UFC 4-023-03
25 January 2005
CHAPTER 8
COLD-FORMED STEEL DESIGN REQUIREMENTS
This chapter provides the specific requirements for designing a cold-formed
steel building to resist progressive collapse.
For composite construction, the application of both the requirements of this
chapter and those provided for the other materials are required. If wood floor
diaphragms are used, the floor system and roof system are required to meet the internal
tie requirements of Chapter 7, while the steel walls are required to meet the tie (vertical,
peripheral, and wall) requirements or AP requirements of this chapter.
8-1
MATERIAL PROPERTIES FOR COLD-FORMED STEEL.
All over-strength factors for cold-formed steel are equal to 1.0.
8-2
COLD-FORMED STEEL TIE FORCE REQUIREMENTS.
8-2.1
General.
Cold-formed steel construction is analogous to closely spaced columns and
beams, with nominal tie resistance provided at each joist to wall stud junction.
Peripheral, internal, vertical, and horizontal ties to columns and walls are required.
Structural members and connections that are provided for other purposes may be
regarded as forming part or whole of the required ties.
As specified below, ties may, in whole or in part, be spread evenly in the
diaphragm or may be grouped at or in beams, walls or other appropriate positions.
8-2.2
Strength Reduction Factor Φ for Steel Tie Forces
For the steel members and connections that provide the design tie strengths,
use the appropriate tensile strength reduction factors Φ from the 2002 version of the
AISI/COS/NASPEC 2001, AISI Standard North American Specification for the Design of
Cold-Formed Steel Structural Members . For example, use a strength reduction factor
of 0.90 for welds with tension or compression normal to the effective area or parallel to
the axis of the weld.
8-2.3
Continuity and Anchorage of Ties.
At re-entrant corners or at substantial changes in construction, take care to
ensure that the ties are adequately anchored or otherwise made effective.
8-1
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