On November 4th 2018 the Opening Ceremony of Signature Bridge in Delhi, India, took place.
The final design of bridge was supplied to the Contractor, a JV formed by Gammon India, Tensacciai and Construtora Cidade, by the Owner DTTDC Delhi Tourism And Transport Development Corporation, and was rifinally developed by a consortium formed by the firms SBP and Construma Consultancy. DMA, which participated to tender as consultant for JV, was in charge of checking the erection analysis, and for all construction engineering design.
DMA developed the Construction Engineering, that includes the Construction Method Concepts, the Detailed Construction Method Statement, the Design of Auxiliary Structures, Rigging Plans and related equipment, as well as the step by step analysis of the erection phases in order to control the bridge geometry and strength during construction.
The bridge has a main span of 251m with steel-concrete deck; the 36m wide deck structure, with three longitudinal beams and transverse girders, is being erected on temporary piers by means of a goliath crane.
The tower is 150m height from the deck level, has two main legs inclined in two directions and a top main body with variable cross section.
Its weight is around 7000t and the way of erecting this structure is a real challenge.
Stay cables, in parallel strands, are anchored on the side longitudinal girders and into the two forward boxes of the Main Body.
The erection method includes, sintetically, the following steps:
– fabrication of panels of the tower and of deck girders, pre-assembly them, and their transportation;
– erection of deck girders and precast slab panels by supporting them on temporary towers and by means of a goliath crane;
– assembling of the tower panels in segments;
– lifting them and installing on a special steel frames as later described;
– lifting segment by means of a crawler crane and placing it over the already erected structure;
– erecting a special structure able to support and brace the inclined legs during their construction;
– proceed up to the end of the erection of the tower;
– install the stay-cables and apply first tensioning;
– dismountle the temporary structures.
The main difficulties in building this bridge were essentially two: to build the composite deck, which width of 36m and length of 575m facig problems of alignments, temperature, temporary restrants, and earthquake effects, and to erect the steel pylon, inclined in two directions, weighting 7000t, which has to be installed up to an height of 160m.
Bridge construction is always a difficult and challenging task.
Large dimensions, inclined high structure, high weights to be lifted bring additional problems.
Anyway, a detailed and integrated study of the construction method, of the lifting plans, of the construction structure, and of the constant checking of the structural behavior, that is a proper Construction Engineering, made possible to overcome even large problems and allowed complex difficult constructions.