1. SAFE USE OF MOBILE CRANES
Author:
Mihajlo Stupar
HSE Manager
PRO Lifting Solutions Ltd
Republic of Serbia
February 2016.

2. ● Mobile cranes are indispensable assistants in lifting heavy loads in the industry. They are
primarily used for lifting, lowering and transporting loads.
● Mobile cranes moved loads horizontally by swinging or traveling. Most of them consist of a
carrier and superstructure equipped with a boom, jib (optional) and hook.
● There are mechanical and hydraulic types of mobile cranes.
● Mechanical mobile cranes are also referred to as "conventional" crane and they have greater
capacity.
● Hydraulic cranes have greater mobility and require less setup time.

3. BASIC DEFINITIONS
● Crane – consist of a rotating structure for lifting and lowering horizontally structure on
rubber tires or crawler treads.
● Hoist – used to lift and lower load.
● Boom – an inclined spar, strut, or other long member supporting the hoisting tackle.
● Boom stops – a device used to limit the angle of the boom at its highest position.
● Brake – to slow or stop motion by friction or power.
● Block – sheaves or grooved pulleys in a frame with hook, eye and strap.
● Jib – extension attached to the boom point to provide added boom lenght for lifting
specified loads.
● Radius – horizontal distance from center of rotation to the hook.

4. CRANE CAPACITY
● Crane capacity is controlled by its operating radius.
● Capacity depends on: position of boom with respect to the carrier (over the front or over the
rear or sides), amount and configuration of the counterweight.
● Crane manufacturers provide lifting data that includes: range diagram, load rating charts,
PCSA rating class, miscellaneous notes and dimensions.
● Safety regulations limit maximum crane load to a percentage of the tipping load (load that
will cause the crane to actually begin to tip).
● Notice that hook blocks, slings, spreader bars, and other load-handling devices are
considered part of the load and their weight must be included in the maximum safe load
capacity calculation.
● Electronic load indicators are available that measure the actual load on the crane and
provide a warning if the safe capacity is being exceed.
● Lifting capacities are based on ≤ 85 % of tipping load on outriggers and on ≤ 75 % of tipping
load on crawlers.
● A standard method of rating the capacity of mobile cranes has been adopted by The PCSA
Bureau of The Construction Industry Manufactures Association (CIMA).
● The key to lifting a maximum capacity load is the outriggers. They provide a solid platform
for the crane safety operations. Statistic show that at least 50 % of crane incidents occur
because crane or outriggers are not set-up properly.

7. LIEBHERR LTM 11200-9.1 – ONE OF THE
BIGGEST MOBILE CRANE IN THE WORLD
● Lifting capacities:
● 1200 t on 2.5 m radius – with heavy lift boom and additional equipment.
● 140 t on 20 m radius, 33.5 t on 50 m radius, etc.

8. TEREX CC 8800-1 – ONE OF THE BIGGEST
CRAWLER CRANE IN THE WORLD
● Lifting capacities:
● 1558 t on 10 m radius, 873 t on 30 m radius, 334.5 t on 60 m radius, etc.
● Crawler crane can move with load. Ofcourse, for this operation you must have very good
ground conditions.

9. RESPONSIBILITIES, CONDITONS
● Have the right crane for the job.
● Assure operator is adequately
trained.
● Assure riggers are competent.
● Ensure crane is in safe
operating condition.
● Know the weight of the load.
● Know where the center of
gravity is.

10. RESPONSIBILITIES, CONDITONS
● Know the rated capacities of rigging.
● Reduce capacities as sling angles increase.
● Know how hitches affect sling capacities.
● Use proper sling sets for the load.
● Protect slings from sharp surfaces.
● Test lift uneven loads for balance.
● Inspect all slings, chains, hooks, etc.
● Stay clear of raised loads.

11. RESPONSIBILITIES, CONDITONS
● Provide overhead protection for other workers.
● Provide proper working area.
● Maintain clearance with overhead power lines.
● Assure adequate ground stability – as load
leverage increases, pressure increases nearest
the load.

12. EQUIPMENT FOR BINDING
● Slings are rated for vertical hitch.
● Chocker hitches can reduce capacities by
half.
● Basket hitches can increase capacity by 2
for straight vertical basket.
● If sling / chain angles are too shallow, the
slings / chains could slip.
● Shallow angles also can over stress slings /
chains.
Chocker Basket

13. EQUIPMENT FOR BINDING
● Slings / chains must be inspected before
each use. They should have tags that
indicates capacities.
● Slings are safer then chains, because on
slings you can see initial damage much
easier.
● Immediately remove damaged or
defective slings from service!!!

14. TENSION IN A SLING LEG
T – tension in a single leg.
WL – weight of load.
N – number of sling legs.
L – lenght of sling leg.
V – vertical distance between hook and load.
● The sling stress is proportional to the
angle of the sling.

