Shoring

Shoring is a central measure to keep structures, components, and geological formations safe and controlled during works. Whether in concrete demolition and special deconstruction, in strip-out and cutting, in rock excavation and tunnel construction, in natural stone extraction, or in special operations: temporary or permanent support structures reroute loads, limit deformations, and prevent uncontrolled fractures. In practice, shoring concepts operate in close interplay with powerful separation and splitting methods, for example when using concrete demolition shears or hydraulic rock and concrete splitters, which can only unfold their full potential safely in a stabilized environment. As part of temporary works, shoring is an integral element of risk management and method planning, ensuring predictable behavior of components and rock while separation technologies act.

Definition: What is meant by shoring?

Shoring refers to the targeted installation of temporary or permanent support elements that take up, reroute, or distribute loads to ensure the structural stability of components or rock. It includes vertical supports (e.g., shoring props and support scaffolds), horizontal bracing (e.g., compression struts and braces), needle beams for wall openings, as well as area-wide stabilizations in rock. Shoring is used in particular when load-bearing elements are weakened, separated, or removed – such as when extracting concrete elements with concrete demolition shears or when controlled splitting of rock with stone and concrete splitters is performed. In contrast to bracing, which primarily controls horizontal forces (e.g., wind, vibrations), shoring primarily addresses the safe transfer of vertical loads; in practice, both measures often overlap. In construction terminology, falsework for supporting formwork can be related, but in deconstruction and extraction the emphasis lies on maintaining residual load-bearing capacity during interventions.

Function and objectives of shoring in deconstruction and extraction

Shoring aims to secure load paths, limit deformations, and make fracture processes controllable. This includes taking dead loads, compensating for changed system boundaries during separation and splitting operations, and stabilizing edge areas. Shoring creates the necessary safety envelope to detach components with concrete demolition shears, multi cutters, combination shears, or steel shears, or to extract blocks with stone split cylinders with minimal damage. Finally, shoring protects adjacent components, utilities, and sensitive facilities – for example during cuts in existing structures or when cutting tanks, where preventing deformations and offsets is crucial.

• Maintain stability margins: safeguard residual capacity during staged removal and splitting.
• Control deformation and crack growth: keep deflections and openings within defined limits for serviceability and safety.
• Guide force introduction: ensure predictable force flow from tools and presses into temporary supports.
• Protect interfaces: reduce collateral impacts on finishes, installations, and neighboring load-bearing elements.

Shoring systems and typical components

Vertical props and steel supports

Adjustable steel supports, shoring props, and head spindles support slabs, beams, and cantilevers. They work with large-area base and head plates and load spreaders (wood sleepers, steel plates) to limit contact pressures. Decisive are sufficient load reserves, protection against buckling, and a plumb alignment without restraint. For interventions with concrete demolition shears in beams or when cutting slab edges, props are preferably arranged in a grid with clearly defined spacings. Capacity tables, allowable screw extension, and eccentricity limits must be observed; where vibration is expected, positive-locking wedges and anti-slip layers increase robustness.

Support scaffolds and tower scaffolds

For higher loads or large spans, modular support scaffolds are used. They provide continuous load paths via standards, ledgers, and diagonals. Tower scaffolds are often used as temporary abutments for needle beams when walls are opened or large facade sections are removed in stages. Depending on height and wind exposure, tying to the existing structure or additional bracing can be required; uniform settlement is promoted by level, co-planar sole plates with sufficient bearing area.

Needle beams and underpinning

Needle beams reroute loads via beams led through the wall into auxiliary substructures. The method is proven for door and window openings, for breakthroughs, and for staged removal of walls with concrete demolition shears. Underpinning stabilizes foundations or wall bases when underlying areas are excavated, underbuilt, or cut out. Deflection limits for needles, sequencing of jacking operations, and, where applicable, grout bedding or dry packs at supports ensure even load transfer without stress peaks.

Horizontal bracing and ties

Tension and compression struts, banding, and bracing secure walls, rows of columns, and frames against overturning, buckling, or sliding. Push-pull props connect components to temporary supports. In shafts, trenches, and tunnel headings, walers and bracing stabilize lateral earth pressures until permanent supports follow. Preloaded ties and verified back-stays minimize slack and limit impact loads during cutting or splitting steps.

Rock and slope shoring

In rock excavation and tunnel construction, blocks are secured with nets, rock bolts, and arches. When using stone and concrete splitters or stone split cylinders, pre-tensioned stabilizations and catch systems limit the risk of uncontrolled opening of joints. After splitting, loose zones must be scaled and, if necessary, immediately stabilized with area-wide systems. Mesh overlaps, anchor patterns, and a top-down installation sequence enhance capture efficiency and reduce residual risk from subsequent falls.

