Structural analysis for deconstruction describes the structural planning and control involved in removing, fragmenting, or separating structures. It links structural analysis of existing buildings with a safe demolition sequence, coordinated cutting and splitting concepts, and the selection of suitable, mostly hydraulic methods. The focus is on intermediate states, load redistributions, and temporary safeguards that enable the controlled use of tools such as concrete pulverizers or rock and concrete splitters. In Darda GmbH’s knowledge base, fundamentals, verification methods, and practical procedures for concrete demolition and special deconstruction, as well as other fields of application, are brought together.
Definition: What is meant by structural analysis for deconstruction
Structural analysis for deconstruction refers to the entirety of structural verifications, methods, and measures that ensure the safe, scheduled, and controlled removal of components or entire load-bearing structures. It includes the analysis of the existing system, the assessment of intermediate states during staging, the planning of the demolition sequence, the design of temporary shoring, and the verification of cutting and splitting operations. Structural analysis for deconstruction works together with construction operations concepts and takes into account vibrations, noise, dust, and neighborhood impacts. It is method-neutral but in practice often relies on hydraulically driven tools such as concrete pulverizers or rock and concrete splitters to release components with low vibration and precision.
Structural fundamentals and specifics in deconstruction
In deconstruction, temporary structural states arise that deviate from the original design. Load paths change, boundary conditions evolve, and components may experience local weakening or notch effects. From the perspective of structural analysis for deconstruction, controlled cutting and splitting lines, defined removal steps, and redundant safeguards are crucial to avoid progressive damage mechanisms.
Typical load cases and intermediate states
- Loss of load-bearing elements (columns, walls) with redistribution into the remaining components
- Partial decoupling of slab fields, beams, and bracing systems
- Local cross-section weakening due to cuts, drillings, or splitting holes
- Overturning, sliding, and buckling risks in exposed or partially released components
- Dynamic effects from lifting operations, grappler engagement, or component detachment
Method selection in the context of structural analysis for deconstruction
The choice of method directly affects structural safety and emissions. Hydraulic fragmentation with concrete pulverizers and targeted expansion using rock and concrete splitters are considered particularly controllable because they operate at low vibration levels, form defined fracture zones, and allow separation processes step by step. Sawing, drilling, and cutting are added where smooth cut surfaces, fits, or selectivity are required.
Concrete pulverizers in structurally controlled deconstruction
Concrete pulverizers grip components over an area, break down the concrete in a granular, controlled manner, and can be positioned precisely. This enables gentle release of load-bearing and non-load-bearing regions, for example during strip-out or the stepwise removal of slab edges. In structural analysis for deconstruction, concrete pulverizers are planned where low boundary vibrations, defined component release, and well-predictable load redistributions are required. The combination with hydraulic power units allows metered forces and repeatable process steps – important for intermediate-state verifications and monitoring.
Rock and concrete splitters for controlled crack guidance
Rock and concrete splitters generate high radial forces by wedge sets in boreholes and steer cracks along planned splitting lines. For structural analysis for deconstruction this means: crack formation becomes localizable, the residual load-bearing capacity of adjacent areas remains calculable, and large components can be separated into manageable segments. Especially with massive cross-sections, thick foundations, or in rock excavation, rock splitting cylinders are an alternative to more vibration-intensive methods.
Other tools in the structural context
- Hydraulic power packs: power supply and fine control of working pressures for reproducible process quality
- Combination shears and multi cutters: flexible separation tasks, including mixed cross-sections
- Steel shears: cut reinforcement or sections with clear load-introduction paths
- Tank cutters: segment vessels and thick-walled hollow bodies in plannable cutting sequences
Investigation, modeling, and verification
Structural planning in deconstruction begins with reliable knowledge of the existing structure. Material properties, reinforcement layout, bond condition, and supports are determined and transferred into a stepwise model. Verifications consider ultimate and serviceability limit states in intermediate stages as well as the effect of temporary auxiliary structures.
Investigation and diagnostics
- Review of as-built documents, reinforcement drawings, and historical modifications
- Non-destructive testing, reinforcement locating, verification of concrete cover
- Core samples and compressive strength, moisture and crack-pattern analysis
- Assessment of prestressing, composite/bond systems, and boundary conditions (e.g., supports/bearings)
Modeling with a staged concept
The structure is modeled in stages. For each stage, engineers define which components are active, which are temporarily secured, and how cutting or splitting measures influence the force flow. Digital as-built models can facilitate the simulation of load redistributions and component interactions with concrete pulverizers or splitting cylinders.
