GUIDELINES FOR MARINE LIFTING & LOWERING OPERATIONS 0027/ND Rev 11 Page 24 of 84 5.5 DYNAMIC AMPLIFICATION FACTORS 5.5.1
Unless operation-specific calculations show otherwise, for lifts by a single crane in air, the DAF shall
be derived from Table 5-1.
Table 5-1 Dynamic Amplification Factors (DAF) in Air Gross weight, W (tonnes) DAF Onshore 2 ) Inshore 3), 5) Offshore 4), 5) 3
1)
< W ≤ 100
1.10
1.07 + 0.05√100/𝑆𝐻𝐿
1 + 0.25√100/𝑆𝐻𝐿
100 < W ≤ 300
1.05
1.12
1.25
300 < W ≤ 1000
1.05
1.10
1.20
1000 < W ≤ 2500
1.03
1.08
1.15
W > 2500
1.03
1.05
1.10
Note:
1) For lifted items weighing less than 3 tonnes, it is recommended to assume the item weighs 3
tonnes and this is used throughout the calculations for the rigging design.
2) For onshore crawler cranes travelling with load, possible dynamic effects should be evaluated
thoroughly. Crane speeds and surface conditions should be considered. If no documentation is
presented, the factors for “inshore lifts” should be used.
3) Inshore is applicable to a lift with a crane vessel to/from a vessel in sheltered waters and is also
applicable to lifting from the deck of a crane vessel onto a fixed platform at an offshore location.
4) Offshore is applicable to a lift by a crane vessel from another vessel to a fixed platform.
5) SHL refers to the Static Hook Load (see Section 6.2.2 and Section 6.2.3).
5.5.2
The DAF as indicated in Table 5-1 above shall also apply to the following in air lift combinations of
vessels, cranes and locations:
For lifts by 2 cranes on the same vessel
For onshore lifts by 2 or more cranes
For lifts by 2 or more hooks on the same crane boom (but see Section 5.5.6 for offshore lifts)
For inshore lifts, in totally sheltered waters, by 2 or more vessels.
5.5.3
The DAF as indicated in Table 5-1 above shall also apply to the following lifts by cranes on jacked-up
crane vessels:
onto or from floating vessels use the “Offshore” or “Inshore” column, as appropriate
onto fixed structures from its own deck, use the “Inshore” column. If the crane is not moving
horizontally on tracks or wheels, and horizontal motions of the load can be minimised by
suitably located crane tuggers, a DAF of 1.0 may be used provided the lifting and lowering
operations are carried out to avoid any dynamic snatching of the load.
5.5.4
For onshore lifts, where there is no crane movement other than lifting or lowering, a DAF of 1.0 may be
used provided the lifting and lowering operations are carried to avoid any dynamic snatching of the
load.
5.5.5
For offshore lifts by 2 or more vessels, the DAF shall be found by dynamic analysis.
5.5.6
For offshore lifts by 2 or more hooks on the same crane boom, total load on the crane boom structure
shall be documented, based on Table 5-1 DAFs multiplied by 1.10 unless certified crane curves for this
specific application can be provided.
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