TPi October 2009

Long-section repairs using Simona PE 100 pipes and the Close-Fit method By Philipp Singer, Ludwig Pfeiffer Hoch- und Tiefbau, Germany, and Jürgen Allmann, Simona AG, Germany

T he following article examines new developments in the field of repair of large-diameter pipes. Advances in technology, machinery and the availability of large-diameter polyethylene pipes are increasingly making it possible to treat larger lengths of pipework – a development which, with improved cost-efficiency, is pushing back the limitations to use of the Close-Fit rehabilitation method. Selection of the rehabilitation method Greater Berlin is subdivided into several drainage zones. Sewers which transport water under gravity route the waste water to a total of 147 pumping plants. From there, the waste water is transported through a 1,127km-long discharge pipe network to the six sewage-treatment plants. Since the year 2000, Berlin Water Resources Authority (Berliner Wasserbetriebe BWB) has also been using Close-Fit methods with pipes made of polyethylene (PE) for repair of the piping system. Close-Fit processes hardly reduce the hydraulic cross- section of the pipes. Particularly in the case of waste water discharge pipes, reductions in hydraulic capacity are frequently not possible owing to the rating for heavy-rain events.

The planning specialists of the BWB always consider pending construction projects integrally. The following question is always the focus of the decision-making process: how can the required construction activity be implemented economically, with as little impairment to traffic, nearby residents and the environment as possible in the shortest possible time? Preference is increasingly given to state-of-the-art repair methods. This was the case with a construction project implemented by German construction company Ludwig Pfeiffer in the summer of 2008. An approximately 100 year-old grey cast iron DN 1,050 pipe was repaired to prepare for a road-construction project in Berlin- Neukölln, in the District of Rudow. The road, located in the centre of the district, is the main shopping street in the area, so operating restrictions on the shops had to be minimised. Consequently, the road was to be fully cordoned off on only one weekend, from Saturday at 8 am to Sunday at midnight. Only two construction pits, one at the start and one at the end, were planned for the construction section, with a length of over 500m. This required a 504m-long repair section. The pipe also ran in a section with an approximately 10° angle – a special challenge for the pipe material ( Figure 1 ). The planners at the BWB drew up the following requirement profile for selecting the method: Inliner of new-pipe quality • Maintenance of the flow capacity • The new inliner should absorb all load influences • Pipe material with excellent hydraulics and a • particularly long service life Only slight impairment to traffic flow • Short construction time • Long repair sections • Draw-in possible even at points where angles occur • in the pipe axis High economy (less costly than open design) •

Figure 1 ▲ ▲ : The high flexibility of Simona PE 100 pipe permits extremely tight radii

60

Tube Products International October 2009

www.read-tpi.com