Demolition sequence, separation cuts, and staging
The sequence determines safety. The position of the first cuts and splitting lines is critical because they reorganize load paths. Structural analysis for deconstruction therefore defines clear interventions, pauses for monitoring, and redundant safeguards before proceeding to the next steps.
Cutting and splitting planning
- Positioning of separation cuts away from main load paths and highly stressed nodes
- Consideration of notch effects, edge distances, and edge stability
- Definition of borehole patterns for splitters to steer cracks
- Integration of concrete pulverizers to thin edges in a controlled manner and limit removal forces
Temporary shoring and auxiliary structures
Shoring towers, needle beams, hangers, or compression struts stabilize intermediate states. Their design is coordinated with tool forces and the self-weight of released components. Hydraulic processes (pulverizers, splitting) benefit from stiff, short load paths that minimize unintended deformations.
Safety, environment, and neighborhood impacts
The goal is low-emission deconstruction with high controllability. In sensitive environments, low vibrations, reduced noise emissions, and little dust are essential. Hydraulic fragmentation with concrete pulverizers and splitting with rock and concrete splitters often meet these requirements particularly well.
Vibration and noise mitigation
By concentrating forces directly on the component and using low process speeds, fewer vibrations are generated. Short engagement times and tuned pressure stages reduce noise. Where required, measurement points for vibration monitoring are installed and limit-value concepts are defined to suit the project.
Monitoring and quality assurance
- Crack and settlement measurements on adjacent components, inclination and displacement sensors
- Regular visual inspections after each removal step, documented release
- Recording of hydraulic pressures and pulverizer/splitter cycles for process traceability
Fields of application and structural boundary conditions
In practice, structural analysis for deconstruction faces varying boundary conditions. The following fields of application illustrate typical focal points and the role of hydraulic tools in the structural concept.
Concrete demolition and special deconstruction
With massive reinforced concrete structures, residual load-bearing capacity, system changes, and component weights are in focus. Concrete pulverizers enable controlled removal under confined space and with low vibration. Rock and concrete splitters separate massive cross-sections into calculable segments before they are rigged or moved.
Strip-out and cutting
Interior components are selectively released without unduly weakening the primary structure. Concrete pulverizers work on non-load-bearing walls and slabs; splitters define crack edges for clean follow-up cuts. Cutting sequences are planned so that temporary stability is ensured at all times.
Rock excavation and tunneling
In underground works, control of vibrations and crack propagation is central. Splitters allow quiet release along planned splitting lines. Structural engineering and geomechanics are considered together to create excavation profiles step by step, safely, and with minimal settlements.
Natural stone extraction
Here, the targeted splitability of the rock is paramount. Rock and concrete splitters produce defined separation surfaces that preserve the integrity of the extracted blocks and make load redirections within the rock mass calculable.
Special applications
Special tasks, such as segmenting tanks or thick-walled hollow bodies, require a structurally coordinated approach. Tank cutters separate walls into manageable segments; steel shears release built-in parts. All steps are carried out considering stable intermediate states and safe load paths.
Practical calculation approaches and metrics
For intermediate states, simplified models with safety reserves are used. Important aspects include the permissible stress increase after the loss of an element, local cross-section reserves at cut edges, and the design of temporary supports. The forces from concrete pulverizers or splitting cylinders enter the verifications as characteristic actions.
Parameters influencing the choice of tools
- Compressive strength and matrix of the concrete or rock
- Degree and layout of reinforcement, prestressing
- Crack state, moisture, frost and chemical preloading
- Component geometry, edge distances, supports
- Environmental requirements regarding vibration, noise, and dust
Typical workflow steps
- Existing-condition survey, diagnostics, and definition of intermediate states
- Structural concept with demolition sequence, shoring, and monitoring
- Cutting and splitting planning (cut locations, borehole patterns, segment sizes)
- Installation of temporary auxiliary structures and protective measures
- Pre-drilling, applying the splitters, targeted fragmentation with concrete pulverizers
- Segmenting, rigging, transport with continuous measurement control
- Clearing, finishing at cut edges, documentation and release
Documentation and verifications over the project lifecycle
Continuous logs, measurement data, and releases after each step are part of quality assurance. Deviations are evaluated and the concept is adapted if necessary. Legal and normative requirements are generally observed; project-specific requirements must be coordinated with the responsible authorities. In this way, deconstruction remains structurally traceable, low-emission, and safe throughout all stages – particularly when using concrete pulverizers as well as rock and concrete splitters from Darda GmbH, embedded in a staged, controlled approach.