Inclined pull describes the introduction of tensile forces at an angle to the ideal axis of a component, a tool, or a load attachment point. In practical fields such as concrete demolition and special deconstruction, interior demolition and cutting, rock excavation and tunnel construction, as well as natural stone extraction, inclined pull occurs frequently—e.g., during lifting, positioning, and separating. For applications with rock and concrete splitters, concrete demolition shears, combination shears, multi cutters, or steel shears from Darda GmbH, understanding inclined pull is essential for correctly assessing load-bearing capacities, avoiding component damage, and planning work sequences safely.
Definition: What is meant by inclined pull
Inclined pull refers to a tensile load that does not act axially (straight in the direction of the component or tool axis) but with an angular offset. This results in a superposition of tensile, shear, and often bending loads. Consequently, usable load-bearing capacities are reduced, and additional effects such as edge spalling, stress concentrations, or misalignments can occur. Inclined pull typically appears with rigging gear at unfavorable sling angles, with dowels and anchors under eccentric loads, with incorrectly aligned stone and concrete splitters, and when working with concrete demolition shears and other cutting tools if lateral components enter the force path.
Causes and typical situations in concrete and rock demolition
Inclined pull arises from geometry, access constraints, and changing load paths. Typical triggers include limited setup areas, challenging attachment points, non-uniform member thicknesses, or wear-induced tolerances. In the application areas of concrete demolition and special deconstruction, interior demolition and cutting, and rock excavation and tunnel construction, the following situations are relevant, among others:
- Rigging loads with large spread angles when lifting gear must lie flat due to spatial constraints.
- Bracing and positioning of concrete demolition shears, combination shears, or multi cutters when the contact point is not in axis.
- Placing splitting cylinders for stone when borehole axes are misaligned or edge distances are small.
- Cutting in reinforced concrete when reinforcement dictates the cut and lateral forces offset the force application.
- Rock wedges and strata that redirect loads and introduce lateral tensile components into the bond.
Mechanical effects of inclined pull
Inclined pull significantly alters the loading. In addition to axial tension, transverse forces and moments arise. This affects tools, components, and fixings:
- Load-bearing capacity: With increasing angle, the usable capacity of many slings, anchors, and dowels decreases.
- Edge and corner regions: The risk of spalling, cracking, and splitting tension increases, especially with small member thicknesses.
- Misalignment and guidance: Tools may skew, track poorly, or jam if the force is not introduced axially.
- Wear: Unfavorable contact zones increase friction and localized stresses, leading to faster wear.
Load angles and force components
The flatter the sling angle and the greater the deviation from the ideal line, the higher the resulting forces in slings and fixings. In practice, permissible angle ranges are specified because lateral components additionally load the members in shear and bending. An exact assessment is project-specific and based on technical documentation.
Inclined pull with stone and concrete splitters
Stone and concrete splitters from Darda GmbH are designed for axial force application. Inclined pull occurs here, among other things, through skewed drill holes, uneven bearing surfaces, or soft edge zones:
- Borehole alignment: Deviations from the target axis generate lateral forces on wedges and splitting blades; the split joint opens unevenly.
- Edge distances: Distances that are too small promote spalling due to combined tensile/shear action.
- Rock layering: Natural joints redirect forces; the split then follows the weakness planes rather than the borehole axis.
Practical recommendations for splitting work
- Create boreholes aligned and plumb; document tolerances.
- Select edge distances and member thicknesses so that lateral stresses remain limited.
- Position Darda GmbH hydraulic power packs so that hose bundles do not act as lateral guides.
- Plan the splitting sequence: Provide pre-cuts and relief cuts to dissipate asymmetric stresses.
Inclined pull with concrete demolition shears and shear tools
With concrete demolition shears, combination shears, multi cutters, steel shears, and tank cutters from Darda GmbH, inclined pull arises particularly when the jaws are not centered or the member cross-section is non-uniform. This leads to lateral forces that additionally load bearings, blades, or teeth and promote spalling in concrete.