Hydraulic presses and power pack technology

Hydraulic cylinders are used to lift, pre-load, and set components. Dedicated hydraulic power units deliver controlled pressure and flow; a pressure-controlled, finely metered buildup prevents shock loads. Pressure indicators, check valves, and matched hoses are central safety and functional components. When preloading prior to separation cuts, a defined prestress reduces the risk of sudden cracking. Where multiple cylinders act in parallel, manifold balancing and, if available, synchronous control improve uniformity; staged venting and filtration protect components and keep pressure ramps predictable.

Connections, couplers, and interfaces between props, walers, and needles must be mechanically compatible and documented; mixed systems require verified adapters and clear torque or pretension specifications.

Planning, design, and sequence

• Survey of existing conditions: Record load-bearing structure, material, component thicknesses, preloads, cracks, moisture, and construction states.
• Load assumptions and load paths: Consider dead loads, live loads, anchor forces, and dynamic influences from separation and splitting processes.
• System selection and design: Define the type of shoring, spacings, head and base bearings, bracing, and safety factors.
• Subgrade and bearings: Ensure bearing capacity, flatness, friction, punching shear capacity, and protection of existing surfaces.
• Installation sequence: Work from safe areas, define preloading, and cut components only after full shoring is in place.
• Monitoring and documentation: Control deformations, settlements, pressure values, and bolt pretension, and document them in a traceable manner.
• Removal of shoring: Release in reverse order, load-free and controlled.
• Method statement and permits: define roles, hold points, exclusion zones, and emergency measures; obtain approvals where required.
• Clash detection and logistics: check access, headroom, crane or lifting paths, and sequencing to avoid conflicts with tools and utilities.
• Contingency planning: predefine reinforcement options and thresholds for pausing or redesign.
• Competence and inspection: appoint qualified designers and supervisors; schedule independent checks at key milestones.

Design and execution should be carried out by qualified specialists in compliance with applicable rules, standards, and regulatory requirements. Safety margins and redundancies must be deliberately planned.

Shoring in application areas

Concrete demolition and special deconstruction

When components are detached with concrete demolition shears, force flows change. Slab edges are underpinned with needle beams, beams are supported with props, and columns are braced using tower scaffolds and diagonals. When removing corbels, balconies, or stair flights, early shoring prevents shear and torsional failures. Sequenced cutting with interim checks of prop pressures and deformations enhances control and minimizes secondary cracking.

Strip-out and cutting

Even if interior walls are classified as “non-load-bearing,” they may have bracing functions. Before wall breakthroughs, slab fields must be propped and frame structures supplemented. When cutting steel stairs, beams, or tanks with steel shears, multi cutters, or tank cutter TC120, temporary hangers and compression struts hold the component in position to avoid jamming the cut edges and to prevent falling parts. Heat and vibration from cutting influence friction and pretension; checks and retightening are necessary at defined intervals.

Rock excavation and tunnel construction

In the heading, crowns and sidewalls are temporarily stabilized by arches, walers, and anchors. When splitting with stone split cylinders, shoring and catch systems are installed in advance to guide the movement direction of blocks. Immediately after the extraction step, nets and anchors limit subsequent failures until permanent supports are installed. The sequence is coordinated with ventilation, mucking, and survey so that monitoring remains uninterrupted.

Natural stone extraction

When detaching raw blocks, wood pads, steel wedges, and beddings ensure uniform bearing. Shoring prevents corners from spalling and blocks from rotating uncontrollably while stone and concrete splitters advance the separation plane. Travel paths for lifting equipment must be kept clear and secured against settlement. Edge protection and controlled tipping or lowering reduce damage to marketable faces.

Special operations

In confined or sensitive areas – such as existing buildings with historic finishes – rubber-mounted head plates, finely metered hydraulics, and slip-resistant pads are used. When dismantling large steel components, frames, crossbeams, and guying are combined to take cutting loads and to guide components in a controlled manner. Pre-assembled modules and color-coded connections simplify installation in tight time windows and reduce the risk of misassembly.

Shoring when using concrete demolition shears and stone and concrete splitters

Separation and splitting processes can be controlled safely and precisely when shoring, force application, and load paths are coordinated. A step-by-step approach is essential:

1. Secure the work area, read the load-bearing structure, define shoring points.
2. Install props, needle beams, or tower scaffolds, preload, and document.
3. Select the force application of the concrete demolition shear or the splitting wedges so that the desired fracture line forms and the residual load-bearing capacity is maintained.
4. Separate or split in stages, observe deformations, and adjust pressure values.
5. Secure components, lower or lift them; only then gradually relieve the shoring.
6. Carry out trial load cycles where feasible to verify behavior before full-force operations.
7. Maintain exclusion zones and communication protocols during every load change and after each cut.

