Structural steel assembly

The employer must maintain structural stability at all times during the erection process. See 1926.754(a).

• Note: FHWA/AASHTO design requirements may apply to specific bridge or highway work; consult 23 CFR 625.4 and the note in 1926.754(a) when falsework or working drawings are required by FHWA.

Permanent floors must be installed as erection of structural members progresses so there are no more than eight stories between the erection floor and the upper-most permanent floor unless the design itself ensures stability. See 1926.754(b)(1).

• If the structural design provides the necessary stability, the eight-story limit may not apply; that exception depends on the design’s demonstrated integrity.

You may not have more than four floors or 48 feet (whichever is less) of unfinished bolting or welding above the foundation or the uppermost permanently secured floor, except where the design maintains structural integrity. See 1926.754(b)(2).

• If the structural design provides adequate stability, the employer may rely on that design rather than the numeric limit.

You must maintain a fully planked or decked floor or safety nets within two stories or 30 feet (whichever is less) directly under any erection work being performed. See 1926.754(b)(3).

• This requirement provides a safe working surface or fall-arrest option beneath active erection areas.

Shear connectors and similar devices must not be attached so they project from the top flange of beams or joists until after the metal decking or other walking/working surface has been installed. See 1926.754(c).

• When constructing composite floors, employees must lay out and install shear connectors only after the metal decking is in place and using the decking as a working platform; see 1926.754(c)(2).
• Shear connectors must not be installed from within a Controlled Decking Zone; see 1926.760(c)(7).

No — shear connectors shall not be installed from within a Controlled Decking Zone (CDZ). See 1926.754(c)(2) and the CDZ provision at 1926.760(c)(7).

• Install shear connectors only after metal decking is installed and when employees are working from the decking as a platform.

When a competent person deems it necessary, plumbing-up equipment must be installed to ensure structural stability; it must be in place and properly installed before loading the structure with construction materials, and it may be removed only with the approval of a competent person. See 1926.754(d)(1), 1926.754(d)(2), and 1926.754(d)(3).

• “Competent person” must evaluate need, installation, and removal to protect stability during erection.

You must not use bundle packaging or strapping for hoisting unless it is specifically designed for that purpose; secure any loose items placed on decking bundles; land bundles on joists in accordance with [1926.757(e)(4)]; land bundles on framing members so they can be unbanded without dislodging; and secure metal decking at the end of the shift or when conditions require. See 1926.754(e)(1)(i)-(v) and 1926.757(e)(4).

• These steps reduce the risk of bundle shifts, falling materials, and unstable decking during erection.

If openings cannot be decked over because of their size or configuration (for example elevator shafts or stairwells), employees working near those openings must be protected in accordance with [1926.760(a)(1)]. See 1926.754(e)(2) and 1926.760(a)(1).

• Otherwise, framed openings should have structural members turned down to allow continuous deck installation, and roof and floor holes should be decked over per 1926.754(e)(2)(i)-(ii).

Metal decking openings shall not be cut until immediately before they are permanently filled with the required equipment or structure that meets the strength requirements, or they must be immediately covered. See 1926.754(e)(2)(iii) and the cover requirements in 1926.754(e)(3).

• Never leave decking holes open longer than necessary; if temporarily covered, use covers that meet the strength and securing requirements in 1926.754(e)(3).

Covers must support twice the weight of employees, equipment, and materials that may be imposed on them, must be secured to prevent accidental displacement, and must be painted with high-visibility paint or marked with the word "HOLE" or "COVER." See 1926.754(e)(3)(i)-(iii).

• Smoke domes or skylight fixtures are not acceptable as covers unless they meet the same strength requirement in 1926.754(e)(3)(i).

Not automatically — smoke domes or skylight fixtures already installed are not considered covers unless they meet the strength requirement of supporting twice the imposed load as required in [1926.754(e)(3)(i)]. See 1926.754(e)(3)(iv) and 1926.754(e)(3)(i).

• If a skylight does meet the strength and securing requirements, it may be used as a cover; otherwise use compliant covers or guard measures.

Where planks or metal decking do not fit tightly around columns, you must install wire mesh, exterior plywood, or an equivalent material of sufficient strength to provide fall protection for personnel and to prevent objects from falling through. See the decking-gaps requirement in 1926.754(e).

• Use materials strong enough to prevent personnel falls and falling-object hazards.

Except as allowed under 1926.760(c), metal decking must be laid tightly and immediately secured upon placement, and during initial placement panels must be located so they have full support by structural members. See 1926.754(e)(5)(i)-(ii).

• The Controlled Decking Zone procedure at 1926.760(c) provides limited exceptions when specific controls are in place.

A derrick floor must be fully decked and/or planked and have the steel member connections completed to support the intended floor loading, and any temporary loads placed on a derrick floor must be distributed over the underlying support members to avoid local overloading of deck material. See 1926.754(e)(6)(i)-(ii).

• These measures prevent collapse or local failure when storing temporary construction loads on derrick floors.

Bundles of metal decking placed on joists must be landed in accordance with the landing requirements at [1926.757(e)(4)], ensuring adequate support to prevent dislodgment or unsafe conditions. See 1926.754(e)(1)(iii) and 1926.757(e)(4).

• Proper landing minimizes the risk of bundles shifting when unbanding and during decking installation.

That phrase means you may exceed the numeric limits in [1926.754(b)(1)-(2)] only when the building’s engineered design demonstrates and ensures adequate structural stability during erection. See 1926.754(b) and the design-note in 1926.754(a), which references FHWA/AASHTO requirements and 23 CFR 625.4.

• In practice, that usually requires engineered calculations or sealed working drawings showing the erection sequence and that the partially completed structure will remain stable under the anticipated loads.

All covers must be secured when installed to prevent accidental displacement by wind, equipment, or employees, and they must be painted with high-visibility paint or marked with the word "HOLE" or "COVER" to warn of the hazard. See 1926.754(e)(3)(ii)-(iii).

• Use durable fastenings and visible markings so workers can both see and rely on the cover’s placement.