should be 1 7/8 inches (51.2 mm) in circumference.
Lifelines and safety belts must be used when working
on unguarded scaffolds at heights of 10 feet (3 m) and
above (as well as on boatswains chairs, as explained
earlier). If working over water, life jackets must be
All scaffolds and scaffold equipment should be
maintained in safe condition. Avoid making repairs or
alterations to a scaffold or scaffold equipment while
in use. Rather than take a chance, NEVER permit
personnel to use damaged or weakened scaffolds!
FIELD-ERECTED HOISTING DEVICES
Because of the nature of heavy construction,
Steel workers must at times erect heavy structural
members when constructing pre-engineered
buildings, piers, bridges, and many other components
related to Advanced Base Functional Components
(ABFC). These members are usually hoisted into
position using cranes, forklifts, or other construction
equipment. In contingency/ combat operations,
however, because of operational commitments this
equipment may not be available and structural
members must be hoisted without the use of heavy
equipment. We will now discuss some of the methods
which can be used for the erection process when heavy
equipment is not available.
The term field-erected hoisting device refers to a
device that is constructed in the field, using material
available locally, for the purpose of hoisting and
moving heavy loads. Basically, it consists of a
block-and-tackle system arranged on a skeleton
structure consisting of wooden poles or steel beams.
The tackle system requires some form of machine
power or work force to do the actual hoisting. The
three types of field-erected hoisting devices used are
gin poles, tripods, and shears. The skeleton structure
of these devices are anchored to holdfasts.
Gin poles, shear legs, and other rigging devices
are held in place by means of guy lines anchored to
holdfasts. In fieldwork, the most desirable and
economical types of holdfasts are natural objects, such
as trees, stumps, and rocks. When natural holdfasts of
suffient strength are not available, proper anchorage
can be provided through the use of man-made
holdfasts. These include single picket holdfasts,
combination picket holdfasts, combination log picket
holdfasts, log deadmen, and steel picket holdfasts.
Natural Types of Holdfasts
When using trees, stumps, or boulders as
holdfasts, you should always attach the guys near
ground level. The strength of the tree, stump, or
boulder size is also an important factor in determining
its suit ability as a holdfast. With this thought in mind,
NEVER use a dead tree or a rotten stump or loose
boulders and rocks. Such holdfasts are unsafe because
they are likely to snap or slip suddenly when a strain
is placed on the guy, Make it a practice to lash the first
tree or stump to a second one (fig. 6-43). This will
provide added support for the guy.
Rock holdfasts are made by inserting pipes,
crowbars, or steel pickets in holes drilled in solid rock.
Using a star drill, drill holes in the rock 1 1/2 to 3 feet
apart, keeping them in line with the guy. Remember to
drill the holes at a slight angle so the pickets lean away
Figure 6-43.Using trees as a holdfast.