Elements shall be straight and free of any defects that would significantly affect structural performance. Cold-formed steel wall framing members shall comply with the requirements of this section.
The provisions of this section shall control the construction of exterior cold-formed steel wall framing and interior load-bearing cold-formed steel wall framing for buildings not more than 60 feet (18 288 mm) long perpendicular to the joist or truss span, not more than 40 feet (12 192 mm) wide parallel to the joist or truss span, and less than or equal to three stories above grade plane. All exterior walls installed in accordance with the provisions of this section shall be considered as load-bearing walls. Cold-formed steel walls constructed in accordance with the provisions of this section shall be limited to sites subjected to a maximum design wind speed of 110 miles per hour (49 m/s) Exposure B or C and a maximum ground snow load of 70 pounds per square foot (3.35 kPa).
Load-bearing cold-formed steel studs constructed in accordance with Section R603 shall be located in-line with joists, trusses and rafters in accordance with Figure R603.1.2 and the tolerances specified as follows:
The maximum tolerance shall be 3/4 inch (19 mm) between the centerline of the horizontal framing member and the centerline of the vertical framing member.
Where the centerline of the horizontal framing member and bearing stiffener are located to one side of the centerline of the vertical framing member, the maximum tolerance shall be 1/8 inch (3 mm) between the web of the horizontal framing member and the edge of the vertical framing member.
Load-bearing cold-formed steel wall framing members shall comply with Figure R603.2(1) and with the dimensional and minimum thickness requirements specified in Tables R603.2(1) and R603.2(2). Tracks shall comply with Figure R603.2(2) and shall have a minimum flange width of 11/4 inches (32 mm). FIGURE R603.2(1) C-SHAPED SECTIONFIGURE R603.2(2) TRACK SECTION
The member designation is defined by the first number representing the member depth in hundredths of an inch "S" representing a stud or joist member, the second number representing the flange width in hundredths of an inch, and the letter "t" shall be a number representing the minimum base metal thickness in mils [See Table R603.2(2)].
TABLE R603.2(2) MINIMUM THICKNESS OF COLD-FORMED STEEL MEMBERS
Load-bearing cold-formed steel framing members shall be cold-formed to shape from structural quality sheet steel complying with the requirements of one of the following:
Screws for steel-to-steel connections shall be installed with a minimum edge distance and center-to-center spacing of 1/2 inch (12.7 mm), shall be self-drilling tapping and shall conform to ASTM C 1513. Structural sheathing shall be attached to cold-formed steel studs with minimum No. 8 self-drilling tapping screws that conform to ASTM C 1513. Screws for attaching structural sheathing to cold-formed steel wall framing shall have a minimum head diameter of 0.292 inch (7.4 mm) with countersunk heads and shall be installed with a minimum edge distance of 3/8 inch (9.5 mm). Gypsum board shall be attached to cold-formed steel wall framing with minimum No. 6 screws conforming to ASTM C 954 or ASTM C 1513 with a bugle head style and shall be installed in accordance with Section R702. For all connections, screws shall extend through the steel a minimum of three exposed threads. All fasteners shall have rust inhibitive coating suitable for the installation in which they are being used, or be manufactured from material not susceptible to corrosion.
Where No. 8 screws are specified in a steel-to-steel connection, the required number of screws in the connection is permitted to be reduced in accordance with the reduction factors in Table R603.2.4, when larger screws are used or when one of the sheets of steel being connected is thicker than 33 mils (0.84 mm). When applying the reduction factor, the resulting number of screws shall be rounded up.
Web holes in wall studs and other structural members shall comply with all of the following conditions:
Holes shall conform to Figure R603.2.5.1;
Holes shall be permitted only along the centerline of the web of the framing member;
Holes shall have a center-to-center spacing of not less than 24 inches (610 mm);
Holes shall have a web hole width not greater than 0.5 times the member depth, or 11/2 inches (38 mm);
Holes shall have a web hole length not exceeding 41/2 inches (114 mm); and
Holes shall have a minimum distance between the edge of the bearing surface and the edge of the web hole of not less than 10 inches (254 mm).
Framing members with web holes not conforming to the above requirements shall be reinforced in accordance with Section R603.2.5.2, patched in accordance with Section R603.2.5.3 or designed in accordance with accepted engineering practice.
