Structural Stability of beams and columns. Inappropriate or inadequate connections of beams and columns is hazardous and can lead to collapses and worker fatalities. This section sets forth performance and specification requirements for connecting beams and columns, in order to minimize the hazard of structural collapse during the early stages of the steel erection process.
General
- During the final placing of solid web structural members, the load must not be released from the hoisting line until [29 CFR 1926.756(a)(1)]:
- The members are secured with at least two bolts per connection, of the same size and strength as shown in the erection drawings.
- These bolts are drawn up wrench-tight.
- The equivalent, as specified by the project structural engineer of record, except as specified in 29 CFR 1926.756(b) of this section.
- A competent person must determine if more than two bolts are necessary to ensure the stability of cantilevered members if additional bolts are needed, they must be installed. [29 CFR 1926.756(a)(2)]
Diagonal Bracing
Solid web structural members used as diagonal bracing must be secured by [29 CFR 1926.756(b)]:
- At least one bolt per connection drawn up wrench-tight.
- The equivalent, as specified by the project structural engineer of record.
Double Connections at Columns
- 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 equivalent connection device is supplied with the member in order to (See Appendix H to this subpart for examples of equivalent connection devices.) [29 CFR 1926.756(c)(1)]:
- Secure the first member.
- Prevent the column from being displaced.
- If a seat or equivalent device is used:
- The seat (or device) must be designed to support the load during the double connection process.
- Before the nuts on the shared bolts are removed to make the double connection, it must be adequately bolted or welded to both [29 CFR 1926.756(c)(2)]:
- A supporting member
- The first member
Columns Splices
Each column splice must be:
- Designed to resist a minimum eccentric gravity load of 300 pounds.
- Located 18 inches from the extreme outer face of the column in each direction.
- Located at the top of the column shaft. [29 CFR 1926.756(d)]
Perimeter Columns
Perimeter columns must not be erected unless:
- They extend a minimum of 48 inches above the finished floor, to permit installation of perimeter safety cables prior to erection of the next story. [29 CFR 1926.756(e)(1)]
- They have two sets of holes, or other devices that:
- Are 42-45 inches above the finished floor, and also at the midpoint between the finished floor and the top cable.
- Permit installation of perimeter safety cables as required by 29 CFR 1926.760(a)(2). [29 CFR 1926.756(e)(2)]
EXCEPTION: Where constructability does not allow, the above requirements can be waived. (See Appendix F to this Subpart.)
Shared from: Occupational Safety and Health Administration,
https://www.osha.gov/SLTC/etools/steelerection/siteprep.html
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