Crane weight is a key figure of work preparation in concrete demolition, special demolition, rock excavation and tunnel construction. It determines whether loads can be safely lifted, held, and precisely positioned. Especially in inner-city deconstruction, in building gutting and in concrete cutting as well as in special operations, the correct crane weight is the basis for structural stability, load-bearing capacity and efficient construction logistics. In practice, it concerns not only the load on the hook, but also the self-weight of the crane with counterweights—both affect load charts, load moments, surface pressure and the selection of suitable attachment and handheld tool, such as concrete demolition shear or hydraulic rock and concrete splitters by Darda GmbH.
Definition: What is meant by crane weight
In day-to-day construction and demolition, crane weight refers to two aspects: first, the total load on the hook—that is, the effective weight the crane lifts, consisting of the load, slinging gear, and any additional components. Second, the self-weight of the crane, including counterweights and equipment, which is decisive for transport, assembly condition, surface pressure, and stability. For use with hydraulic demolition and cutting tools from Darda GmbH, the hook load is usually the focus, as it determines the permissible load at the respective radius. At the same time, the crane’s self-weight—especially in confined conditions and on sensitive substrates—must not be neglected.
Calculating the total load on the crane hook
The robust determination of crane weight at the hook follows a simple principle: add up all masses the crane moves and account for realistic allowances. For deconstruction and demolition using concrete demolition shear, stone and concrete splitters, or supplementary tools such as combination shears, multi cutters, steel shear and tank cutter, the calculation typically includes:
- Dead weight of the tool (e.g., concrete demolition shear or stone splitter)
- Adapters, rotators, suspensions, quick coupler and any mounting plate
- Slinging gear: chains, wire ropes, shackles, spreader beam
- Hydraulic components: hoses, oil fill, couplings; if required, the power unit to be lifted
- Accompanying components or material pieces that move along when the load is released
- Operational allowances for dynamics, acceleration, braking, slewing, and wind
As a practical formula: Hook load = Tool + Attachments + Slinging gear + Hydraulics + Carry-along components + Allowances. Allowances are often set conservatively to cover dynamic effects. The center of gravity must also be considered: an eccentric load can reduce the effective utilization of the load chart, even if the pure mass is within the rated load.
Example calculation: Concrete demolition shear in building deconstruction
For building gutting and selective separation of components, a concrete demolition shear is used on a tower crane. Assumed values:
- Concrete demolition shear: 680 kg
- Rotator/adapter: 55 kg
- Slinging gear (chain, shackles): 35 kg
- Hydraulic hoses and oil: 20 kg
- Carry-along concrete piece when releasing: 120 kg
- Dynamic allowance (approx. 10%): about 91 kg
Result: 680 + 55 + 35 + 20 + 120 + 91 = 1,001 kg hook load. This load must be checked against the load chart at the intended radius. In addition, the angles of the slinging gear must be considered: shallow angles increase leg forces and thus the stress on chains or wire ropes significantly.
Example calculation: Stone and concrete splitter in tunnel construction
In rock excavation and tunnel construction, stone splitting cylinders are used with compact hydraulic power units. If the unit is moved to the tunnel face, it can be part of the hook load:
- Stone splitting cylinder: 52 kg
- Tool carrier/spreader: 18 kg
- Slinging gear: 12 kg
- Hydraulic hoses and oil: 10 kg
- Power unit (to be lifted): 145 kg
- Allowance (approx. 10%): 24 kg
Result: 52 + 18 + 12 + 10 + 145 + 24 = 261 kg hook load. If the power unit is relocated separately onto a secured platform, the hook load is reduced accordingly. This creates load reserves for longer radii or unfavorable sling angles.
