Over the last 25 years, cold-formed steel framing — also referred
to as light gauge steel framing — has become an increasingly
framing for entire structures, curtain walls, roof framing and
trusses and many other applications. This increased popularity
is a result of steel framing’s lower material cost, its resistance to
weather, pests, fire and mold and the fact steel is easily recycled.
Additionally, placement costs are considerably lower when compared
to other construction methods due to faster installation
and the absence ofweather restrictions associated with this type
of construction. As the use of steel framing and other similar
cold-formed steel shapes and accessories has grown in usage and
diversity of applications, there has been an equivalent growth in
the number of users in the architectural, engineering, contracting
and manufacturing communities.
Progress has been made in recent years to standardize light gauge
steel framing by the Steel Stud Manufacturers Association. One
of the most substantial results of this organization’s efforts has
been the introduction of a universal designation system for light
gauge framing members, which has replaced the use of individual
manufacturer’s proprietary nomenclature and regional
references to cold-formed members. Simply put, gauges have
been replaced by mil thicknesses, and alpha nomenclature for
flange widths is now stated in mathematical equivalents. Additionally,
the SSMA requires all of its members to meet minimum
requirements for engineering properties, making all member-
manufactured components equal.
This system now allows specifiers and designers to refer to products
in a generic manner that applies to all manufacturers and
geographic regions, thus eliminating much confusion among
all parties involved. Most important, this system has been
accepted and adopted by the cold-formed steel framing manufacturers
and contractors, and the system is beginning to enjoy
acceptance in the design community.
The designs of this type of construction should be prescriptive
based, with the products, processes, means and methods accurately
called out within the contract documents, or performance
based, where the contractor bidding and performing the work
has some latitude regarding the design. A combination of these
formats is acceptable and frequently used; however, all three are
often incorrectly applied to the specifications and/or design,
which leads to confusion for contractors. This is a result of a
combination of factors such as deficient and/or contradictory
information within and between the documents, a lack of
understanding of the systems and methods, and improper coordination
between the specifier, architect and structural engineer.
This is further complicated by the “fast track” nature of construction
today. Ultimately, such confusion leads to cost overruns
for owners and contractors, project delays and the inability
for companies to fairly compete.
When considering or evaluating which design should be utilized
or exists on a project, attention should be given to the language
in the American Institute of Architects AIA Document-
A201, General Conditions of the Contract for Construction.
This states: “3.12.10 The Contractor shall not be required to
provide professional services which constitute the practice of
architecture or engineering unless such services are specifically
required by the Contract Documents for a portion of the Work
or unless the Contractor needs to provide such services in order
to carry out the Contractor’s responsibilities for construction
means, methods, techniques, sequences and procedures. The
Contractor shall not be required to provide professional services
in violation of applicable law. If professional design services or
certifications by a design professional related to systems, materials
or equipment are specifically required of the Contractor by
the Contract Documents, the Owner and the Architect will
specify all performance and design criteria that such services
must satisfy. The Contractor shall cause such service or certifications
to be provided by a properly licensed design professional,
whose signature and seal shall appear on all drawings, calculations,
specifications, certifications, Shop Drawings and other
submittals prepared by such professional Shop Drawings and
other submittals related to the Work designed or certified by
such professional, if prepared by other, shall bear such professional’s
written approval when submitted to the Architect. The
Owner and the Architect shall be entitled to rely up on the adequacy,
accuracy and completeness of the services, certifications
or approvals performed by such design professionals, provided
the Owner and Architect have specified to the Contractor all
performance and design criteria that such services must satisfy.
Pursuant to this Subparagraph 3.12.10, the Architect will
review, approve or take other appropriate action on submittals
only for the limited purpose of checking for conformance with
information given and the design concept expressed in the Contract
Documents. The Contractor shall not be responsible for
the adequacy of the performance or design criteria required by
the Contract Documents.”
Also, the 2003 International Building Code states the following:
“106.1 Submittal documents. Construction documents,
special inspection and structural observation programs and other
data shall be submitted in one or more sets with each application
for a permit. The construction documents shall be prepared
by a registered design professional where required by the
statutes of the jurisdiction in which the project is to be constructed.
