2.1.3
Hoist
CMAA 70 and as specified herein.
2.1.4
Comply with the mandatory and advisory safety requirements of ASME B30.2,
29 CFR 1910.147, 29 CFR 1910.179, 29 CFR 1910.306, and all applicable
provisions of 29 CFR 1910.
2.2
STRUCTURAL REQUIREMENTS
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NOTE: Specify welded box girders for bridge spans of
15 m 50 feet or more.
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[Provide welded box girders for the bridge.] Make girder to end truck
connections with unaltered ASTM A 325M ASTM A 325 high strength bolts, ASTM
A 563M ASTM A 563 nuts, and ASTM F 959 or ASTM F 436M ASTM F 436 washers.
Galvanized or coated bolts shall not be used. Make structural bolted
connections not referenced above with ASTM A 325M ASTM A 325 or ASTM A 307
bolts.
[2.2.1
Seismic Forces (SF)
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NOTE: Seismic forces should be considered in the
design of all cranes in Seismic Zones 3 and 4.
Enter the appropriate factor in the formula for SF
as determined below:
Seismic Zone
Factor
3
0.45
4
0.60
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Consider seismic forces in the design of the crane. Apply seismic forces
laterally, parallel to the bridge girders and parallel to the runway
girders as two separate load cases. Apply seismic forces concurrently with
the dead load (DL) and trolley load (TL). Locate the concentrated load in
the same positions as when calculating vertical shears and bending moments.
Consider twisting moments due to eccentric horizontal forces. Allowable
combined stresses shall be 133 percent of Stress Level One in CMAA 70.
Calculate combined stresses due to seismic forces for the following load
combination:
Seismic Loading = DL + TL + SF
where SF = [_____] DL (distributed) + [_____] TL
(concentrated)]
2.3
MECHANICAL REQUIREMENTS
used to support components of the hoist power transmission train shall be
ductile. All bearings, except those subject only to small rocker motion,
shall be anti friction type.
SECTION 14636N
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