The general rule: two bolts, wrench-tight
Before a solid web structural member is released from the hoisting line, 29 CFR 1926.756(a)(1) requires, at each connection:
- at least two bolts,
- of the size and strength shown on the erection drawings,
- drawn up wrench-tight or the equivalent specified by the structural engineer of record.
Finger-tight does not meet the wrench-tight requirement. Four is not a bolt count: it is the minimum number of anchor rods per column under 1926.755(a)(1).
Diagonal bracing: one bolt
Solid web members used as diagonal bracing are the exception. Under 1926.756(b) they need at least one bolt per connection, drawn up wrench-tight.
The trap runs both ways: applying the two-bolt rule of (a)(1) to diagonal bracing is the common mix-up, and so is using the one-bolt bracing rule for ordinary members. There is no two-and-one split in the rule. Match the member to its paragraph:
- ordinary solid web member: two bolts, 1926.756(a)(1)
- solid web member used as diagonal bracing: one bolt, 1926.756(b)
Cantilevers: a competent person decides
Under 1926.756(a)(2), a competent person decides whether a cantilevered member needs more than two bolts before it is released from the hoisting line. That judgment adds bolts for cantilevers; it does not remove the one-bolt minimum for bracing.
Do not hand this decision to the wrong party:
- The project structural engineer of record approves anchor rod repairs, replacements and field modifications under 1926.755(b)(1), and specifies wrench-tight equivalents, but is not named for the cantilever bolt count.
- The controlling contractor notifies the erector in writing about anchor rod changes under 1926.755(b)(2).
- The crane operator is given no decision in 1926.756.
The quick memory line: two bolts for members, one for diagonal bracing, and a competent person on cantilevers.