Column stabilizer plate
Where steel joists are used and columns are not framed in at least two directions with solid web members, 29 CFR 1926.757(a)(1)(i) requires a vertical stabilizer plate on each column:
- at least 6 in × 6 in (152 × 152 mm),
- extending at least 3 in (76 mm) below the joist bottom chord,
- with a 13/16 in (21 mm) hole for guying or plumbing cables.
End attachments: K-series vs LH, DLH and girders
1926.757(b) sets the minimum at each joist end. Candidates often swap these:
- K-series, (b)(1): two 1/8 in (3 mm) fillet welds 1 in (25 mm) long, or two 1/2 in (13 mm) bolts, or the equivalent.
- LH and DLH joists and joist girders, (b)(2): two 1/4 in (6 mm) fillet welds 2 in (51 mm) long, or two 3/4 in (19 mm) bolts, or the equivalent.
Joist girders are in (b)(2) with LH and DLH; leaving them out of the rule is the common error. One weld or one bolt is half the requirement.
Spans and crew limits
- 60 ft or less at or near columns: designed so one employee can release the hoisting cable without erection bridging, 1926.757(a)(3).
- More than 60 ft at or near columns: set in tandem with all bridging installed, unless a qualified person designs another method that is in the site-specific erection plan, (a)(4). A 72 ft span falls here.
Under 1926.757(d), for spans over 60 ft through 100 ft, no more than two employees may be on the joists until all other bridging is installed and anchored. So an 85 ft span allows two.
Bridging bundles
Under 1926.757(e)(3), a bridging bundle may weigh no more than 1,000 lb, must rest on at least 3 joists secured at one end, with its edge within 1 ft (12 in) of the secured end. A 900 lb bundle on 3 joists 10 in from the secured end complies; 1,200 lb, 2 joists or 18 in each fail. The 4,000 lb figure is the decking bundle limit in (e)(4).