Once supervising engineers of HMR and concessionaire L&T Metro Rail Hyderabad (L&TMRH) gain expertise from these two spans, work on taking up five to eight road junctions crossovers across the three metro corridors in one go will be attempted, said HMR Managing Director N.V.S. Reddy on Sunday.
Of the 80 junctions where the elevated track atop the viaduct will be constructed across, 28 junctions require longer obligatory spans involving on the spot construction or ‘in-situ’ construction.
“It is like building 80 flyovers over busy traffic junctions without disrupting traffic movement in the already saturated junctions”, explained Mr. Reddy.
As bridging the major junctions with ‘in-situ’ construction method will take four to five months for each junction, several junctions will be attempted simultaneously to save time, he averred.
Mr. Reddy pointed out that the traffic study conducted by LEA Associates, engaged by HMR for traffic management solutions for the intersections, has made the task even more challenging as the study has projected bigger obligatory spans for many of the junctions for the sake of future traffic flows.
After several rounds of technical discussions by the metro rail engineers and consultants, it was decided to bridge the junctions’ upto a span length of 34 mtrs (112 feet) with segmental construction by the same launching girders, which are building the viaduct.
In this on the spot bridge construction method, temporary supports will be provided for the elevated concreting deck and after tying the steel reinforcement, concreting will be done in three stages. After curing the viaduct for 14 days, it will be safely secured by pre-stressing the inserted high strength steel strands and thereafter, the temporary supports will be removed.
A 50 feet gap will be left between the temporary supports to allow the traffic to flow, effectively three lanes on each side, the MD added.
There are around 28 junctions with longer obligatory spans involving on the spot construction method.