Where special conditions exist, the building official is
authorized to require additional construction documents to be
prepared by a registered design professional.”
Within a prescriptively designed project, the specifications outline
the usage of the light gauge framing by calling out the
acceptable manufacturers, reference standards, desired galvanized
coating(s) and accessories. The yield strength of steel,
thickness in mils, member depth, flange width(s) and spacing
required, as determined by the structural engineer, should be
indicated on the structural drawings in the sections and general
notes. This information should also be included within the
body of the specification. The architectural drawings should
reflect and support this information as well.
Another desirable means of sizing members can be to provide a
wall, limiting height or member schedule in lieu of or in addition
to the information in the sections, details, notes and specifications.
Other components that complete a Steel framing system
such as bridging, clip angles, web stiffeners, fasteners and other
accessories should be both specified and indicated on the drawings
as to size, metal thickness, location, spacing and application.
All these methods should use the SSMA designations wherever
applicable. Where such SSMA references do not exist, specific
items with equivalent properties should be listed as well.
The prescriptively based format is unique to each project, and
the structural engineer and/or architect has full responsibility
for the design. Because of this, shop drawings are not necessary
and submittals are limited to providing manufacturer’s standard
literature and, in some cases, certificates to verify that the proper
steel strength and coatings have been provided. An alternative
to this approach is for the design team to provide completed
shop drawings from the manufacturer or an engineer specializing
in light gauge steel framing in addition to or to supplement
the architectural and structural drawings.
Regardless of which of the processes above is used, the contractor
installing the work is accountable for supplying the
appropriate materials and correct installation per the documents.
This exact method of light gauge steel framing design,
although rarely utilized, is the most economical, fair and least
complicated of the three types of designs.
Similar to a prescriptively designed project, within a performance
design, the specifications indicate the acceptable manufacturers
and reference standards, any desired deviations from
manufacturer’s typical products, or minimal requirements such
as thickness or yield strength, stud width or spacing to accommodate
other requirements such as insulation R-values.
For the contractor to properly determine the correct metal
thickness, member and flange width(s) and spacing required,
all performance criteria must be included in the design specifications.
These consist of snow, wind and live loads, where
applicable, and the deflection criteria. The performance requirements
should be in accordance with the applicable codes and
industry standards. These codes and standards must be included
in the contract documents.
The SSMA publishes limiting heights based on common loads
and deflection criteria in numerous tables. Similar tables are also
presented by steel framing manufacturers in their literature.
When these common criteria are shown in the specifications,
contractors can easily select the proper member sizes, thicknesses,
widths and spacing from these tables to develop an estimate
for a performance design.
When confronted with uncommon or excessive criteria, a contractor
must consult outside services or manufacturers’ engineering
services during the bid process to properly size members,
or round up to the next highest common standard within
the tables, thereby increasing the cost of construction. The duration
allowed for the bidding process today rarely allows for sufficient
outside engineering consultation, and, if time does allow,
this additional effort more often than not results in a noncompetitive
estimate by the contractor gaining information that is
not reflected in the documents.
When this performance process is properly applied to a project,
the successful bidder, once awarded the project, provides standard
literature, fully detailed shop drawings and calculations by
an engineer properly registered within the project’s jurisdiction,
completing the performance design process.
This format enables an owner to benefit from the value of light
gauge systems, to gain the advantage of a contractor’s experience,
expertise and ingenuity, and to have an installer with the
responsibility of design. Due to the freedom available within
these systems and this method, the performance method should
be used only in markets where there are known, capable contractors,
and avoided on public works projects.
As the description suggests, combination designs are a merger
of the two systems described above. When utilized correctly,
this method can be used to the advantage and financial benefit
of all interested parties. Contract documents can be prescriptive
in nature but allow the bidders to provide an economical
light gauge steel framing system, realize a competitive
advantage by using their expertise and resources, and offer the
owner and/or contractor “value engineering.”
