Open web steel joists

A vertical stabilizer plate at each column is required and it must be at least 6 inches by 6 inches, extend at least 3 inches below the bottom chord of the joist, and contain a 13/16-inch hole to attach guying or plumbing cables (1926.757(a)(1)(i).

• Use the hole to guy or plumb the column during erection.
• Ensure the plate location and size match the requirement on erection drawings.

The bottom chords of steel joists at columns must be stabilized to prevent rotation during erection (1926.757(a)(1)(ii).

• Stabilization is commonly achieved by restraining the bottom chord with the vertical stabilizer plate at the column and field-bolting the seat.
• Do not release hoisting cables until stabilization and required bolting/restraints are in place (1926.757(a)(1)(iii)).

Hoisting cables may not be released until the seat at each end of the steel joist is field-bolted and each end of the bottom chord is restrained by the column stabilizer plate (1926.757(a)(1)(iii).

• This ensures the joist and columns have lateral stability before the hoisting rigging is removed.
• If constructibility prevents field bolting at the column, see the alternate stabilization rules in 1926.757(a)(2). (1926.757(a)(2)).

An alternate means of stabilizing the joist must be shop-installed on both sides near the column, be designed by a qualified person, provide equivalent stability to the column stabilizer and field-bolting, and be included in the erection drawings (1926.757(a)(2)(i)(A)-(D)).

• Hoisting cables still cannot be released until the joist seat is field-bolted and the joist is stabilized (1926.757(a)(2)(ii)).
• Keep documentation of the qualified person’s design and show it on erection drawings for inspection and coordination.

If the joist at or near the column spans 60 feet (18.3 m) or less, the joist must be designed with sufficient strength so that one employee can release the hoisting cable without erection bridging being required (1926.757(a)(3).

• Confirm the joist design allows single-employee cable release before attempting it.
• If the span exceeds 60 feet, erection bridging or tandem setting rules apply (1926.757(a)(4)).

Joists that span more than 60 feet must be set in tandem with all bridging installed unless a qualified person designs an alternative erection method that provides equivalent stability and that alternative is included in the site-specific erection plan (1926.757(a)(4).

• Tandem setting means placing joists together so they help support each other during erection.
• Any alternate method must be documented in the site-specific erection plan and prepared by a qualified person.

No — a steel joist or steel joist girder must not be placed on any support structure unless that support structure is stabilized (1926.757(a)(5).

• Stabilize supports (columns, beams, temporary shoring) before landing joists to prevent tipping or collapse.
• Verify stability per erection drawings and the qualified person’s directions.

When steel joists are landed on a structure, they must be secured to prevent unintentional displacement prior to installation (1926.757(a)(6).

• Use temporary ties, blocks, or other means so bundles or individual joists cannot slide or fall.
• Secure landing points per the erection plan and follow safe rigging and material-handling practices.

No — any modification that affects the strength of a steel joist or steel joist girder cannot be made without approval of the project structural engineer of record (1926.757(a)(7).

• Structural changes that alter members, holes, or connections require engineer approval in writing.
• Keep approvals with erection documents and ensure the modifications are reflected in drawings.

Connections of individual steel joists to steel structures in bays of 40 feet (12.2 m) or more must be fabricated to allow field bolting during erection, except for steel joists that have been pre-assembled into panels; these connections shall be field-bolted unless constructibility prevents it (1926.757(a)(8)(i)-(ii).

• Preassembled panels are an exception and must be handled per paragraph (b)(4) when hoisting.
• If constructibility prevents field bolting, document the alternate means and include it in the erection drawings per 1926.757(a)(2).

Not unless you have written approval from a qualified person — steel joists and steel joist girders shall not be used as anchorage points for a fall arrest system unless written approval is obtained from a qualified person (1926.757(a)(9).

• A qualified person must evaluate the member’s capacity and provide written approval and instructions for use as an anchorage.
• Do not improvise fall arrest anchors on joists without that written engineering approval.

A bridging terminus point is a fixed point where erection bridging can be anchored, and a bridging terminus point must be established before bridging is installed (1926.757(a)(10).

• Terminus points provide the end anchors needed to install and tension erection bridging.
• If permanent terminus points aren’t available during erection, temporary terminus points must be provided (1926.757(c)(5)).

K-series joists must be attached at each end with a minimum of two 1/8-inch fillet welds 1 inch long or two 1/2-inch bolts (or equivalent), and LH/DLH series joists must be attached with two 1/4-inch fillet welds 2 inches long or two 3/4-inch bolts (or equivalent) (1926.757(b)(1)-(2)).

• The term “equivalent” means a connection that provides equivalent capacity; document equivalence in erection drawings or by engineer direction.
• Ensure weld quality and bolt sizing meet the specified minimums on the connections.

Except as provided for preassembled panels, each steel joist must be attached to the support structure at least at one end on both sides of the seat immediately upon placement in the final erection position and before additional joists are placed (1926.757(b)(3)).

• Panels pre-assembled with bridging must be attached at each corner to the structure before hoisting cables are released (1926.757(b)(4)).
• Follow the specified attachment method for the joist series (weld or bolt) when securing to supports.

For joists that require bridging under Tables A and B, both sides of the seat at one end must be attached before hoisting cables are released (1926.757(c)(1)).

• Joists over 60 feet must have both ends attached as specified in paragraph (b) and meet the provisions of paragraph (d) before hoisting cables are released (1926.757(c)(2)).
• On joists that do not require erection bridging under Tables A and B, only one employee is allowed on the joist until all bridging is installed and anchored (1926.757(c)(3)).

