A concrete foundation forms the load-bearing connection between the structure and the subsoil. It distributes loads safely, prevents inadmissible settlements, and protects the structure against influences such as frost, moisture, and vibrations. In planning, new construction, retrofit, and deconstruction, sound fundamentals of geotechnical engineering, reinforced concrete construction, and execution techniques interlock. For interventions in existing structures, in the spirit of a controlled, low-vibration approach, concrete pulverizers as well as hydraulic rock and concrete splitters are frequently used, as established in concrete demolition and special demolition, in building gutting and cutting, in rock excavation and tunnel construction, or in special operations.
Definition: What is meant by concrete foundation
A concrete foundation is a structural element made of concrete (often with reinforcement) used to transfer a building’s loads safely into the subsoil. It carries vertical and horizontal loads, limits deformations, and ensures serviceability. Depending on use, subsoil, and actions, pad foundations, strip foundations, foundation slabs (floor slabs), or pile foundations are employed. The choice of foundation type follows applicable standards and guidelines and is governed by load-bearing capacity, settlement behavior, frost resistance, water exposure, and construction constraints.
Configuration and types of concrete foundations
The design principle of a concrete foundation is simple: bundle loads, limit contact pressures, control movements. Implementation varies significantly:
- Pad foundation: concentrated load transfer from columns and masts; compact cross-section, often with sockets and anchor plates.
- Strip foundation: linear support beneath load-bearing walls; uniform load distribution along the wall axis.
- Foundation slab (floor slab): areal foundation to distribute large loads and minimize differential settlements.
- Deep foundation with piles: load transfer into deeper, competent soil layers; common with soft soils or high loads.
Layering and details
Typical layers include a frost protection layer, where applicable a capillary break layer, a blinding layer, reinforcement, the concrete cross-section, waterproofing/protection layers, and connections. Key aspects are concrete cover, high-quality compaction, and controlled curing to minimize cracking.
Planning, subsoil, and design
Foundation planning is based on subsoil investigations. Soil type, density, groundwater level, and settlement behavior are decisive for the choice of foundation type. Design criteria include:
- Load-bearing capacity of the subsoil and the reinforced concrete section
- Serviceability (settlements, deformations, crack widths)
- Frost resistance and foundation depth
- Water exposure (elements in contact with soil, waterproofing, drainage)
- Seismic and horizontal loads from wind, impact, or earth pressure
Load assumptions and load transfer
Permanent and variable loads are transformed via the foundation geometry into allowable bearing pressures in the soil. Load transfer occurs areally (slabs), linearly (strips), or at discrete points (isolated footings). For dynamically loaded machine foundations, vibration checks govern the design.
Materials: concrete, reinforcement, formwork
The concrete type is selected according to loading and exposure classes. Adequate concrete cover protects reinforcement against corrosion. For waterproofing against ground moisture and pressurized water, joint design, construction joint sealing, and connections are crucial. Formwork must be dimensionally accurate and stable; concreting is carried out uniformly with suitable compaction, followed by careful curing.
Quality assurance on site
Essential tests include fresh concrete consistency and temperature, concrete strength, dimensional accuracy, anchorage lengths of reinforcement, concrete cover, and documented curing. Deviations are identified early and corrected.
Execution: step by step to the concrete foundation
- Removal of topsoil, excavation of the pit, slope stabilization or shoring where required.
- Installation of frost protection and blinding layers, screeded to a plane surface.
- Assembly of formwork and placement of reinforcement with spacers; position embedded parts precisely.
- Concreting in suitable lifts, compact, level the surfaces.
- Curing (keeping moist, protecting from sun/wind), stripping after sufficient strength is reached.
- Install waterproofing and penetrations, construct drainage and bearing structures.
Detail points: frost, water, penetrations
Foundations are located below the local frost depth or receive an effective frost protection layer. Waterproofing systems are designed against ground moisture and water exposure. Pipe and cable penetrations receive tested sealing elements. Connections to vertical elements must be executed to be crack-resistant and moisture-tight.
Identifying and avoiding damage
- Settlements due to inadequate subsoil assessment or undersized foundation areas
- Cracks from restraint, insufficient curing, or unsuitable reinforcement
- Moisture damage caused by deficient waterproofing
- Corrosion due to insufficient concrete cover
Prevention is achieved through careful planning, controlled concreting, adequate concrete cover, defined joint design, and consistent quality assurance.
