don’t overlook the details that can bring a job to a standstill. We refuse to let little problems become big problems.
Flexural Buckling
Buckling mode in which a compression member deflects laterally without twist or change in cross-sectional shape.
Flexural-Torsional Buckling
Buckling mode in which a compression member bends and twists simultaneously without change in cross-sectional shape.
Flush-Frame Connection
A bolted, joist end connection that allows for the top of the joist top chord to sit level and flush with the supporting girder beam. The flush frame connection allows for the girder beam to be composite design and can also increase the floor vibration performance. New Millennium provides standardized joist flush frame connection details, calculations, and CAD files available for download.
Flute
The fold or bend in a sheet of steel deck which forms a groove or furrow.
FM Global
A leader in property loss prevention engineering and adjustment. It helps companies prevent and control property loss through research, engineering, and education. Previously known as Factory Mutual or Factory Mutal Systems.
Folding Partition
A moveable wall on a track suspended from a steel joist or beam, which usually folds like an accordion and can be stored in a closet or pocket in a wall.
Footing
A concrete pad or mat located under a column, wall, or other structural member that distributes loads from that member into the supporting soil.
Foundation
The substructure that supports a building or other structure.
Frame
A structural framing system consisting of members joined together with moment or rigid connections, which maintain their original angular relationship under load without the need for bracing in its plane. See Rigid Frame.
Framed Opening
Headers or other structural members, which surround an opening in a roof which can be for mechanical units, stairwells, etc.
Framing Plan
Floor or roof plans that identify individual marks, components, and accessories furnished by the steel joist manufactures in a detailed manner to permit proper erection of the steel joist and joist girders. See Erection Plan and Placing Plan.
Free-Body Diagram
A diagram on which all of the external forces acting on a body are shown at their respective points of application.
Frequency
A measure of floor vibration. It is the speed of the oscillations of vibration and is expressed in cycles per second or Hz (Hertz).
G-Type Joist Girder
The triangular portion of a roof located above the elevation of the eave line of a double-sloped roof.
Gable
Product of a load factor and the nominal load.
Gable Joist
A special profile steel joist where the top chord is double pitched at an extreme pitch (for example, 3/12) and the bottom chord is straight or level.
Gage
1) The thickness of a sheet of deck; or 2) The distance from centerline hole to centerline hole across a set of holes, usually perpendicular to the steel joist or joist girder.
Galvanized
The process of coating steel with zinc for corrosion resistance.
Gambrel
A roof having two slopes on each side, the lower slope usually steeper than the upper one.
gbXML
New subset of BIM efforts that focuses on green building design and operation and organizes information for energy simulation purposes.
Girder
A main horizontal, primary structural member spanning between two main supports, which carries other members or vertical loads.
Girt
Horizontal structural member that supports wall panels and is primarily subjected to bending under horizontal loads, such as wind load.
Grade
The ground elevation around a building.
Gravity Load
Load, such as that produced by dead and live loads, acting in the downward direction.
Grillage Beam
A short beam used like a bearing plate to distribute large reactive loads to a wall such as the load from a joist girder.
Gusset Plate
A steel plate used to connect structural steel members or to reinforce members. It is usually inserted between the top or bottom chord of a steel joist or joist girder.
H-Series Joist
A series of joist adopted in 1961 so proportioned that the allowable tension or bending stress does not exceed 22,000 psi or 30,000 psi depending on whether 36 ksi or 50 ksi yield steel was used.
Hardness
Is a measure of the resistance of a material to scratching and indention.
Header
A structural member located between two steel joists or between a steel joist and a wall, which carries another steel joist or joists. Usually made up of an angle, channel, or beam with saddle angle connections on each end for bearing.
Head-of-wall
Head-of-wall refers to the linear gap at the top of a wall assembly and the bottom of a floor or roof. U.S. building codes stipulate the presence of a head-of-wall fire resistive joint system in that gap. Versa-Dek® dovetail deck meets head-of-wall requirements by staggering its deck flutes to create a UL-rated, uninterrupted concrete break that compartmentalizes fire and smoke at the bearing wall. It creates a condition that does not require fire sealant, which can be expensive and labor-intensive to install.
Heel
The outside point of a structural angle, where the two perpendicular legs intersect.
High Strength Bolts
A structural steel bolt having a tensile strength greater than 100,000 pounds per square inch, usually A325 or A490.
High Strength Steel
Structural steel having a yield stress greater than 36,000 pounds per square inch.
Hinge Support
This type of support has one degree of freedom, it can freely rotate about its axis but it cannot displace in any direction. Two mutually perpendicular reactive forces exist at the hinge and their lines of action pass through the center of the hinge. See Pin Connection or Support.
Hip Roof
A roof that slopes from all four sides of a building. The line where two adjacent sloping sides intersect is called the ‘hip’.
Hip and Valley
A system of roof framing, where support members form valleys and ridges.
Hoist
A chain or electric lifting device usually attached to a trolly, which travels along a monorail or bridge crane.
Homogeneous Material
A material having the same engineering design properties throughout.
Hooke’s Law
The linear relationship of forces and deformations, or stresses and strains.
Horizontal Bridging
A continuous angle or other structural shape connected to the top and bottom chord of a steel joist horizontally whose l/r ratio cannot exceed 300.
Horizontal Shear Stress
Is zero at the outer fibers of a section and is maximum at the neutral axis. It tends to cause one part of the section to slide past the other. Formula: Horizontal Shear stress (in psi)=(V * Q)/I*t, where ‘V’ is the external vertical shear on the section in lbs, ‘I’ is the moment of inertia of the section in inches^4, ‘Q’ is the statical moment about the neutral axis of the entire section of that portion of the cross-section lying outside of the cutting plane and ‘t’ is the width at the cutting plane.
Hot-Rolled Shapes
Structural steel sections which are formed by rolling mills from molten steel which can be angles, channels, W Shapes, S Shapes, etc.
HP Shapes
A hot rolled shape with symbol HP used for bearing piles, which have essentially parallel flanges and equal web and flange thickness.
Hysteresis
A term that describes the behavior of a structural member subjected to reversed, repeated load into the inelastic range whose plot of load verses displacement is characterized by loops. The amount of energy dissipated during inelastic loading is indicated by the enclosed area within these loops.
IAI
Abbreviation for ‘International Alliance for Interoperability’.
IBC
Abbreviation for ‘International Building Code’.
An American building code standard, published by the ICC, and currently adopted by most US jurisdictions having authority over building permits and construction.
ICBO
Abbreviation for ‘International Conference of Building Officials’. (Uniform Building Code)
A minimum model of regulatory code dedicated to public safety through development and promotion of uniform codes and standards.
ICC
Abbreviation for ‘International Code Council’.
An American nonprofit standards organization for building trades. The ICC is responsible for developing and publishing the majority of the building trade codes, including the IBC, currently adopted by cities, counties, and states within the US. The ICC also completes product evaluation services for the building trades (ICC-ES Reports), including New Millennium joist and deck products.
