JamStud® is a revolutionary addition to the light gauge steel stud industry, producing significant economies in both design and installation when compared with conventional “C” Shaped studs. JamStud’s unique configuration delivers increased strength and stiffness, minimizing or eliminating the use of built-up jamb and header sections in a curtain wall assembly. In conventional c-shape construction, jambs are typically the initial components designed. As different thickness of steel studs is difficult to determine in the field, the rest of the wall studs are kept as the same thickness as the jambs, which may result in less than optimal thickness for the wall. JamStud’s shape is easily differentiated from the typical c-shape, enabling the selection of the most optimal member sizes.
- Design Example
- Design Comparison
- Section Properties
- Section Dimensions
- Wind Pressure (PSF) and Deflection Limits
JamStud® Design Example
1. Basis for Tables:
The JamStud® allowable heights tables in this site cover the following basic load combination for the Allowable Stress Design
(ASD) Method (IBC2006 and ASCE 7-05):
- D + WC&C (Strength determination) WC&C is the Component and Cladding wind load. The Dead Load (D) acting on the stud is assumed minimum and therefore neglected in the tables.
For the deflection determination, IBC 2003, IBC2006-Sec. 1604.3 and AISI-Wall Stud Design Standard 2004, Sec. B1 allow for a
reduction factor of 0.7 on the Component and Cladding wind load (0.7WC&C).
The “JamStud® - Allowable Heights” tables are based on the following assumptions:
- 4-Way distribution of lateral wind pressure acting on the opening
- Opening height extends from the floor level to the bottom surface of the header
- Jamb member supports wind pressure from the opening, wind pressure from half of the distance to the adjacent stud, and header reaction
The input for the tables includes the JamStud® section, opening width (ft.), opening height (ft.) design wind pressure (WC&C, psf), and specified deflection limit. The output from the tables reflects the allowable JamStud height (ft.-in.) and the controlling
design factor, whether it is deflection or strength ("f" denotes strength, nothing denotes deflection). An “*” denotes critical web crippling at support of Jamb. The use of stiffening clips at supports typically eliminates the web crippling condition.
2. Design Example:
Service (un-factored) Loads:
Wind Pressure (C&C) = 30 psf
Wall Width = 6.0”
Wall Height = 14.0 ft.
Opening Width = 8.0 ft.
Opening Height = 10.0 ft
Stud Spacing = 16” o.c.
Specified Deflection Limit = L/360
Bridging (Lateral Bracing) is recommended at a vertical spacing of 60” o.c. with both JamStud® flanges connected to
Use the Table:
Go to "JamStud® - Allowable Heights" table with 6.0 in. stud member, 30 psf wind load, L/360 deflection limit, 8.0 ft. opening width, and 10.0 ft opening height. Possible JamStud® selections from table for 14.0 ft. height are 600JS250-97 (allowable height = 15' 1") and 600JS350-68 (allowable height = 14' 6 "). The alternative with typical 43mil “cee” studs results in a built-up section composed of (3) 600S162-43 capped by (2) 600T162-43.
The second JamStud® option, 600JS350-68, is a lighter section with less mil thickness. Use a 600JS350-68 (50ksi) (with design thickness = 0.0566" and Fy = 50 ksi). Allow 2 rows of bridging for the wall (including jamb stud) arranged so that the maximum spacing does not exceed 60 in. (5 ft.).
3. Extra Design Considerations:
Strength determination in the "JamStud® - Allowable Heights" tables includes checks for bending and shear capacity values of the stud and a check for lateral end reaction of the stud for web crippling. If tables indicate critical web crippling (denoted with an "*"), you may use a clip at the top and bottom ends of stud to eliminate the web crippling condition.
Design Comparison of Jamb Members
|Please download the JamStud Tech sheet (PDF) to view Section Properties.|
Available Section Depths:
350, 362, 400, 550, 600, and 800
Available Flange Widths:
250 and 350
*JamStud is available in the following minimum delivered thicknesses:
*See attached PDF for more information.
Please download the JamStud Tech sheet (PDF) to view Wind Pressure (PSF) and Deflection Limits.