15. SLING ANGLE AND CAPACITY
87 % 70 % 50 %
● Rated capacities must be reduced as sling ahgle increases.
● Slings should be set at a minimum of 60 degree angle.

16. CAUSES OF CRANE ACCIDENTS
● The main causes of crane accidents are:
● lack of planing and supervision,
● incorrect siting or setup cranes,
● failure to cerrectly calculate or estimate the
load,
● failure of personel to carry out the correct
procedures,
● use of wrong liftinting gears,
● lack of proper maintenance,
● careless and complacent,
● faulty device or machines.

17. SELECTING THE CRANE
● Cranes should always be selected to
handle the maximum anticipated load with
capacity to spare.
● Other consideration for the selection of
the crane are the nature of lift, ground
condition, site constraints, etc.

18. THE CRANE OPERATOR
● Make sure the crane operator can see the:
● Rated load capacities,
● Operating speeds,
● Special hazard warning and
instruction.
● The crane shall only be operated
by a trained, health and competent
operator, with cooperation of
trained lifting supervisor, trained
riggers and trained signalman.

19. DOCUMENTS FOR THE CRANE
When the crane arrives on site, the following
documents should come along with the crane
for inspection and review when requested:
● a vaild Certificate for the mobile crane,
● Valid certificates for all lifting gears that
comes with the crane,
● The log book or log sheet for the
recording of the operational tests carried
out by the operator before the start of
every workshift.
If the operator is unable to produce the
above documents, the crane supplier
should be contacted and the documents
obtained before the machine is put into
use. It is advisable to state that the
production of these documents will be
required when the crane is hired.

20. SITING OF CRANE
● The stability of the crane depends heavily on te proper siting and setting of the crane.
● Unless stated by the manufacturer, the crane should have its outriggers fully extended
with the wheels off the ground.
● The ground should be level and capable of supporting the full weight of the crane and its
load.
● In addition, sufficient and suitable packing in the form of steel or plastic plates or timber
mats should be placed under the outriggers to evenly distribute the weight. Surface of
these plates or mats should be at least twice bigger then surface of outriggers which is
above.
● The crane should also be positioned so that:
● The operator has a clear view of the operation as far as practicable,
● There is sufficient operating space,
● It is well away from edges of excavation and fixed structures which people
may be trapped by the moving parts such as counterweights, etc.
● Fully extend all outriggers for maximum capacity.

21. Proper outrigger setup
Not recommended outrigger setup. In this
situation load should be on the other side
of the crane, then the maximum pressure
will not be on this outrigger.

22. Improper outrigger setupPoor outrigger setup
No comment...

23. WORK NEAR POWER LINES
● Who is at risk –
● Operators are normally safe if they stay in the cabin.
● Ground personnel are over 8 times more likely to be killed.

24. PLANNING AND SUPERVISION
● All lifting operations should be properly planned by a competent person before the actual
execution and not left solely to the crane operator.
● Investigation into crane accidents revealed that one of the root causes of these accidents
was due to lack of proper planning and supervision. This is particularly so for simple
routine lifts. All contractors are advised not to be complacent during any lifting
operation, and to plan and supervise the operation carefully.
● Site constraints that would have an impact on the safe operation of the lifting should be
considered before the execution on the lift. Examples of such constraints are:
● lifting next to or over an excavation pit,
● materials or machines placed along the access way thereby reducing the
available space to extend the outriggers,
● site is located nearby busy traffic, or existing building or structures.
● Careful planning is especially critical for difficult lifts such as pick up and carry
operations, tandem lifting and tilt-up operation.

26. LOAD RADIUS INDICATOR
● The mandatory load radius indicator gives the
safe working load at the configuration that the
crane has been set, and gives a warning signal
when the radius is unsafe.
● The indicator:
● must be calibrated regulary,
● must be configured for both main and
auxiliary hooks (when both hooks
are used),
● the operator must be trained to use /
set the indicator correctly to tally
with the actual configuration
adopted.
● It is important to note that the load radius
indicator served primarily as an operational aid.
Although the indicator can warm the operator of
an impending overload, it should not be used as
the only tool to test the stability limit of the crane
during operations.

27. CHECKS AND MAINTANCE
● The crane should be in good working
condition when it arrives on site and before
the start of the workshift. In addition to
regulary inspections, the manufacture's
recommendation on the inspection and
maintance regime should also be followed
closely.

28. BASIC RADIO COMANDS HAND SIGNALS
● Use load line.
● Use wipline.
● Boom up – boom down.
● Boom up and hold the load.
● Boom down and hold the load.
● Swing right – swing left.
● Take the load up – down with the load.
● Extend boom – retract boom.
● Etc...

29. In these 2 accidents nobody
has died, but material
damage is very high, as you
can see on the pictures...
Why these accidents
happened?
Failure of operators to
carry out the correct
procedures...

32. T A K E C A R E , B E S A F E ;-)T A K E C A R E , B E S A F E ;-)