Construction minutiae
The bridge will be able to bear the highest prescribed load as per the Indian Road Congress specification. When asked to explain the uniqueness in its construction, sources said this bridge is made of a single girder, which is resting on eleven wells and two pile foundations on high bank – one on each of the banks of the Brahmaputra.
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When asked to explain the technique applied in constructing this single girder, sources said the girder was initially constructed as cantilever girders from each pier and then all ends of the girders were joined together to produce a continuous girder, sources said.
A common way to construct concrete cantilever spans is to counterbalance each cantilever arm with another cantilever arm projecting in the opposite direction, forming a balanced cantilever; when they are attached to a solid foundation, the counter balancing arms are called anchor arms. Thus, in a bridge built on two foundation piers, there are four cantilever arms, two of which span the obstacle, and two anchor arms which extend away from the obstacle. Because of the need for more strength at the balanced cantilever’s supports, the bridge superstructure often takes the form of towers above the foundation piers.
“The DPR suggested that there would be a reinforce earth in the main carriageway from grid separator to the approach which can be risky with the high seismic force. Therefore, shock transmission units have been fixed to block the seismic force. The design also suggested that the well should go up to -11 levels which is not safe and we decided to take it to -16 levels,” the source added.
The remaining work of reeling and crash bearer will be completed before 31st December including layering the bridge with bitumen. One of the most important features is that the Jalukbari Rotary will be signal free and will have interconnecting flyovers, one underpass and sleep road. The signal free crossing means that the vehicles coming from all the four directions will not collide with one another and can run in their own direction without having to halt. “A signal-free crossing has also been set up where there are three loops and ramps. The vehicles passing from each side can pass through the loop without hampering the traffic at any time,” the source added.
After the construction of this project, a major missing link in the state will be eliminated. Places like Baihata Chariali, Sipajhar, Mangaldai and a few others will become satellite townships of Guwahati, reducing the pressure on the city itself. Besides, a new green Guwahati can be created in the north bank housing an additional population of two lakhs with provisions of green industrial, commercial, educational and IT hubs that will make the city ready for the Act East Policy.
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