Severance describes the targeted separation of materials such as concrete, reinforced concrete, natural stone, and metal. In construction, deconstruction, and rock excavation it is a core step to release structural elements, create openings, reconfigure load transfer, or access the excavation pit. Depending on the task, different methods are used: mechanical splitting, cutting, shearing, or milling. In practice, concrete pulverizer as well as hydraulic rock and concrete splitters are frequently used, supported by hydraulic power pack. The spectrum ranges from selective concrete demolition and building gutting through rock excavation and tunnel construction to natural stone extraction and special operations under sensitive boundary conditions.
Definition: What is meant by severance
Severance is the controlled opening, dividing, or splitting of solid materials along planned cut or fracture lines. The goal is a reproducible result in terms of dimensional accuracy, edge quality, low vibration levels, and dust exposure. The choice of method depends on material type, component thickness, reinforcement ratio, accessibility, and constraints such as noise control and low vibration levels. In concrete and rock, severance is often executed via hydraulic splitting or reduction with a concrete pulverizer; metal components are separated with steel shear or hydraulic demolition shear. Hydraulic power pack supply the tools with operating pressure and flow rate to provide the required forces.
Techniques and methods of severance in everyday construction and deconstruction
Method selection and execution determine safety, speed, and result quality. Mechanical splitting with stone and concrete hydraulic splitter (wedge) enables low-vibration work in massive components and rock. Concrete pulverizer separate and reduce reinforced concrete and expose reinforcing steel, which is then cut with steel shear or hydraulic demolition shear. Multi cutters cover changing material combinations, while tank cutters are suitable for severing vessels and shell plates. Depending on the task, methods are combined to optimally control cut guidance, load transfer, and material separation.
Hydraulic splitting of concrete and rock
In hydraulic splitting, splitter cylinders generate a wedge effect in the borehole under controlled pressure. This method is low in vibrations, precise, and scales very well for thick cross-sections. Stone and concrete hydraulic splitter (wedge) as well as rock wedge splitter are widely used in rock excavation, tunnel construction, and for separating massive concrete foundation. Advantages include low secondary damage, good crack guidance, and the ability to open confined areas without blasting works.
Crushing and severing with shears
Concrete pulverizer grip, press, and fracture the concrete cover, exposing reinforcing steel. This can be cut with steel shear or hydraulic demolition shear. The method is particularly suitable for selective deconstruction, building gutting, and creating openings because it reduces loads step by step and separates components into transportable pieces. Multi cutters support work where concrete, masonry, and metal occur in succession.
Cutting, sawing, and drilling as a complement
Sawing and core drilling produce precise cut edges and core drillings. In practice, they are often combined with concrete pulverizer: first comes the clean cut guidance, then the reduction and separation. In this way vibrations can be minimized, dust sources limited, and components safely repositioned.
Metal components and tanks
When severing metal structures, tanks, and pipelines, a safe, spark-reduced approach is important. Steel shear, hydraulic demolition shear, and tank cutters are used where thermal processes are undesirable. Decisive factors are material thickness, coatings, and controlled load transfer to avoid deformation and uncontrolled movement.
Severance in concrete demolition and special deconstruction
In concrete demolition, components are separated in accordance with position and structural analysis. Concrete pulverizer enable the orderly removal of slabs, walls, and foundations. For massive cross-sections, reduction is often combined with stone and concrete hydraulic splitter (wedge). In special deconstruction, the principle is stepwise reduction: first severance, then demolition separation and removal. This keeps structural stability manageable, vibrations low, and materials can be discharged separately.
Typical work steps
- Inventory and definition of cut and split lines
- Temporary securing: shoring, load transfer, protective enclosure
- Preparation: boreholes for hydraulic splitter (wedge), marking of cut guidance
- Equipment selection: concrete pulverizer for reduction, stone and concrete hydraulic splitter (wedge) for controlled fractures, steel shear for reinforcement
- Execution with accompanying ground vibration monitoring and crack monitoring
- Finishing and construction waste separation for recycling
Rock excavation and tunnel heading: controlled crack guidance
In rock excavation and tunnel heading, low vibration is often decisive. Hydraulic splitting with rock wedge splitter enables the opening of block formations, enlarging benches, and the precise release of rock beds. Severance can be planned along predrilled lines, overbreak is reduced, and adjacent structures remain protected. In expansion phases, concrete pulverizer take over cutting off leveling layers, shotcrete remnants, and built-in component.
Building gutting and cutting in existing structures
In building gutting, non-load-bearing components are removed, openings created, and attachments separated. Concrete pulverizer work with low dust and low vibration levels in existing buildings. Multi cutters support where material layers change. For precise door, window, and breakthrough openings, the combination of cutting methods followed by reduction is recommended so that transport pieces remain small and portable.
