Steel erection requirements

A "column" is a load-carrying vertical member that is part of the primary skeletal framing system, while a "post" is a smaller vertical structural member that meets one of two specific conditions. See the definition language in the steel erection standard 1926 Subpart R and the OSHA Letter of Interpretation explaining the distinction at Column vs post definitions | 2007-09-17.

• Columns are part of the primary structural frame and are treated as primary load-carrying members.
• Posts are defined in 1926.751 as either (a) a vertical member that weighs 300 pounds or less and is axially loaded, or (b) a member that is not axially loaded but is laterally restrained by the member above it.

No — neither the height of the member nor the magnitude of the load by itself changes a member's classification; the definition in the standard controls. OSHA clarified that only the criteria in 1926 Subpart R determine whether a vertical member is a "post" or a "column", as explained in the Letter of Interpretation Column vs post definitions | 2007-09-17.

• A vertical member is a "post" only if it (1) weighs 300 pounds or less and is axially loaded, or (2) is not axially loaded but is laterally restrained by the above member.
• If those conditions are not met, the member is treated as a column regardless of height or applied load.

A vertical member qualifies as a "post" when it weighs 300 pounds or less and is axially loaded (meaning the load presses down along its longitudinal axis). This is the weight-and-loading test in the steel erection definitions. See the definitions in 1926 Subpart R and the OSHA clarification in Column vs post definitions | 2007-09-17.

• "Axially loaded" means the load acts along the member's axis (compressive loading down the member).
• The 300-pound threshold is an explicit part of the regulatory definition; both the weight and axial loading condition must be met for the member to be a post under that clause.

Yes — a vertical member that is not axially loaded but is laterally restrained by the structural member above it meets the regulatory definition of a "post." OSHA confirms this second clause in the definition in 1926 Subpart R and in the Letter of Interpretation Column vs post definitions | 2007-09-17.

• The lateral-restraint clause has no separate weight threshold, so the member can be classified as a post under this condition regardless of weight (provided it is not axially loaded and is laterally restrained).

No — 1926.756(c)'s double-connection requirement applies to connections involving members on opposite sides of a column web or a beam web over a column, and it does not apply to double connections made at a beam away from a column. OSHA explained this in the Letter of Interpretation Double connections beam location | 2006-05-09 and the text of 1926 Subpart R.

• The standard targets the specific hazard that occurs when beam ends being double-connected are not supported by the column and a free-standing column shifts, displacing connected members.
• Appendix H illustrates connection devices but the double-connection rule itself is limited to column-associated connections.

When two structural members on opposite sides of a column web (or a beam web over a column) are connected sharing common connection holes, at least one bolt with its wrench-tight nut must remain connected to the first member unless a shop-attached or field-attached seat or an equivalent device is supplied to secure the first member. This requirement is stated in 1926 Subpart R and explained in the OSHA Letter of Interpretation Double connections beam location | 2006-05-09.

• The purpose is to keep the first member secured and prevent the column from being displaced while the second connection is made.
• Appendix H provides examples of acceptable seat or equivalent connection devices for this purpose.

OSHA limited 1926.756(c) to connections at columns because the most serious collapse hazards occur when beam ends being double-connected are not supported by a column and an eccentric load causes a free-standing column to shift, displacing the members and risking the connector's fall. OSHA discussed this rationale in the preamble to the 2001 rule and reiterated it in the Letter of Interpretation Double connections beam location | 2006-05-09 alongside the 1926 Subpart R text.

• For many floor-beam (filler beam) situations, the connector can sit on a header beam and the structure is generally more stable by the time these beams are installed, making the column-focused rule appropriate.

Appendix H provides examples of connection devices that OSHA regards as equivalent to a shop-attached or field-attached seat used to secure a first member during a double connection at a column; it helps show acceptable ways to prevent the member from slipping while the second connection is made. This is explained in 1926 Subpart R and in the Letter of Interpretation Double connections beam location | 2006-05-09.

• Appendix H illustrations are intended as examples of acceptable devices (such as clipped-end or seat-type connections) and not as an exhaustive list.
• The appendix example of a clipped end connection illustrates the device, not the requirement that it be used away from columns.

The clipped-end connection shown in Appendix H is an example of an acceptable connection device, but the specific double-connection rule in 1926.756(c) does not apply to beam connections that are away from a column. OSHA clarified that the Appendix illustration was intended to show what a clipped-end connection looks like, not to expand 1926.756(c) to connections away from columns. See 1926 Subpart R and Double connections beam location | 2006-05-09.

• If you plan to use a clipped-end or other seat device at a column, Appendix H shows acceptable examples.
• For beam-away-from-column connections, 1926.756(c) does not require the bolt-or-seat measures described there.

No — the double-connection requirement in 1926.756(c) does not apply to typical floor-beam (filler beam) installations away from a column, because the standard is focused on the column-related hazard and OSHA determined that filler beam connections generally occur when the structure is more stable and the connector can use other support. See 1926 Subpart R and the Letter of Interpretation Double connections beam location | 2006-05-09.

• OSHA noted the connector often can sit on the header beam and the structure is typically stable when floor beams are installed, so the column-specific measure was deemed sufficient.

The double-connection requirement is designed to prevent collapse or displacement of connected members (and the resulting fall of the connector) that can occur when beam ends being double-connected are not supported by the column and a free-standing column shifts under eccentric load. OSHA explains this safety concern in the preamble to the standard and in the Letter of Interpretation Double connections beam location | 2006-05-09 as part of the 1926 Subpart R rule.

• The rule requires at least one bolt to remain or an equivalent seat/device to be used so the first member cannot slip when the second member is connected.
• The measure specifically addresses situations where a column could shift and displace members that are being double-connected, creating a fall and collapse hazard for workers.

Yes — under the regulatory definition in 1926.751, a vertical member that is not axially loaded but is laterally restrained by the member above it meets the definition of a "post" even if it weighs more than 300 pounds. OSHA confirmed this interpretation in the Letter of Interpretation Column vs post definitions | 2007-09-17 and in 1926 Subpart R.

• The definition contains two distinct pathways to be a post: (1) weight ≤ 300 lb and axially loaded, or (2) not axially loaded but laterally restrained; the second pathway does not include a weight limit.