Mumbai is developing an ambitious construction project to extend the metro network in order to improve the mobility of a city with more than 18 million people. Pedelta, in a joint venture with the local company CES and Ardanuy, carried out the preliminary design for a new elevated viaduct for the corridor Gatkopar-Mulund in the northeast of the city.
The viaduct is more than 12 km long and is part of one of the main corridors. The project includes 13 metro stations. The main viaduct is formed by a succession of stretches between stations with spans of 25 or 30 m (simply supported). The deck consists of two independent identical U channel prestressted concrete girders, one for each track, spaced at 2 cm between central webs. The girders have a depth of 2.15 m and are continuous to increase their stiffness and to reduce deflections and vibrations while keeping the same depth as the rest of the viaduct. The internal prestressing (PT) consists of about 14 cables of 19 strands, of 30 cm diameter.
From an aesthetic point of view, a U girder reduces the visual height of the structure. A careful design of the external surfaces was done, creating a multi-plane surface to reflect lines of the horizontal alignment and reinforce the shadows to make the girder appear thinner due to the edge line and varying shades of reflective light.
Due to the bridge being located in a very populated urban area, the use of precast PC elements is also important to minimize the impact during construction. At some points, the viaduct crosses important roads with an extradosed deck.
The preliminary design has been carried out meeting the Indian Codes and other technical requirements of the last version of Eurocode 1 (part 2, bridges) that includes modern criteria for the verification of Serviceability Limit States.