Steel frameworks are load-bearing, resource-efficient constructions made of bar-shaped elements that are used in many structures—from bridges and halls to towers and temporary safety and auxiliary structures. Throughout the lifecycle of such load-bearing systems, planning, fabrication and assembly as well as maintenance, deconstruction and recycling play a central role. Especially during deconstruction there is a clear practical link to hydraulically powered tools: concrete pulverizers and stone and concrete splitters support the material-pure separation of composite constructions and facilitate the dismantling of adjacent components, while steel shears, combination shears, Multi Cutters and tank cutters enable the precise separation of sections, gusset plates and claddings. Compact hydraulic power units supply the required energy, including for special operations in sensitive or confined areas.
Definition: What is meant by steel framework
A steel framework is a bar structure made of steel whose load-bearing capacity is primarily secured by triangles. Top and bottom chords are connected by diagonals and verticals (posts) that transfer loads through pinned or quasi-pinned nodes. The result is efficient load transfer with low self-weight. Typical connections are bolted, riveted or welded; cross-sections range from angle, T and I-sections to closed hollow sections. Steel frameworks are used in roofs, bridges, cranes, headframes, stage structures, support systems in tunnel construction and for temporary shoring. In existing structures, composite situations often occur, for example when a framework is grouted with concrete or enclosed by masonry—this shapes planning, repair and deconstruction.
Structural principles and typical components of a steel framework
The structural behavior of a framework is based on the unambiguous geometry of triangles that channel normal forces into members. Compression often dominates in the top chord, Tension in the bottom chord; diagonals alternate depending on the load case. Nodes are detailed to minimize eccentric moments and to simplify fabrication and erection.
Members and cross-sections
Common choices are hot-rolled angle and I-sections, box and circular hollow sections for high torsional stiffness, as well as connection plates and gusset plates. The choice depends on span, actions, connections and corrosion protection.
Connections and nodes
Historic frameworks are often riveted, more recent structures bolted or welded. During refurbishment and deconstruction this affects the approach: rivets are removed by cutting off heads and pressing out shanks, bolts are released or cut, welds are selectively severed. Precise cut guidance at nodes is crucial to avoid unintended load redistribution.
Load-bearing behavior, stability and robustness
Steel frameworks transfer permanent and variable loads, wind and thermal actions through a network of tension and compression members. Slender compression members require checks for local and global buckling; bracing stabilizes the spatial system. Redundancy improves robustness—important for construction stages during dismantling, when load paths are temporarily altered.
Construction methods, protection and typical applications
Frameworks are found in industrial halls, bridges, conveying structures, stage and trade-fair builds, silos and tanks, as well as for support in tunnel construction. Corrosion protection is provided by coatings or metallic overlays; during deconstruction this influences cut quality. In composite constructions with concrete or masonry, material-pure separation is essential for recycling—this is where concrete pulverizers and stone and concrete splitters are used.
Dismantling and deconstruction of steel frameworks: planning and approach
Deconstruction falls under concrete demolition and special demolition as well as building gutting and cutting. It requires a structurally coordinated sequence, low-emission methods and a separation strategy for steel and adjacent construction materials.
Principles of deconstruction planning
- Survey of existing conditions: geometry, cross-sections, connections, material condition, coatings, asbestos/PAH risks.
- Temporary safeguarding: shoring, yoke beam girders, load-relief measures; calculate construction stages.
- Separation concept: sequence of cuts, lowering or lifting processes, anchorage points, crane or lifting techniques.
- Emissions strategy: sparks, noise, dust, vibrations; where appropriate, prefer cold, hydraulic cutting processes.
Tool selection in the context of steel framework
- High-precision steel shears: For sections, gusset plates, tension/compression members; clean cut, low spark generation.
- Combination shears and Multi Cutters: Flexible for mixed materials and tight access conditions.
- Tank cutters: For shell plates, silos, tanks and large-area steel skins; suitable for special operations.
- Concrete pulverizers: To expose embedded nodes, remove topping concrete/composite lugs, separate reinforced-concrete connections.
- Stone and concrete splitters and rock wedge splitters: For low-vibration deconstruction of foundations, bearings and masonry at framework nodes.
- Hydraulic power packs: Supply the tools with pressure and flow; selection based on cut thickness, cycle time and work environment.
