“the third-lane-enlargement of the main corridor of the Northern Italy”

Construction of the third lane of the Venice-Trieste A4 highway: Mestre – Padova, San Donà – Alvisopoli and Gonars – Villesse sections

Locations

Veneto and  Friuli Venezia Giulia Regions

General Description

The third lane of the “Serenissima” A4 highway is one of the most emblematic projects in which NET had the opportunity to apply the paradigm of the system engineering design. The first stretch was designed between Mestre-Venice and Padua, and later two other sections were done between San Dona di Piave and Alvisopoli and between Gonars and Villesse.

In fact, in every work related to the construction of the third lane in the above sections, the design activities were always performed by adopting a multidisciplinary “system-engineering” approach, in order to identify the best technical solutions based on multi-criteria analysis.

Along the over 70 km of road sections designed, there are a total of:

  • 35 overpasses
  • 1 new road junction and adaptation / displacement of other 3
  • 17 bridges & viaducts
  • 31 underpasses

Some important works of environmental mitigation, green areas, hydraulic facilities, water collection and treatment systems were designed as well.

In addition to the transport study carried out for the entire development of the 3 stretches,  the analysis of accidents was also performed on the S.Donà-Alvisopoli and Gonars-Villesse sections, with a particular focus on the road safety of the Palmanova Node.

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MESTRE - PADOVA SECTION

MESTRE – PADOVA SECTION

Implementation Period

1989 – 1996

Value of Works

 114 M€ – Design
67 M€ – Construction Supervision

Client

Società delle Autostrade di Venezia-Padova S.p.A.

Services provided

Preliminary, Final and Construction Design, Construction Supervision

The assignment concerns the construction of the third lane of the A4 Highway, between the junction of Venice and “Padova Est” tollgate.

The overall length of intervention is more than 20 kilometers and, among the others, the following works were carried out:

  • Design of the Third Lane in both running directions;
  • Design of the side escape emergency roads;
  • Design for demolition of 9 flyovers and new design for their reconstruction including the relative re-organization of the local road network;
  • Pavement Design – resurfacing the road with creation of new layers of bitumen;
  • New tollgate of Dolo (VE) with 8 lanes complete with barriers, station building, parking connected to the road network, normal and special systems;
  • Design and upgrade of the road networks on the rivers Brenta, Tergola, Fiumicello and on the Taglio canal;
  • Design of 4 underpasses and 1 overpass.
SAN DONÀ DI PIAVE - ALVISOPOLI SECTION

SAN DONÀ DI PIAVE – ALVISOPOLI SECTION

Implementation Period

2008 – going

Value of Works

530 M€

Client

Autovie Venete S.p.A.

Services provided

Final Design for Design & Build Contract, Environmental Impact Study

The assignment concerns the construction of the third lane of the A4 Highway, between the junctions of San Dona di Piave and Alvisopoli in the province of Venice. The project extends for an approximate length of 33.5 km and includes the upgrade of the Cessalto and Portogruaro junctions, the displacement of the San Stino di Livenza tollgate for which the Environmental Impact Assessment and the Environmental Effects
Assessment were drawn up.

NET has also analyzed the accident rate over the whole stretch of the project, which includes a statistical analysis of the road accidents
over the last three years and the kinematic reconstruction of the various types of accident, in order to identify the risk factors tied to the infrastructure and identify suitable measures for minimizing them.

The application of an innovative traffic simulation model, based on a statistical description of the behavior of the vehicles assemble into groups of similar characteristics (mesosimulation), allow the possibility to evaluate the impact of circulation on the construction sites and to organize their space-time position in the best way with the aim to guarantee the maximum possible levels of safety.

The project also includes the upgrading of important structures, namely 12 bridges and viaducts, 18 flyovers, 20 subways, sized to forecast the future increase to 4 lanes of the motorway route, and the realization of important water systems for collecting and treating the surface runoff.

GONARS - VILLESSE SECTION

GONARS – VILLESSE SECTION

Period

2008 – 2010

Value of works

152 M€

Client

Autovie Venete S.p.A.

Services provided

Final Design for Design & Build Contract

The assignment concerns the construction of the third lane of the A4 Highway, between the junctions of Gonars (Udine province) and Villesse (Gorizia province).

The project extends for an approximate length of
17 km and includes the upgrade of the Palmanova node, where the
A4 and the A23 “Alpe-Adria” motorway interconnect, considered as
one of the most congested road stretches with the highest accident
rate along the whole Veneto/Friuli motorway network.

NET has also analyzed the accident rate along the whole stretch of the project, which included the statistical analysis of all the road accidents over the last three years, and the kinetic reconstruction of the various types of accident, in order to identify the risk factors tied to the infrastructure and identify the most suitable measures for minimizing them.

Even the project of the construction site was developed with the aim of ensuring the highest possible levels of safety and optimize the conditions of vehicular traffic flow.

Under the environmental profile, the creation of new green areas
along the motorway have been programmed, to compensate the estimated increase in CO2 emissions, in compliance with the indications of the Kyoto Protocol; first flush collection and treatment plants have also been designed, based on constructed wetland technology.

The project also included the upgrading of all structures – one viaduct, 7 flyovers and 7 subways – which have been sized forecasting the
future enlargement of the motorway stretch to 4 lanes.

NODO DI PALMANOVA

In questo tratto autostradale, è presente il cosiddetto “Nodo di Palmanova”, uno svincolo localizzato in prossimità dell’omonimo centro abitato. Lo svincolo consente l’interconnessione tra l’autostrada A23 “Alpe-Adria”, che proviene da Tarvisio e corre in direzione nord – sud con l’autostrada A4 “Serenissima” Torino – Trieste, che corre in direzione est – ovest.

In virtù di queste caratteristiche peculiari, il Nodo di Palmanova, nel complesso delle attività di progettazione per la realizzazione della terza corsia, ha rivestito una notevole importanza e meritato, pertanto, specifici approfondimenti di tipo:
infrastrutturale, in quanto punto singolare in cui si concentrano rampe ed opere d’arte da dimensionare adeguatamente e da verificare;
trasportistico per garantire la fluidità del deflusso veicolare in un punto caratterizzato da numerose manovre di immissione (anche da sinistra) e confluenza di correnti veicolari, di cambi di corsia, di riduzioni di carreggiata etc.;
– di sicurezza perché è importante identificare i fattori di rischio per supportare ed indirizzare correttamente la progettazione dell’ampliamento nell’ottica della sicurezza stradale.

A tal fine è stato, quanto mai opportuno l’approccio di sistema, tipico di NET ma sicuramente innovativo per questo tipo di progettazione, che prevede uno studio approfondito e multisettoriale.
Le alternative infrastrutturali sono state analizzate e quindi confrontate sulla base di indicatori di deflusso veicolare, sicurezza e costi.
L’analisi trasportistica è stata fatta usando modelli di macrosimulazione, microsimulazione e mesosimulazione del traffico, caratterizzati da un diverso grado di dettaglio e aggregazione delle informazioni.
La sicurezza dei veicoli in transito nel nodo di Palmanova è stata valutata a partire dagli incidenti stradali effettivamente accaduti e dalla ricostruzione dei fattori di rischio che li hanno determinati.
La fase di confronto è avvenuta utilizzando una classificazione molto semplificata, in uno schema di tipo “multicriteri”. L’obiettivo finale era quello di individuare la soluzione che garantisse il miglior deflusso veicolare nel rispetto dei requisiti di sicurezza stradale e con i costi più bassi.