Single piers (pillars) will be predominant along the entire 72-km stretch on which the elevated Metro will be constructed across three of most dense traffic corridors of the city.
Work has also begun on the old Gandhi Hospital land, which was taken over by the Metro rail authorities a few days ago. Rail crossing work at Bharatnagar is likely to start in July, while work is progressing on six other stretches. They are Jubilee Hills check post, Road No.5, Begumpet-Rasoolpura (2 km), L.B. Nagar-Moosarambagh (7 km), Miyapur-S.R. Nagar (11 km) and Nagole-Mettuguda (8 km).
“Constructing piers when the Metro line is passing right beside a flyover is another engineering challenge due to the complexities involved in getting the foundation work right,” says Hyderabad Metro Rail (HMR) Managing Director N.V.S. Reddy. One half of the flyover will be closed during the foundation work for piers as a precautionary measure.
They hold the viaduct, which serves as a platform for rails to be laid, and this is formed by stringing and sticking the segments together.
Owing to curvy paths, the viaduct has to take to cross over obstacles in the form of flyovers and on ground railway lines, two other kinds of piers – cantilever and portal or inverted ‘U’ shape are also going to be laid at various locations depending on the topography.
If single piers form 80 per cent, these two constitute the other 20 per cent with a few other peculiar shaped piers too proposed at select sites like the hammer head pier. What citizens are witnessing currently on the six stretches where work on piers is on is the construction of single piers. Other shapes are likely to surface in the coming days.
Considering that the precise mapping of utilities pipelines like telecom, power and water is not available with the departments concerned, the Metro rail engineers will have to plan for the piers foundation stage only after carefully digging around.
“We have to either take the power lines underground or overground depending on the Metro line alignment. Where we can’t shift the cables or pipelines, we are going for an open foundation or ‘pile’ foundation where concrete is poured around,” says Reddy.
Sheer hard rock all through the alignment also makes digging tough, especially with a ban on using explosives. Digging machines, too, have turned ineffective thanks to the hardness of rock, so the concessionaire, L&T Metro Rail, Hyderabad, is forced to do manual chiselling.
