The French highway network spans almost 12,000 route km, 60 percent of which are administered in a concession system by private companies such as APRR (Autoroutes Paris-Rhin-Rhône).

Thousands of metal culverts have been installed along the roads to channel water and more than 50 percent of these are steel circulars or arches. After being in service for 30 to 40 years, these culverts have reached their maximum lifetime and are at risk to collapse any time, causing road ruptures as far back as 20 years ago: Road embankment, paving and culverts needed to be repaired immediately, which required an expensive construction of temporary diversions for both water and traffic.

As a consequence, the highway companies conducted an extensive inventory. First surveys provided a better overview: A significant number of the steel constructions (corrugated galvanized iron culverts) and a number of concrete culverts showed serious defects. Consequently, all six highway companies introduced a compulsory rehabilitation program, in accordance with the technical specifications by the French Water Act of 1992.

On this account, HOBAS GRP Pipe Systems have contributed to the security upgrade of the construction and highways. Thanks to its environment-friendly characteristics and its exceptionally long-lifetime properties, HOBAS GRP is a material that fulfills all requirements. It should also be noted that the HOBAS solutions for this project are based on trenchless technologies, which permit work without traffic disruptions.
The project was located on Highway A31, which connects the town Beaune and Luxembourg and is part of the APRR network. APRR is a subsidiary of the Eiffage Group, the seventh largest building and concession company in Europe, and is in charge of the second-most important French highway network with 1,800 km. This project is noteworthy for its dual purpose:

  • To rehabilitate damaged metal pipes that were severely corroded for some parts,
  • To extend the road by one lane in each direction.
Year of Construction:  2007
Duration of Construction:  8 months
Length of Pipes Laid:  635 m
Pressure Class:  PN 1
Diameter:  DN 1,200, DN 1,400, DN 1,500,
    DN 1,800, DN 2,000, DN 2,100, DN 2,400
Stiffness Class:  SN 5,000 and SN 10,000
Length of NC-Line:  50 m
NC-Line:  ID 2880 x 1800
Application:  Rehabilitation (Relining) and
    Open Installation (Extension Sides)
Client:  APRR (Autoroutes Paris Rhin Rhône)
Contractor:  Roger Martin, Eiffage Traveaux
    Publics Reseaux
Advantages:  Hydraulic Properties, Long
    Lifetime, Light Weight

Moreover, rehabilitation involves a group of 11 large-scale hydraulicconstructions, nine of which were originally elliptical, one wascircular but strongly buckled and one was in the shape of an arch. Thetotal length of installed pipe adds up to 685 m.

APRR first invited tenders that HOBAS France approached. An overall solution was developed considering the geometry of each channel and grouping the constructions by size. This led to the proposal of four different and individual NC-Line profiles, plus one circular CC-GRP Pipe OD 1720 for the rehabilitation of nine elliptical constructions. Standard CC-GRP HOBAS pipes were suggested for the remaining circular constructions and for the arch a NC-Line ID 2880×1800. Apart from this, an alternative solution was proposed sliplining NC-Line arches and HOBAS CC-GRP pipes using both flush couplings and standard FWC couplings.

APRR opted for the latter proposal. The mixed technologies confirm the adaptability and flexibility of HOBAS products. Thus, 635 m of pipes, ranging from DN 1,200 to 2,400, were installed between May 2007 and the end of November 2007. Slightly more than 50 m of HOBAS NC-Line profiles completed the lot.

“Works were accomplished more easily, thanks to the simple handling and jointing of HOBAS pipes,” explained Norbert Cheminot, civil engineer and head of the special constructions office of Eiffage Traveaux Publics Reseaux, contractor in charge of pipes installation and specialist for trenchless technologies. “Working on highways without disrupting the traffic is always a challenge. The HOBAS solution required less heavy equipment and turned the usually complex storage and handling into easy installation.”

HOBAS Pipe Systems provided a clever and made-to-measure technical solution combining standard CC-GRP pipes with arch-shaped NC-Line panels and offers a long lifetime under constant mechanical loading. The highway companies appreciate the products’ hydraulic properties despite a small reduction in dimension and a low roughness coefficient thanks to the smooth liner surface, maximizing the flow rate and minimizing maintenance. “It was very important for us to find a rehabilitation solution that meets the terms of the French Water Act, something that would not affect the hydraulic condition of the existing pipeline and offer a long life-time,” said Mr. Caisey a technical member of APRR’s area staff.

This article was submitted by HOBAS and edited by Trenchless Technology.

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