Special demolition refers to the targeted, controlled deconstruction of structures, structural elements, and rock formations under complex boundary conditions. The focus is on precise, often low-vibration and dust-minimized methods that combine material separation, safety, environmental protection, and the reuse of material streams. Tools such as concrete demolition shears and rock and concrete splitters from Darda GmbH are used to selectively release load-bearing and non-load-bearing structures, cut reinforcement, or split massive rock bodies in a controlled manner—within city centers, existing buildings, tunnels, industrial plants, and sensitive zones.
Definition: What is meant by special demolition
Special demolition is the technically and organizationally demanding deconstruction in which the demolition method is precisely matched to the condition of the structure, location, material mix, and the assets to be protected (people, neighboring buildings, infrastructure). It is characterized by tailor-made methods such as hydraulic splitting, cutting, and crushing of concrete, masonry, steel, and rock, often combined with selective interior demolition and separation techniques. The aim is controlled deconstruction up to source-segregated material separation, in order to obtain secondary raw materials, limit emissions, and make construction workflows safe and efficient.
Methods and tools in special demolition
Special demolition uses a graduated tool chain: hydraulic splitting with rock and concrete splitters and rock splitting cylinders for low-vibration opening of massive cross-sections; cutting or shear-based methods with concrete demolition shears, combination shears, multi cutters, and steel shears for separating concrete, reinforcement, and steel profiles; tank cutters for cold, low-spark separation tasks on vessels; and hydraulic power packs as the energy source. Depending on the structural condition, these means are used individually or in combination, for example: pre-drilling and splitting thick concrete elements, followed by breaking out with concrete demolition shears and final separation of exposed reinforcement. The result is controlled fracture patterns, reduced transfer forces into the structural system, and easily managed site logistics.
Areas of application and typical tasks
Special demolition covers several fields where the interplay of methods is decisive.
Concrete demolition and specialized deconstruction
When dismantling load-bearing elements (columns, walls, slabs), controlled load redistribution and low vibrations are essential. Concrete demolition shears open concrete shells, size pieces for removal, and cut reinforcement. In heavily reinforced or very thick cross-sections, rock and concrete splitters accelerate the process by defining cracks and predictably separating demolition pieces.
Strip-out and cutting
In selective dismantling within existing structures, combination shears, multi cutters, and steel shears are used for cutting beams, pipes, and fixtures. Concrete demolition shears minimize noise and dust in interior areas; tank cutters are used wherever sparks or heat generation would be critical.
Rock demolition and tunnel construction
In underground works and rock areas, controlled splitting is crucial for profile-accurate excavations, niches, or cross-section enlargements. Hydraulic splitters operate with high force yet low vibration—an advantage near sensitive neighbors, heritage-protected structures, or operational facilities at the surface.
Natural stone extraction
For the extraction of natural stone blocks, a clean fracture pattern is central. Splitting cylinders generate defined split cracks along rows of boreholes. This allows raw blocks to be extracted resource-efficiently and with high dimensional accuracy.
Special operations
In explosion-hazard areas, hospitals, laboratories, or during ongoing operations, cold-cutting, low-vibration methods are required. Here, coordinated tool combinations from Darda GmbH enable safe deconstruction while surrounding areas remain in use.
Rock and concrete splitters compared to concrete demolition shears
Rock and concrete splitters use hydraulically generated spreading forces to induce tensile stresses in the component and create controlled cracks. Advantages: low vibrations, few secondary damages, high effectiveness in massive cross-sections and rock. Concrete demolition shears perform shearing/pressing cutting and crushing actions and are ideal for downsizing, shaping demolition pieces, and exposing or cutting reinforcement. In combination, split lines are set first, then components are removed to size with the shear and the reinforcement is separated.
Hydraulic power packs and energy supply
Hydraulic power units supply splitting cylinders, concrete demolition shears, combination shears, and other attachments with constant flow rate and pressure. Appropriate sizing reduces energy losses, prevents overheating, and increases working performance. In emissions-sensitive areas, units with alternative drives or exhaust after-treatment are advisable to limit immissions and improve workplace quality.
Planning, sequence, and documentation
A structured planning process is a prerequisite for safety and efficiency. In addition to surveying the existing structure, materials analysis, and structural analysis, scheduling is crucial.
Typical planning modules
- Investigation: element thicknesses, reinforcement layout, material separation, embedded items
- Method selection: splitting, shearing, cutting—individually or combined
- Sequencing: load diversion, temporary shoring, staged demolition
- Logistics: piece sizes, removal, intermediate storage, recycling paths
- Emission control: dust, noise, shocks, vibrations
- Documentation: proof of separation, mass balances, quality of recovery
Safety, health, and environment
Protecting workers, neighbors, and the environment shapes special demolition. Low-vibration methods with rock and concrete splitters and concrete demolition shears reduce immissions. Dust suppression, extraction, encapsulation, and low-emission power packs improve air quality. Legal requirements for occupational safety and the environment must be observed; depending on the project, further measures may be necessary, to be planned individually and professionally supervised.
Practical focal points
- Workplace organization: stable footing, fall protection, escape routes
- Media management: route hydraulic hoses safely, prevent leakage
- Monitoring: crack propagation, component deformations, measuring and warning systems
- Communication: clearly coordinate exclusion zones and lifting operations
Material separation and urban mining
Special demolition promotes source-separated collection: concrete, masonry, steel, non-ferrous metals, and plastics are recorded separately. Concrete demolition shears facilitate exposing the reinforcement, splitters enable large, clean concrete pieces that can be processed efficiently. This creates high-quality secondary raw materials; closed-loop circulation reduces primary extraction and transport effort.
Selection criteria for tools
The selection is based on element thickness, degree of reinforcement, accessibility, environmental constraints, and required cut quality. Hydraulic performance, tool geometry, and controllability are decisive.
Key criteria at a glance
- Component: thickness, strength class, moisture, crack pattern
- Reinforcement: diameter, position, density, lap splices
- Accessibility: interior, height, constrained positions, anchor points
- Immissions: noise and vibration limits, dust thresholds
- Performance: cutting force, spreading force, stroke speed, cycle times
- Energy: compatibility with existing hydraulic power packs
Operation, maintenance, and service life
Regular functional checks, correct setting of pressure and flow, and care of blade and tooth segments ensure performance and service life. For splitting cylinders, clean boreholes, suitable wedges, and careful lubrication are crucial. Hydraulic power packs benefit from filter maintenance and oil care; this keeps Darda GmbH tools reliable and efficient.
Performance data and metrics
For work planning, reference values are helpful and vary by tool and component.
Typical reference values
- Spreading force (splitters) and resulting crack width per stroke
- Cutting force (concrete demolition shears, steel shears) in relation to reinforcement diameter
- Opening/closing speed and cycle times as pacemakers
- Required operating pressure and flow rate of the power pack
- Piece sizes for manageable logistics and crane/lifting operations
Particularities in special operations
In explosion-hazard rooms or near hazardous substances, cold, low-spark separation methods are preferred. Tank cutters, concrete demolition shears with controlled fracture guidance, and splitting techniques minimize ignition sources. Planning includes clearance measurements, inertization, and safe disposal; execution is carried out by qualified specialists.
Practice-oriented work steps
- Investigation and exposure: identify lines, reinforcement, embedded parts
- Preparation: define drilling patterns for splitting cylinders, set up exclusion zones
- Pre-splitting: splitters set crack lines in massive cross-sections
- Downsizing: concrete demolition shears shape transportable pieces and cut steel
- Sorting: place steel, concrete, masonry separately and document
- Finishing: clean edges, create cut surfaces, relieve residual loads