Ice Dam
A dam or blockage formed on a roof by the buildup of ice along the eave of a building.
IDM
Abbreviation for ‘Information Delivery Manual’ – European effort in IFC, see NBIMS.
IFC
Abbreviation for ‘Industry Foundation Classes’.
A broad term for standard formats used for most BIM electronic data exchange, developed by the IAI.
IGES
Abbreviation for ‘Initial Graphics Exchange Specification’.
Standard format for exchanging three-dimensional data and information.
Impact Factor
The factor by which the static weight is increased by dynamic application.
Impact Load
A weight that is dropped or a dynamic load generated by movement of a live load such as vehicles, craneways, etc.
Impact Strength
The ability of a material to absorb the energy of a load delivered rapidly to a member.
Impact Wrench
A pneumatic device used to tighten nuts on bolts.
Inclusions
Nonmetallic material that is entrapped in sound metal.
Inelastic Action
Deformation of a material that does not disappear when the force that produced it is removed.
Inelastic Analysis
Structural analysis that takes into account inelastic material behavior, including plastic analysis.
Inflection Point
Represent a point of zero moment in structural member.
Influence Line
An influence line is a curve whose ordinates give the values of some particular function (shear, moment, reaction, etc.) in an element due to a unit load acting at the point corresponding to the particular ordinate being considered. Influence lines for statically determinate structures are straight lines and for statically indeterminate structures the lines are curved and their construction involves considerable analysis.
Instability
A condition reached when a structure or structural member is loaded in which continued deformation results in a decrease in its load-resisting capacity.
Insulation
Any material used to reduce heat transfer in a roof or building.
Integrated Project Delivery
The collaborative process of people, systems, business structures and practices that harnesses the talents and insights of all participants to optimize project results, increase value to the owner, reduce waste, and maximize efficiency through all phases of design, fabrication, and construction.
Intermittent Weld
A weld that is not continuous. It is broken by recurring, unwelded spaces.
Internal Pressure
The pressure inside a building, which is a function of the wind velocity and the number and locations of openings.
Interior Bearing
Bearing supports that are interior to two exterior supports.
IPD
Abbreviation for ‘Integrated Project Delivery’.
ISO 9000
Abbreviation for ‘International Organization for Standardization’.
A series of quality management and assurance standards that companies follow to achieve certification.
Isotropic
A material having equal physical properties along all axes.
J-Series Joist
A series of steel joist adopted in 1961 so proportioned that the allowable tension or bending stress does not exceed 22,000 psi and was made from A36 steel.
Jack Truss
A small triangular shaped truss on a hipped roof that bears on a girder truss at the deeper end and at a perimeter wall or beam at the shallow end.
JBE
Abbreviation for ‘Joist Bearing Elevation’.
Jib Crane
A cantilevered boom or beam with a hoist and trolley used to pick up loads in all or part of a circle around which it is attached.
Jig
A device which holds work or pieces of material in a certain position until rigidly fastened or welded during the fabrication process.
Jobsite
The specific location where a structure is being built.
Joint
The minimum depth the weld metal extends from its face into a joint.
Joist
A structural load-carrying member with an open web system which supports floors and roofs utilizing hot-rolled or cold-formed steel and is designed as a simple span member. Also known as steel joist or bar joist. Currently, the SJI has the following joist designations: K-Series including KCS, LH-Series and DLH-Series.
Joist Designation
A standard way of communicating the joist safe uniformly distributed load-carrying capacities for a given span such as 16K5 or 24K10 where the first number is the nominal steel joist depth at midspan and the last number is the chord size. See Longspan Designation and Joist Girder Designation.
Joist Girder
A primary structural load-carrying member with an open web system designed as a simple span supporting equally spaced concentrated loads of a floor or roof system acting at the panel points of the member and utilizing hot-rolled or cold-formed steel.
Joist Girder Designation
A standard way of communicating the girder design loads. For example, for 48G6N10.5K, “48G” is the nominal girder depth at midspan; “6N” is the number of steel joist spaces on the span of girder; and “10.5K” is the kip load on each panel point of the girder.
Joist Manufacturer
The producer of steel joists (bar joists) special profile joists (specialty joists) or joist girders who is SJI approved.
Joist Spacing
The distance from one steel joist to another.
Joist Substitute
A structural member who’s intended use is for very short spans (10 feet or less) where open web steel joists (bar joists) are impractical. They are usually used for short spans in skewed bays, over corridors or for outriggers. It can be made up of two or four angles to form channel sections or box sections.
K-Distance
The distance from the outside fiber of a rolled steel beam to the web toe of the fillet of a rolled shape.
K-Series Joist
A series of steel joist adopted in 1986 based on a load/span type of determination.
KCS Joist
Is a K-Series steel joist that is designed to support uniform load plus concentrated loads or other non-uniform loads.
Kerf
The width of a cut produced during a cutting process.
Key Plan
A small reference plan or outline of the whole building on each plan sheet divided into smaller areas, for which each sheet is drawn. It can also show different sequences, phases, sheet number that area is drawn on, etc.
Kicker
A structural member used to brace a steel joist or beam usually at an angle.
Kilo
SI prefix for 10^3 or 1000.
Kip
A unit of weight equal to 1000 pounds.
Knee Brace
A structural brace positioned diagonally between a beam or column and a steel joist panel point.
Knife Plate Seat
A vertical plate used as a steel joist seat whose width is small for bearing purposes. It is used for hip and valley bearing conditions, canted seat conditions, and extreme skewed conditions.
KSI
Abbreviation for ‘Kips per Square Inch’.
KSI is a unit that represents 1000 pounds per square inch.
KSF
Abbreviation for ‘Kips per Square Foot’.
KSF is a unit that represents 1000 pounds per square foot.
Lamellar Tearing
Is a separation or crack in the base metal caused by through-thickness weld shrinkage strains of adjacent weld metal.
Lateral Buckling
Buckling mode of a flexural member involving deflection normal to the plane of bending.
Lateral Bracing
Members, fasteners, or welds, which brace a member at certain locations to prevent lateral movement.
Lateral-Torsional Buckling
Buckling mode of a flexural member involving deflection normal to the plane of bending occurring simultaneously with twist about the shear center of the cross section.
Lean Principles
Controlling project to minimize cost i.e. steel joists and metal decking delivered to site in accurate liftable bundles, ready for trailer straight to erection.
Lean-To
A structure depending upon another structure for support and having only one slope such as a shed.
LEED
Abbreviation for Leadership in ‘Energy and Environmental Design’.
The standard for Green Building design.
Leeward
The direction toward which the wind is blowing, which is opposite the side from which the wind blows. Opposite of windward.
Leg
The flat projecting part of a structural angle.
Leveling Plate
A steel plate used on top of a foundation on which a structural column can be placed.
Limit State
Condition in which a structure or component becomes unfit for service and is judged either to be no longer useful for its intended function (serviceability limit state) or to have reached its ultimate load-carrying capacity (strength limit state).