The combination design method also allows the design professional(
s) reassurance that the integrity of the intended design is
maintained by contractors providing either placement or fullengineered
shop drawings from the manufacturer or an outside
engineering source. However, to properly provide such a design,
all required design criteria, standards and intent need to be clearly
shown on the contract documents. In addition to this, when
the work is a combination of prescriptive and performance
designs, the division of responsibilities must be very clear and
properly coordinated between the structural drawings, architectural
drawings and project specifications. Conflicts of any
kind will often lead to items being priced by multiple bidders,
causing increased costs to the project or, worse yet, have these
same items missed altogether.
An additional issue in this regard is the “acceptability” of any
submitted value engineering items. It does the bidder no good
to win the project based on the savings from several VE items,
only to have them arbitrarily rejected by the general contractor,
architect or engineer-of-record. In short, when investigating VE
options, it pays to make sure that the contractor(s), architect
and engineer are all on the same side of the issue ahead of time.
In summary, steel framing projects can save money for all parties
involved, provided that the design professional provides the
contractor with correct and complete design specifications
and/or criteria, depending on whether the design is prescriptive
based, performance based or a combination of both. When the
design professional provides incomplete or inaccurate design
specifications or criteria, the steel framing contractor is forced
to perform duties that cost everyone time and money, and may
be a violation of statutory requirements.
To properly design, specify, estimate and construct a cold
formed Steel framing project, the following documents need to
be reviewed:
- American Institute of Architects (AIA). AIA Document-A201,
General Conditions of the Contract for Construction. 1997 Edition. - American Iron and Steel Institute (AISI). Specifications for the
Design of Cold Formed Steel Structural Members. 1996 Edition. - American Society for Testing Materials (ASTM):
- C645 — Specifications for Nonstructural Steel Framing Members.
- C754 — Specifications for Installation of Steel Framing Members
to Receive Screw-Attached Gypsum Panel Products. - C955 — Specification of Load-Bearing (Transverse and Axial)
Steel Studs, Runners (Tracks), and Bracing or Bridgingfor Screw
Application of Gypsum Panel Products and Metal Plaster Bases. - C1007 — Specification for the Installation of Load Bearing
(Transverse and Axial) Steel Studs and Related Accessories. - C1513-01 — Standard Specification for Steel Tapping Screws for
Cold-Formed Steel Framing Connections. - A1003/A1003M-02a — Standard Specification for Steel Sheet,
Carbon, Metallic- and Nonmetallic-Coated for Cold-Formed
Framing Members. - Association of Wall and Ceiling Industries—International
(AWCI). Cold-Formed Steel Framing Primer: A Guide to
Understanding and Application. 2001 Edition. - American Welding Society (AWS) D1.3-98. Structural Web
ing Code – Sheet Steel. 1998 Edition. - Gypsum Association (GA). Fire Resistance Design Manual
(GA-600-03). 2003 Edition. - EIFS Industry Members Association (EIMA). Guide to Exterior
Insulation and Finish Systems Construction. 2000 Edition. - International Building Code (IBC). 2003 Edition.
- Steel Stud Manufactures Association (SSM). Product Technical
Information. 2002 Edition. - Underwriters Laboratories Inc. (UL). Fire Resistance Directory.
2003 Edition.
About the Author
The AWCI Interior & Exterior Steel Framing Committee is
part of the Construction Technology Council of the Association
of Wall and Ceiling Industries—International. AWCI publishes
several documents and provides technical support to their
membership and the construction industry. AWCI’s CTC provides
input to many related industry and standards writing
organizations.
AWCI’s CTC is composed of AWCI contractor, supplier, staff,
professional and other association members who meet semiannually
and work throughout the year to provide these services.
This article contains contributions from CTC Vice Chairman
Brent Allen, South Texas Drywall Inc., Columbus, Ohio; Interior
& Exterior Steel Framing Committee Chairman Renny
Huntley, The Huntley Construction Group Corporation,
Caparra Heights, Puerto Rico; and committee members: Greg
Ralph, Dietrich Industries, Pittsburgh; Pat Ford, Matsen Ford
Design Associates, Pewaukee, Wis.; Gregg Miller, T.E.A.M.
Panels International, Englewood, Colo.; and Kevin Larson,
Olympic Wall Systems, Inc., Minnetonka, Minn.; and AWCI
Director of Technical Services Lee G. Jones.
