The insertion method refers to the controlled shifting or jacking-in of structures such as bridge superstructures, frame structures, or tunnel segments into their final position. It combines fabrication and assembly with precise construction logistics, surveying, and low vibration levels deconstruction works. In practice, it frequently interfaces with tasks from concrete demolition and special deconstruction, building gutting and cutting, as well as rock excavation and tunnel construction. Here, among other tools, concrete pulverizers and hydraulic wedge splitters from Darda GmbH are used to remove or adjust components safely, quietly, and with dimensional accuracy.
Definition: What is meant by the insertion method
The insertion method means pushing, sliding, or advancing prefabricated or cast-in-place concrete structures into their planned position. Typical applications are the longitudinal insertion of bridge superstructures, lateral shifting for replacement construction, the insertion of frame structures (box-jacking) under traffic routes, as well as assembly insertions of tunnel segments. Characteristic features are sliding or jacking systems with hydraulics, PTFE slide bearings or rollers, short construction and closure times, and high requirements for fit accuracy, friction management, and deconstruction carried out alongside the works.
Areas of application and types of the insertion method
The method is established in several construction types and is used wherever traffic interruptions must be minimized, structure quality maximized, and excavation pits kept small.
- Bridge insertion: Longitudinal insertion of superstructures from the preassembly area over temporary supports to the abutment; lateral shifting for sideways repositioning in replacement builds.
- Frame insertion/box-jacking: Insertion of massive reinforced concrete frames under rail lines or roads during short closures.
- Assembly insertion in tunnel construction: Bringing in prefabricated segments, switchgear houses, or portals in confined conditions.
- Special uses: Insertion of protective or work platforms, support scaffolds, or temporary bridges for construction-stage stabilization.
Process and technical components
Planning, surveying, and temporary states
Upfront tasks include structural analysis, shoring, construction phase logistics, and a tight surveying concept. Dimensional accuracy of the slideway, defined insertion axes, and tolerance-compliant structure edges are critical to success.
Sliding and jacking technology
Sliding sleds, PTFE slide bearings, slide plates, steel sections, and hydraulic presses work together. A hydraulic power pack provides the pressure for advancement and lifting systems, typically delivered by dedicated Hydraulic Power Units. Friction management with lubrication reduces forces, protects surfaces, and stabilizes the motion sequence.
Materials, joints, and bearings
Waterstops, spherical or pot bearings, grout mortar, and bearing seats must be cleanly prepared. Edges, chamfers, and joint flanks are often cut in advance or reworked after insertion.
Interfaces to concrete demolition and special demolition
The success of an insertion largely depends on precise demolition and cutting works. In close proximity to existing structures, utilities, or rail infrastructure, low vibration levels methods are required. Here, concrete pulverizers and hydraulic wedge splitters from Darda GmbH help to release components in a controlled manner, separate reinforcement, and maintain edge tolerances.
- Removal of caps, cantilevers, and bearing areas on existing structures in replacement projects.
- Relief cut of abutments, temporary supports, and slideways.
- Creation of predetermined breaking lines, openings, and joints for the insertion path.
- Reworking of bearing edges, chamfers, and transitions after insertion.
Tools and methods in the insertion environment
Concrete pulverizers for dimensionally accurate removal
Concrete pulverizers enable concrete crushing with integrated reinforcement separation. They are suitable for bearing seats, parapet caps, parapets, and radii where smooth, load-bearing edges are required and vibrations must be limited.
Hydraulic wedge splitters in confined excavation pits
Hydraulic wedge splitters, such as hydraulic rock and concrete splitters, work quietly and without explosives. They create controlled crack patterns in massive concrete or rock, for example in excavation shoring, in cross-section enlargements around insertion pits, or when loosening foundation remnants next to live traffic routes.
Steel shear and Multi Cutters for reinforcement and steel sections
During deconstruction of support scaffolds, steel cross-beams, or heavily reinforced components, steel shear and Multi Cutters are helpful. They cut sections, mats, and strands without sparks in sensitive environments.
Combination shears and concrete pulverizers indoors and outdoors
Combination shears combine cutting and crushing functions. In building gutting, wall openings, joints, and shafts required for the insertion path or installation openings can be produced.
Hydraulic power packs for mobile supply
Hydraulic power packs provide the necessary energy for splitters, pulverizers, and shears. A matched power selection supports swift work sequences and consistent quality even during short closure windows.
Rock removal and tunnel interfaces in the insertion method
At portals, cross-section widenings, and rock overhangs, low vibration levels methods are crucial. Rock splitting cylinders and hydraulic wedge splitters from Darda GmbH enable controlled rock excavation around insertion ramps and tunnel interfaces without affecting surrounding structures.
Construction sequence: step by step
- Preparation: Define surveying, temporary states, clearances, and safety zones.
- Construction of the slideway and auxiliary structures; setup of hydraulics and bearing points.
- Deconstruction and trimming on the existing structure with concrete pulverizers, splitters, and shears; relief cut of the insertion alignment.
- Preassembly of the structure (superstructure, frame, segment) at the preassembly site.
- Insertion: controlled advancement, cyclic lifting and shifting, monitor friction management.
- Final bearing: lowering onto permanent bearings, grouting, and forming connection joints.
- Rework: edge profile, waterproofing layer, repair of contact surfaces, and removal of auxiliary structures.
Tolerances, quality assurance, and documentation
Essential are seamless surveying, defined tolerances at bearing edges, and a documented coefficient of friction during shifting. Clean demolition edges facilitate final bearing and reduce rework. Core drilling, saw cuts, and targeted splitting lines can secure fits and improve surface quality.
Safety, environment, and emission reduction
Work in the insertion environment often takes place during closures or under partial operation. Low noise emission and dust exposure as well as low vibration levels removal techniques are therefore advantageous. Water spray system, localized dust extraction, and material-appropriate separation protect personnel and surroundings. Using suitable pulverizers and splitters minimizes secondary damage and reduces recompaction or repair.
Typical error sources and how to avoid them
- Insufficient relief cut of the insertion alignment: identify clashes early and rework precisely with concrete pulverizers.
- Excessive friction: clean sliding surfaces, ensure lubrication, monitor insertion forces.
- Unclear temporary states: secure temporary shoring and bearings by calculation and measurement.
- Rough edges at bearing seats: use controlled crushing and splitting instead of percussive methods.
- Missing disposal concepts: separate construction waste and align waste disposal logistics with closure times.
Inner-city and sensitive locations
In dense urban fabric, under live traffic, or near utilities, the insertion method is suitable due to short closures and limited vibrations. Precision demolition with concrete pulverizers and hydraulic wedge splitters from Darda GmbH supports dimensional accuracy at interfaces, reduces noise, and facilitates permitting processes in urban areas.
Role in concrete demolition and special demolition, building gutting and cutting
Before insertion, gutting, openings, joints, and temporary routes must be created. After insertion, adjustments at transitions, bearing seats, and impact surfaces follow. Tools such as concrete pulverizers, combination shears, Multi Cutters, and steel shear cover the spectrum from concrete to reinforcing steel; hydraulic power packs ensure continuous performance. In rock or massive concrete, hydraulic wedge splitters complement the low vibration levels removal.