Perfect Pipe provides compelling benefits for sewer rehabilitation in Strasbourg

A new residential neighborhood is currently under construction at the premises of a former brewery in Strasbourg. ­Heavy-duty, corrosion-protected DN1000 Perfect Pipe concrete-plastic composite pipes in varying lengths provided the perfect solution for this new development.

More than three years ago, Beton Müller, a precast producer based in the German region of Baden, made a ground-breaking decision: Back then, the business added an innovative Perfect Pipe production line to its portfolio and has since been able to manufacture corrosion-resistant concrete-plastic composite pipes from fluid concrete with high structural capacity in a largely automated process. The underlying production system was developed by Schlüsselbauer Technology. Beton Müller uses this system to manufacture Perfect Pipes that combine the benefits of structurally stable concrete and highly resistant plastic, thus providing ideal characteristics for use in modern, durable sewerage systems.

Infrastructure for residential development

The family-run company Bernhard Müller Betonsteinwerk GmbH has been in business for over 125 years and develops, produces and sells precast components for civil engineering. Its product range is greatly appreciated on the market and includes concrete pipes, manhole bases and structures as well as various custom elements. It is continuously being extended by innovative products – most recently, a lockable bicycle box made from concrete was added to the portfolio. Beton Müller currently operates three production and sales sites in the State of Baden-Württemberg. The main plant and company headquarters are located in Achern, about 20 km south-west of the city of Baden-Baden. The second site is operated by a subsidiary – it is situated in Kirchardt near Heilbronn. At the third production site in Breisach-Gündlingen, Beton Müller has been producing various Perfect Pipe concrete-plastic composite pipe designs since 2012. Since 2013, these products have been successfully used in many projects. Beton Müller is increasingly focusing its sales activities on the international level, not least because the sites operated by the company are located close to the bordering countries of Switzerland and France, particularly to the neighboring Alsace region only separated by the Rhine River.

Last year, this development gave rise to the celebration of the successful entry of Beton Müller Perfect Pipe into the French pipe construction market on the occasion of a first major project in Strasbourg. In the Cronenbourg district, the premises of a former brewery that had been operated until 2001 are used to build a new, large-scale residential neighborhood. When considering the options available for the comprehensive new infrastructure to be installed, “Communauté Urbaine de Strasbourg”, the municipal wastewater utility, had favored a corrosion-resistant pipe system right from the outset. The related shortlist also included pipes made from vitrified clay and cast iron. However, specifiers ultimately decided in favor of the rigid, fully corrosion-resistant Perfect Pipe concrete-plastic composite design.

In summer 2015, the first civil engineering lot included the installation of a DN1000 Perfect Pipe string to replace the previously used, parallel ceramic pipelines at Route d’Oberhausbergen, which is located directly adjacent to the new residential development. The second lot was completed in May this year; it included the installation of a 170 m long new sewer system at the premises of the former brewery. Again, DN1000 Perfect Pipes with complete HDPE liner were installed in an open-cut process. Besides standard, 3 m long pipes, the range of installed products also included various shorter connecting pipes and flexible pipe unions and elbows. This part of the project also included construction of three complete manhole systems, which were also produced by Beton Müller. The manhole bases integrated in these systems are produced from a single cast applying the Perfect production method developed by Schlüsselbauer Technology. Among other benefits, they excel with their high product quality but also provide the option of including custom channel configurations and continuously adjustable connecting elbows and feed heights.

Consistent corrosion protection, high structural capacity

For the Strasbourg project, Lingenheld Travaux Publics was again selected as the civil contractor, as in the previous year. Its employees were fascinated by the ease of installation of Perfect Pipes with shaped base. A simply compacted subgrade that also considers the required gradient is sufficient for quick installation. Two integrated spherical-head lifting anchors permit safe and accurate lifting of pipes into the open trench using a set of lifting chains attached to the excavator. Pipes are connected by factory-installed plastic connectors (the so-called Perfect connectors), which also ensure consistent corrosion protection of the entire system owing to their tight fit with the HDPE inner liner integrated inside the pipes whilst retaining the original cross-section. Additional, time-consuming welding of pipe ends at the job site is no longer required. Subsequent backfilling and compaction of the soil and trench is an equally quick and easy work step thanks to the sophisticated Perfect Pipe shape that eliminates the need for vulnerable compaction in the gusset area.

