A portable demolition shear is a hand-guided, hydraulic tool for the controlled deconstruction of concrete, masonry, metal components, and composite structures. It is typically powered by an external hydraulic power pack and enables selective breaking, crushing, or cutting with minimal space requirements. In practice, it is mainly used where low-noise, low-vibration methods, precision work, and high occupational safety are required, such as in building gutting, special demolition, and work in sensitive existing buildings. Depending on jaw geometry and tool inserts, the functional focus of a portable demolition shear is assigned either to breaking concrete (comparable to concrete demolition shears) or to cutting rebar, profiles, and sheet metal (related to steel shears, Multi Cutters, and tank cutters). In rock-mechanics environments, it is often combined with hydraulic rock and concrete splitters to first split components and then selectively remove edges or residual concrete.
Definition: What is meant by portable demolition shear
A portable demolition shear is a compact, hand-guided hydraulic shear whose design and mass allow safe handling by one or two people. Force is transmitted via cylinders to a jaw with interchangeable jaws or blades. Unlike excavator attachments, the power supply is external: a hydraulic power pack provides pressure and oil flow, which are routed to the shear via hoses. Portable demolition shears are used for gentle removal, reduction, and separation in existing structures when pinpoint work is required—such as at slab edges, wall breakthroughs, stair flights, bridge caps, or service shafts. Depending on the version, they are available as concrete demolition shear (breaking/crushing), as combination shear (breaking and cutting), as steel shear (cutting profiles/rebar), or as a Multi Cutter (interchangeable inserts).
Design and operating principle of a portable demolition shear
The basic structure includes the housing, hydraulic cylinder, joint/lever kinematics, and the jaw with specific inserts. Under hydraulic pressure, the shear closes with high force, opens with spring or hydraulic assistance, and thus runs short, controlled work cycles. Critical parameters are jaw opening, maximum breaking or cutting force, and jaw geometry, which stabilizes material grip and efficiently introduces energy into the component.
Hydraulics and power supply
A hydraulic power pack typically delivers the required working pressure and oil flow. Hose bundles with quick couplings connect the power pack and the shear. Proper sizing of pressure, flow rate, and hose length affects the shear’s speed (oil flow) and force (pressure). For confined areas, electric hydraulic power units with low exhaust emissions and noise are recommended.
Jaw geometry and changeable tools
Crushing jaws have toothed contact surfaces to crush concrete and release aggregates. Cutting jaws feature replaceable blades for cutting reinforcing steel, profiles, or sheet metal. Combination shears combine both, while Multi Cutters broaden the scope with specialized inserts. The modular concept allows a portable demolition shear to be adapted to changing tasks in concrete demolition and building gutting.
Force transmission and kinematics
Via joints and lever arms, the piston force of the hydraulic cylinder is converted into jaw force. Many shears feature progressive kinematics: fast approach under low load, high force in material engagement. This results in an efficient work cycle with good control at the component.
Applications in deconstruction and extraction
Portable demolition shears cover numerous tasks in existing structures and are often combined with other tools from Darda GmbH, such as concrete demolition shears, combination shears, Multi Cutters, steel shears, tank cutters as well as stone and concrete splitters and stone splitting cylinders. Method context is provided under concrete demolition – deconstruction.
- Concrete demolition and special demolition: Selective removal of walls, slab edges, column heads, or bridge caps. Concrete demolition shears break concrete with low vibration; cutting jaws cut rebar precisely.
- Building gutting and cutting: Removal of partition walls, shafts, parapet elements; cutting of utilities, cable trays, and light steel profiles. Multi Cutters and steel shears complement the demolition shear for metal cutting.
- Rock demolition and tunnel construction: In combination with stone and concrete splitters: first split, then smooth edges, remove residual concrete or shotcrete, produce fitting interfaces.
- Natural stone extraction: After splitting with stone splitting cylinders, the demolition shear removes protrusions, straightens fracture edges, or separates fix points.
- Special operations: Work in areas with restricted access, on intermediate slabs with limited load capacity, or in sensitive zones with requirements for noise and dust reduction.
Advantages and limitations of the portable demolition shear
- Advantages: pinpoint work, low vibrations, reduced noise, simple logistics, working without a heavy carrier, good visibility of the work area, selective cutting and breaking.
- Limitations: restricted jaw opening and material thicknesses, reduced performance in high-strength concrete and very dense reinforcement, dependence on the hydraulic power pack and hose routing.
Selection criteria and sizing
- Material and task: concrete strength, aggregate size, reinforcement ratio, masonry type; need for breaking, cutting, or both.