Lintel
A horizontal structural member spanning a door, window, or other wall opening which supports a wall or any construction immediately above.
Live Load
Loads on a member that are not permanent and are likely to be moved at some point in the life of the structure. They can be loads produced by the use and occupancy of the building. These loads do not include dead load, wind load, snow load, or seismic load.
Load
Force or other action that results from the weight of building materials, occupants and their possessions, environmental effects, differential movement, or restrained dimensional changes.
Load Combination
The combination of loads that produce the worse loading condition in a structural member.
Load Effect
Forces, stresses, and deformations produced in a structural component by the applied loads.
Load Factor
Factor that accounts for deviations of the nominal load from the actual load, for uncertainties in the analysis that transforms the load into a load effect, and for the probability that more than one extreme load will occur simultaneously.
Load Table
A table of standard steel joist designations which give the total safe uniformly distributed load-carrying capacities and live load-carrying capacities of the steel joists for different span lengths. The table also gives the approximate weight per foot of each steel joist designation.
M Shapes
A hot rolled shape called a Miscellaneous Shape with symbol M that cannot be identified as W, HP, or S Shapes.
Major Axis
The axis of a structural member possessing the largest section modulus and radius of gyration, thus having the greatest flexural and axial compressive strength.
Mark
An identification number or method of relating to the erector which steel joist, joist girder or other separate part of the building goes at what location when being erected, i.e., J1, K25, L7, G12, or JG9. See Piece Mark and Part Number.
Masonry
A type of construction from materials such as concrete blocks, bricks, concrete, stone, or ceramic blocks which is laid unit by unit and set in mortar.
Material
Steel joists (bar joists), Joist Girders, metal decking and accessories as provided by the Seller.
Maxwell Diagram
A graphical method of determining stresses in a truss, by combining force polygons of all the joints into one stress diagram.
MBMA
Abbreviation for ‘Metal Building Manufacturers Association’.
An association of metal building systems manufacturers whose objectives are to compile and publish recommended design standards that ensure high-quality metal buildings.
MC Shapes
A hot rolled shape called a Miscellaneous Channel with symbol MC.
Mega
SI Prefix for 10^6 or 1000000.
Member Release
An idealization to model how members are attached to “each other”. It designates whether forces and moments at the ends of a member are considered fixed to or released from the member’s point of attachment.
MEP
Mechanical, Electrical, and Plumbing – generally encompassing construction elements of various trades to be considered in a BIM approach.
Metal Building
Also known as a steel building, a metal structure fabricated with steel for the internal support and, commonly but not exclusively, for exterior cladding.
Metal Building System
A building system consisting of a group of coordinated components, which have been designed for a certain loading. These components are mass produced and assembled in various combinations with other structural materials to produce a building.
Metal Decking
Also known as steel decking, a structural corrugated steel component used as the material layer between the primary structural components.
Metal Joists
Open Web Steel Joist (OWSJ), a lightweight steel truss consisting, in the standard form, of parallel chords and a triangulated web system, proportioned to span between bearing points. Also known as steel joists or bar joists.
Metal Stud
A structural steel member used for framing walls just as a regular wooden one.
Mezzanine
A low floor between two stories in a building, usually just above the ground floor.
MHI
Abbreviation for ‘Material Handling Industry’.
MHI is a not-for-profit organization formed to advance the interests of the material handling industry which includes the movement, storage, control, and protection of material and products throughout the process of their manufacture, distribution, consumption, and disposal.
Mil
A measurement of thickness of paint. One mil=.001 of an inch.
Milled
A surface that has been accurately sawed or finished to a true plane.
Mill Test Report
A report of a heat of steel that indicates the customer’s order number, grade of steel, number and dimensions of pieces shipped, and the chemical compositional makeup of hot rolled structural steel members. It also indicates physical properties, such as yield strength, tensile strength, elongation, impact, and ultimate strength.
Minor Axis
The axis of a structural member possessing the smallest section modulus and radius of gyration, thus having the least flexural and axial compressive strength.
Miter Cut
A single cut made at an angle to the member length. See Bevel Cut.
Modulus of Elasticity (E)
Is the slope of the straight-line portion of the stress-strain curve in the elastic range found by dividing the unit stress in ksi by the unit strain in in/in. For all structural steels, the value is usually taken as 29,000 ksi. This is also called Young’s Modulus.
Moment
The tendency of a force to cause a rotation about a point or axis, which in turn produces bending stresses.
Moment Connection
A connection designed to transfer moment as well as axial and shear forces between connecting members.
Moment Diagram
A diagram that represents graphically the moment at every point along the length of a member.
Moment of Inertia (I)
A physical property of a member, which helps define rigidity or stiffness and is expressed in inches raised to the fourth power. It is a measure of the resistance to rotation offered by a section’s geometry and size.
Moment Plate
A welded or bolted steel plate used to develop a rigid connection to the supporting member so that moment transfer can occur.
Monorail
Usually a single rail support for a material handling system.
MPC
Abbreviation for ‘Materials Properties Council’.
MPC was established in 1966 in response to the growing need for valid data on the engineering properties of metals.
MPS
Abbreviation for ‘Model Progression Specification’.
Muller-Breslau Principle
Is a simple method to draw approximate shapes of influence lines.
Mullion
A vertical member or division between the panels of a window.
Mylar
A type of strong, thin polyester sheet used for producing blueprints of architectural drawings.
MT
A hot rolled structural tee shape with symbol MT, which is cut or split from M Shapes.
Nailers
Strips of lumber attached to the top chord of a steel joist (bar joist) so plywood or other roofing can be nailed directly to the joist.
Native
Description applied to data that is “allowed to be changed” after it has been transferred.
NBIMS
Abbreviation for ‘National BIM Standard’. – US effort in IFC.
NCEES
Abbreviation for ‘National Council of Examiners for Engineering and Surveying’.
NCEES provides leadership in professional licensure of engineers and land surveyors.
NCS
Abbreviation for ‘National CAD Standard’.
Developed through the cooperation of the American Institute of Architects (AIA), the Construction Specifications Institute (CSI), and NIBS.
Nearside
For steel joists and joist girders, when looking at the member with the tagged end to the left, it is the side you see first and is closest to you.
Neutral Axis
The surface in a member where the stresses change from compression to tension, i.e., represents zero strain and therefore zero stress. The neutral axis is perpendicular to the line of applied force.
Newton
The SI unit of measure for force (N).
NFPA
Abbreviation for ‘National Fire Protection Association’.
NFPA is an international nonprofit organization that reduces the burden of fire on the quality of life by proposing codes and standards, research, and education on fire-related issues.
NIC
Abbreviation for ‘Not in Contract’.
NIST
Abbreviation for ‘National Institute of Standards and Technology’.
An organization that works with industry and government to advance measurement science and develop standards.
Nominal Load
Magnitude of the load specified by the applicable building code.
Nominal Strength*
Strength of a structure or component (without the resistance factor or safety factor applied) to resist the load effects, as determined in accordance with these Standard Specifications.
