Large bracing structures beneath an active motorway

Among the project’s most extensive deliveries was the establishment of large temporary bracing structures built from HEM700 steel beams and CHS Ø406 mm cross-bracing tubes.

The structures were established in three levels and served to provide the necessary bracing of the sheet pile enclosures during the civil works.

The work was carried out beneath an active motorway, which placed considerable demands on installation planning, access conditions, material handling and coordination with the rest of the construction site.

The large dimensions and structural geometries required precise adaptation and a carefully planned installation process, in which the individual steel elements had to be fitted into the structures under the existing space constraints.

Sejerslev managed the necessary material handling itself and provided, among other things, its own wheel loader for handling and internal transport of the heavy steel structures on site.

Custom-made anchor and relief structures

As part of the establishment and bracing of the sheet pile enclosures, Sejerslev delivered and installed 235 anchor bars with associated, individually adapted relief beams.

Each relief beam had to be adapted to the specific geometric conditions in order to ensure correct load transfer from the anchor bars to the rest of the structure.

Where the anchor bars were passed through the sheet pile walls, Sejerslev developed and executed specially adapted closure details with a focus on waterproofing around the penetrations.

The work combined custom fabrication, precise adaptation and site welding, and placed considerable demands on the interaction between the load-bearing capacity of the structures, the actual geometry of the sheet piling and the necessary sealing solutions.

Extensive welding works and waterproofing of sheet piling

A significant part of Sejerslev’s contract consisted of waterproofing the sheet pile enclosures by welding the vertical sheet pile interlocks.

In total, nearly 9,200 linear metres of site welding were carried out in order to establish watertight joints between the individual sheet pile profiles.

The work was carried out directly on the construction site and comprised long, continuous weld runs under varying access and working conditions.

The scale of the task placed considerable demands on staffing, welding capacity, quality control and continuous production planning.

Sejerslev’s experience with specialised welding and major infrastructure projects made it possible to plan and execute the work as an integrated part of the overall civil works.

Precision cutting and adaptation directly on site

In addition to the factory-fabricated steel delivery, Sejerslev carried out extensive cutting and adaptation works directly in the established excavations.

The work included precision cutting of more than 1,000 holes in steel structures and sheet piling for the passage of reinforcement bars.

The holes had to be positioned and executed with regard to the actual conditions on site, which placed particular demands on accuracy and practical execution.

In addition, Sejerslev carried out the trimming of nearly 1,000 linear metres of sheet piling, where the sheet pile walls were cut to the specified final level heights.

This part of the contract required both a precise surveying basis and flexible execution, as the work had to be adapted to the progress of the other civil engineering activities.

Embedded plates and steel superstructures

As part of the overall contract, Sejerslev delivered, installed and welded more than 300 embedded plates for the various excavations.

The work comprised precise positioning, adaptation and fixing of the individual steel parts in interaction with the reinforcement and concrete works.

In addition, Sejerslev delivered and installed approx. 40 metres of steel superstructure (sheet pile heads), which formed part of the project’s overall steel structures.

The many different steel parts and installation tasks required continuous coordination with the other contracts and a production setup that could quickly adapt to changes in the needs of the construction site.

Specialised production of driving heads in 180 mm steel

A particularly technically demanding part of the delivery comprised the development and manufacture of three custom-designed driving heads for the installation of the project’s very large and long sheet pile profiles.

The driving heads were custom-made for the contractor’s driving equipment and had to be adapted to the specific hammer as well as the considerable mechanical impacts the structures are subjected to during the driving process.

The structures were manufactured from steel plates with a thickness of up to 180 mm and built up as heavy, welded-up special structures.

The great material thicknesses placed particular demands on welding procedures, heat input and control of the thermal effects during manufacture.

Prior to welding, the material was preheated to approx. 150 °C. After welding, the structures were heat-treated at approx. 580 °C in order to reduce welding-related residual stresses.

The manufacture thus required a combination of advanced materials understanding, specialised welding technique and the capacity to handle exceptionally heavy steel structures.

The driving heads are an example of Sejerslev’s ability to develop and manufacture customer-specific solutions for tasks where conventional standard components are not sufficient.

Produced at Sejerslev

The extensive steel structures were manufactured at Sejerslev’s own production facilities, where modern machine technology is combined with specialised craftsmanship.

Production included CNC plasma cutting, automatic sawing, assembly and adaptation of steel structures, as well as both robot-based and manual welding.

Sejerslev’s own CLOOS welding robot was used for the structures and welding tasks suited to automated production, while complex geometries, heavy material thicknesses and specially adapted parts were handled through manual specialised production.

The overall production capacity made it possible to handle both larger series of steel parts, heavy structures and one-off special components within the same contract.

With technical clarification, machining, welding and quality control gathered in-house, Sejerslev could ensure close coordination between engineering and production while responding quickly to changes in the project’s execution.

Active participation in planning and project management

Sejerslev’s role on the E45 project comprised not only production and execution, but also active participation in the ongoing planning of the contract’s performance.

Throughout the course of the project, Sejerslev contributed to the preparation and adjustment of work and time schedules as input to the main contractor’s overall production planning.

This included coordination of production sequences, installation activities, access conditions and the necessary resources, so that the steelworks could be fitted into the other civil engineering activities.

The close involvement made it possible to identify execution-related challenges at an early stage and turn them into concrete technical and operational solutions.

Flexible execution under time pressure

Major infrastructure projects are characterised by complex dependencies between many different contracts, where delays in one activity can quickly affect the overall schedule.

On the E45 project, Sejerslev has on several occasions helped to recover delays from other parts of the project through flexible planning and rapid changeover.

This has been achieved, among other things, through rapid changeover of production, flexible resource planning and the mobilisation of employees for both night and weekend work.

With direct access to its own production facilities, specialised welders and installation personnel, Sejerslev has been able to respond at short notice whenever the project’s progress required an extraordinary effort.

This flexibility has been a central element of Sejerslev’s delivery and has contributed to critical work activities being completed, even when prerequisites and schedules changed along the way.

The project thus demonstrates Sejerslev’s strength as a technical and operational partner that does not merely deliver steel structures according to the drawing material, but actively contributes to getting complex civil engineering projects completed – from the first technical challenge to the final weld on site.