- Jaw opening and jaw shape: component thicknesses, grip and approach points; suitable geometry for secure access.
- Force and oil supply: required breaking/cutting force; compatibility with the hydraulic power pack (pressure, oil flow).
- Weight and ergonomics: handling, overhead positions, posture changes, carry distances.
- Changeable tools: availability of crushing jaws, cutting blades, combination jaws; Multi Cutters for diverse media.
- Environmental conditions: space, ventilation, noise control, dust management, hose routing, media guidance.
Workflow: safe and efficient procedure
- Assess the component: identify buildup, reinforcement, load path, utilities, and embedded items.
- Secure the work area: shoring, barriers, load take-up, exposed edges.
- Prepare hydraulics: position the power pack, plan hose routing, check for tightness and function.
- Segment: divide components into manageable sections; mark approach points.
- Break or cut: work with suitable jaws; meter forces and avoid offsets.
- Follow-up work: cut reinforcement, clean up edges, lower or recover component sections.
- Sort and document: material separation, disposal/recycling, record inspection and measurement points.
Tips for reinforced components
First crush and reduce concrete with a concrete demolition shear, then cut exposed reinforcement with a steel shear or a combination shear. For larger diameters, multi-stage cuts or the supplementary use of stone and concrete splitters are appropriate.
Distinction: portable demolition shear, concrete demolition shear, and stone and concrete splitters
A portable demolition shear refers to the hand-guided design. As a concrete demolition shear, the focus is on low-vibration breaking of concrete. In contrast, stone and concrete splitters generate high radial forces via wedges for controlled splitting—ideal for thick, compression-resistant components and rock, often with lower noise and dust than cutting operations. The choice depends on component thickness, material structure, boundary conditions, and the desired separation principle.
- Choose a concrete demolition shear when concrete is to be selectively reduced and reinforcement exposed.
- Choose splitters when massive cross-sections must be opened with low vibration or to complement saw kerfs.
- Choose combination/steel shears when metal content dominates or separation cuts in profiles/sheets are required.
Hydraulic power packs, hoses, and couplings
For stable performance, the hydraulic power pack must reliably provide the portable demolition shear’s required working pressure and oil flow. Route hose bundles to avoid kinks, crushing, and trip hazards. Quick couplings simplify tool changes; leak-free connections and cleanliness protect the hydraulics from wear. In sensitive indoor areas, low-emission or electrically powered power packs have proven effective.
Energy sources and operating modes
Electric hydraulic power packs offer quiet, emission-free operation for interiors. Internal-combustion units are suitable outdoors or with adequate ventilation. Sizing is based on the required number of cycles, line length, and tool size.
Maintenance, wear, and servicing
- Regularly check jaws and blades for wear; rotate or replace damaged inserts in good time.
- Inspect, lubricate, and monitor pins, bearings, and guides for play.
- Check hydraulic hoses for abrasion and tightness; clean couplings.
- Observe hydraulic oil quality and filter condition per the manufacturer’s specifications.
- Function tests before starting work; adhere to documented maintenance intervals.
Occupational safety, health, and environment
- Personal protective equipment: eye, hand, hearing, and foot protection; respiratory protection if dust is generated.
- Dust and noise reduction: wet methods, extraction, adapted work technique; hand–arm vibration testing.
- Load handling: secure grip position, stable body posture, aids for transport and overhead work.
- Environmental aspects: keep media clean, avoid hydraulic leaks, collect materials separately.
Ergonomics and operator concepts
Low tool weight, balanced center of gravity, secure grip points, and short hose runs reduce fatigue and increase precision. Short work cycles with clear visibility of the engagement point improve quality.
Productivity and quality assurance
- Optimize the work cycle: select the right combination of pressure (force) and oil flow (speed).
- Plan segmentation: divide components into sensible sections to avoid edge spalling and uncontrolled cracks.
- Use tool changes: switch between crushing and cutting jaws or use combination shears to reduce rework.
- Material separation: separate concrete, steel, and mixed fractions early to facilitate disposal and recycling.
Practical examples of typical applications
During the gutting of an existing building, light partition walls and shaft claddings are cut out with the portable demolition shear, concrete edges are locally crushed, and reinforcement is cut with a steel shear. In bridge environments, caps can be removed in a controlled manner without disturbing the load-bearing structure. In tunnel construction or rock work, stone and concrete splitters are first used, after which the demolition shear cleans up residual concrete or adjusts contours. For vessels and tanks, after safety-compliant preparation, cutting tasks are carried out with suitable shear tools; for thicker walls, tank cutters or Multi Cutters are considered.