The term inclined installation describes the deliberate use of inclined angles: tools, boreholes, or component access points are intentionally positioned not at right angles but at an incline to steer the load path, account for component geometries, and influence fracture propagation. In practice, this is especially relevant in concrete demolition, special demolition, rock excavation and tunnel construction, as well as in natural stone extraction. Typical applications include orienting concrete demolition shears at edges, using rock and concrete splitters in obliquely drilled holes, and positioning cutting or shearing tools in confined situations. The following content combines fundamentals with concrete procedures as they occur in projects within the Darda GmbH product portfolios.
Definition: What is meant by inclined installation
Inclined installation refers to aligning and installing tools, power units, or boreholes at a defined angular position to the component surface or component axis. The aim is to direct the resulting forces (compression, tension, shear) so that fractures progress in a controlled manner, edge areas are protected, access to components in tight spaces is even possible, or the geology (bedding, jointing) is purposefully utilized. In inclined installation, angles, edge distances, support/bearing conditions, and material properties are systematically coordinated. This enables the planned creation of artificial fracture planes in concrete or rock, selective separation of components, and reduction of risks such as spalling, jamming, or uncontrolled overbreak.
Technical fundamentals and operating principles
The effect of inclined installation is based on the targeted alteration of the load path. When a tool is applied at an incline, compressive and shear stresses shift. In concrete, this redirects crack initiation; in rock, crack propagation is influenced by joints, bedding, or anisotropy. With inclined boreholes for splitting cylinders, an asymmetric stress state arises that guides the crack network in the desired direction. With concrete demolition shears, an inclined bite ensures the teeth engage gently and the shear cone is directed away from sensitive edges.
Angles, support, and load path
Installation angles, supports, and friction conditions are key. Small changes in angle (often 10–30 degrees) can significantly shift load paths. At the same time, the support must be stable: the risk of the tool sliding or tipping must be avoided. In splitting operations, the angle influences the opening path of the crack front; in shearing and cutting operations, it determines the position of the shear cone and the contact pressures in the jaw.
Material behavior of concrete and rock
Concrete is strong in compression but susceptible to cracking in tension. An inclined attack creates combined stress states that initiate cracking without unnecessarily loading surrounding areas. In rock, natural planes of weakness dominate. Inclined installation leverages these by aligning boreholes and tools to bedding or jointing to minimize energy input.
Inclined installation in concrete demolition and special demolition
In concrete demolition, inclined installation is used where components must be separated selectively, edge distances are small, or adjacent components must be protected. Darda GmbH product areas such as concrete demolition shears, rock and concrete splitters, combination shears, and Multi Cutters are guided so that the angular position remains defined and reproducible.
Edge distances, reinforcement, and shear cone
With concrete demolition shears, an inclined bite reduces the risk of breakout at thin slab edges. The shear cone is directed away from the edge into the component. In reinforced zones, an inclined approach is useful to expose individual bars before the main forces are applied. When splitting with cylinders, obliquely placed boreholes guide the crack path away from critical areas (penetrations, supports).
Tool selection and procedure
The choice between concrete demolition shear, splitter, or combination shear depends on component thickness, reinforcement ratio, access, and desired separation joint. Inclined installation supports the objective by defining the fracture line and reducing peak loads. Basic criteria:
- Component geometry: slabs, walls, beams, corbels—inclined approaches help protect edges.
- Reinforcement layout: bite at an angle to expose bars one after another instead of causing widespread overload.
- Access: in confined spaces, guide the shear jaw or splitting cylinder at an angle to minimize lever arms.
- Low vibration: inclined splitting boreholes create defined crack paths with low emissions.
Inclined installation in rock excavation and tunnel construction
In rock excavation and underground works, boreholes are often deliberately inclined to couple the crack path to joints, bedding, or layers. Rock splitting cylinders and rock and concrete splitters use inclined installation to detach blocks in a controlled way. This reduces secondary jumps and lowers the risk of uncontrolled overbreak.
Drilling pattern, borehole depth, and angular accuracy
A consistent drilling pattern with a uniform inclination angle is crucial. Excessive scatter in angular accuracy leads to unpredictable cracking. Borehole depth is chosen so that the planned separation joint is fully captured without weakening adjacent zones. For tunnel contours, an inclined drilling pattern enables peeling off overhangs before finishing profile surfaces cleanly.
Natural stone extraction: Gentle detachment through inclined approach
In natural stone extraction, inclined installation supports detachment along natural beds. Splitting cylinders are aligned so that opening pressure follows planes of weakness. This preserves surfaces and reduces the risk of scaling or corner breakage.
Strip-out and cutting: Safely mastering inclined access
In strip-out work, openings, shafts, and installations are often only accessible at an angle. Multi Cutters, steel shears, and tank cutters are therefore applied with a defined inclination to avoid drag edges and to cut round or curved surfaces (e.g., tanks) to shape. An inclined cut reduces tool jamming and favors controlled chip or fragment formation.
Hydraulics and assembly in inclined installation
Darda GmbH hydraulic power units are set up with stable footing; hose lines are routed kink-free and with low load so that no additional bending moment is introduced when the tool is at an incline. Coupling points are positioned so the operator can keep the angular position stable.
- Component analysis: check geometry, supports/bearings, reinforcement or jointing.
- Angle planning: define target angle (typically 10–30 degrees), specify edge distances and clamping/embedment lengths.
- Drilling pattern/starting points: for splitting operations, arrange boreholes with uniform inclination; for shears, mark the first bite points.
- Support and work position: secure slip resistance, bracing, and clearance from collision zones.
- Connect hydraulics: check pressure and return, verify absence of leaks.
- Test run: brief load test at the planned angle; check sound, pressure, movement.
- Work sequence: build load slowly, maintain constant angle, observe crack or cut.
- Rework: dress edges, cut reinforcement selectively, inspect surface.
Occupational safety, environmental protection, and legal notes
Safety takes priority: stable positions, safety distances, retreat options, and barriers are mandatory. Inclined angles must not lead to unstable body postures or uncontrolled movements. Personal protective equipment is to be used; minimize sparks, noise, and dust (suitable extraction or wetting). Legal requirements and recognized rules of technology must be observed; project-specific approvals and inspections are performed in each case by responsible professionals. The information in this article is general in nature and does not replace project-specific planning.
Planning, documentation, and quality assurance
Angles, starting points, drilling patterns, and sequences are defined and documented in advance. Photos of angular positions, pressure or force logs, and visual inspections of the separation joint ensure quality. For sensitive components, a test field is recommended to validate angle selection and optimize parameters such as hole spacing, embedment depth, or shear position.
Typical mistakes and how to avoid them
- Approach too steep: increased jamming, uncontrolled crack redirection—choose a moderate angle.
- Insufficient support: movable supports lead to vibration and crack jumps—secure work surfaces.
- Neglecting angular accuracy: scatter in the drilling pattern creates unpredictable breaks—use templates or lasers.
- Underestimating edge distances: spalling risk—specify and maintain edge and corner distances.
- Hydraulic hoses under tension: bending moments on the tool—route lines without stress.
- Rebar not exposed: bars block the crack—apply the concrete demolition shear at an angle, pre-cut bars.
Inclined installation in special operations and confined spaces
In special operations such as overhead work, in shafts, or on inclined surfaces, inclined installation is often the only practical approach. Tools are selected and guided to create short lever arms and low reaction forces. Concrete demolition shears with a narrow jaw, compact rock and concrete splitters, and precisely guided cutting tools enable controlled work despite restricted access.