Typical triggers at components
- Reinforcement eccentricity: Tension bars deflect the cut line; lateral forces increase the effort required for separation.
- Geometric constraints: Column heads, beams, inserts—the point of attack is rarely ideal.
- Load redirection: During holding and stabilizing, holding forces act obliquely to the tool axis.
Optimize working method
- Apply jaws parallel and over an area; correct alignment before cutting.
- Meter the holding force so that no unnecessary lateral pull is introduced.
- For thick concrete, reduce the cross-section in stages to minimize lateral forces.
- Check tool changes and blade condition; dull edges increase the lateral pressure required.
Rigging and lifting: sling angles, pivot points, load distribution
When rigging components during deconstruction, an overly shallow sling angle results in high forces in the sling legs and in inclined pull at the attachment points. At the same time, torques arise if the center of gravity is not below the crane hook.
Principles
- Limit sling angles; the flatter the angle, the higher the leg forces.
- Rig symmetrically to avoid transverse tension and torsion.
- Use intermediate devices such as edge protectors, spreader beams, or spreaders to centralize loads.
- Choose attachment points so that the force introduction is as axial as possible.
Planning and execution: approach against inclined pull
Systematic work preparation reduces inclined pull already on site. In demolition and extraction projects at Darda GmbH, a step-by-step approach has proven effective.
Work preparation
- Component analysis: Identify load paths, reinforcement layout, joints, and rock fractures.
- Plan load paths: Define attachment points, sling angles, and temporary works.
- Define tool strategy: Sequence of splitting, shearing, and cutting operations.
- Design the drilling and splitting pattern to introduce forces axially.
Execution
- Regularly check alignment and correct as needed.
- Release loads in stages to relieve asymmetric stresses.
- Use intermediate supports and cribbing to limit overturning moments.
- Define clear team communication; specify hand signals and approvals.
Evaluation and control of inclined pull
The assessment is based on geometry, permissible angle ranges, and manufacturer specifications for tools and rigging gear. Specific requirements apply to fixings, dowels, and anchors, particularly concerning edge and axial distances under oblique tensile loading.
Checkpoints
- Alignment of boreholes, tools, and rigging gear documented.
- Edge distances and member thicknesses verified.
- Wear condition of wedges, jaws, and cutting edges checked.
- Hydraulics: Select hose routing and power pack position to avoid introducing lateral forces.
Occupational safety and legal notes
Inclined pull increases the risk of uncontrolled load movements, spalling, and tool jamming. Protective measures must be defined on a project-specific basis. The applicable regulations, operating manuals, and approved work procedures must be observed. Stated load capacities, sling angles, or member resistances vary by system and installation situation and must be assessed by a competent person in each individual case. Legal and safety-related requirements are always of a general nature and do not replace an individual on-site assessment.
Practical guide: avoid, limit, control inclined pull
- Avoid: Prioritize axial alignment; use suitable rigging gear and spreader beams.
- Limit: Optimize sling angles and lifting geometry; reduce cross-sections in advance.
- Control: Guide loads in a controlled manner; define safety zones; staged work with intermediate support.
- Follow-up: Documentation, visual inspection, and maintenance of Darda GmbH tools, in particular splitting cylinders, concrete demolition shears, and associated hydraulic power packs.
Relevance to Darda GmbH application areas
In concrete demolition and special deconstruction, axial placement of concrete demolition shears minimizes inclined pull at component edges. In interior demolition and cutting, precise alignment helps introduce cutting forces in a straight line. In rock excavation and tunnel construction, drilling pattern planning determines the direction of splitting forces. In natural stone extraction, joints and strata influence the force flow; an adapted splitting pattern reduces lateral pull. For special applications—such as on tanks or heavy steel sections—suitable rigging gear and defined cutting sequences limit inclined pull on steel shears and tank cutters.