13.7 FABRICATION YARD CRANES 13.7.1
Fabrication yard cranes should normally possess an approval, issued by a recognised authority.
13.7.2
It should be documented that regular maintenance is carried out for all parts of the crane important for
the safety of the lift.
13.7.3
Allowable crane loads should be based on load-radii curves/tables. These should, as applicable,
clearly state:
a)
Crane boom type and length.
b) Counter weight position(s) and minimum number of hoist line legs.
c) Maximum load, limited by overturning or structural strength.
d) Crane equipment, e.g. hook, block, hoist lines, jib, to be included in crane hook load.
e) Operational limitations.
13.7.4
For multiple crane operations involving travelling, effective crane radii should be calculated considering
maximum out of plumb for hoist lines. The crane capacities should be calculated based on these radii.
See section 13.3.4 and 13.3.5 for further details.
13.7.5
Adequate sub-structure / ground strength should be documented for the supports of any crane
outriggers and crawler crane operations, especially, for example, in areas over culverts, drains,
underground services, proximity to the edge of an excavation, quayside locations, etc. Special
attention should be given to toe peak loads of the crawler crane tracks, areas which has been recently
back-filled or areas susceptible to reduced strength following inclement weather.
13.7.6
If there is insufficient information regarding ground capacity, load testing (including the complete crane
track) shall be carried out.
13.7.7
Operational limitations for travelling counter weights should be considered and the position and weight
should be checked.
13.8 OPERATIONAL AND PRACTICAL CONSIDERATIONS FOR ONSHORE LIFTS 13.8.1
Assuming all effects have been assessed, a calculated minimum clearance to the crane boom of 0.5 m
is normally acceptable. For roll-up operations planned hoist line angles need to be considered when
the minimum clearances are calculated and, for lifts involving travelling cranes, possible deviations
from vertical hoist lines (see Section 13.7.4) need to be considered when establishing minimum
clearances for lifts.
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