SPR Europe`s UNILINER™ for sewer pipe rehabilitation: Pipe lining nightshift in the city of Brussels

For the overnight rehabilitation of a 169-metre long oval profile of 600/900 using a UNILINER™ system synthetic fibre liner, it became clear that light-curing GRP liners do not have a monopoly when it comes to extremely short construction times.

 

The environmental service provider VIVAQUA is not only one of Belgium’s largest suppliers of drinking water, but also responsible for operating, managing and maintaining the southern sewage disposal system in Brussels metropolis. This task also requires the repair of damaged sewers and sewage systems. In this role, VIVAQUA recently had to get to grips with one of the main sections of the Brussels drainage system, in the district of Saint-Agatha-Berchem. This concrete oval profile running along the Gentsesteenweg road had damages requiring rehabilitation along approximately 600 metres of its length. According to the deterioration of the pipe CIPP lining almost lend itself as the solution.

 

However, certain constraints existed at the site, which made the project an ambitious undertaking even in the planning phase, and in the end resulted in changing the originally planned method. The drain lay directly beneath or rather next to the main traffic artery of the Belgian capital, which is not only used by an extremely dense flow of vehicles. Immediately above the sewer is a tram route, on which several tramlines run from early in the morning until late in the evening. Because of the tramline, the initial idea of rehabilitating the sewer with a synthetic fibre liner using hot water curing failed. This was particularly the case for the longest individual section of the 600/900 oval profile, measuring 169 metres. Firstly, given the nominal width and length of this sewer, the curing process using hot water would have considerably exceeded the permitted time frame. Secondly, problems with the construction site facilities were foreseeable: as the access shafts lay underneath the overhead line of the tram, the heavy liner could not be lifted into the open shaft using a truck-mounted crane. Another pressing restriction was the time frame, which was defined by the Brussels urban transport providers. Construction site equipment could only be in position on the route between the last tram of the day at 10 p.m. and the first of the morning, just after 5 a.m. During this time the current in the overhead line was switched off as a precaution.

 

Against this background, in mid January 2012 a suggestion was employed, which had been put forward by KMG PT in Belgium: the inversion of the synthetic fibre pipe liner UNILINER™ of SPR Europe with an interior wall thickness of 13.5 millimetres and cured to a new pipe using the steam curing process. With this technology, the installation team inverted the liner using a 3.5-metre high, mobile winding tower. Once the liner was installed close-fit into the sewer, it was cured by means of steam injected into the liner by a truck-mounted steam generator. Thus, the liner could actually be cured in the calculated wall thickness during the Brussels nightshift that was all in all an impressive technical and organisational feat, which succeeded thanks to close consultation and smooth co-operation with the client and the Brussels traffic police.

 

The police had one special task shortly before the liner was installed: they ordered the removal of a 7.5-ton lorry, which was parked above the target shaft for the rehabilitation work, and supervised the towing away of the vehicle by the recovery service. Despite the unforeseen additional step which caused extra time pressure, the KMG PT Team was able to successfully conclude the project for all involved within the given time frame.