Conceived and designed by French syndicat of transport from Paris department (STIF), T Zen is the future high-level bus service network (BHNS), (le futur réseau de bus à haut niveau de service (BHNS) francilien), in the Île-de-France region. A new means of transport maximized every step of the way: dedicated traffic lane, easily identifiable and locatable stations, correspondence with other facilitated networks, high frequency and amplitude, spacious, luminous and comfortable vehicles, time information Real in station and on board of vehicles, etc.
Olivier Goyat, Olivier Goyat, Director of Works of Eurovia Concrete, who developed T Zen 1, stated that using concrete was a natural choice. Besides the fact there is no rutting with concrete, its strength and flexibility were also the main advantages, as well as the maximised skid resistance and the little maintenance needed.
Its first line, T Zen 1, was created in 2011. It connects the RER stations of Lieusaint-Moissy (77) and Corbeil-Essonnes (91). It also accompanies the development of the towns of Lieusaint, Saint-Pierre-du-Perray, Saint-Germain-les-Corbeilles and Corbeil-Essonnes. On a route of 14.7 km, 9.6 km are in own site, that is to say on a site dedicated and priority to the lights. To ensure a great regularity to the users, with a bus every 7 minutes.
“It was a pilot project. When it was launched in 2005, it was clear that BHNS should not be associated with conventional roads. The client was in a high demand, “says Maud Leforestier, Architect of Richez Associés, prime contractor for the project alongside Systra and Arcadis.
Resistance and flexibility: The choice of concrete was made naturally, explains Olivier Goyat developed the layout of the T Zen 1 line: “These tracks are very solicited, with zones of acceleration to the exit of the stations as well as tight turns. Under such conditions, the mix flows and creates ruts because the bitumen is visco-elastic. With concrete, no rutting.”
“And we also get a greater freedom of creation,” adds Maud Deforester. “We were able to design a pavement without leveling to be at the level of pedestrians, with a V profile in the center to collect rainwater.”
Plot without joints: With the exception of stations and roundabouts, the 9.6 km of site was constructed of continuous reinforced concrete (CRCP). The sections between the stations, continuously cast, thus dispense with seals. This promotes greater durability, ride comfort and low noise emission. Another advantage of concrete is its exceptional mechanical strength. An absolutely necessary asset to support the weight of BHNS, which can exceed 22 tons!
Maximized adhesion: The texture of the coating has also been the subject of special care in order to maximize the adhesion of the vehicles. By hydraulic pickling, the laitance around the aggregates was removed in order to obtain the necessary roughness. An exercise that requires extreme precision. Any excess of roughness accelerates the wear of the tires. The expensive equipment must be used as long as possible. This stripping also made it possible to energize the colors, says Maud Leforestier: “There are more brown shades that mix with the beige and produce a vibration along this ribbon that crosses a very wooded landscape.”
No maintenance during … 20 years! Finally, the concrete is distinguished by a very low maintenance cost, even non-existent. “These roads need only a regeneration of roughness, to improve the adhesion, once every twenty years,” says Olivier Goyat. A long-term investment capable of supporting the life of the T Zen line 1.
For the full article, in French, please go to: http://bybeton.fr/ruban-de-velours-bhns?lang=en.
