The main feature of the fortified complex at Cittadella at a figurative level is the 'cardo' and 'decumano' road layout of Roman derivation and the city walls, with their circular plan. The average height of the city walls is roughly fourteen metres to the level of the walkway and eighteen metres to the top. They are built 'a sacco' in other words they have a strong central core in a mixture of lime and pebbles enclosed in two sections of clay and stones with a mainly box-like construction that is developed with different techniques above and below. Four gateways provide access to the city.

In the scheme for refurbishing and converting the whole fortification - to create council offices, shops an open-air theatre and public park - a systematic approach was taken to resolving the structural problems and architectural restoration finalised at both the conservation of the profile of the monument (thereby keeping in check the decay of the wall construction) and a new use, in other words the possibility to examine the layout. It was therefore necessary to consider the linguistic unification of the scheme, utilising mainly wood and weathered steel, the latter being able to create an interesting figurative and chromatic dialectic with the hefty existing walls.

Perhaps the most evocative and representative part of this intervention was the design of the breach of the north-west section, opened during the period of the war against the league of Cambrai. Here the desire was not only to restore the continuity of the walkway, with the construction of two staircases in painted steel, but also to create a place to stop and go down to ground level near the terraces along the ditch.

The system of steps and walkways uses C-sectioned metal beams partly pre-assembled with cross-bracing in correspondence to the uprights of the railings and supports. The upright of the balustrade consists of two steel plates placed together and bolted to the main beams.
In the intermediate parts, the main beams are set on columns with a reinforced concrete core with a C-shaped section and masonry cladding while the ends are set in the walkway

In correspondence with the masonry columns, the metal balustrade becomes a masonry one, opportunely reinforced, with the aim of guaranteeing adequate resistance. The idea behind the staircase, here proposed as a great machine of ascent, aims to reproduce the image and sense of the complicated wooden structures that adorned the walls of Cittadella in Medieval times.

Conversion of the fortified complex at Cittadella (PD
Design: Studio Valle Architettura e Urbanistica, Patrizia Valle
Realisation: 2001/2009