Reinforcement tying

Tying of reinforcement is a fundamental work step in reinforced concrete construction – and it also plays an important role in deconstruction. Whether reinforcement bars, meshes or cages: Connections made with binding wire fix the position of the reinforcement, ensure load transfer and dimensional accuracy before concreting, and prevent slipping during transport or when exposing during demolition. In practice, tying links the construction requirements of new builds with workflows in concrete demolition and special demolition, for example when a concrete pulverizer, rock wedge splitter and concrete splitter or steel shear are used to separate components selectively and release the reinforcement in a controlled manner. Properly executed ties help maintain specified concrete cover, keep assemblies dimensionally stable and reduce rework in both construction and selective deconstruction.

Definition: What is meant by reinforcement tying?

Reinforcement tying refers to the manual or semi-mechanical connecting of reinforcement bars and meshes with binding wire. The aim is to securely fix the position, spacing and rebar lap splice of the reinforcing steel before concreting, as well as to temporarily secure exposed reinforcement during deconstruction. Typical executions are single and double ties, cross and saddle ties at crossing and overlap points. Tying does not affect the calculated load-bearing capacity of the reinforcement like welding or bolted systems, but it is essential for maintaining concrete cover, geometry and assembly workflows. In practice, tying is coordinated with spacer systems, chairs and bar supports to ensure the specified cover and bar alignment are preserved during handling and concreting.

Purpose and fields of application of tying

In new construction, tying serves to position reinforcement cages, mesh laps and detail reinforcement (e.g., at support areas, punching shear or shear reinforcement) correctly. In deconstruction, it stabilizes exposed reinforcement, bundles bars prior to cutting and prevents uncontrolled movements when lifting component segments. In combination with equipment such as a concrete pulverizer or rock wedge splitter and concrete splitter, tying supports controlled separation cuts by securing rebar-bearing edges and keeping cut sequences plannable – a prerequisite for selective concrete demolition, building gutting and cutting. Beyond that, temporary tying assists retrofit and strengthening works by holding existing and added reinforcement in defined positions until permanent fixation is established.

Binding wire, tie types and execution

Unalloyed, annealed binding wires are used for tying, sometimes with corrosion protection (e.g., galvanized) or sheathing, matched to exposure conditions and handling. Wire gauges are selected according to bar diameter and stresses during transport. As a guide, soft-annealed wire of approx. 1.2-1.6 mm is typical for standard cages and meshes, with locally increased gauges for heavy bundles and demolition tasks. The goal is a secure, not overly tight, fit that resists handling loads without cutting into the bar surface.

Typical ties

• Single tie: fast, resource-efficient standard for mesh crossings.
• Double tie: higher holding force, suitable for laps and splice areas.
• Cross or saddle tie: positive-fit securing at crossing points with dynamic loading.
• Loop ties: for spacers, stirrups and edge restraints.
• Figure-eight tie: improved restraint at overlap zones and re-entrant corners.

Installation notes

• Keep wire ends short and neatly tucked to avoid injury risk and conflicts with concrete cover.
• Place spacers before tying, check and document concrete cover.
• For transport loads and dense cages, provide local double ties.
• In deconstruction, place wire ties so bundles are secured before cutting with steel shears or Multi Cutters.
• Orient tie tails away from exposed concrete faces and cover-critical edges.
• Avoid placing ties where they would be crushed by supports or interfere with compaction.

Tools and handling

• Use twisting hooks or tying pliers for repeatable results; battery tie tools can increase productivity in repetitive work zones.
• Aim for snug twists without over-tightening to prevent wire fracture and bar surface damage.
• Cut or bend back protruding ends flush with the reinforcement contour.

Tying in concrete demolition and special demolition

When exposing reinforcement with a concrete pulverizer, the concrete is selectively crushed, the steel remains largely intact and is accessible. Now a temporary tying prevents individual bars or mesh panels from swinging out. Before cutting with steel shears or Multi Cutters, steel packages are bundled, lifting points defined and load paths planned. If hydraulic rock and concrete splitters are used, splitting joints are created with low vibration; tying holds edge reinforcement together until the section is removed in a controlled manner. The result is safe, reproducible work steps with clean cut edges and minimized secondary damage to adjacent components. Good practice includes defining exclusion zones, securing loose bar ends against fall hazards and aligning tie positions with the intended cut and lift geometry.

Work sequence: from exposure to removal

1. Component analysis: probe the reinforcement layout, identify lap splices and anchorage zones, plan load transfer.
2. Expose: open the concrete with a concrete pulverizer; alternatively create splitting lines with a rock wedge splitter and concrete splitter.
3. Secure: tie exposed bars into bundles with binding wire, stabilize edge reinforcement.
4. Sever: cut rebar with steel shears or Multi Cutters in defined sections, size the compact hydraulic power units appropriately.
5. Lift off: rig, lift and set down segments in an orderly manner; release wire ties as needed.
6. Sort: stage steel and concrete fractions separately, keep transport routes clear.
7. Document: record tie positions, cut sequence and lifting points for traceability and future reference.

