When talking about large diameter pipes (> DN 1000), usually the thought goes to “Obsolete” stone materials or fiberglass that in the past have dominated the design scenario for the construction of large infrastructure works.

Assuming that, for many aspects and applications, these types of materials are still appreciated, today, with the technological contribution from plastics, we can face new design challenges with large diameter pipes of the latest generation that combine high structural performance with high sealing performance, especially for complex infrastructure works.

For several years now, the HD-PE Spiral pipe (from the production technique of the wrapped spiral) has become increasingly popular on the design scene.

The most interesting case is certainly represented by the mitigation works
of the hydraulic risk of Leonardo da Vinci Airport – Rome-Fiumicino
which required the laying of 7,000 m of pipes between DN 1400 and DN 2000.

In the airport context, in addition to the objective difficulties of designing the work at a structural level (in this specific case there was also a high presence of groundwater even at surface levels), there are also economic difficulties, represented by the need of the airport operator to reduce as much as possible the time required for the construction of the tracks.

Especially when we talk about an international airport like Rome and in particular runway 1 (the only one suitable for AirBus 380 takeoff and landing) this is a fundamental aspect, of strategic importance, because losing only a few hours of takeoffs or landings, can mean compromising turnover on the one hand, and reputation in the eyes of users of the airport on the other.

Taking into consideration these multiple factors, the decision was focused on the DN 2000 Polyethylene Type (SGK) Spiral Pipes produced by CENTRALTUBI Spa for the following reasons:



The particular sealing system, unique in its kind, with electro-welded gasket, was one of the crucial elements for the design choice. This because with the polyfusion determined by the welding process, there are no points of potential hydraulic leakage or infiltration in the presence of groundwater, which are usually represented, given the large diameters used, by the elastomeric gasket joints or other mechanical systems.



The “Spiral” production technique allows to design the profile, the wall thickness and the ring stiffness of the pipe according to the type of application.

In this specific case, since the pipeline does not have to actively participate to the static resistance in the very high load areas (the front wheel of the A380 generates a dynamic load of 25 tons/cm2) identified in particular in the areas below the runway floor, it was wrapped by a suitably designed reinforced concrete box. In this case it was possible to use a minimum ring stiffness of the PE pipe equal to SN 2 KN/m, which has thus allowed important economies of scale of the work.



Thanks to the high lightness and flexibility of the pipes SGK it was possible to carry out welds outside the excavation, optimising time and laying pre-assembled long bars inside the reinforcement, all thanks to the monolithic property that the welding between one bar and the next gave to the entire collector, giving them the opportunity to move around  48mt trunks at a time.

This installation technique has significantly reduced the construction time required to cross the surface of the building.

On runway 1, 4 parallel bars of DN2000 were used, in order to minimize the impact on the ordinary operation of the port.

The versatility of this type of pipe also allows its use as a storage tank in several versions, for water treatment or lamination, in case of problems related to hydraulic inactivity.

But this is another chapter that we will have the opportunity to discuss in the near future.

For further information, please contact our technical area directly:


Centraltubi S.p.A.
Via Foglia 11 – 61026 LUNANO (PU) – ITALIA
Tel. 0722/70011

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