Non-Bearing Wall
A wall that supports no vertical load, other than its own weight.
Noncompact Section
A steel section, which does not qualify as a compact section, and the width-thickness ratios of its compression elements do not exceed the values designated in the AISC Manual.
Nonrigid Structure
A structure that cannot maintain its shape and may undergo large displacements and would collapse under its own weight when not supported externally.
NRCA
Abbreviation for ‘National Roofing Contractors Association’.
NRCA represents roofing professionals and is a leading authority in the roofing industry for information, education, technology, and advocacy.
NSPE
Abbreviation for ‘National Society of Professional Engineers’.
NPSE helps PEs advance their careers, explore pathways for growth, connect with peers across disciplines, educate the public, and work together for important professional and societal change.
NTS
Abbreviation for ‘Not to Scale’.
Offset Bowstring Joist
A special profile steel joist where the top chord is curved and the bottom chord is straight or level.
Offset Ridge
When the ridge of a steel joist that has the top chord pitched two ways is not in the center of the member or bay.
On The Flat
A measurement of distance horizontally on a plan, no slopes involved.
One-third Increase
When designing steel members for forces produced by wind or seismic conditions, the allowable stresses in the design formulas may be increased 1/3 above the values otherwise provided.
OSHA
Abbreviation for ‘Occupational Safety and Health Administration’.
A federal organization whose purpose is to save lives, prevent injuries, and protect the health of the workers of America.
Outrigger
A structural member that is usually perpendicular to a steel joist and attaches under the outstanding leg of one of the steel joist top chord angles. It then bears on a beam or wall and cantilevers across, similar to a top chord extension.
Outstanding Leg
The leg of a structural angle which is projecting toward or away from you when viewing.
Overhang
The extension of the top chord of a steel joist beyond the outside of the bearing support. See Top Chord Extension.
Owner
The entity that is identified as such in the Contract Documents.
P-Delta Effect
The secondary effect of column axial loads and lateral deflection on the moments in structural members.
Panel or Panel Length
1) The distance between two adjacent panel points of a steel joist or joist girder; or 2) A sheet of steel deck for a roof or floor.
Panel Point
The point where one or more web members intersect the top or bottom chords of a steel joist or joist girder. See Joint.
Parallel Chord
Type of steel joist or joist girder, which has its top and bottom chords parallel to each other. The member can be sloped and still have parallel chords.
Parametric
Describes objects or components characteristics and relationships.
Parapet
The portion of a vertical wall of a building, which extends above the roofline at the intersection of the wall and roof.
Part Number
See Mark and Piece Mark.
Partially Restrained
A type of connection that displays a moment rotation behavior that can neither be described as pinned nor fixed.
Partition
A wall that is one story or less in height used to subdivide the interior space in a building and can be a bearing wall or a non-bearing wall.
Pascal
The SI unit of measure for stress or force per unit area (N/m^2).
PE
Abbreviation for ‘Professional Engineer’.
Peak
The highest point of a gable or also the highest point on a steel joist or joist girder where the sloped chords meet. See also Apex.
Penthouse
A small, enclosed structure above the roof of a building.
Permanent Load
Load in which variations over time are rare or of small magnitude. All other loads are variable loads.
Permit
An official document or certificate by a governmental agency or building official authorizing performance of a building process or other specified activity.
Piece Mark
See Mark and Part Number.
Pilaster
A reinforced or enlarged portion of a masonry wall to provide support for vertical roof loads or lateral loads on the wall.
Pin Connection or Support
A connection where no moment is transferred from one member to another, only axial and shear forces. This type of support has one degree of freedom, it can freely rotate about its axis but it cannot displace in any direction. Two mutually perpendicular reactive forces exist at the pin and their lines of action pass through the center of the pin. See Hinge Support.
Pipe
A hollow cylinder of metal used for the conveyance of water or gas or used as a structural column, which comes in sizes of standard, extra strong and double-extra strong.
Pipe Bridge
A structural system where two steel joists are used to carry loads such as piping or ducts. The two steel joists have to have diagonal bridging and their top and bottom chords have to be laced together with structural members to provide stability for the whole structure.
Pitch
Is the slope or inclination of a member. It is defined as the ratio of the total rise to the total width. It also is defined as the angle that the top chord makes with the lower chord. There can be single or double-pitched members.
Placement Plans
Drawings that are prepared depicting the interpretation of the Contract Documents requirements for the material to be supplied by the Seller. These floor and/or roof plans are approved by the Specifying Professional, Buyer or Owner for conformance with the design requirements. The Seller uses the information contained on these drawings for final material design. A unique piece mark number is typically shown for the individual placement of steel joists (bar joists), Joist Girders and accessories along with sections that describe the end bearing conditions and minimum attachment required so that material is placed in the proper location in the field.
Placing Plan
See Erection Plan and Framing Plan.
Plan North
The North arrow symbol on a contract drawing, usually 90 degrees to the longitudinal axis of the plan so that communication will be easier for the elevations of the building, sections, etc.
Plane Frame
A two-dimensional structural framework.
Plastic Design
A design concept based on multiplying the actual design loads by a suitable load factor and then using the yield stress as the maximum stress in any member.
Plate
A thin, flat piece of metal of uniform thickness usually over 8 inches to 48 inches in width.
Plate Girder
A built-up structural beam typically fabricated from plate material.
PLF
Abbreviation for ‘Pounds per Linear Foot’.
A unit of load obtained by multiplying pounds per square foot times the tributary width on a joist.
Plug
A rod, plate, or angle welded between a two-angle web member or between a top or bottom chord panel to tie them together usually located at the middle of the member. See Tie or Filler.
Plug Weld
A weld in a slot in a piece of steel, which overlaps another piece. A principle use for a plug weld is to transmit shear in a lap joint. See Slot Weld and Puddle Weld.
PMC
Abbreviation for ‘Project Management Contract’.
A PMC is a legally binding agreement between a client and a manager that defines project goals, scope, responsibilities, payment terms, and risks.
Poisson’s Ratio
Defined as the ratio of the unit lateral strain to the unit longitudinal strain. It is constant for a material within the elastic range. For structural steel, the value is usually taken as 0.3. It gradually increases beyond the proportional limit, approaching 0.5.
Polar Moment of Inertia (J)
Is the sum of any two moments of inertia about axes at right angles to each other. It is taken about an axis, which is perpendicular to the plane of the other two axes.
Ponding
Retention of water at low or irregular areas on a roof due solely to the deflection of flat roof framing.
Portal Frame
A rigid frame structure that is designed to resist longitudinal loads, where diagonal bracing is not permitted. It has rigidity and stability in its plane.
Pounds (LB or #)
A unit of weight.
Pour Stop
An angle used around the sides of a floor to contain the concrete when it is being poured.
Powder Actuated
A fastening method that uses a powdered charge to imbed the fastener into the member.
Prefabricate
To manufacture or construct parts or sections of structural assemblies beforehand, ready for quick assembly and erection at a jobsite.