Adaptive control of hydraulic pressure via suitable hydraulic power packs supports the controlled sequence and reduces shock effects on shoring elements.

Subgrade, bearings, and load distribution

The bearing capacity of the subgrade determines the safety of the shoring. Smooth floors require slip-resistant layers, soft subgrades require large-area sleepers. On slabs, punching shear and shear reserves must be verified; in soil-contact areas, moisture and compaction influence settlement. Head bearings must be force-fitting, level, and aligned; intermediate layers of hardwood or steel plate distribute contact stresses and prevent edge pressures.

• Increase bearing area: double-up sleepers or use steel grillages where contact pressures are high.
• Improve friction: introduce textured pads or anti-slip mats on smooth substrates.
• Protect finishes: use separation layers and edge protectors without compromising stiffness.
• Level control: shim systematically and recheck plumb after preload.

Measurement and monitoring concepts

Settlement pins, crack gauges, laser measurements, or tilt sensors provide reliable indicators of shoring effectiveness. Thresholds and response plans are defined in advance: if they are exceeded, the process is interrupted and the shoring is readjusted or reinforced. Clear documentation creates traceability for all project participants. Baseline measurements prior to intervention, defined read-out intervals, and event-triggered checks after each major cut or split step are integral to the concept.

• KPIs: maximum settlement and tilt, permitted crack width change, allowable pressure drift.
• Frequency: continuous for critical stages, otherwise interval-based with spot checks.
• Alerting: tiered alarms with hold points and authorization to proceed.

Safety and organization

• Cordon off hazard zones, keep load and slewing areas clear, provide fall protection.
• Plan rescue routes and keep them open at all times.
• Install hydraulic systems tight, clean, and depressurized; keep an eye on the pressure indicator.
• Provide redundancy in critical shoring (e.g., double props, additional bracing).
• Consider weather influences on friction, bearings, and deformations.
• Use only qualified personnel and communicate work instructions bindingly.
• Permit-to-work and toolbox briefings: formalize start conditions and changes, record handovers.
• Lockout-tagout for hydraulics and power: prevent unintended activation during adjustments.
• Housekeeping and access control: maintain clear escape routes and stable working platforms.

Legal requirements, manufacturer instructions, and regulatory conditions must always be observed; binding assessments are project-specific and carried out by authorized specialist bodies.

Typical mistakes and how to avoid them

• Unclear load paths: simulate and document load redistributions before separation.
• Undersized bearings: provide sufficiently large load-spreading areas.
• Missing bracing: always secure vertical props against overturning and sliding.
• Removing too early: release shoring only after complete unloading.
• Underestimated vibrations: include dynamic influences from separation and splitting processes.
• Hydraulic errors: avoid pressure spikes, fix leaks immediately, protect hoses.
• No monitoring: define thresholds and perform measurements consistently.
• Poor interfaces: mismatched couplers or adapters reduce capacity and introduce play.
• Inadequate communication: undocumented changes to the sequence or setup increase risk.

Practical examples

When opening a reinforced concrete wall, needle beams were supported on tower scaffolds, the slab was propped in a grid, and the opening was produced in stages with concrete demolition shears. Settlements remained small due to preloading and monitoring. In tunnel heading, safety nets and temporary arches were installed before splitting benches; area-wide stabilization followed immediately after splitting. When dismantling a tank shell, internal frames and guying ensured dimensional stability while cut segments were secured and removed in a controlled manner.

In a heritage structure with variable slab thicknesses, a staged propping scheme with pressure monitoring was implemented. After baseline readings, cuts were sequenced from low to high risk, with interim retightening of head spindles. Exclusion zones and synchronized hydraulic lifts kept deformations within target values until permanent measures were in place.

Distinction from bracing and underpinning

Shoring primarily addresses vertical load transfer, bracing stabilizes against horizontal actions and imperfections, and underpinning relocates load-bearing lines downward. In practice, these measures are combined: a wall opening may require props (shoring), diagonals (bracing), and local foundation additions (underpinning) at the same time – especially when separation and splitting works with concrete demolition shears or stone and concrete splitters are performed in load-bearing structures. Clear differentiation of purpose, design checks, and installation sequence prevents conflicts and ensures a coherent temporary works strategy.