Cold-formed steel track
The top or bottom track of a wall, standard or deflection (slip) track: the stud's lateral reaction into it, the stud's and the track's strength there, the movement gap and the track's fasteners to the structure. To AISI S240-20 B3.2.5 with AISI S100-16 G5 and J4.
Inputs of the track #
- Studs: an SSMA designation or custom dimensions, Fy, the spacing, the configuration of Table B3.2.5.1-1 (single stud, double studs, at an opening or not), and the lateral reaction per stud at this track by load type.
- Track: standard or deflection; thickness (mils), Fy and Fu (ASTM A1003: 45 ksi for 33 ksi steel, 65 ksi for 50 ksi), the flange; for a standard track whether both stud flanges are screwed, and the screw size.
- Deflection track: the flange, the slip gap e (stud end to track web), the structure's movement that closes the gap and your tolerance (both your values), and the distance from the stud's web to the track's end.
- Track to the structure: screws into a steel support (its thickness and Fu, S100 J4.3), or anchors or power-actuated fasteners with the available strength you take from their evaluation report; the spacing along the track and the fasteners at each location.
Auto-design varies the track thickness (thinnest first), the fastener spacing and their number. Studs, reaction, gap and track type are kept.
Checks performed #
| Check | Basis |
|---|---|
| Stud to standard track, both flanges screwed | S240 Eq. B3.2.5.1-1, Tables B3.2.5.1-1, -2 |
| Track thinner than an interior stud | S240 Eq. B3.2.5.1-2 |
| Track at back-to-back jamb studs | S240 Eq. B3.2.5.1-3, Table B3.2.5.1-4 |
| Otherwise: stud web crippling, halved next to an opening | S240 B3.2.5.1(d), (e); S100 G5 |
| Deflection track within Table B3.2.5.2-1, fastened at no more than the stud spacing | S240 B3.2.5.2.2 |
| Deflection track: stud web crippling, bearing at most the engagement or 1 in. | S240 B3.2.5.2.1, S100 G5 |
| Deflection track flange | S240 Eqs. B3.2.5.2-1, -2 |
| Stud web at least wdt/2 from the track's end | S240 B3.2.5.2.2 |
| Gap at least the movement plus the tolerance | Your criteria |
| Screws into a steel support | S100 J4.3.1, J4.3.2 |
| Anchors or power-actuated fasteners | Evaluation report (entered) |
Limitations #
- The reaction is the stud's end reaction you enter; the stud itself is designed by the stud or curtain wall types.
- The track's web between fasteners, its splices and slide clips are not designed.
- Anchorage into concrete is your entry from the product's report: this type does not apply ACI 318 Chapter 17 or S100 J7.
- Screw shear Pss is the value SSMA prints from CFSEI F701-12; use the manufacturer's value if it differs.
Verification examples #
Verification status: 10 values compared in 4 examples (0 published, 4 hand calculations from the cited equations): 10 within tolerance, 0 recorded deviations. No published example: every value is a hand calculation. That checks the program against this reading of the code, not the reading itself. Code basis: not yet recorded for this module.
No published worked example of a track or deflection track is in the free library. The values are hand calculations of S240 Eqs. B3.2.5.1-1, -3, B3.2.5.2-1, -2, S100 G5 and J4.3.1. CFSEI technical notes W100 to W103 or AISI D110 would replace them.