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Figure 3. S-GPR display

S-GPR is equipped with a GPS receiver, so it can georeferences all

  buried object. Moreover multimedia data can be associated to the

georeferenced objects: for example you can mark and describe

 points of interest near the object, or introduce some photos of the

environment or an audio description. Finally you can import

georeferenced data in a GIS system or in a CAD file. In GIS

systems you can see georeferenced traces with all buried objects

recorded during the investigation, with information about the

distance from the Start Point and the depth. Further if you click on

the bullet you can see the photo of the buried object (figure 4).

Figure 4. S-GPR data imported in GIS system

3. Environmental low impact diggingTechnology: 1DDTM 

 Normally the impact of FTTx network construction is in the order of 

70% or more of the total network cost, while a specific construction

engineering is very seldom applied. In order to overcome all the

  problems caused by traditional digging technologies, each step of 

the process has been analyzed. Thanks to the simultaneous use of a

trench saw and a suction pump, the digging work can be completed

very quickly, with reduced dimension machinery, and with no

residual material to be removed. The last element of this solution is

the innovative material used to fill-in the trench, with a very fast

hardening time to allow to complete the work in few hours,

restoring the pavement to the previous state. This technique is called1DDTM

, because you can open and close digging works in only one

day.

With a global approach we traduced the problem of working

downtown into an effort of reducing whole critical dimensions

related to the usual trenching machines, beginning from trench

dimensions.

The “mini-trench 5x30 cm” is a new Sirti trenching standard,

characterized by reduced dimensions of 5 cm wide and 30 cm deep.

This type of narrow trench allows to operate with reduced

dimension machinery in small size road typically of European cities

  producing a lower quantity of waste material with the target to

reduce operating expense.

The true innovation during the trenching phase, introduced with

1DD™ system, is the simultaneous and synergic work of a powerful

suction machine with the trench saw as showed in figure 5.

Figure 5. Trench saw combined with suction machine

This combined action allows the waste material to be collected

while produced by the saw, leaving the site clean, immediately after 

the end of the trenching phase and completely removing dust

  problems. It is well evident the difference between a cut with or 

without suction machine work, as illustrated in figure 6.

Figure 6. Difference between cut result with or without

suction machine

The following innovation is related to pavement re-establishment.

According to traditional techniques the trench is normally filled

with cave material and binder on top, finally a layer of pavement is

  posed. This phase is very expensive and time consuming because

 pavement can be restored only after the backfilling material is ready

and usually it takes at least 24 hours.

With the 1DD™ system, thanks to an innovative material which has

got mechanical and esthetical characteristics similare to the

 pavement, the trench is filled completely in one operation and with

  just one material. Moreover the fast hardening time, main

characteristic of this material, allows to close the working site in

 just a few hours (figure 7).

Figure 7. Innovative material before and after hardeningcompleted

Thanks to the behavior of this innovative material, the site can be

opened to the traffic just a couple of hour after the filling. Its

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  physical and mechanical characteristics, combined with the

esthetical result, avoid laying of the asphalt carpet reducing

operating phases, working days and related costs.

According with material design, a new mixing machine has been

developed (Figure 8). The mixing machine features several

solutions that allow the best trench filling without keeping the site

clean and it has been designed to equip common trucks.

Figure 8. The mixing machine

So the whole system can be divided in two different modules: the

first, which will perform the trenching phase, is composed by the

saw and the suction machine; the second, which will perform re-

establishing phase, is composed by one truck with the mixingmachine. This two modules can work in line or in different

times/places, allowing major flexibility, but anyway assuring the

gain of solution.

4. Fender The development of cables characterized by smaller and smaller 

diameter (figure 9), but with the same potentiality of fibers, has

  permitted the realization of new infrastructures with the goal of 

space optimization.

Figure 9. Cable evolution

For this reason Sirti has realized a new kind of infrastructure, called

Fender, standardized by Telecom Italia in 2009. It represents a new,

modern solution to realize a compact infrastructure by means of a

multiplicity of ducts, longitudinally interconnected via a plastic

membrane, so they can be laid in planar way or not. Fender can be

formed with 2 up to 9 mini ducts. The outer layer of the mini ducts

is produced using HDPE of a high-molecular type which guarantees

the required rigidity, easy handling and other mechanical features.

The inner layer forms a permanent sliding surface which reduces

considerably the friction coefficient of the cable with respect to the

tube. Each mini duct of the Fender can be different in colour for an

easy in field identification.