Press Brake
A machine used in cold-forming metal sheet or strip into a desired cross section or structural shape.
Primary Members
This is the main load carrying members of a structure such as a beam or joist girder.
Principle of Superposition
States that the resultant is the algebraic sum of the effects when applied separately.
Primer or Paint
The initial coating of a member applied in the shop, which is not a finish coat and only protects from rust for a limited time.
Prismatic Beam
A beam with uniform cross section.
Profile Drawing
A drawing or diagram showing the outline of a steel joist, including dimensions and, where applicable, the web system configuration and bridging rows. (See Side-View Diagram.)
Proportional Limit
The point on a stress-strain curve where the linear relationship between stress and strain ends and usually coincides with the material yield point.
PSI
Abbreviation for ‘Pounds per Square Inch’.
A unit of stress or pressure.
PSF
Abbreviation for ‘Pounds per Square Foot’.
A unit of stress on a steel joist.
Puddle Weld
An arc spot weld commonly used to connect thin sheet steel (such as steel decking) to thicker, structural supporting members below (such as joists or beams).
Purlin
Horizontal structural member that supports roof deck and is primarily subjected to bending under vertical loads such as dead, snow or wind loads.
Quality Assurance
System of shop and field activities and controls implemented by the owner or his/her designated representative to provide confidence to the owner and the building authority that quality requirements are implemented.
Quality Control
System of shop and field controls implemented by the seller and erector to ensure that contract and company fabrication and erection requirements are met.
Radius of Gyration (r)
Is the distance from the neutral axis of a section to an imaginary point at which the whole area of the section could be concentrated and still have the same moment of inertia. Formula: The square root of (the moment of inertia in inches^4 divided by the area of the section in inches^2) expressed in inches.
Rafter
The main beam supporting a roof system or a sloping roof framing member.
Rake
The edge of a roof that intersects the gable part of a roof.
RCSC
Abbreviation for ‘Research Council on Structural Connections’.
RCSC is a non-profit organization that develops standards for structural steel joints and publishes the “Specification for Structural Joints Using High Strength Bolts,” among other bolted connection documents.
Reaction
The force or moment developed at the points of a support.
Redundants
The reactions that are not necessary for static equilibrium.
Reinforcement
An additional member added to a structural member to provide additional strength.
Reinforcing
The process of strengthening a member with an additional piece of material.
Relaxation
Is a decrease in load or stress of a member under a sustained constant deformation.
Repair
The reconstruction or renewal of any part of an existing structure or building for the purpose of its maintenance.
Required Strength*
Forces, stress, and deformations produced in a structural component, determined by either structural analysis, for the LRFD or ASD load combinations, as appropriate, or as specified by these Standard Specifications.
Residual Stress
Pre-induced stresses within a structural member due to uneven cooling of the shape after hot-rolling.
Resistance
The capacity of a structure or structural member to resist the effects of loads or forces imposed on it.
Resistance Factor
Factor that accounts for unavoidable deviations of the nominal strength from the actual strength and for the manner and consequences of failure.
Retaining Wall
A wall designed to resist the lateral displacement of soil, water, or any other type of material.
RFI
Abbreviation for ‘Request for Information’.
The RFI procedure is used in the construction industry when it is necessary to confirm the interpretation of a detail, specification, or note on the construction drawings or to secure a documented directive or clarification from the architect or client that is needed to continue work.
Rib
A fabricated fold or bend in a sheet of steel deck which projects up from a horizontal plane.
Ridge
The highest point on the roof of a building formed by two intersecting slopes or the horizontal line made by the top surfaces of the two intersecting sloping roof surfaces.
Rigid Connection
A connection where moment is transferred from one member to another. See also Fixed-End Support.
Rigid Frame or Structure
A structural framing system consisting of members joined together with moment or rigid connections, which maintain their original angular relationship under load without the need for bracing in its plane. See Frame and Stability.
Rise
The vertical distance from the bottom to the top of an entity.
RMI
Abbreviation for ‘Rack Manufacturers Institute’.
An institute organized in 1958 by industry leaders as a not-for-profit trade association. Its mission is to advance standards, quality, safety, and general fitness for intended use of industrial steel storage rack systems.
Rod
A smooth solid round bar used for the web system of a steel bar joist.
Roof Covering
The exposed exterior roof skin of a building, which can be sheets, panels or other materials.
Roof Overhang
A roof extension that projects beyond the ends or sides of a building.
Roller Support
This type of support has two degrees of freedom, it can freely rotate about its axis or displace in one direction in the plane. Only one reactive force exists at a roller, which acts perpendicular to the path of the displacement and its line of action passes through the center of the roller.
S Shapes
A hot rolled shape called an American Standard Beam with symbol S.
Saddle Angle
The angle connection or seat on the end of a header or frame, which bears from the side on the top chord of a steel joist. This angle should be designed to carry the reaction of the header or frame to the center of the steel joist and must rest on and weld to both top chord angles.
Safety Factor
Factor that accounts for deviations of the actual strength from the nominal strength, deviations of the actual load from the nominal load, uncertainties in the analysis that transforms the load into a load effect and for the manner and consequences of failure.
Sag Rod
A tension member used to limit the deflection of a girt or purlin in the direction of the weak axis.
Scab On
A member fastened or welded to another member for reinforcement.
Scissor Joist
A special profile steel joist where the top and bottom chords are double pitched and parallel to each other.
Scupper
Any opening or drain in the side of a structure, flat roof, or downspout for the drainage of rainwater.
Scuttle
A framed opening in a roof used for access to the roof from inside a building.
SDI
Abbreviation for ‘Steel Deck Institute’.
An institute that brings uniformity to the design, manufacture, quality control, and construction practices applicable to cold-formed steel deck.
SEAA
Abbreviation for ‘Steel Erectors Association of America’.
An organization that sets uniform standards among the many steel erectors and helps promote safety in the erection industry.
Seat Depth
The out-to-out depth of the end bearing shoe or seat of a steel joist or joist girder which is the distance from the top of the top chord to the bottom of the bearing seat angle or plate.
Section Modulus (S)
A physical property of strength of a structural member. It relates bending moment and maximum bending stress within the elastic range. Formula: S=I/c where ‘I’ is the moment of inertia of the cross-section about the neutral axis in inches^4 and ‘c’ is the distance from the neutral axis to the outermost fibers.
Seismic Load
Assumed lateral and vertical forces acting in any horizontal direction that produce stresses or deformations in a structural member due to the dynamic action of an earthquake.
Self Tapping Screw
A mechanical fastener for attaching metal deck, panels, or other materials to a structure, which taps its own threads in a predrilled hole.
Seller
A company certified by the Joist Institute engaged in the manufacture and distribution of steel joists (bar joists), Joist Girders and accessories.
Semper Gumbie
Marine-speak for “always flexible”, a principal requirement of BIM based collaboration among all participants in a construction project.
Sequence
A breakdown of when materials are to be made or delivered for a project with one following after the other.
Service Load
Load under which serviceability limit states are evaluated.