Web holes in gable endwall studs not conforming to the requirements of Section R603.2.5.1 shall be permitted to be reinforced if the hole is located fully within the center 40 percent of the span and the depth and length of the hole does not exceed 65 percent of the flat width of the web. The reinforcing shall be a steel plate or C-shape section with a hole that does not exceed the web hole size limitations of Section R603.2.5.1 for the member being reinforced. The steel reinforcing shall be the same thickness as the receiving member and shall extend at least 1 inch (25.4 mm) beyond all edges of the hole. The steel reinforcing shall be fastened to the web of the receiving member with No.8 screws spaced no more than 1 inch (25.4 mm) center-to-center along the edges of the patch with minimum edge distance of 1/2 inch (12.7 mm).
Web holes in wall studs and other structural members not conforming to the requirements in Section R603.2.5.1 shall be permitted to be patched in accordance with either of the following methods:
Framing members shall be replaced or designed in accordance with accepted engineering practice when web holes exceed the following size limits:
The depth of the hole, measured across the web, exceeds 70 percent of the flat width of the web; or
The length of the hole measured along the web exceeds 10 inches (254 mm) or the depth of the web, whichever is greater.
Web holes not exceeding the dimensional requirements in Section R603.2.5.3, Item 1 shall be patched with a solid steel plate, stud section or track section in accordance with Figure R603.2.5.3. The steel patch shall, as a minimum, be the same thickness as the receiving member and shall extend at least 1 inch (25.4 mm) beyond all edges of the hole. The steel patch shall be fastened to the web of the receiving member with No. 8 screws spaced no more than 1 inch (25.4 mm) center-to-center along the edges of the patch with a minimum edge distance of 1/2 inch (12.7 mm).
All exterior cold-formed steel framed walls and interior load-bearing cold-formed steel framed walls shall be constructed in accordance with the provisions of this section.
Cold-formed steel framed walls shall be anchored to foundations or floors in accordance with Table R603.3.1 and Figure R603.3.1(1), R603.3.1(2) or R603.3.1(3). Anchor bolts shall be located not more than 12 inches (305 mm) from corners or the termination of bottom tracks. Anchor bolts shall extend a minimum of 15 inches (381 mm) into masonry or 7 inches (178 mm) into concrete. Foundation anchor straps shall be permitted, in lieu of anchor bolts, if spaced as required to provide equivalent anchorage to the required anchor bolts and installed in accordance with manufacturer's requirements.
TABLE R603.3.1 WALL TO FOUNDATION OR FLOOR CONNECTION REQUIREMENTSa, b
FRAMING CONDITION
WIND SPEED (MPH) AND EXPOSURE
85 B
90 B
100 B 85 C
110 B 90 C
100 C
< 110 C
Wall bottom track to floor per Figure R603.3.1(1)
1-No. 8 screw at 12" o.c.
1-No. 8 screw at 12" o.c.
1-No. 8 screw at 12" o.c.
1-No. 8 screw at 12" o.c.
2-No. 8 screws at 12" o.c.
2 No. 8 screws at 12" o.c.
Wall bottom track to foundation per Figure R603.3.1(2)d
Wall bottom track to wood sill per Figure R603.3.1(3)
Steel plate spaced at 4' o.c., with 4-No. 8 screws and 4-10d or 6-8d common nails
Steel plate spaced at 4' o.c., with 4-No. 8 screws and 4-10d or 6-8d common nails
Steel plate spaced at 3' o.c., with 4-No. 8 screws and 4-10d or 6-8d common nails
Steel plate spaced at 3' o.c., with 4-No. 8 screws and 4-10d or 6-8d common nails
Steel plate spaced at 2' o.c., with 4-No. 8 screws and 4-10d or 6-8d common nails
Steel plate spaced at 2' o.c., with 4-No. 8 screws and 4-10d or 6-8d common nails
Wind uplift connector strength to 16" stud spacingc
NR
NR
NR
NR
NR
65 lb per foot of wall length
Wind uplift connector strength for 24" stud spacingc
NR
NR
NR
NR
NR
100 lb per foot of wall length
For SI: 1 inch = 25.4 mm, 1 mile per hour = 0.447 m/s, 1 foot = 304.8 mm, 1 pound = 4.45 N.
Anchor bolts are to be located not more than 12 inches from corners or the termination of bottom tracks (e.g., at door openings or corners). Bolts are to extend a minimum of 15 inches into masonry or 7 inches into concrete.
All screw sizes shown are minimum.
NR = uplift connector not required.
Foundation anchor straps are permitted in place of anchor bolts, if spaced as required to provide equivalent anchorage to the required anchor bolts and installed in accordance with manufacturer's requirements.
