Section R505 Steel Floor Framing
- The maximum tolerance shall be 3/4 inch (19.1 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.
COLD-FORMED STEEL JOIST SIZES
|MEMBER DESIGNATIONa||WEB DEPTH |
|MINIMUM FLANGE WIDTH (inches)||MAXIMUM FLANGE WIDTH (inches)||MINIMUM LIP SIZE |
MINIMUM THICKNESS OF COLD-FORMED STEEL MEMBERS
|DESIGNATION THICKNESS |
|MINIMUM BASE STEEL THICKNESS |
- Manufacturer's identification.
- Minimum base steel thickness in inches (mm).
- Minimum coating designation.
- Minimum yield strength, in kips per square inch (ksi) (MPa).
- A minimum of G 60 in accordance with ASTM A 653.
- A minimum of AZ 50 in accordance with ASTM A 792.
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 R505.2.4 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.
SCREW SUBSTITUTION FACTOR
|SCREW SIZE||THINNEST CONNECTED STEEL SHEET (mils)|
- Holes shall conform to Figure R505.2.5.1;
- 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 21/2 inches (64.5 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 R505.2.5.2, patched in accordance with Section R505.2.5.3 or designed in accordance with accepted engineering practices.
FLOOR JOIST WEB HOLES
- Framing members shall be replaced or designed in accordance with accepted engineering practices where 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 R505.2.5.3, Item 1, shall be patched with a solid steel plate, stud section, or track section in accordance with Figure R505.2.5.3. The steel patch shall, as a minimum, be of the same thickness as the receiving member and shall extend at least 1 inch (25 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 mm) center-to-center along the edges of the patch with minimum edge distance of 1/2 inch (13 mm).