Natural stone extraction: releasing blocks by splitting
In natural stone extraction, severance is used to release raw blocks along natural joints or defined lines. Stone and concrete hydraulic splitter (wedge) as well as rock wedge splitter produce controlled fractures with high edge quality. The low-vibration approach protects the rock mass, minimizes microcracks, and facilitates further processing of the blocks.
Equipment overview: tool selection for severance
The choice of equipment depends on material, component thickness, accessibility, and environmental requirement (construction). Tools from Darda GmbH cover a wide range of severance without the need for thermal processes.
Concrete pulverizer
Concrete pulverizer reduce concrete and expose reinforcement. They are universally applicable in concrete demolition, building gutting, and special deconstruction. By targeted gripping, pressing, and fracturing, components are separated into manageable units.
Stone and concrete hydraulic splitter (wedge) and rock wedge splitter
Hydraulic splitting systems generate high line forces in the borehole. They separate massive concrete and rock in a controlled, low-vibration manner. Ideal for thick foundations, piers, rock heads, and tunnel connections.
Hydraulic demolition shear, steel shear, and multi cutters
Shears sever metal parts such as reinforcing steel bars, profiles, beams, and sheets. Hydraulic demolition shear and multi cutters are designed for changing material packages and support selective deconstruction when concrete, masonry, and metal come together.
Tank cutters
Tank cutters sever vessel shells and pipelines in a controlled manner. They are an option when thermal processes are not an option for safety or emissions reasons.
Hydraulic power pack
Hydraulic power pack provide pressure and flow for shears and splitting systems. Performance, cooling, and hose line management influence cycle times, energy efficiency, and ergonomics.
Planning, structural analysis, and cut guidance
Professional planning reduces risks and rework. Cut and split lines must be coordinated with the load-bearing behavior. Load redistribution, temporary shoring, and the sequence of severance must be defined in advance.
Cut geometry and tolerances
Edge quality, angular accuracy, and dimensional accuracy determine the rework. Mechanical splitting produces rougher fracture surfaces that can be refined if necessary. Concrete pulverizer and shear processes should be guided to keep spalling limited.
Reinforcement detection and material analysis
Locating reinforcement, prestressing steel, utilities, and built-in components prevents surprises. Material thicknesses, aggregates, and strength class (concrete/steel) influence tool settings and method selection.
Demolition sequence
From the edge to the core, from top to bottom, and with controlled load transfer: a clear sequence avoids unwanted cracks and spontaneous component movement.
Safety, health, and environment
Safe severance requires clear responsibilities, protection zones, and suitable personal protective equipment. Emissions must be limited and the surroundings protected.
Vibrations, noise, and dust
Hydraulic splitting and work with concrete pulverizer are generally low in vibrations. Dust and noise can be limited by suitable methods, water mist, and work organization, supported by noise control measures and dust suppression.
Hazard analysis and protective measures
A general hazard analysis includes cutting and crushing hazard, pressurized media, falling parts, hydraulic leakages, and media in tanks. Measures must be defined object-specifically and checked regularly.
Environmental aspects
Material separation, leakage prevention, proper disposal, and minimization of secondary damage are key goals. For work on tanks and pipelines, general specifications for explosion protection and fire protection must be observed.
Power supply and hydraulic power pack
Powerful hydraulics are a prerequisite for efficient severance. Operating pressure, flow rate, and heat dissipation determine force, speed, and continuous output.
Power classes and matching
Tools require matched units. Too little flow rate slows cycles; excessive operating pressure can overload material and equipment. Proper sizing increases process stability.
Hose management
Short runs, protection against crushing, and clean quick coupling reduce pressure losses and leakage risk. Regular visual inspections are advisable.
Energy efficiency
Demand-based power, stand-by strategies, and good cooling reduce energy demand and increase availability.
Quality assurance, documentation, and follow-up
The quality of severance is evident in accurate cuts, limited cracking, and clean material separation. Documentation creates traceability and facilitates handover.
Inspection and rework
Visual inspection, measurements, crack monitoring, and, if necessary, surface treatment secure the result. Edges are smoothed or beveled as needed.
Recycling and material flow management
Separated concrete, reinforcing steel, and natural stone can be specifically recovered. Clean severance facilitates sorting and reduces disposal costs.
Typical failure patterns and how to avoid them
Common causes of problems include unclear cut guidance, insufficient securing, wrong equipment selection, or overloading tools. These include edge spalling, uncontrolled crack formation, jammed tools, and inefficient cycles. Avoidance is achieved through clear planning, careful borehole geometry during splitting, suitable shear sizes, matched hydraulic power pack, and continuous monitoring of the component response.