Repair, underpinning, and strengthening
Where load-bearing deficits exist or uses change, strengthening methods are employed: foundation enlargements, underpinning, injections, or overlays. The choice of method depends on subsoil, load level, accessibility, and the vibration sensitivity of the surroundings. For localized openings, slots, or partial removals in existing structures, concrete pulverizers and stone and concrete hydraulic wedge splitters are advantageous because they operate with low vibration and protect adjacent components.
Low-vibration operation
Hydraulically operated stone splitting cylinders separate massive concrete in a controlled manner without generating continuous impact vibrations. Concrete pulverizers reduce member thicknesses, release edges, and facilitate sequential removal. In combination with compact hydraulic power units, performance is provided to suit demand.
Deconstruction of concrete foundations
The deconstruction of foundations in existing structures requires a planned, low-emission approach. Objectives are material separation, occupational safety, protection of adjacent structures, and minimizing noise and vibrations.
- Concrete demolition and special demolition: breaking and removing in segments with concrete pulverizers; splitting technology for thick cross-sections.
- Building gutting and cutting: preparatory separation cuts, relief cuts, openings for crane hooks or lifting points.
- Rock excavation and tunnel construction: for foundations on rock or in tunnel drives, stone splitting devices enable controlled separations at the concrete/rock interface.
- Special operations: in sensitive areas (laboratories, hospitals, existing structures with vibration limits), low-vibration methods with splitting cylinders and concrete pulverizers are particularly suitable.
Tools working together
Stone and concrete splitting devices initiate controlled cracks; concrete pulverizers crush the blocks; multi cutters and steel shear cut reinforcement and embedded parts; combination shears unite gripping and cutting. Hydraulic power packs supply the attachments. This coordinated chain reduces rework and facilitates clean material separation.
Machine foundations and dynamic actions
Machine foundations impose special requirements: stiffness, mass, vibration isolation, and precise anchor points. During modifications, foundation recesses or anchor pits are often created with concrete pulverizers; splitting technology enables openings without large-scale vibrations, protecting measuring machines, control rooms, and sensitive equipment.
Foundations in water and transportation works
Foundations in moist or water-bearing soils require special measures such as excavation pit enclosures, suitable concrete compositions, and watertight joints. During deconstruction under traffic or in confined sites, segmented removal concepts with splitting cylinders and concrete pulverizers help limit noise and vibration.
Occupational safety, emissions, and environmental protection
Deconstruction and strengthening works on foundations are subject to strict safety and health requirements. In general:
- Dust and noise reduction through targeted methods, water mist, and coverings
- Verify load paths and stability during removal phases, plan shoring
- Route hydraulic hose lines and power units safely, provide drip protection
- Mark hazard zones, provide safe operator stations
Requirements arise from the relevant occupational safety rules and must be implemented project-specifically.
Sustainability and recycling
Sustainable handling of concrete foundations begins in planning (material efficiency) and continues into deconstruction: crushed concrete serves as recycled construction material, reinforcement steel is recovered for metal recycling. Clean separation is supported by targeted crushing with concrete pulverizers and the separate cutting of reinforcement with steel shear.
Practical guide: selective removal of a foundation block
- Component investigation: determine reinforcement layout, embedded parts, utilities; assess load behavior and residual stability.
- Preparation: define access routes, protective measures, load paths, and lifting points.
- Pre-weakening: create grooves or core drilling; make targeted separation cuts.
- Splitting: use Rock Splitters (stone splitting cylinders) to initiate cracks and create controlled segmentation.
- Crushing: concrete pulverizers reduce segments to transportable sizes; cut reinforcement with steel shear or multi cutters.
- Removal and recycling: separate material streams, document materials, organize disposal or reuse.
Special boundary conditions in existing structures
In dense urban settings, on existing buildings, or near sensitive facilities, vibration and noise limits must be observed. Low-vibration splitting technology and controlled crushing with concrete pulverizers are proven methods for this. In industrial plants with adjacent peripherals, cutting torches may additionally be used on neighboring tanks before foundation areas are accessible; this is carried out with particular care and in compliance with safety requirements.
Maintenance and service life
Long service lives are achieved through suitable concrete, adequate concrete cover, controlled crack widths, functioning drainage, and high-quality waterproofing. Regular inspections detect moisture paths, spalling, or signs of corrosion at an early stage. Interventions proceed stepwise—from cosmetic repair to structural strengthening.