A partial foundation block is a foundation segment made of concrete or reinforced concrete that is produced in sections or remains in place. It appears in practice both in new construction—such as during section-by-section casting under ongoing operations—and in existing structures, when only specific foundation areas are adapted, underpinned, or selectively removed during conversion, building gutting, or special demolition. During execution, safe load transfer into the subsoil is paramount; during deconstruction, the focus is on low-vibration separation and the precise downsizing of massive cross-sections. Controlled methods such as splitting of concrete and the selective use of concrete demolition shears are particularly relevant for this. Darda GmbH is known in this context for tools and methods in concrete demolition and natural stone extraction.
Definition: What is meant by partial foundation block
A partial foundation block is understood to be a sectionally executed or remaining segment of a foundation that independently takes on load-bearing tasks or acts as part of an overall system. This includes: sectionally cast strip or isolated footings, segmented foundation blocks under machines, remaining foundations after deconstruction, as well as temporarily produced underpinning sections. The geometry ranges from point and strip-like components to slab and block foundations with defined construction joints, lap splices, and joint seals. Typical requirements include the reliable transfer of vertical and horizontal loads, the limitation of settlements, regulated bond at construction joints, and undamaged integration into the subsoil or onto rock.
Structure and typical execution forms of partial foundation blocks
Partial foundation blocks generally arise through sectional production or selective deconstruction. In new construction, strip and isolated footings are often cast in partial fields to account for construction workflows, subsoil conditions, or constraints from adjacent existing structures. In existing structures, partial pieces remain as residual foundations after demolition measures; these are later completely removed, adapted, or strengthened for new load cases. Decisive are the formation of construction joints, the position and overlap of lap splices, protection against moisture and frost, as well as the quality of concrete compaction and curing. For massive foundation bodies, partial pieces are planned as blocks to integrate embedded parts, anchors, or machine base points in an orderly manner.
Use cases in new construction and existing structures
Partial foundation blocks appear in numerous scenarios: when extending existing buildings, underpinning walls, replacing foundation slabs in sections, in plant construction with machine foundations, and in deconstruction when only individual foundation zones must be removed. In spatially confined environments and near sensitive neighboring buildings, low vibration levels methods are often chosen. Precisely there, hydraulic rock and concrete splitters and concrete demolition shears from Darda GmbH are used in the application areas of concrete demolition and special demolition as well as building gutting and concrete cutting to separate, downsize, and separate partial pieces in a controlled manner.
Planning fundamentals: structural analysis, subsoil, and joints
The load-bearing behavior of a partial foundation block is reliable only in interaction with the subsoil. Load assumptions, allowable bearing pressures, settlement behavior, and any groundwater levels must be considered. Construction joints between partial pieces require a clear function: either monolithic load transfer with lap splices and dowels, or intentionally sliding with joint sheets, waterstops, and defined load transfer via adjacent sections. Particular attention is paid to shear joints under horizontal actions as well as protection against frost heave. For water-exposed components, joint seals are planned, while for dynamically loaded machine foundations a homogeneous stiffness distribution and adequate damping are important.
Relevance for deconstruction and conversion
In existing structures, the position of joints and reinforcement determines how a partial piece can be separated. Exposed construction joints, pre-made saw or core-drilled separation cuts, and defined drilling patterns facilitate the use of hydraulic splitters and concrete demolition shears and reduce uncontrolled crack propagation.
Sectional production: construction sequence and quality
For production, formwork, reinforcement, and concreting are organized section by section. A robust construction-stage structural analysis ensures that partial loads from the superstructure or machines are temporarily taken up until the overall system becomes effective. Quality assurance includes compaction, concrete curing to mitigate early shrinkage, clean joint preparation (blasting, brushing, pre-wetting), and documented positioning of lap splices. In practice, partial pieces are coordinated so that cranes, access routes, and utility runs remain possible without downtime.
Construction joints as functional joints
In the partial foundation block, construction joints are deliberately used as functional joints: either for safe bond (e.g., by roughened joints and lap splices) or, where separation is required, as subsequent predetermined breaking or separation joints that facilitate selective deconstruction.
Deconstruction of partial foundation blocks: methods and equipment selection
During deconstruction, the focus is on controlled separation without unnecessary vibrations and without endangering adjacent components. Splitting and shearing methods have proven themselves, breaking massive foundation bodies into manageable pieces while simultaneously separating reinforcement. Equipment from Darda GmbH is deployed on jobsites of various sizes—from tight inner courtyards to industrial plants.
