Competence in concrete

Partnership with VSB infra

Special solutions are standard for concrete paving projects. WIRTGEN slipform pavers are therefore planned by a team in collaboration with the customer, and then manufactured according to the customer‘s specifications.

From 80, 60, 50 and 30 to 15. What sounds like a number sequence from math classes is actually a combined offset mold that WIRTGEN developed for VSB infra GmbH & Co. KG. As usual, CEO Kay Petersen initially approached Martin Datzert, Sales Advisor at the WIRTGEN GROUP sales and service company, WIRTGEN WINDHAGEN. “We‘ve known each other for 17 years now. This has created a basis of trust. I know that I can rely fully on WIRTGEN‘s solution competence.“

Quality is decisive for me and this is what WIRTGEN delivers. A good relationship is founded on trust – in both business and at home.
Kay Petersen, CEO of VSB infra GmbH & Co. KG

Supporting partners

To be able to react quickly to construction projects and their varying requirements, Petersen was looking for a way to use his 1.10 m-wide offset mold in a flexible manner. “We used to have around six weeks from the time the order was placed to the start of construction work, but now our slipform pavers have to be on the job site in the space of two weeks,“ comments Petersen, pointing out the increasing demands when it comes to response times. The WIRTGEN solution: inlays with different widths. “With these inlays, our customers can quickly and simply reconfigure their offset molds with a modular insertion concept to suit requirements,“ Datzert explains. Though this custom design initially involved additional costs, Petersen did not hesitate for a second: “The special solution is in constant use and has long since paid off.“

In addition to the specialist expertise, he also commends the way that WIRTGEN develops solutions. “The projects are closely coordinated with us and we are regularly informed about their progress,“ the CEO adds, describing cooperation with the construction machine manufacturer. He appreciates the way that WIRTGEN‘s track-proven process chain is immediately triggered at the brand headquarters when an enquiry is received.

The WIRTGEN design department is the hotbed from which innumerable special solutions have sprung. What starts with a theory and a CAD drawing on the PC ...

... is then put into practice by the manufacturing specialists in production.

Creating solutions

The first step is for the product manager to gain an overview of the framework conditions. “It’s important to know each piece of the puzzle – from the application requirements through to transport specifications – and to meticulously document all information. Only then can we offer a suitable solution,” says Martin Datzert.

Before this is possible, the WIRTGEN designers have to investigate the feasibility of various approaches. Markus Zimmermann, Development and Engineering Design department: “We have a great deal of experience in developing special solutions for slipform pavers – experience we acquired while tackling the wide range of demands that concrete paving involves.” Be this as it may, finding ways to fulfil new customer wishes presents the applications specialists with a never-ending series of exciting challenges. Quite often the customer’s ideas are so precise that they even bring their own sketches with them. Kay Petersen also had a drawing in his briefcase at the time. “Our partners know what they want. Ultimately, clear specifications of any kind help us to achieve ideal results with the best level of quality.” This is something Zimmermann and Datzert agree on.

Our partners know what they want. Ultimately, clear specifications of any kind help us to achieve ideal results with the best level of quality.
Martin Datzert, Sales Advisor, WIRTGEN WINDHAGEN

Safeguarding quality

In another special project, the task was to design for the customer a slipform paver that was able to lay down two concrete tracks for a rail track bed in a tunnel. This was not possible with a standard slipform paver. WIRTGEN came up with three possible solutions. The customer finally opted for the version that featured a SP 25i as the basic machine, since it can be used flexibly as a small inset/offset paver and because its compact dimensions gave it the necessary maneuverability for tunnel work.

Kay Petersen (r.) talking shop with Master Craftsman Thomas Buchholz and discussing the WIRTGEN concrete paver’s operating concept during his visit.

Special solutions such as the SP 25i with a double mold and higher crawler units are also of interest to CEO Petersen. “I can turn to WIRTGEN at any time and be sure to find the right solution.”

However, to be able to pave both concrete tracks in one pass, it was necessary to completely reconfigure the standard slipform paver in a number of places. These modifications were required as the SP 25i was to pave the first track in inset mode, which means between the crawler units; the second track was to be laid down in offset mode, which involves mounting the mold outside the crawler tracks. The material is fed by a truck that unloads the fresh concrete into the conveyor auger located at the front of the concrete paver.

To enable simultaneous loading of both molds, the WIRTGEN engineers developed a special design in which a curved loading chute was mounted on the side beam of the SP 25i. This evenly distributes the concrete transported by the conveyor auger to the chute among the two molds. “One major challenge was to maintain the flow of material to the molds in the bends, even on very steep slopes, as concrete only flows at angle of more than 60°,” Zimmermann explains. The design engineers were able to satisfy these customer demands, too, with suitable modifications to the curved loading chute.

The inset mold was also modified to adapt it to the inside of the track due to the slope requirement. As platforms for the rail network already exist at regular intervals, the offset molds have a flatter design than the standard molds. This enables the slipform paver to reach under the concrete profile for the platforms with the offset mold. In addition, modifications to the crawler units were necessary to meet the requirements of this application. The advance motor protection on the outside of the standard version of the SP 25i had to be mounted between the crawler units due to the confined conditions in the tunnel. Each of the crawler units are now 160 mm higher to prevent the advance motor protection from protruding into the concrete profile.

On the SP 25i special solution, the crawler units are 160 mm higher than on the standard version.

Our team is made up of specialists who know all about special solutions.
Thomas Buchholz, WIRTGEN Master Craftsman for Slipform Pavers

From professionals for professionals

As soon as the customer gives the green light for production of a special solution, the professionals in production take over. In this case, the SP 25i was rolled into the production hall for special machines. Thomas Buchholz, Master Craftsman for Slipform Pavers, can rely unconditionally on his production team: “We have an experienced team that has built countless slipform pavers. For us, special solutions are all in a day’s work. Every move is fast and accurate.”

VSB infra has also executed various rail projects. CEO Petersen was therefore particularly interested in taking a closer look at the special SP 25i solutions during his visit to the Windhagen works. “The demands involved in concrete paving present construction companies and machine manufacturers with a constant stream of new challenges. This is why I am really glad to have the support of such a strong and reliable partner as WIRTGEN. Until now we have met all challenges together.”


are included in the WIRTGEN concrete paving portfolio – not including special designs.


wide road surfaces are an easy job for the slipform pavers in inset mode.


high monolithic profiles can be paved by WIRTGEN concrete pavers in offset mode.


Learn more about our product program in slipform paving.

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