Realization of Bucharest subway line 5, named "Magistrala 5" represents an important step for the progress of metropolitan transportation system. This work is part of a vast development program for the metropolitan transportation which provides completion of Line 4 and construction for the new lines 5, 6 and 7. In fact, line 5 represents the direct connection between west-zone (sector 6) and east-zone (sectors 2 and 3) of the city. The segment in question covers the execution of first 9 stations starting from the head line/ west part of the city (Raul Doamnei) reaching the semi-central zone, in the neighbourhood of Cotroceni district and, especially, The Opera House. The work, gained in public bidding in April 2011 by JV Astaldi (JV leader) - FCC Construcction - Delta ACM 93 - AB Construct, includes realisation of nine stations for a complete lenght of 1372 m, two line tunnels, each one 6223 m long and a sum of works of art among which ventilation shafts, power stations and substations.
This project provides realisation of 9 new stations along the subway line route, characterized by a single structural typology; this one composed by a primary r.c. side diaphragms system, esential functional elements to carry out excavations and provisional support for the plates, and a final lining consisting of a r.c. walls line in addition to the internal structure. The constructive typology of the stations and the geological and hydrological conditions for the affected areas allowd division for the 9 stations in 2 groups, each one having some problems analyzed and resolved. First part contains stations between Raul Doamnei and Orizont. These works are realised in favorable geologic/geotehnical conditions compared to Academia Militara and Eroilor 2 stations in terms of, generally, homogeneous and less permeable lands where, also, water field level is lower compared to street level. These stations present a medium level difference between the excavation bottom compared to the baseline of about 14 meters and lenghts from 180 to 350 metri. Between these first seven, the deepest station is Parc Drumul Taberei having an excavation bottom that reaches approximately 16 meters while the longest one is Raul Doamnei reaching about 350 metri. The architectonic structure follows generally the same scheme realised for the old subway stations. Stations are generally realised by two functional levels: on the upper level there are public spaces and technical spaces; lower level represents the platform plan for trains acces. All the stations are designed with different acces points from the street, at least four in the majority of cases. Stations are all accessible from both sides of the main street nearby, a square dedicated to the station being provided in the case of Parc Drumul Taberei. Academia Militara and Eroilor 2 are the last two stations of the lot in execution; placed close to Dambovita River, in Cotroceni district area. These two stations are part of the second group, considering that differ a lot compared to the others seven in terms of geometry and construction techniques. In this zone, land quality differs entirely from the other zone: there are, in fact, inhomogeneous fields with increased permeability, beside a superior level for the aquifer compared to the previous. These geomorphological characteristics, beside the geometric requirements for the track, complicate the realisation of these stations requesting to bring down the quota of construction and a special attention for aquifer s control along the execution stages. Academia Militara station, unlike others, is characterized by a medium depth of 22 meters, is equiped with an additional level comparing to the others and a reduced area/surface: lenght of aprox. 180 meters for a functional area of 9750 square meters. Eroilor 2 station presents a 23 meters medium depth for a length of 220 m. For this station, the architectonic scheme differs from the one used for other stations, considering that Eroilor represents a connection node with "Magistrala 1".
The Ventilation shafts
Ventilation shafts and water pumping stations are located along the line in interstations Brancusi - Romancierilor, Romancierilor - Parc Drumul Taberei, Drumul Taberei 34 - Favorit, Favorit - Orizont, Orizont - Academia Militara and Academia Militara - Eroilor 2. From structural point of view these works are composed generally by a surface r.c. ventilation room situated at approximately 6 meters depth, and a deeper shaft intercepting track lines by connection segments. Power substations are generally part of stations structures and are placed, in their majority in special dedicated spaces. Power transformers stations for traffic management were designed as independent structures, nearby Parc Drumul Taberei and Academia Militara stations.
The subway tunnel covers the entire segment Raul Doamnei - Opera, for a complete lenght of 6,2 Km; track lines are separated and each of the two tunnels has a functional diameter of 5,7 m. The depth for the railway path varies by zone: Raul Doamnei - Orizont segment is characterised by an itinerary presenting about 14 meters medium quota difference from the superior face of the tunnel to the street level; once passing from Orizont to Academia Militara, the tunnel goes down a lot, to reach the deepest point, undercrossing Dambovita river, that meaning a quotta diference over 21 meters. The tunnel is realised by mechanical excavation with EPB ecquipments. Starting station is Academia Militara, based on the space available for construction and terms of execution. From structural point of view, the tunnel is realised by mounting r.c. prefabricated segments, 30 cm in width. Connection between segments is ensured by joints equiped with sealing and blocking systems.
General Data Line 5 Drumul Taberei - Pantelimon. Section Raul Doamnei - Eroilor
- Overall Length = 6223 m
- No. stations = 9
-Total stations Length = 1372 m
- Double tunnel length = 823 m
- Simple tunnels length = 8056 m