Severing connections: rivets, bolts, welds
Riveted nodes are released by cutting off the rivet heads and pressing out the shanks, or by cutting along the plates. Bolted connections can—depending on condition—be loosened or cut with shears. For welded nodes, plan the cut guidance along the weld preparations. cold-cutting hydraulic methods reduce sparks and heat input—an advantage in fire- and explosion-hazard areas.
Steel framework in tunneling and bridges: particularities in deconstruction
In rock excavation and tunneling, lattice girder beams and steel arches support the tunnel face; when enlarging cross-sections they must be removed in a controlled manner. Concrete pulverizers are suitable for locally removing shotcrete and exposing the lattice elements; steel shears or combination shears then take over cutting the struts. On bridges, bearing areas, wind bracing and nodes are often encased in concrete—here stone and concrete splitters speed up the exposure and minimize vibrations in the existing structure.
Repair, strengthening and partial replacement
During refurbishment, corroded or damaged members are replaced, nodes strengthened or load paths modified. Precise cuts and low heat input facilitate accurate fit-ups. Preparatory tasks such as removing putty, plaster, grouts and concrete encasements are often performed with concrete pulverizers; subsequent cuts in steel components are made by steel shears or Multi Cutters.
Occupational safety, emissions and boundary conditions
- Stability in the construction stage: define cut sequence and safeguards, ensure load transfer.
- Limit sparks and heat input: prefer hydraulic cutting methods, consider fire protection.
- Minimize noise and vibrations: splitting technique on concrete, shears instead of thermal cutting where possible.
- Work spaces and ergonomics: use compact tools and suitable booms; provide safe anchorage points.
- Consider coatings: dust and particle management; proper handling of old coatings.
Material separation and recycling
Material-pure separation increases the recovery value: steel is almost completely recycled, crushed concrete can serve as recycled aggregate. Concrete pulverizers and stone and concrete splitters enable the targeted release of composite interfaces; steel shears produce reusable cut pieces. Separate material streams facilitate documentation, transport and disposal.
Practical scenarios
Industrial hall with a framework roof
Before deconstructing the roof: building gutting and cutting of fit-out components, exposing the bearings with concrete pulverizers, cutting off framework members with steel shears in a shored condition. Foundations are loosened with stone and concrete splitters with low vibration.
Framework bridge
Segmented dismantling: securing with yoke beam girders, releasing the cross bracing, cuts at gusset plates. Concrete encasements are opened beforehand with concrete pulverizers; afterward, material-pure separation of the steel parts.
Silo or tank deconstruction
Claddings and shell plates are separated in sections with tank cutters or combination shears. Steel framework or ring stiffeners on the inside are cut in an orderly manner after exposure and set down.
Selection criteria for tools and hydraulic power packs
- Material and thickness: section thicknesses, gusset-plate thicknesses, coatings.
- Accessibility: free space, cut direction, position of the power packs.
- Power demand: cutting force, jaw opening, cycle times; size the hydraulic power pack.
- Environment: spark suppression, noise limitation, vibration sensitivity (existing structure, neighboring buildings).
- Logistics: piece weights, lifting gear, removal routes, interim storage.
Step-by-step approach to deconstructing a steel framework
- Survey and documentation of the existing structure, including connections and construction stages.
- Define the separation and safeguarding concept, including an emissions strategy.
- Gutting and exposure: concrete pulverizers and hydraulic rock and concrete splitters for encasements and bearings.
- Provide temporary shoring and load redistribution.
- Orderly cuts on bracing and nodes with steel shears, combination shears or Multi Cutters.
- Segment-wise lowering or lifting, transport and interim storage.
- Low-vibration deconstruction of foundations and bearing areas.
- Material-pure separation, weighing and documentation of the material streams.
Quality assurance and documentation
Measures and construction stages are to be checked continuously: cut accuracy, integrity of adjacent components, adherence to emission targets. The performance data of the hydraulic power packs, the number of cuts and the wear condition of tools are recorded. This evidence supports the optimization of future projects and legally compliant documentation.
Special operating conditions and special operations
In explosion-hazard areas, hospitals, laboratories or heritage-listed structures, low-spark, low-vibration and quiet methods are required. This is where hydraulic shears, concrete pulverizers and stone and concrete splitters play to their strengths. Compact tools and mobile hydraulic power packs facilitate work in shafts, on scaffolds or in tunnels, where space and energy supply are limited.