Serviceability Limit State
Limiting conditions affecting the ability of a structure to preserve its appearance, maintainability, durability, or the comfort of its occupants or function of machinery, under normal usage.
Set Back
The distance from the outside edge of an angle or other member to the edge of a gusset plate or angle welded near the end.
Shaft
An interior space, enclosed by walls, which extends through one or more stories or basement which connects successive floors and/or roof for elevators, dumbwaiters, mechanical equipment, etc.
Shape Factor
The ratio of the plastic section modulus Z to the elastic section modulus S or the ratio of the plastic moment Mp to the yield moment My.
Shear
A condition or force causing two contacting parts of a material to slide past each other in opposite directions parallel to their plane of contact.
Shear Center
The point in a cross section of a structural member to which a load may be applied and not induce any torsional stress in the cross section.
Shear Diagram
A diagram that represents graphically the shear at every point along the length of a member.
Shear Release
A boundary condition that constrains a member end from axial displacement and rotation but allows movement in a direction perpendicular to the members longitudinal axis.
Shear Stud Connector
A steel device used in composite design which is welded to the top flange of a beam or top chord of a steel joist which transfers shear from a concrete slab to the supporting member.
Shear Wall
A wall that resists horizontal shear forces applied in the plane of the wall.
Shim
A piece of steel used to level a steel joist seat. It can be a bent plate, flat plate or rod.
Shipping List
A list that gives each part or mark number, quantity, length of material, total weight, or other description of each piece of material to be shipped to a jobsite. See also Bill of Lading.
Shop Drawings
1) Can also be called the erection plans or framing plans 2) The actual drawings used by a shop to fabricate a product which includes all dimensions, materials, tolerances, etc.
Shore
The process of temporarily supporting a structure or structural member with auxiliary members.
SI (Le Systeme International d’Unites)
The international abbreviation for the ‘International System of Units’ or metric system.
Side Lap
The lap at the sides of a sheet of steel deck and is attached by screws, welds, or mechanical clenching of the deck side laps between support.
Side Lap Screws
A screw used to connect the sides of two adjacent sheets of metal decking together, #10 being the standard size.
Side-View Diagram
A drawing or diagram which shows the outline of a steel joist with dimensions and also maybe the web system configuration and bridging rows. See Profile Drawing.
Side Wall
An exterior wall which is parallel to the ridge of the building.
Sidesway
The lateral movement of a structure, when subjected to lateral loads or unsymmetrical vertical loads.
Simple or Single Span
A span with supports at each end, no intermediate support, that restrain only against vertical displacement with the ends of the member being free to rotate.
Single Curvature
When moments produce a deformed or bent shape of a structural member having a smooth continuous curve or arc.
Single Slope
A sloping roof in one plane which slopes from one wall to the opposite wall.
Single-Ply Roof
A type of roofing system using thermoplastic membranes, which are seamed by either hot air or solvent welding of one sheet to the next, or using thermoset membranes that are seamed with an adhesive.
SJI
Abbreviation for ‘Steel Joist Institute’.
SJI is a non-profit organization of active steel joist manufacturers that maintains sound engineering practice throughout the steel joist industry. The institute cooperates with business and government agencies to establish steel joist standards and does continuing research of their products to maintain the integrity of their products.
Skew
The condition when two entities come together at an angle, which is not 90 degrees or perpendicular to each other.
Skylight
An opening or roof accessory in a roof or ceiling for admitting light. If it bears across a steel joist, the top chord angles may be unbraced for design considerations.
Slag
A non-metallic byproduct of the welding process forming a hard crust over the molten steel, which should be chipped away for inspection of a weld.
Slender Element Section
A steel section whose width-thickness ratios of any compression element exceeds the values of a noncompact section.
Slenderness Ratio
The ratio of the effective length of a column to the radius of gyration of the column about the same axis of bending.
Slip-Critical Joint
A bolted joint in which the slip resistance of the connection is required.
Slope
The angle or inclination a structural member makes with reference to a horizontal position expressed in inches of vertical rise per 12 inches of horizontal run, i.e. 3/12.
Slot Length
The length of a slotted hole in a steel joist bearing seat or other structural connection.
Slot Weld
A weld made in an elongated hole (slot) in one member of a joint, fusing that member to another member.
Snow Drift
The triangular accumulation of snow at high/low areas of structures expressed in PSF or PLF.
Snow Load
Are forces applied to a member by snow accumulation on the roof of a structure.
Soffit
A panel that covers the underside of an overhang, cantilever end, or mansard.
Soil Pressure
The load per unit area that a structure exerts through its foundation on the underlying soil.
Span
The centerline-to-centerline distance between structural steel supports such as a beam, column or Joist Girder or the clear span distance plus four inches onto a masonry or concrete wall.
Spandrel Joist or Beam
A structural member at the outside wall of a building, supporting part of the floor or roof and possibly the wall above.
Special Design
A design required by a loading diagram or other special notes, because a standard steel joist or joist girder cannot be specified from a load table.
Special Profile Steel Joists
Open Web Steel Joist (OWSJ), a lightweight steel truss consisting of chords and a triangulated web system, proportioned to span between bearing points, similar to standard steel joist, but with unique architectural profiles. See Specialty Joists.
Specialty Joists
Open Web Steel Joist (OWSJ), a lightweight steel truss consisting of chords and a triangulated web system, proportioned to span between bearing points, similar to standard steel joist, but with unique architectural profiles. See Special Profile Joists.
Specification
The detailed description of requirements, materials, dimensions, etc. of a proposed building or project.
Specified Minimum Yield Stress
Lower limit of yield stress specified for a material as defined by ASTM.
Specifying Professional
The licensed professional who is responsible for sealing the building Contract Documents, which indicates that he or she has performed or supervised the analysis, design and document preparation for the structure and has knowledge of the load-carrying structural system.
Splice
Connection between two structural members joined at their ends by either bolting or welding to form a single, longer member.
Sprinkler System
A system for fire protection usually consisting of overhead piping connected to a water supply to which automatic sprinklers are attached that discharges water in a specific pattern for extinguishment or control of a fire.
Square
In deck terminology, it is the term for 100 square feet of metal deck or roofing surface. Formula: number of squares = (deck area in ft2) divided by 100
Square Cut
A cut to a structural member made at 90 degrees to the length of the member.
SRI
Abbreviation for ‘Steel Recycling Institute’.
SRI is an industry association dedicated to communicating the sustainable efforts of the North American steel industry.
SSPC
Abbreviation for ‘Steel Structures Painting Council’.
A professional technical society whose primary objective is to improve the technology and practice of prolonging the life of steel and concrete structures with protective coatings.
SSR
Abbreviation for ‘Standing Seam Roof’.
A type of roof system where the metal decking is attached to clips which are then attached to the beam or steel joist. Usually, this type of roof system cannot be counted on to provide lateral stability or support to the steel joist top chord.
SSRC
Abbreviation for ‘Structural Stability Research Council’.
SSRC is dedicated to research and education in the stability of steel and steel-concrete composite structures.
