The cut describes the targeted severing or removal of the ends, heads, and projections of components made of concrete, steel, rock, or masonry along a defined line or plane. It is a central procedure in concrete demolition and special demolition, in strip-out and cutting, as well as in rock breakout, tunnel construction, and natural stone extraction. In practice, controlled hydraulic methods are used, such as splitting with rock and concrete splitters or breaking with concrete pulverizers, supplemented by shears and cutters for steel, tanks, and pipelines.
Definition: What is meant by cut
Cut means the controlled removal of the head or edge area of a component up to a specified elevation, contour, or edge. The goal is to produce a new, clean termination surface, to deliberately expose reinforcement, to segment components for deconstruction, or to create connection faces for strengthening, vertical extensions, or refurbishment. In contrast to a full through-cut, the cut often serves for partial removal with precise material limits and a defined residual load-bearing capacity in the remaining component.
Fields of application and typical components for the cut
The cut is used in numerous scenarios: pile head and foundation cut, slab edge cut, edge and cornice cut, free-cut for openings, cut of steel sections and reinforcement ends, pipe and tank cut, as well as rock cuts in extraction or heading. Depending on material and boundary conditions, different tools are appropriate: concrete pulverizers for low-vibration removal of concrete, rock and concrete splitters for controlled splitting of massive cross-sections, combination and steel shears for metallic components, multi cutters for mixed construction materials, and tank cutters for vessels and pipelines.
Methods and tool selection for the cut
The suitable method depends on material type, cross-section, reinforcement density, accessibility, environmental requirements, and the required level of accuracy. In practice, hydraulic, spark-reduced, and low-vibration methods have proven themselves, especially in sensitive environments and in selective deconstruction.
Removal with concrete pulverizers
Concrete pulverizers break out concrete in a controlled manner and are suitable for pile heads, upstands, column and wall heads. The advantage lies in selective removal while simultaneously exposing the reinforcement, which can then be cut with shears. Compared to percussive tools, the method reduces dust and noise.
Splitting with rock and concrete splitters
Hydraulic splitting wedges or stone splitting cylinders generate defined splitting forces in the borehole. In this way, a cut can be initiated linearly without unduly stressing the remaining component. This method is suitable for massive cross-sections, high-strength concretes, or rock heads, for example in tunnel construction and natural stone extraction.
Shears and cutters
Combination shears and steel shears cut rebar, sections, and plates. Multi cutters are suitable for heterogeneous material. For pipelines and vessels, tank cutters are used that enable spark-reduced cuts, provided the necessary safety measures are observed.
Power supply
Hydraulically operated tools are supplied via hydraulic power units. The correct configuration of pressure and flow rate is crucial for cut quality, cycle performance, and equipment preservation.
Cut of pile heads and foundations
In pile head cutting, the excess head concrete is removed down to the target elevation to create a level bearing surface or a defined connection.
- With concrete pulverizers, head concrete can be broken off in sections, the reinforcement remains accessible and can be cut with shears.
- In high-strength or heavily reinforced piles, removal is often prepared using rock and concrete splitters: after a row of boreholes, splitting cylinders create a predetermined breaking line, and the cut is then completed quickly.
- For foundation heads with large cross-sections, splitting minimizes vibrations and reduces cracking in the remaining component.
Cut on walls, columns, slab edges
As part of strip-out and cutting, upstands, edge beams, parapets, and bearing edges are cut to create openings or to adjust elevations.
- Concrete pulverizers for selective removal without a full through-cut, particularly in occupied or sensitive areas.
- Pre-scoring boreholes followed by splitting when vibrations or spark formation must be minimized.
- Combination with shears for cutting exposed reinforcement and embedded components.
Cut in steel construction and reinforcement
Cutting reinforcement bars, steel beams, and plates requires high cutting forces and clean separation faces for defined connection details.
- Steel shears for beams, sections, plates, and guardrails.
- Combination shears for mixed deconstruction when concrete and steel are processed sequentially.
- Multi cutters for varying material thicknesses and hard-to-access cut positions.
Cut of tanks, pipelines, and vessels
In pipe and tank cutting, safety and emission control take priority. Spark-reduced cutting methods and controlled workflows are decisive.