Despite the fact that the Strasbourg municipality usually prefers concrete, cast iron and vitrified clay as pipe materials, the client was convinced of the Perfect Pipe concrete-plastic composite primarily due to its three main characteristics: firstly, the consistent corrosion resistance of the entire system, which is ensured by the inner HDPE liner and the innovative connector system using pre-assembled plastic parts. The high structural resistance of the Perfect Pipe, which is made from high-strength, steel-reinforced concrete, was the second compelling argument in favor of this option. Designers were very clear about the fact that only a heavy-duty pipe solution was possible because the major part of the new wastewater collector was to be installed at a depth of over 5 m, and another pipeline section had to be integrated directly underneath a heavily frequented road. The design produced by Beton Müller (a reinforced-concrete pipe with base) is the perfect solution for a pipe cross-section of this dimension (DN1000 internal diameter). Yet another compelling argument in favor of selecting the Perfect Pipe system were its tried and tested, favorable installation characteristics that enabled a smooth, quick and safe installation process. Due to specific circumstances, the Strasbourg pipeline had to be laid in the direction of flow. The connector system typically used with Perfect Pipes also permits such a “reverse installation” sequence, which was just another key criterion for the decision-makers at Communauté Urbaine de Strasbourg.

Cost-efficient production and high component quality

The Perfect Pipes installed in Strasbourg are DN1000 reinforced-concrete pipes with base and bell-shaped socket and the corresponding tapered end. All pipes are equipped with a continuous liner made from corrosion-resistant HDPE and factory-installed connectors. Beton Müller produces these Perfect Pipes at the Breisach-Gündlingen plant using production equipment supplied by Schlüsselbauer Technology. The manufacturing process starts with the fabrication of the HDPE Perfect Liner that is to cover the inside of the finished pipe. This liner is permanently resistant to chemical attack. The final external contour of the pipes produced at Beton Müller is created by filling the steel molds with easily compactible concrete. The liner is initially fixed to a steel core to ensure dimensional stability of the corrosion protection layer. For the Strasbourg pipes, an additional steel reinforcement cage was inserted before closing the mold. After casting and subsequent in-mold curing, finished pipes are demolded and are ready for further use. Beton Müller uses this sequence to produce Perfect Pipes in diameters ranging from DN250 to DN1200 in various lengths and designs. What all these pipes have in common is their above-average anticipated service life of over 100 years.

Joachim Strack, managing director of Beton Müller, refers to the Strasbourg project as a true milestone in establishing Perfect Pipe as a solution for the French market, and is thus quite positive about what has been achieved: “We thank all parties involved for the exceedingly good and smooth cooperation. Installation of pipes requires not only ultra-precise planning but also a perfectly coordinated team on the job site itself, so we are all the more satisfied with the successful completion of this major project.”

A total pipeline length of over 20 km has already been installed since Beton Müller first introduced the Perfect Pipe technology in 2012. Many clients and users submitted positive feedback and thus strengthened the belief of the company to be on the right track with the Perfect Pipe system, according to managing director Strack. “Today, we are able to quickly respond to specific customer needs and to provide an attractive, reasonably priced product to our clients not least because of the continuous improvement and automation of the production process in close collaboration with our technology partner, Schlüsselbauer. A huge positive is the exceedingly cost-efficient production process of the Perfect Pipe system – even large diameters of up to DN1200 can be produced ‘from start to finish’ by just two or three workers on the shop floor. Besides the outstanding product quality, it is primarily this optimized cost efficiency that strengthens our belief in the Perfect Pipe system as a product with very promising prospects.”

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