Fori Imperiali Station
Fori Imperiali Station is located between the Clivio di Venere, where the “Basilica di Massenzio” and the “Tempio di Venere e Roma” are located, and the “Clivio di Acilio”.
During the design of the station, the historical, archaeological and monumental restrictions inherent in the area of intervention had to be considered. The structural and plant engineering constraints, and the regulations in force on general safety and fire prevention, also had to be kept to in compliance with the UNI standards for the design of spaces and communication elements inside underground stations.
The station is designed as a rectangular box built between bulkheads of a thickness of 1.20 meters, which will accommodate the stairwell, and from where four platforms will branch out-the first two, also built between bulkheads, along the first rail while on the other track the platforms will align the second rail in a traditionally built tunnel. The stairwell will occupy the central area of the structure. The station will be spread over five floors: an atrium floor, two floors that are given over to technical rooms, the platform floor and a floor under the platforms.
The excavation will take place with the top-down method, a method which involves the construction of the various floors during individual stages of in-depth analysis, thus limiting the use of temporary buttressing. During the construction of the perimeter walls and the roof cover, which occupies an area of about 6.500 square meters between the two Clivi and the Flavio-Colosseo amphitheatre, it was necessary to remove part of the Muro del Muñoz, which will be relocated once the works have been completed.
The working plan for the station walls was reached after the installation of a series of temporary instruments: micropiles with tie-rods on the Clivio di Acilio side and continual boring piles on the Clivio di Venere Felice side.
The choice of micropiles was dictated by the reduced space available and by the need to adopt site machinery as light as possible due to the proximity of large existing masonry walls. Instead, on the Venere Felice side, the possibility of creating a construction site on part of the pavement enabled us to use the boring piles. (Trelicon)
The future Fori Imperiali Station of Line C will connect to the existing “Stazione Colosseo” of Line B, by crossing a walkway which will leave from the atrium of the Line C station and which will divide into two parts: the first higher part will pass over the current tunnel of the line B platform and will lead to the platform on the Colosseum side, while the lower second one will finish directly on the platform of Line B on the side facing Piazza Venezia.
The various construction phases make it a unique and complex work not only due to the difficulties inherent in the building of it, as for example, the geometry of the route of the line tunnels or the connection of the concourse of the Line C station to that of the existing Line B Colosseo, but also because of its location; the Via dei Fori Imperiali, the centre and culture of both ancient and modern Rome. This road is often used in cultural, religious and social demonstrations which must fit around the leaving open of the accesses for example to the villa of Rivaldi and to the Clivio di Venere, as well as having to allow the flow of public transport on the Via dei Fori Imperiali to continue. These alone are only some of the reasons which have made it necessary to develop the building activity in five different construction site phases, shifting and moving both pedestrian routes and vehicular traffic from time to time until the final configuration for the excavation of the station is reached.
Every single phase has seen the completion of new protected pedestrian walkways and safety measures necessary to maintain pedestrian and vehicular accessibility, all in accordance with the Enti necessities for authorized permission.
The activities regarding the new site set-up for the start of phase 4 were completed recently (may 2018), which have involved the moving of the road and the pavement on the Clivio di Venere side, to allow the completion of the roof covering of what will be the future Stazione Fori Imperiali of Line C. Once the roof covering has been completed, a new traffic change will be carried out (phase 5) which will allow the excavations to proceed under cover and then too, the construction of the various floors of the station.
The construction of an underground line station, in a city like Rome, is also an occasion to unearth historical/archaeological findings. The preparatory works for the building of the roof covering of the Stazione dei Fori Imperiale, have provided the opportunity to document, with extensive new excavations, the archaeological stratigraphy saved by the excavations of the Velia hill. This has allowed a reassessment of previous data to reconstruct an overall picture of archaeological evidence of this very significant sector of the central area.
Being placed at the centre of an area rich in historical and monumental buildings, during the design phase we decided to take into consideration a series of preparatory interventions for the protection of these historical/monumental assets. Among the preparatory works for the construction of the station and the passage of the tunnel line, we will now mention the interventions to date completed on the Basilica di Massenzio and on the “Tempio di Venere e Roma”.
The “Basilica di Massenzio” in the present day is profoundly changed compared to the original construction. The current consistency of the monument is the result of many centuries of vicissitudes. Since the beginning of the 19th century, work has been undertaken on the monument to stop its deterioration, such as the consolidation of its most decaying parts.
On the basis of the considerations set out above, together with the analyses drawn up by the Scientific Technical Committee established by the Metro C spca, which included experts in the European field of underground works in urban environments, some permanent structural interventions were carried out as well as some temporary ones in order to protect the heritage. This was achieved through the use of tube-joint scaffolding and metallic buttresses.
For both the “Basilica di Massenzio” and the “Tempio di Venere e Roma” we went ahead with the construction of a protection system. The installed structure consists of a continuous scaffolding built around the columns; on the longtitudinal axis the scaffold itself stabilizes the vibrations from the excavation of the station while on the transverse axis bidirectional struts are placed, capable of safely absorbing any vibrations.
Engineer Marco Cervone: Construction Manager Section T3