L&T Metro Rail Hyderabad (L&TMRH) has completed the Lakdikapul metro rail over-bridge (ROB) viaduct, thus closing the remaining gap of Corridor-I between Ameerpet and L.B. Nagar. The bridge would enable track laying, electrification and signalling works between Khairatabad and Lakdikapul metro stations for commissioning Metro train operations in the remaining 16-km stretch between Ameerpet and L.B. Nagar of Corridor-I.
Challenges faced
Hyderabad Metro Rail MD N.V.S. Reddy on Sunday inspected the site and praised the engineers for going about the task despite serious logistic issues like little space for putting the pillars — there was a busy road and an MMTS station on the two sides of the railway track.
Railways, too, put forth a condition that the foundation depth of metro rail pillars should be at least 10 feet below track level for future expansion of their own lines.
Hard granite rock had to be cut to a depth of 43 feet and deep pits had to be secured with special shoring and shuttering mechanism consisting of heavy steel beams, and extra protection for the road above.
Special type of integrated metro pillar and the viaduct was designed above as a single monolithic structure, unlike in case of all other bridge pillars which have bearings to take care of and transfer different kinds of forces.
Tackling all engineering challenges, the 392-foot Lakdikapul ROB was completed by using the specially fabricated ‘Bridge Builder’, like it was done in case of Begumpet Metro ROB, he said.
No traffic disruption
The 100-ton Bridge Builder, built and simulated first at the Uppal depot, and heavy duty cranes lifted the precast segments and placed them together without disrupting round-the-clock trains or road traffic.
About 13 segments weighing 45 tons each were incrementally launched as a cantilever hanging bridge from both sides with railways giving three hours beyond midnight once a week for each segment launch. Once the segment was placed in position, it was glued and attached to the already completed portion of viaduct with HTS cables (steel wires) and pre-stressed.
The bridge consisted of the main portion (span) over the railway lines being 171 feet and both ends being 118 feet and 103 feet, respectively. The MD congratulated L&T railway bridge team led by ROB experts K.M. Rao and Y. Kondalu, both ex-railway bridge engineers, for successfully “completing a challenging ROB with high precision and safety”.