Interfaces to equipment and application areas

Tying is not an isolated step but an integral part of the process chain in several application areas:

• Concrete demolition and special demolition: stabilization of reinforcement during selective separation; combination of concrete pulverizer for exposure and steel shear for cutting.
• Building gutting and cutting: temporary securing of bar ends in slabs and walls before openings are created.
• Rock excavation and tunnel construction: where shotcrete with mesh reinforcement (fabric) is removed, tying holds mesh fields together until cuts are made.
• Natural stone extraction: more peripheral; tying mainly concerns surrounding reinforced foundation or plant components.
• Special applications: with complex geometries or confined conditions, tying serves to bundle and safely handle exposed reinforcement.

Quality assurance and documentation

Clean tying supports dimensional accuracy and occupational safety. This includes spot checks of concrete cover, the number of ties at critical nodes and the securing points before cutting. In deconstruction, a brief documentation of the cut sequence and fixing points is recommended, particularly for load-bearing components or staggered interventions over time. This keeps work steps traceable and makes coordination with structural analysis, site management or safety coordination reliable.

• Acceptance criteria: ties at every mesh crossing as specified, increased frequency at laps and supports.
• Sampling: define inspection intervals for dense cages and demolition bundles.
• Records: photo documentation of tie locations, cover measurements and lift points.

Occupational safety and normative notes

Ties create hold points, but they are not a load-bearing substitute for slinging or lifting gear. Personal protective equipment, secured work platforms and controlled handling of stored energy (e.g., in prestressed areas) take priority. Normative foundations for reinforcing steel, concrete cover and connecting means as well as company instructions must be observed; binding information is provided by the relevant codes and specialist designers. In case of doubt, obtain structural approval before separating load-bearing elements.

• Use cut-resistant gloves and eye protection when twisting wire and cutting reinforcement.
• Define exclusion zones below cutting and lifting operations; prevent bar rebound and swinging.
• Verify that utilities and embedded services are identified before exposure and cutting.

Avoiding common mistakes

• Too few or poorly placed ties: leads to reinforcement slipping or mesh panels springing open during cutting.
• Long wire ends: increase injury risk and conflicts with concrete cover.
• Uncoordinated cut sequence: missing tying at edge reinforcement promotes uncontrolled breaks.
• Over-tightened ties on corroded bars: may weaken the cross-section; gentle tightening is sufficient.
• Mixing of fractions: missing bundling makes clean separation of steel and concrete more difficult.
• Ties positioned in cover-critical zones: risk of insufficient cover and exposure of wire to the environment.
• Unsuitable wire type for exposure class: increased corrosion risk or premature failure of temporary ties.

Special constellations

Prestressed elements

With prestressed concrete, wire ties are permitted only as temporary securing; cuts are made only after approval and defined stress release. Extra caution is required. Establish a release plan, monitor for strand rebound and secure the area until forces are demonstrably reduced.

Dense reinforcement and nodes

In nodal areas with high bar congestion, slim wire routing and short ends are important to maintain concrete cover. If necessary, adjust tie sequencing. Pre-assembling sub-cages and tying from least to most constrained nodes can improve access and quality.

Corroded or contaminated bars

Light cleaning of contact areas improves grip. In advanced corrosion, add fixing points and reduce cut lengths. If section loss is significant, consider supplemental restraints and revised lift planning.

Material and sustainability aspects

Quantities of binding wire are small but influence recycling quality: bundling reinforcement with wire makes steel fractions compact, manageable and efficient to transport. In new construction, proper tying leads to less rework, lower material losses and higher execution quality, which can positively affect the service life of reinforced concrete components. Clean separation of steel and concrete supports high recycling rates and minimizes transport emissions through better payload utilization.

Practical, execution-oriented examples

• Wall opening in an existing structure: the concrete pulverizer trims the concrete near the edge, tying gathers the exposed mesh reinforcement into two bundles, then cutting with a steel shear – lifting the segment without swinging. Lifting points are verified and tie removal is sequenced to prevent bar spring-back.
• Slab opening: before splitting the slab, edge bars along support lines are tied to control the crack path; the splitter creates the intended joint, rebar is bundled and cut. Temporary ties remain in place until the segment is supported and lowered to the staging area.
• Column base strengthening: when exposing jacketing, wire ties hold stirrups and longitudinal bars in position until new spacers and supplementary reinforcement are installed. Final checks confirm cover and alignment before concreting.