ST
A hot rolled structural tee shape with symbol ST, which is cut or split from S Shapes.
Stability
Condition reached in the loading of a structural component, frame or structure in which a slight disturbance in the loads or geometry does not produce large displacements.
Stabilizer Plate
A steel plate at a column or wall inserted between the end of a bottom chord of a steel joist (bar joist) or Joist Girder to weld the bottom chord to or to restrain the bottom chord from lateral movement.
Standard Specifications
Documents developed and maintained by the Steel Joist Institute for the design and manufacture of open web steel joists and Joist Girders. The term “SJI Standard Specifications” encompass by reference the following: ANSI/SJI-K-1.1 Standard Specifications for Open Web Steel Joists, K-Series; ANSI/SJI-LH/DLH-1.1 Standard Specifications for Longspan Steel Joists, LH-Series and Deep Longspan Steel Joists, DLH-Series; and ANSI/SJI-JG-1.1 Standard Specifications for Joist Girders.
Standard Steel Joists
Open Web Steel Joist (OWSJ), a lightweight steel truss consisting of parallel chords and a triangulated web system, proportioned to span between bearing points. Also known as metal joists or bar joists.
Starter Joist
A steel joist (bar joist) that is spaced close to a wall for deck support, usually 6 inches.
Static Equilibrium
A member or body that is initially at rest and remains at rest, when acted upon by a system of forces.
Static Load
A load applied slowly and then remains nearly constant.
Statically Determinate
A member or structure that can be analyzed and the reactions and forces determined from the equations of equilibrium.
Statically Indeterminate
A member or structure that cannot be analyzed solely by the equations of statics. It contains unknowns in excess of the number of equilibrium equations available. Additional equations must be written based on a knowledge of elastic deformations.
Steel Decking
Also known as metal decking, a structural corrugated steel component used as the material layer between the primary structural components.
Steel Joists
Open Web Steel Joist (OWSJ), a lightweight steel truss consisting, in the standard form, of parallel chords and a triangulated web system, proportioned to span between bearing points. Also known as metal joists or bar joists.
Stiffener
A member used to strengthen another member against buckling or to distribute load or to transfer shear. Usually a flat bar, plate, or angle welded perpendicular to the longitudinal axis of the member.
Stiffness
The resistance to deformation of a structural member, which can be measured by the ratio of the applied force to the corresponding displacement.
Story
That portion of a building that is between the upper surface of any floor and the upper surface of the floor next above.
Story Drift
The difference in horizontal deflection at the top and bottom of a story.
Strain Hardening
The condition when ductile steel exhibits the capacity to resist additional load than that which caused initial yielding after undergoing deformation at or just above the yield point.
Strength Limit State
Limiting condition affecting the safety of the structure, in which the ultimate load-carrying capacity is reached.
Stress
An internal force that resists a load. It is the intensity of force per unit of area, i.e., psi (pounds per square inch).
Stress Concentration
A localized stress which is considerably higher than average due to sudden changes in loading or sudden changes in geometry.
Stringer
In buildings, a structural member supporting stair steps.
Strong Axis
The cross section that has the major principal axis.
Structural Analysis
Determination of load effects on members and connections based on principles of structural mechanics.
Structural Drawings
The graphic or pictorial portions of the Contract Documents showing the design, location and dimensions of the work. These documents generally include plans, elevations, sections, details, connections, all loads, schedules, diagrams and notes.
Structure
A mechanism designed and built or constructed of various parts jointed together in some definite manner to carry loads and resist forces.
Structural Steels
A large number of steels suitable for load-carrying members in a variety of structures because of strength, economy, ductility, and other properties. Strength levels are obtained by varying the chemical composition and by heat treatment.
Strut
A structural member used as a brace to resist axial forces.
Stud
A wood or metal vertical wall member, to which exterior or interior covering material may be attached. It can be either load bearing or non-load bearing.
Suction
A partial vacuum due to wind loads on a building, which cause a load in the outward direction.
Sump Pan
A metal decking accessory used at drain locations to close the opening where holes are cut in the metal deck.
Superimposed Load
Usually means a load that is in addition to the dead weight of the steel bar joists and bridging.
Sweep
The curvature of a structural member in the transverse direction of its vertical axis.
Tagged End (T.E.)
The end of a steel joist (bar joist) or Joist Girder where an identification or piece mark is shown by a metal tag. The member must be erected with this tagged end in the same position as the tagged end noted on the placement plan.
Tangent Modulus
The slope of the stress-strain curve of a material in the inelastic range at any given stress level.
TAUC
Abbreviation for The Association of Union Constructors.
Founded as the National Erectors Association, TAUC acts as an advocate for union contractors to enhance cooperation between the three entities involved in the successful completion of construction projects: the union, the contractor, and the owner-client.
Tee
A hot rolled shape with symbol T and is shaped like a “T”.
Temporary Structure
Anything not a part of the permanent structural system, to be removed before or after the completion of the structure.
Tensile Strength (of material)
Maximum tensile stress that a material is capable of sustaining as defined by ASTM.
Tension
A condition caused by the action of stretching or pulling of a component.
Thermal Block
A spacer that has a low thermal conductance.
Thrust
The horizontal component of a reaction, or an outward horizontal force.
Tie
A rod, plate, or angle welded between a two angle web member or between a top or bottom chord panel to tie them together usually located at the middle of the member. See Filler or Plug.
Tie Joist
A steel joist (bar joist) that is bolted at a column.
Tilted Joist
A steel joist supported in a manner such that the vertical axes of the steel joist is not perpendicular with respect to the ground.
Toe
The outside points of each leg of a structural angle.
Toe of Fillet
1) The end or termination edge of a fillet weld; or 2) The end or termination edge of a rolled section fillet.
Toe of Weld
The junction between the face of a weld and the base metal.
Ton
A unit of weight equal to 2000 pounds.
Top Chord
The top member of a steel joist (bar joist) or joist girder.
Top Chord Bearing
The bearing condition of a steel joist (bar joist) or joist girder that bears on its top chord seat.
Top Chord Extension (TCX)
The extended part of a steel joist (bar joist) top chord. This type of extension only has the two top chord angles extended past the joist seat.
Torque Wrench
A wrench containing an adjustable mechanism for measuring and controlling the amount of turning force exerted when used to tighten nuts and bolts.
Torsional Buckling
Buckling mode in which a compression member twists about its shear center axis.
Torsion Loads
A load that causes a member to twist about its longitudinal axis. Simple torsion is produced by a couple or moment in a plane, perpendicular to the axis.
TOS
Abbreviation for ‘Top of Steel’.
Total Project Cost Accountability
New Millennium’s unique combination of digital design and engineering expertise that can lead to a wide range of project benefits, from enhanced architectural achievement, to cost reductions and owner-developer revenue gains.
Toughness
The ability of steel to absorb large amounts of energy without being readily damaged.
Transverse
Crossing from side to side or placed crosswise.