Figure 10. Example of Fender  

Fender has been designed to be used in different network scenarios

such as:

•  Sub-duct inside an existing duct already occupied by an

existing cable, for example in 125mm duct, typically in

 primary access network, where there are copper cables (figure

9.a).

•  Execute Sub-duct of an empty existing 50mm duct (figure 9.b).

•   New infrastructure using one or more Fender into a Minitrench

or traditional trench (figure 9.c).

Figure 11. Possible installations of Fender 

Sirti developed two types of Fender, where mini ducts thickness

changes according to installation (table 1).

Table 1. Application Fields of Fender and its dimension

Application Field

Thickness of Fender miniduct ≤ 1mm Outdoor Sub-ducting

Thickness of Fender miniduct ≥ 2mm Direct Buried

5. Fender Protection SystemAs it often happens that rodents attack optical fibres cables (figure

12), to prevent dramatic damages as network blacks out, it is

mandatory to provide an effective protection solution in handholes

or in other critical places where optical fibres pass-through.

Figure 12. Fault caused by rodent in handhole

For this reason it has been developed a protection system composed

  by a set of components in special rodent-proof plastic material,

called Fender Protection System, that assures the

telecommunication infrastructure integrity. In fact Fender Protection

System protects mini ducts and the mini cables inside by rodents

a b c

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attach, mechanical pressures or by possible flooding in the

handhole.

In Figure 13 it is illustrated the Fender Protection System matrix.

From left to right you can see the splittable duct-mini ducts sealing

element, 0.5 bar pressure resistant, the mini ducts protection

element, the mini ducts joints protection closure, the element for the

extra length cable protection (up to 50metres of cable), that you can

install to the wall of the handhole, the element sealing mini cable-

mini duct and the mini ducts junction box.

Figure 13. Main components of Fender Protection System

Fender Protection System isn’t only theoretical, but it is justinstalled in some experimental telecommunication plants. In the

following figures, you can see some photos of an experimental plant

of Telecom Italia.

Figure 14. FPS for extra length cable in handhole

Figure 15. FPS for a pass through cable in a 40x40cm

preexisting handhole

6. ConclusionsThe technologies presented in the document are just utilized in

various telecommunication plants: S-GPR system is used for all

  plants of various operator in which 1DDTM is provided;  in Italy

about 220 kms of infrastructure has been realised using 1DD™

system and new plants for telecom operators and municipalities are

in progress. In 2009 the first installations of Fender and Protection

System has been realized in collaboration with Telecom Italia and

other installations in infrastructures just occupied have been made

successfully.

7. Pictures of AuthorsEdoardo Cottino (e.cottino@sirti.it)

Edoardo Cottino is the Chief Technology Officer of Sirti Group.

Appointed to this position in February 2004, Edoardo is responsible

for driving Sirti toward the next-generation networks, advanced

technology and application, R&D policy and standards activities. 

Born 1957, Edoardo holds a Masters in Electronic Engineering fromTurin’s Polytechnic and a Master in Business Administation from

Bocconi University of Milano. After a small experience as avionic

system design engineer, in 1985 move to Sirti in the borning Optical

Technology Laboratory following the plant activities. For more of 

ten years has followed the evolution of Italian optical fiber network 

focusing the activity in matter of fibers, cables, accessory and

transmission system.

In 1995 he became head of Cables and Optical Technologies Dept.

with the goal to study and analyse the evolution of the

telecommunication network. In 1999 he has called to guide all

 Network Technologies Divisions of Sirti.

From 1990 he is active member of ITU-T standardization bodie in

Study Group 6 “Outside Plant” and now in Study Group 15

“Transport and Access” where served as rapporteur in manyquestions, he participated at several European Research Project and

holds a number of patents. He is author and co-author of more fifty

 publications.

Nicola Di Buono (n.dibuono@sirti.it)

  Nicola Di Buono graduated in Electronic Engineering with

Microelectronic and Telecommunication specialization at

Polytechnic of Turin in 2005. In 2006 he joined Sirti in the

Technology Office, where he studies new projects and systems

chiefly but not only in the telecommunications area. Recently he is

working on the innovation for Access Network and in particular he

is involved in experimental trials for new network technologies.

International Wire & Cable Symposium 132 Proceedings of the 58th IWCS/IICIT