Severance

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 pulverizers as well as hydraulic rock and concrete splitters are frequently used, supported by hydraulic power packs. 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. Precise severance delivers millimeter-range dimensional accuracy, controlled crack paths, and minimized emissions under challenging site constraints.

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 low dust exposure. The choice of method depends on material type, component thickness, reinforcement ratio, accessibility, and constraints such as permissible noise 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 a steel shear or a hydraulic demolition shear. Hydraulic power packs supply the tools with operating pressure and flow rate to provide the required forces.

Key objectives include predictable crack initiation and propagation, limited overbreak, and component handling that maintains structural stability during the sequence of works.

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 splitters (wedge) enables low-vibration work in massive components and rock. Concrete pulverizers separate and reduce reinforced concrete and expose reinforcing steel, which is then cut with a steel shear or a 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 splitters (wedge) as well as rock wedge splitters are widely used in rock excavation, tunnel construction, and for separating massive concrete foundations. Advantages include low secondary damage, good crack guidance, and the ability to open confined areas without blasting.

• Planning parameters: matched borehole diameter to splitter size, borehole spacing adapted to thickness and strength, sufficient edge distance, and staged splitting from free edges toward the core.
• Crack control: pilot splits and relief holes improve guidance near sensitive interfaces and reduce spalling.
• Monitoring: visual tracking of crack lines and vibration logging enhance process stability in built-up environments.

Crushing and severing with shears

Concrete pulverizers grip, press, and fracture the concrete cover, exposing reinforcing steel. These can be cut with a steel shear or a 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. Jaw geometry, rotation capability, and cycle times influence throughput and separation quality.

Cutting, sawing, and drilling as a complement

Sawing and core drilling produce precise cut edges and core holes. In practice, they are often combined with concrete pulverizers: 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. Diamond wire and track sawing expand the range where access or thickness makes conventional tools less efficient.

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. Prior gas-free certification and inerting concepts are essential for tanks and pipelines with potential residues.

Severance in concrete demolition and special deconstruction

In concrete demolition, components are separated in accordance with position and structural analysis. Concrete pulverizers enable the orderly removal of slabs, walls, and foundations. For massive cross-sections, reduction is often combined with stone and concrete hydraulic splitters (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 applications include balconies, stair cores, machine foundations, and bridge appendages.

Typical work steps

• Inventory and definition of cut and split lines
• Temporary securing: shoring, load transfer, protective enclosure
• Preparation: boreholes for hydraulic splitters (wedge), marking of cut guidance
• Equipment selection: concrete pulverizers for reduction, stone and concrete hydraulic splitters (wedge) for controlled fractures, steel shear for reinforcement
• Execution with accompanying ground vibration monitoring and crack monitoring
• Finishing and construction waste separation for recycling
• Documentation: method statement updates, acceptance of interim states, and as-built records

Rock excavation and tunnel heading: controlled crack guidance

In rock excavation and tunnel heading, low vibration is often decisive. Hydraulic splitting with rock wedge splitters 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 pulverizers take over cutting off leveling layers, shotcrete remnants, and embedded components. Pre-splitting along designed contours enhances profile accuracy and reduces support loads.

Building gutting and cutting in existing structures

In building gutting, non-load-bearing components are removed, openings created, and attachments separated. Concrete pulverizers 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. Negative pressure zones and water misting reduce dust migration in occupied structures.

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 splitters (wedge) as well as rock wedge splitters produce controlled fractures with high edge quality. The low-vibration approach protects the rock mass, minimizes microcracks, and facilitates further processing of the blocks. Careful alignment maintains parallelism of fracture planes and optimizes block yield.

Equipment overview: tool selection for severance

The choice of equipment depends on material, component thickness, accessibility, and environmental requirements. Modern hydraulic tools cover a wide range of severance without the need for thermal processes. Selection should consider tool weight and reach, jaw opening width, required line forces, and available hydraulic capacity.

Concrete pulverizer

Concrete pulverizers 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. Primary pulverizers focus on initial break-up, while secondary types optimize separation and downsizing.

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. Correct borehole geometry and stepwise loading ensure predictable crack propagation.

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. Blade condition and cutting clearance are decisive for clean cuts and lower energy demand.

Tank cutters

Tank cutters sever vessel shells and pipelines in a controlled manner. They are used when thermal processes are undesirable for safety or emissions reasons. Mechanical cutting avoids ignition sources and limits heat-affected zones on coated materials.

Hydraulic power pack

Hydraulic power packs provide pressure and flow for shears and splitting systems. Performance, cooling, and hose line management influence cycle times, energy efficiency, and ergonomics. Remote control and telemetry improve positioning and oversight in constrained or hazardous areas.

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. Method statements, permits, and monitoring concepts form the framework for safe execution.

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. Tolerances are documented and checked against the specification for interfaces and follow-on trades.

Reinforcement detection and material analysis

Locating reinforcement, prestressing steel, utilities, and built-in components prevents surprises. Material thicknesses, aggregates, and strength class (concrete or steel) influence tool settings and method selection. Non-destructive testing and trial openings validate assumptions in critical areas.

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. Defined hold points allow verification that redistribution and supports perform as intended.

Safety, health, and environment

Safe severance requires clear responsibilities, protection zones, and suitable personal protective equipment. Emissions must be limited and the surroundings protected. Interfaces with ongoing operations are secured with exclusion zones and signaling.

Vibrations, noise, and dust

Hydraulic splitting and work with concrete pulverizers 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.

• Use water-cooled drilling and sawing, localized extraction, and mist cannons for airborne dust reduction.
• Apply vibration and noise monitoring with threshold alerts at receptors and sensitive equipment.
• Schedule high-noise activities and implement acoustic screens to meet project limits.

Hazard analysis and protective measures

A general hazard analysis includes cutting and crushing hazards, pressurized media, falling parts, hydraulic leakages, and media in tanks. Measures must be defined object-specifically and checked regularly.

• Lockout-tagout for hydraulic and electrical sources; pressure relief before maintenance.
• Securing severed elements against rotation or sliding with restraints and controlled lifting points.
• Gas measurement and purging for vessels and pipelines prior to mechanical cutting.

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. Water management for drilling and sawing slurry prevents discharge to soil and sewers.

Power supply and hydraulic power packs

Powerful hydraulics are a prerequisite for efficient severance. Operating pressure, flow rate, and heat dissipation determine force, speed, and continuous output. Energy source selection aligns with site rules and emission limits.

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. Oil cleanliness and filtration extend component life and maintain valve response.

Hose management

Short runs, protection against crushing, and clean quick coupling reduce pressure losses and leakage risk. Regular visual inspections are advisable. Minimum bending radius and protected routing lower fatigue and snag risks.

Energy efficiency

Demand-based power, standby strategies, and good cooling reduce energy demand and increase availability. Variable-displacement pumps and auto-idle features further enhance efficiency at partial load.

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. Photo logs, measurement reports, and monitoring records substantiate compliance with acceptance criteria.

Inspection and rework

Visual inspection, measurements, crack monitoring, and, if necessary, surface treatment secure the result. Edges are smoothed or beveled as needed. Anchoring points and interfaces are prepared according to the specified roughness or cleanliness class.

Recycling and material flow management

Separated concrete, reinforcing steel, and natural stone can be specifically recovered. Clean severance facilitates sorting and reduces disposal costs. Processed concrete can serve as recycled aggregate where specifications permit.

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 packs, and continuous monitoring of the component response. Early test sections and parameter tuning reduce risk on critical details.