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Kiewit Bridge & Marine Best Safety Practices and Safety
Policy Manual
11/06 Section 2.30 / Design of Lifting Beams and Spreader Bars
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SECTION 2.30 DESIGN OF LIFTING BEAMS AND SPREADER BARS
The use of lifting beams and spreader bars is common in
structures work. This policy will serve as adesign guideline in
order to establish common design standards and meet applicable
regulations.These devices are categorized as below the hook lifting
devices as defined by ANSI/ASME B30.20.Below are a few points from
this standard that must be considered when designing such
devices.
1. Section 20 1.2.2A lifter shall be designed to withstand the
forces imposed by its rated load, with a minimumdesign factor of 3,
based on yield strength, for load bearing structural components.
Tocomply with this section, use a load factor of 2.0 and design the
components according to
AISC ASD requirements. The maximum allowable stress per AISC is
0.667 Fy. Thiscorrelates to a 1.5 factor of safety against yield.
Applying a 2.0 load factor will increase thefactor of safety up to
3.0.
2. Section 20 1.2.1This section discusses the requirements for
permanently marking the lifting beam or spreaderbar with the rated
load. A note shall be placed on all drawings to permanently etch
withwelding rod the rated load and the lifter-weight in a visible
location. Painting this information orthe use of tags does not
satisfy this requirement.
3. Section 20 1.4.2This section discusses the requirements for a
rated load test. Each lifter shall be tested to aminimum of 125% of
the rated load. This requirement shall be placed on all drawings.
Thissection discusses the proper methods and inspections relating
to testing.
In addition to the above ANSI requirements, the following
guidelines should be followed:
1. A registered professional engineer will stamp all lifting
beam or spreader bar drawings. A copyof the drawings and
calculations are to be sent to the District Engineer and a copy
retained onthe project. The job shall maintain a log with all
picking beam and lifting device calculations ina filing system. The
project engineer should maintain this log.
2. All rigging should be checked for geometric considerations as
well as load capacity. Thedesigned rigging should be specified on
the drawing.
3. Sling angles significantly impact the design of these items.
Sling lengths should be specifiedon the drawing.
4. Often a lifting beam or spreader bar can be used in different
configurations. All possible loadconditions must be analyzed. If
required, a table of load ratings and loading configurationsshould
be placed on the drawings.
5. Pad eyes should be investigated closely. A large beam and/or
pad eye can have a significanteccentricity that will affect the
design. A check of the shackle clearances should be made.Cheek
plates are suggested on pad eyes to center the shackle and avoid
side loading the padeye.
6. Long spreader bars should be inspected for allowable
tolerances. A maximum sweep shouldbe specified on the drawings.
7. Any modifications or variances to the drawings need to be
reviewed and a new drawingissued.
