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The lifting capacity of Tower crane depends on various factors.
The limitation for lifting weight starts from the base of the tower crane. Each and every component of the tower crane affects the load lifting capacity of the tower crane.
For a typical tower crane Maximum unsupported height – 80 meters (265 feet) Maximum Reach – 70 meters (230 feet), Maximum Lifting Power – 19.8 tons (18 Metric Tons), 300 tonne-meters. Counter weights – 20 tons (16.3 Metric Tons).
If the crane height is more than 265 feet, then some means of sturdy support is required. It may be some steel wires fixed from the crane mast to the different parts of the building. The maximum weight that the tower crane can lift is 18 Metric Tons. However the quantity of weight to be lifted keeps on decreasing as the distance from crane center increases. So it is always better to lift loads keeping them as close as possible to the crane’s center.
The factor 300 tonne-meter is instrumental in understanding the load limitation. It is the moment of the load lifted about the crane’s center. So moment = load * distance.
A 300 tonne-meter limit can be inferred as a load of 10 tons being lifted at a distance of 30 meters from the center of the crane. So moment about the crane’s center is 10 tons * 30 meters = 300 tonne-meter.
Basic precautions for a Tower Crane with respect to load being lifted:
Maximum load limit switch: This switch along with its accessories monitors the pull (strain) on the cable and thus does not allow the maximum load limit to cross 18 tons, after which it trips the motor and gives audible and visual alarms.
Load moment limit switch:This limit switch along with its accessories ensures the load-moment (tonne-meter) rating does not exceed beyond the given limit, after which the hoist motor and traversing motors are tripped with audible and visual alarms.
These towers are held at the base by concrete structures/pads, with the help of anchor bolts. These concrete slabs are made ready several weeks before the arrival of the tower cranes. These concrete pads weigh about 2 tons.
Every tower crane has it's own safe load capacity,so based on the safe load capacity you will be able to determine if the tower crane is safe to carry the load or not.consequently, prior to lifting a permit to lift must be in place in lifting refers to as standard or complex lift,all third party certificate of the tower crane must be in place and valid to proof the integrity of the tower crane prior to lifting,a lifting supervisor must be in place along with 2 riggers depending on the standard,ensure the lifting gears has been inspected and followed the accepted inspection procedure with the aid of a check list,ensure the crane operator is competent enough for carrying out the task by checking his driving license and third party certificate,furthermore, ensure all lifting regulations and standards conform accordingly to the contractual requirements and required statutory of the project/country.
The torque of the tower crane tells you how much the cranes can lift depending on how far out of the crane arm it is. One must be very careful about the wind and the burden you lift as there may be a large wind surface on the load.
The weight and capacity depend on the crane size, but no matter what size a crane is we need to pay attention to some basic details: The strenght of the wind, move any cargo/load as close to the ground as possible, avoid any quick movements that might unbalance the cargo and any professional crane operator must knownhow to stop the load's counter balance movement.
A Tower Crane Should not lift more than 10 tons of wieght.
Management In Risk and take advantages and disadvantages in that the major factor Risk and Due Deligence
How much load can the tower crane lift? Fifteen Tones and 135 metre height.
What are the causions you should care? person operating the machine must not lift more than the machine capacity
Thanks, and I agree with eng.Imraan should take care about risk management.
Work involving cranes is always high risk and therefore greater care should be undertaken to ensure that risks are minimised.
It is important only certified, qualified and experienced operators are tasked with these kinds of crane activities.
It is also important that when lifting certain loads, exclusion zones are set up to protect the workers below as well as the public, this is something that is often not done because it is perceived as a waste of time but as this incident proves it is a vital and necessary step.
Improperly secured loads are a common source of crushing on work sites because of the size and weight of loads. On a construction site building materials, equipment and debris are some of the items lifted so when they fall there is the possibility that the load will hit workers below, they cause crushing injuries, some fatal. Most important thing we should have proper training and knowledge in details what are the capacity, advantages and disadvantages of using tower cranes, and how they will apply it in the constructions even we are safety practitioners.
A Tower Crane Should not lift more than 5 - 6 tons of wieght.
Due to height and safety of movement.
All Safety procedures such as nets, surroundings should be clear at all times by communicating with the signal man to make sure all safety at all times.
The Lashing belts should be fixed properly and ensure safety of the goods as well as surroundings.