Tributary Width or Area
The design area that contributes load to a structural member. It is one half the distance between members on either side of the member.
Trimmer Joist
One of the steel joists supporting a header. The header applies a concentrated load at that point on the trimmer joist.
Truss
In general, a structural load-carrying member with an open web system designed as a simple span with each member designed to carry a tension or compression force. The entire structure will act like a beam.
Tube
A hollow structural steel member shaped like a square or rectangle used as a beam, column, or for bracing. Usually the nominal outside corner radius is equal to two times the wall thickness.
Turnbuckle
A rotating sleeve or link with internal screw threads at each end and used to tighten or connect the ends of a rod.
Turn-of-the-Nut-Method
A method for pre-tensioning high-strength bolts by the rotation of the wrench a predetermined amount after the nut has been tightened to a snug fit.
UBC
Abbreviation for ‘Uniform Building Code’.
A minimum model regulatory code for the protection of public health, safety, welfare and property by regulating and controlling the design, construction, quality of materials, use, occupancy, location and maintenance of all buildings and structures within a jurisdiction. The last printing of the UBC was released in 1997 and is now succeeded by the IBC.
UL
Abbreviation for ‘Underwriters Laboratories, Inc.’.
A non-profit product safety testing and certification organization.
Ultimate Load
The force necessary to cause rupture.
Ultimate Strength
The maximum stress attained by a structural member prior to rupture which is the ultimate load divided by the original cross-sectional area of the member.
Ultimate Strength Design
See LRFD.
Unbraced Frame
A frame providing resistance to lateral load by the bending resistance of the frame members and their connections.
Unbraced Length
Distance between braced points of a member, measured between the centers of gravity of the bracing members.
Unbraced Top Chord
The specific length where the top chord of a steel joist has no lateral bracing by steel deck, bridging, or any other means.
Undercut
A notch or groove melted into the base metal next to the toe or root of a weld and left unfilled by weld metal.
Underslung
Description of a joist that is suspended from upper support points where most of the mass of steel is below the actual support points.
Uniformly Distributed Load
A load or force, for practical purposes, that may be considered constant over the entire length or partial length of the member.
UNO
Abbreviation for ‘Unless Noted Otherwise’.
Uplift
The wind load on a member that causes a load in the upward direction. The gross uplift is determined from the adopted Building Code, commonly the IBC and referenced standards such as ASCE-7. The net uplift is the gross uplift minus the allowable portion of dead load including the weight of the steel joist and is the load that the specifying professional shall indicate to the joist manufacturer.
Uplift Bridging
The bridging required by uplift design. Usually always required at the first bottom chord panel point of a K-Series, LH- or DLH-Series steel joist and at other locations along the bottom chord as required by design.
Upstanding Leg
The leg of a structural angle, which is projecting up from you when viewing.
Valley
The angle formed by two sloping sides of a roof.
Value Engineering
The application of the Scientific Method to the study of selecting the optimum or best system that meets the need of the customer.
Vapor Barrier
A physical membrane that prevents moisture or water vapor from penetrating to the other side.
Variable Load
Load not classified as permanent load.
Varying Distributed Load
A load or force, for practical purposes, that may be considered varying over the surface of the member, for example a snow drift.
Versa-Dek®
A dovetail steel deck profile offered by New Millennium, typically exposed and utilized for its aesthetic properties. It is available in 2” and 3 ½” depths, acoustic, and composite formats.
VG-Type Joist Girder
A type of Joist Girder where steel joists are located at panel points where vertical webs intersect the top chord only. This type of girder is used for ducts to pass thru since the steel joists do not interfere with their passage.
Vibration
The oscillating, reciprocating, or other periodic motion of a rigid or elastic body or medium, such as a floor when its position or state of equilibrium has been changed.
W Shapes
A hot rolled shape called a Wide Flange Shape with symbol W, which has essentially parallel flange surfaces.
Wall
A vertical or near vertical structure that encloses or separates spaces and may be used to resist horizontal or vertical forces or bending forces.
Wall Anchor
A small piece of angle or other structural material that is usually bolted to a wall, to which a starter steel joist or bridging angle is welded or bolted to.
Wall Covering
The exterior wall skin consisting of sheets or panels.
Washer
A flat ring of metal with a hole in the middle used to give thickness to a joint or to distribute pressure under the head of a nut or bolt.
Weak Axis
The cross section that has the minor principal axis.
Weathering Steel
A type of high-strength steel which can be used in normal outdoor environments, without being painted. Should not be used in corrosive or marine environments.
Webs
The vertical or diagonal members joined at the top and bottom chords of a steel joist (bar joist) or Joist Girder to form triangular patterns.
Web Buckling
The buckling of a web plate.
Web Configuration
The arrangement of the actual web system of a steel joist or joist girder, which can be shown with a profile view of the member.
Web Crippling
The local failure of a web plate in the region of a concentrated load or reaction.
Welded Splice
A splice between two materials, which has the joint made continuous by the process of welding.
Welding
The process of joining materials together, usually by heating the materials to a suitable temperature.
Weldability
Is the ability of steel to be welded without its basic mechanical properties being changed.
Welding Washer
A metal device with a hole through it, to allow for plug welding of deck to structural steel.
Wind Column
A vertical member supporting a wall system designed to withstand horizontal wind loads. Usually between two main vertical load carrying columns.
Wind Load
A force or lateral pressure in pounds per square foot that is applied to a member due to wind blowing in any direction.
Windward
The direction or side toward the wind. Opposite of leeward.
WN-Series Joist
The WN-Series joist is a steel and wood hybrid product, with a wood nailer attached to the top chord of the steel joist. The WN-Series joist utilizes a continuous wood nailer (spliced) and fasteners to develop a composite system increasing the overall joist strength and lateral stiffness during erection. The WN-Series joist is also a tension-controlled design for increased load sharing under extreme gravity over-load conditions
Working Drawings
The complete set of contact drawings prepared by a registered architect or engineer.
Working Load
Also called service load, is the actual load that is acting on the structure.
Working Point
The point where two or more centroid lines of structural members intersect.
WRC
Abbreviation for ‘Welding Research Council’.
This organization conducts cooperative research in welding with interested scientific societies, government departments, and any company using welded products.
WSD
Abbreviation for ‘Working Stress Design’.
A structural design method whereby a structural element is designed so that the unit stresses computed under the action of working or service loads do not exceed the specified allowable values. (See Allowable Stress Design and Elastic Design.)
WT
A hot rolled structural tee shape with symbol WT, which is cut or split from W Shapes.
X-Brace
Structural bracing that resembles the letter “X”.
Yield Point
First stress in a material at which an increase in strain occurs without an increase in stress as defined by ASTM.
Yield Strength
Stress at which a material exhibits a specified limiting deviation from the proportionality of stress to strain as defined by ASTM.
Yield Stress
Generic term to denote either yield point or yield strength, as appropriate for the material.
Young’s Modulus
See Modulus of Elasticity.
“Z” Section
A structural section in the shape of a “Z” cold formed from a steel sheet.