- Tank cutters for vessel heads, dome structures, and pipe runs, provided substances have been properly removed or inerted.
- Combination with steel shears for segmentation and compaction for transport.
Note: Safety and environmental protection measures must be planned project-specifically and are general in nature; they do not replace legal advice.
Cut in rock breakout, tunnel construction, and natural stone extraction
In geological environments, rock edges, crown areas, or pedestals are cut in a controlled way to create profile-compliant contours. Rock and concrete splitters as well as stone splitting cylinders enable low-vibration cuts along rows of boreholes. This offers advantages in densely built-up areas, with listed neighboring structures, and in mining headings.
Planning, structural analysis, and cut path
Qualified preparation determines the quality of the cut. This includes investigating the component, material classification, determining reinforcement, checking the residual load-bearing capacity, defining the cut or removal line, as well as selecting the equipment and the power supply via hydraulic power packs. Temporary shoring and protective measures must be implemented before starting. Information on load-bearing capacity and structural stability must always be verified project-specifically.
Occupational safety, emissions, and surroundings
Hydraulic cuts generally reduce dust, noise, and vibration. Nevertheless, effective measures for dust suppression, noise reduction, and splash protection must be planned. Indoors, zero exhaust emissions, space requirements, and load transfer of the equipment must be considered. In sensitive areas (laboratories, clinics, existing buildings in operation), concrete pulverizers and splitting methods have proven effective.
Workflow: cut step by step
- Survey of existing conditions and definition of the removal contour with tolerances.
- Expose embedded parts, utilities, and edge areas; create access.
- Selection of the method (pulverizer, splitting, shear, cutter) and sizing of the hydraulic power packs.
- Install pilot boreholes or scoring notches if splitting is planned.
- Cut the concrete with concrete pulverizers or splitting cylinders; simultaneously secure the remaining component.
- Cut exposed reinforcement with steel shears or combination shears.
- Finish the termination surface (remove burrs, fill or reprofile defects as required).
- Segmentation, sorting, and transport of the material.
- Quality control: dimensions, flatness, exposed lengths, documentation.
Quality requirements and tolerances
For a proper cut, defined elevations, flatness, exposed lengths of reinforcement, and sufficient surface roughness are decisive. The requirements depend on the subsequent trade (e.g., overlay concrete, strengthening, waterproofing). Control measurements and photo documentation ensure traceability.
Common mistakes and how to avoid them
- Insufficient investigation leads to unexpected reinforcement or inserts – solution: low-destructive testing, trial exposure.
- Intervention forces too high on the remaining component – solution: splitting methods with matched borehole geometry or removal sequence with concrete pulverizers.
- Sparks and heat input with sensitive media – solution: spark-reduced cutting methods and safe substance removal prior to pipe or tank cut.
- Inadequate power supply – solution: design hydraulic power packs according to the pressure/flow requirements of the attachments.
Tool chain and power supply
The performance capability of a cut results from the interaction of attachment, carrier machine, tool geometry, and the hydraulic power pack. For high cycle rates, stable pressure levels, sufficient flow, and short hose runs are beneficial. In confined conditions, compact solutions with low mass input and high maneuverability excel.
Selective deconstruction, recycling, and sustainability
The cut facilitates the clean separation of concrete, steel, and natural stone. Selectively removed components can be sorted by type, which optimizes transport and disposal and promotes reuse. Concrete pulverizers and splitting methods favor large, sortable pieces and reduce fines.
Special deployments and special conditions
Underwater, in tunnel heading, in potentially explosive atmospheres, or with sensitive neighbors, low-vibration, spark-reduced, and low-emission methods are the means of choice. Rock and concrete splitters as well as concrete pulverizers can be tailored to these requirements, provided project-specific protective and release measures are implemented.
Relation to Darda GmbH’s fields of application
The cut forms an intersection of key fields of application: In concrete demolition and special demolition it enables precise connections and segmented removal; in strip-out and cutting it creates openings and flatness; in rock breakout and tunnel construction it defines contours; in natural stone extraction it separates bed faces; in special deployments it is a key method when emissions must be limited and residual load-bearing capacity preserved.