"NM" in Tables A and B means diagonal bolted bridging is not mandatory for that joist and span; the tables list span thresholds where erection bridging is required for specific joist types (1926.757(c).

• If the joist/span combination in the table shows a dimension (e.g., 32–0), follow the table threshold and the erection bridging rules in paragraph (d).
• If it shows "NM," diagonal bolted bridging isn’t mandatory but other stabilization requirements may still apply.

Employees are not allowed on steel joists where the span is equal to or greater than the span shown in Tables A and B except in accordance with 1926.757(d), which contains erection-bridging and personnel limits (1926.757(c)(4)).

• When permanent bridging terminus points cannot be used, additional temporary bridging terminus points are required to provide stability (1926.757(c)(5)).

A row of bolted diagonal erection bridging must be installed near the midspan of the joist, hoisting cables may not be released until this bolted diagonal erection bridging is installed and anchored, and no more than one employee is allowed on these spans until all other bridging is installed and anchored (1926.757(d)(1)(i)-(iii)).

• This midspan bridging provides immediate lateral stability for the span before full bridging is completed.

For spans over 60 feet through 100 feet, all rows of bridging must be bolted diagonal bridging, two rows of bolted diagonal erection bridging must be installed near the third points of the joist, hoisting cables may not be released until these are installed and anchored, and no more than two employees may be on these spans until all other bridging is installed and anchored (1926.757(d)(2)(i)-(iv)).

• The two-row requirement increases intermediate stability on long spans during erection.

For spans over 100 feet through 144 feet, all rows of bridging must be bolted diagonal bridging; hoisting cables shall not be released until all bridging is installed and anchored; and no more than two employees shall be allowed on these spans until all bridging is installed and anchored (1926.757(d)(3)(i)-(iii)).

• For steel members spanning over 144 feet, erection methods must follow 1926.756, which contains additional requirements for very long spans (1926.757(d)(4)).

When a joist specified in the referenced paragraphs is a bottom chord bearing joist, a row of bolted diagonal bridging must be provided near the support(s) and installed and anchored before the hoisting cables are released (1926.757(d)(5)).

• This support-area bridging prevents rotation or instability where the bottom chord bears on the support.

When bolted diagonal erection bridging is required, the bridging must be indicated on the erection drawing, the erection drawing is the exclusive indicator of proper bridging placement, shop-installed bridging clips or equivalents must be used where bridging bolts to joists, the nut securing the first piece on a common bolt must not be removed to attach the second piece, and bridging attachments must not protrude above the top chord (1926.757(d)(6)(i)-(v)).

• Follow placement exactly as shown on erection drawings; do not relocate bridging without a qualified-person revision to the drawings.

The employer placing a load on steel joists must ensure the load is distributed so as not to exceed the carrying capacity of any joist; except as allowed under paragraph (e)(4), no construction loads are permitted on joists until all bridging is installed and anchored and all joist-bearing ends are attached; and the weight of a bundle of joist bridging shall not exceed 1,000 pounds (454 kg) (1926.757(e)(1)-(3)).

• Check joist capacity and erection plan before landing materials on joists.
• Do not overload bridging bundles or individual joists during erection.

A bundle of decking may be placed on steel joists before all bridging and joist-bearing ends are attached only if all of the conditions in 1926.757(e)(4) are met: a qualified person has determined and documented in a site-specific erection plan that the structure can support the load, the bundle is placed on at least three joists, the supporting joists are attached at both ends, at least one row of bridging is installed and anchored, the bundle weight does not exceed 4,000 pounds (1816 kg), and placement follows paragraph (e)(5); additionally, the edge of the construction load must be placed within 1 foot (0.30 m) of the bearing surface of the joist end (1926.757(e)(4)(i)-(vi) and (e)(5)).

• If any of these conditions aren’t met, do not place decking bundles on the joists.
• The intent is to limit localized load and ensure bridging and connections control stability.

A qualified person must determine that the structure or portion of the structure can support the load and this determination must be documented in a site-specific erection plan (1926.757(e)(4)(i)).

• The site-specific erection plan should include calculations or notes from the qualified person about load distribution and capacity.
• Keep the plan accessible to the erection crew and site supervisors for verification during placement.

Under the exception, the decking bundle must be placed on a minimum of three steel joists, and the joists supporting the bundle must be attached at both ends before placing the bundle (1926.757(e)(4)(ii)-(iii)).

• This reduces the chance that a single overloaded joist will be overstressed.
• Verify the end attachments meet the required welds or bolts specified for the joist series in paragraph (b).

The weight of a bundle of joist bridging shall not exceed 1,000 pounds (454 kg) (1926.757(e)(3)), and the total weight of a bundle of decking placed under the exception in 1926.757(e)(4) must not exceed 4,000 pounds (1816 kg) (1926.757(e)(4)(v)).

• Always check the site-specific erection plan and joist capacities before landing bundles.
• Place bundles so their edge is within 1 foot (0.30 m) of the secured end per 1926.757(e)(5).

Shop-installed bridging clips or functional equivalents must be used where the bridging bolts to the joists, and when two pieces of bridging are attached to the joist by a common bolt, the nut that secures the first piece must not be removed from the bolt to attach the second piece (1926.757(d)(6)(iii)-(iv)).

• Using shop-installed clips ensures correct clip placement and fit during erection.
• Do not re-thread or remove nuts that secure already-installed bridging pieces — use the second stud or appropriate attachment method as designed.