Rome, 23 December 2024
This morning, Piazza Pia was returned to the city of Rome, with a new pedestrian area and the extension of the existing Lungotevere in Sassia underpass.
With a total of 85.3 million Euro invested, the works - carried out by Anas (FS Italiane Group) as the implementing party on behalf of the government's Extraordinary Commissioner for the Jubilee, Roberto Gualtieri - began on the night of 21 August 2023.
The main objective of the extension of the Lungotevere in Sassia underpass was to give back to the Eternal City the pedestrian space that in the past ensured the passage from Castel Sant'Angelo to St. Peter's, with a uniquely beautiful square, inserted in full harmony with Marcello Piacentini's palaces dominating over Piazza Pia and Via della Conciliazione.
The works, of great engineering value, are the result of a continuous synergy between all the institutional stakeholders involved, through which it was possible to close the construction sites in an extraordinarily short time, given the complexity of the operations.
As of today, Romans, pilgrims and devotees will enjoy an "extraordinary route", welcoming visitors in a single embrace extending from the Castel Sant'Angelo area to St. Peter's, an extraordinary square uniting the capital of Italy with the Holy See.
Thanks to those works, the road network in Piazza Pia has been moved completely underground, by extending the existing underpass built as part of the Jubilee 2000 works.
The project is completed by the external works on the areas included in and facing Piazza Pia, by a careful paving design for the entire area, the proposal of a new public lighting system, the redevelopment of the urban green system, the construction of two large fountains placed in the centre of the new Piazza Pia, and the enhancement of accessibility systems for persons with reduced mobility.
By extending the existing road axis, the roadbed has maintained the same pre-existing geometric characteristics: a carriageway consisting of three lanes, two of which are three metres wide and one of which is 3.5 metres wide. There will be two service pedestrian crossings, with the left one being 50 cm wide and the right one 100 cm wide. Two fountains have been placed in the centre of the square to create two water mirrors reflecting the sky. There will be large green spaces with high-quality trees to enhance the project and mitigate the "heat island" effect.
The area affected by the new underpass is home to several "underground utilities", most notably the presence of two of the city's primary catchers: the Basso Farnesina and the Basso di Destra. Coming from the north, they pass under two arches of the "Passetto" - the masonry archway connecting the Vatican to Castel Sant'Angelo - and, crossing Piazza Pia, connect just before the entrance to the existing underpass to form a new, single collector.
The new underpass was constructed gradually to ensure the preservation of the sewage system throughout the construction. The initial stages involved a sewer by-pass excavated between bulkheads adjacent to the existing catcher, which, once put into operation, allowed the demolition of the original catcher and the completion of the underpass structures.
At the end of June 2024, the construction site experienced a crucial moment due to the discovery of extensive archaeological findings covering a large area right in the access ramp to the new underpass. Thanks to an emergency archaeological intervention and the work of the Superintendency, it was possible to secure everything and resume the excavations. The exhibits will be displayed in the gardens of Castel Sant'Angelo.
The excavation has yielded an important series of Campana reliefs, figurative terracotta used for roof decoration, with unusual mythological scenes, reused as sewer covers in the fullonica, but originally probably made to cover some structure in the garden, perhaps the portico itself.
With a synergy between all the stakeholders involved - which turned out to be fundamental - the diaphragm was torn down last July, followed by the connection of the new underpass to the existing one. Finally, the excavation works to bring the level of the underpass up to level were completed, and the bottom slab constructed.
Given the peculiar context - strongly urbanised and characterised by the presence of historical buildings of high archaeological value - it was decided to use the "cut and cover" or "top down" excavation technique, which allowed for simultaneous works on the surface and inside the underpass, thus speeding up the completion time, which was completed in only 450 days, thanks to 110 professionals working 24 hours a day, in three shifts.
EUR 85.3 million investment
7K square meter area
60 professionals for archaeological excavations
110 workers working three shifts around the clock for 450 days
450,000 paving stones laid
35,000 cubic metres excavated
600 foundation piles for a total development of 9000m