Influence of radius, load moment, and load charts
Crane weight should never be considered in isolation. As radius increases, the permissible load decreases because the load moment grows. For deconstruction this means: a tool that can be lifted without issues near the tower or slewing ring may exceed the permissible load at large radius. With concrete demolition shear and combination shears, the planned position of the component in the building is therefore just as important as the hook load. In natural stone extraction and rock breakout, horizontal reaches in pits and at edges must be considered. The crane’s load charts are the binding basis for planning; the specific configuration (counterweights, boom configuration, reeving) determines the approvals.
- Radius and slewing: during slewing, short-term additional forces may occur.
- Wind: particularly with large-surface components, the exposed area increases and thus the load.
- Hoisting speed: smooth, steady operation reduces dynamic peaks.
Crane weight, crane self-weight, and surface pressure
In addition to the hook load, the crane’s self-weight with counterweight acts on the ground. In inner-city concrete demolition, in building gutting and concrete cutting, and in special demolition on floor slab, the permissible surface pressure is often the limiting factor. Load distribution plates and mats help reduce contact pressure. In tunnels and in rock breakout, subgrade strength, slope, and space conditions influence the setup area. The crane weight in the assembled condition (with or without additional ballast) must therefore be checked early against the permissible surface pressure.
Slinging, load distribution, and center-of-gravity control
Safe slinging does not change the crane weight in sum, but it affects the acting forces and stability. Side pulls, unfavorable sling angles, and undetected centers of gravity can cause overloads. Concrete demolition shear and multi cutters have defined lifting points; slinging at stable, designated areas with suitable shackle and chain nominal sizes is mandatory. With stone and concrete splitters, small, precise slinging gear should be used to minimize movement during splitting.
Angles and additional forces
As the angle between the slinging gear and the horizontal decreases, the leg forces increase significantly. Therefore, choose the steepest possible sling angles, use spreader beams and—where sensible—divide the load into segments. Good center-of-gravity positioning reduces swinging and dynamic allowances, improving the effective utilization of the load chart.
Crane weight in typical applications
In concrete demolition and special demolition, loads are often irregular and difficult to access. Segmented deconstruction with concrete demolition shear lowers the hook load per lift. In building gutting and concrete cutting, pre-cutting reinforcement and shoring components reduces unintended carry-along. In rock demolition and tunnel construction, lightweight stone splitting cylinders make handling at large radii easier, while the power unit can be positioned separately. In natural stone extraction, step-by-step splitting enables heavy raw blocks to be converted into transportable loads. Special operations, such as with tank cutters, require particularly conservative load planning, as additional safety distances and protection systems influence crane weight and logistics.
Work preparation: Procedure for safe weight determination
- Define tool selection (e.g., concrete demolition shear or stone and concrete splitters) and document manufacturer weights.
- Record attachments, adapters, slinging gear, and any spreader beams with nominal weights.
- Consider power units, hoses, oil fills, and operational additional masses.
- Realistically estimate carry-along components and residual material; better to calculate conservatively.
- Set dynamic allowances; assess wind and slewing shares.
- Check radius and load moment against the load chart; verify the crane’s configuration.
- Check surface pressure and setup area; plan load distribution.
- Lift a trial load, test braking/slewing gently; ensure communication between crane operator and rigger.
Practical ways to reduce crane weight
In many situations, hook load can be reduced without impairing work quality:
- Relocate power units separately and lift only the required tool.
- Shorten hoses as needed and route them neatly to reduce additional mass and swinging.
- Correctly size slinging gear: sufficiently load-bearing, but not excessively heavy.
- Pre-cut or split components to lift smaller, controlled segments.
- Position suspensions close to the center of gravity; use spreader beams to avoid flat angles.
Organization, documentation, and notes
For legally compliant and efficient planning, a written load and lifting plan with weight data, slinging gear, radii, and communication paths is recommended. The operating manual of the devices from Darda GmbH and the crane manufacturer’s documentation must be observed. Requirements from occupational safety and relevant standards are binding; these notes are general in nature and do not replace an individual on-site assessment. A clear division of roles between crane operator, rigger, and site management ensures implementation. Where possible, actual weighing of critical components should verify the assumptions.