Designing access roads to Porto Marghera
The new urban gate in Venice
Since the 1990s, there have been several operations in the Prima Zona Industriale (First Industrial Area) of Porto Marghera (Venice) aimed at transforming and re-converting the industrial hub following the slump of the original manufacturing businesses. The key player in this process was the Parco Scientifico e Tecnologico Vega (Vega Scientific and Technological Park) created in the areas previously used by fertiliser production plants. Today, it houses companies involved in research, innovation and advanced services. The Vega Centre and all the other businesses situated in about 100 hectares of the First Industrial Area generate significant traffic flows on the road structure which has various incongruences.
The NET Engineering project (Final Design, Working Drawings and Works Management) intends to solve these difficulties with a significant engineering work, a true urban gate suitable for the transformation and development prospects of the area. The work, designed entirely using BIM, plans the creation of a new multi-level intersection along the current SR 11, Via della Libertà, the only access road to Venice, improving accessibility to the industrial area and increasing safety along the highway but with a clear separation between through traffic (traffic crossing the area) and local flows.
Accessibility will be through a new large roundabout connecting both the SR 11 and the Mestre urban network. Through traffic will pass over the roundabout on a viaduct and then enter an above-ground artificial tunnel. Creation of a further raised roundabout connected with a ramp giving direct access to Mestre-Venice is planned above the deck of the tunnel. This manoeuvre, currently not possible from the existing viaducts which will be partially demolished and structurally upgraded, will improve the Mestre-Venezia connection and have a positive influence on the currently congested local traffic.
The viaduct was designed as a double closed caisson in exposed self-protecting integral scheme steel (i.e. a deck in-built to upright supports and so without specific constraint devices), extended over four spans. The piles, also in self-protecting steel, consist of double shafts separated at the summit to sustain two neighbouring pairing stem and joined at the feet forming a ‘V’ in the section going into the foundation.
The design solution arises from various factors. First of all, work had to be done in narrow spaces – the new road lies between the Vega Centre, whose name it takes, and the vast sidings of Mestre station. Secondly, the operation consists of works shaped in a particular way so that ground level obstructions are reduced, to allow construction in an area where traffic cannot be interrupted and to limit maintenance. This required study of the special deck structures starting from a non-standard approach and non-conventional methodologies. This led for example to modelling the whole viaduct as a ‘shell’, omitting the classic truss modelling, resulting in clear economies in materials and greater understanding of an operation in itself complex which perceives the deck as a winged structure.
NET Engineering paid special attention to the formal aspect of the work with the aim of bringing it into line with the value of the Vega Centre, at the same time recalling some elements already used for the Darwin Bridge in Padua as a characteristic feature of the designer’s vision.
Careful study of how the new infrastructure slots into the urban context (a feature of bridges visible from below where the underlying spaces are used ordinarily), the search for a design alternative that makes the best use of the space, reorganising it and responding to the client’s needs through a harmonic solution, enabled the post-industrial area to be valorised and an important identity to be returned to the whole area.
