28.B.26 Erection bridging.
- Where the span of the steel joist is equal to or greater than the span shown in Tables 28-1 and 28-2, the following must apply:
- (1) A row of bolted diagonal erection bridging must be installed near the mid-span of the steel joist,
- (2) Hoisting cables must not be released until this bolted diagonal erection bridging is installed and anchored, see Figure 28-1, and
- (3) No more than one employee must be allowed on these spans until all other bridging is installed and anchored.
- Where the span of the steel joist is over 60 ft (18.2 m) through 100 ft (30.4 m), the following must apply:
- (1) All rows of bridging must be bolted diagonal bridging,
- (2) Two rows of bolted diagonal erection bridging must be installed near the third points of the steel joist,
- (3) Hoisting cables must not be released until this bolted diagonal erection bridging is installed and anchored, and
- (4) No more than two employees must be allowed on these spans until all other bridging is installed and anchored.
- Where the span of the steel joist is over 100 ft (30.4 m) through 144 ft (43.9 m), the following must apply:
- (1) All rows of bridging must be bolted diagonal bridging,
- (2) Hoisting cables must not be released until all bridging is installed and anchored, and
- (3) No more than two employees must be allowed on these spans until all bridging is installed and anchored.
Figure 28-3
- For steel members spanning over 144 ft (43.9 m), the erection methods used must be in accordance with Sections 28.B.18 through 28.B.22.
- Where any steel joist specified in paragraph b above or Section 28.B.26.a-c is a bottom chord-bearing joist, a row of bolted diagonal bridging must be provided near the support(s). This bridging must be installed and anchored before the hoisting cable(s) is released.
- When bolted diagonal erection bridging is required by this section, the following must apply:
- (1) The bridging must be indicated on the erection drawing;
- (2) The erection drawing must be the exclusive indicator of the proper placement of this bridging;
- (3) Shop-installed bridging clips, or functional equivalents, must be used where the bridging bolts to the steel joists, see Figures 28-3, 28-4 and 28-5; (see next course subsections)
- (4) When two pieces of bridging are attached to the steel joist by a common bolt, the nut that secures the first piece of bridging must not be removed from the bolt for the attachment of the second; and
- (5) Bridging attachments must not protrude above the top chord of the steel joist.
Knowledge Check Choose the best answer for the question.
28-7. Until all bridging is installed and anchored, how many employees are allowed on the span of a steel joist that is over 100 ft (30.4 m) through 144 ft (43.9 m)?
You forgot to answer the question!