The stiffest challenge so far is the construction of guide bunds on the turbulent Brahmaputra river within the short time of four to five months a year because of the rainy season and flood, a top official of the Northeast Frontier Railway said.
"Construction of guide bunds has been the most challenging task of this project as it has to be completed up to the safe level ...... during the very short working period of four to five months," N F Railway General Manager, Construction R K Singh. Singh said that early flood in the river restricts the working season to a very short period of approximately five months, from November to March only.
"It demands huge mobilisation of equipment for execution of the massive work of the project," Singh explained. Another major challenge is transportation of concrete across river channels of 600m to 900m width from both the banks. However, it has been overcome by adopting pumping of concrete through pipeline laid over buoys with multiple concrete pumps, he says.
"The width of the river at the alignment location of the bridge was approximately 10.30 km. Approach embankments inside the dyke up to the abutments of the bridge were constructed before placing the guide bunds at the approaches of the bridge," the railway official said.
The 4.94 km bridge, stated to be the lifeline of the Northeast, will facilitate connectivity between north and south banks of the Brahmaputra in the eastern region of Assam and Arunachal Pradesh. Situated 17 km downstream of Dibrugarh city, the bridge is being constructed for double line broad gauge track and a three-lane road, Singh said. The national security of the country's eastern region would also be further strengthened after commissioning of the bridge, he added.