Rock and concrete hydraulic splitters
Splitters operate via splitter cylinders inserted into boreholes that extend a splitting wedge using hydraulic pressure. In this way, massive foundation cross-sections can be deliberately put on crack and opened without blasting. Advantages include low vibration levels, low noise emission, minimized dust exposure, and high dimensional accuracy—decisive in special demolition, building gutting and concrete cutting, and sensitive environments.
Concrete demolition shears
Concrete demolition shears break up the exposed foundation concrete, remove cover concrete from reinforcement, and prepare a segregated removal. In combination with compact hydraulic power units from Darda GmbH, even thick-walled foundation sections can be broken step by step. For reinforced concrete, the sequence aligns well: splitting to initiate cracks, shear strokes for fracture, followed by cutting the reinforcement with combination shears or steel shear.
Other material-appropriate tools
Combination shears and Multi Cutters separate inserts, anchors, and reinforcement. Steel shear cut beams or steel sections embedded in the foundation head. In special demolition, depending on the task, an adapted tool set may be required, always with a view to safety, emissions, and component behavior.
Procedure in partial deconstruction: from separation joint to haul-off
An orderly sequence reduces risks and construction time. The basic workflow can be structured as follows:
- Expose and survey: identify utilities, anchors, joint positions, and reinforcement layout; secure temporary load transfer.
- Separation cuts and drilling pattern: define core drilling and saw cuts; adjust borehole spacings to concrete strength and reinforcement ratio.
- Splitting: deploy splitter cylinders, observe crack propagation, open sections in a controlled manner.
- Downsizing: use concrete demolition shears; match piece sizes to lifting equipment and disposal.
- Steel separation: separate reinforcement and inserts with combination or steel shear.
- Material flow: collect concrete debris and steel separately; organize transport and recycling.
Special boundary conditions: subsoil, rock, and water
Partial foundation blocks often meet heterogeneous subsoil layers or rock surfaces. In rock breakout and tunnel construction, splitting facilitates the planned trimming of the bearing area without shaking the surroundings. Where groundwater is present, seals at joints and transitions must be considered; in deconstruction, water protection, sediment retention, and dust suppression with water mist are common measures. In frost-prone areas, frost aprons and capillary-breaking layers remain crucial for durability.
Safety, emissions, and environmental protection
Occupational safety begins with a hazard analysis and extends to monitoring of noise emission, dust exposure, and vibrations. Splitting methods and concrete demolition shears are advantageous here because they work without percussive energy and act precisely. Personal protective equipment, barriers, lifting accessories, and clear signaling of work areas are mandatory. For the environmental balance, segregated sorting is key: mineral concrete debris can be used as recycled construction material, and steel is routed to recycling.
Quality assurance and documentation
In new construction, casting sections, joint treatments, lap splices, and concrete curing are documented. In deconstruction, existing documentation, trial openings, and test cuts serve verification. Measurements of vibrations and noise evidence compliance with specifications. Clear documentation of drilling patterns, splitting sequences, and piece weights supports proof and improves planning for future projects.
Practical notes for planning and execution
- Select partial pieces so that construction stages remain stable and logistically accessible; consider crane and transport routes early.
- Deliberately design construction joints as bond or separation joints; align joint treatment with the intended function.
- For deconstruction, define separation cuts and drilling patterns early; determine concrete strength, reinforcement content, and inserts.
- Prioritize splitters in sensitive environments; plan concrete demolition shears for accurate downsizing and preparation for steel separation.
- Size hydraulic power packs according to demand; regularly check hoses, couplings, and pressures.
- Map material flow and recycling already in the concept; match piece weights to lifting equipment and haulage.
Relation to products and application areas of Darda GmbH
In the context of the partial foundation block, rock and concrete hydraulic splitters as well as concrete demolition shears are particularly relevant: they enable sectional opening and downsizing of foundation bodies under controlled conditions—a benefit in concrete demolition and special demolition, in building gutting and concrete cutting, and, where foundations tie into rock, also in rock breakout and tunnel construction. Hydraulic power packs ensure the energy supply, while combination shears, Multi Cutters, and steel shear efficiently complement steel separation. This enables partial pieces to be safely released, handled in an orderly manner, and routed to orderly reuse—without unnecessary vibrations and with high precision.