CHENNAI: One of Chennai’s most ambitious road infrastructure projects is coming up on Anna Salai, directly above an operational underground Metro tunnel. A 3.2-km elevated corridor is being built on Anna Salai, and authorities are racing to complete the project by the end of November.The state highways department says it has completed about 70% of the four-lane elevated corridor. The project, built with pre-fabricated steel components, is a step toward easing traffic flow between Teynampet and Saidapet, one of the busiest stretches of Anna Salai.What makes the project especially important is its location. The 3.2-km long corridor will be about 2.4 km at ground level, directly above the underground Metro tunnel.This includes a stretch of 460 meters over the Teynampet and Nandanam Metro stations. The Metro tunnel is going down about 14 to 15 meters below Anna Salai and that has forced engineers to resort to construction methods that will minimize the chances of disturbing the operational underground system.The elevated corridor has been built to carry traffic over the congested road intersections below. Once the facility is operational, the officials expect the project to reduce the travel time between Teynampet and Saidapet from around 30 minutes to around five minutes, but the actual saving will depend on the traffic conditions.The corridor is also expected to reduce congestion at seven major junctions including Eldams Road, SIET College Road, Cenotaph Road, Nandanam, CIT Nagar, CIT Nagar First Main Road toward T Nagar and Jones Road.The presence of the Metro tunnel below has meant that the project has had to use a different method of constructing foundations. Officials said the drilling for the flyover foundations only went seven meters from the road surface, giving a big buffer from the Metro tunnel below.By 1 August, 46 of the 69 planned piers had been erected and reinforced concrete deck slabs laid for some 2km of the 3.2km corridor. Work is ongoing to install a further 41 portal frames along the 460 meter section above the two Metro stations.There has also been a lot of prefabrication on the project. Some 15,000 tons of steel components including piers, pier caps and girders are being fabricated at factories in Gujarat and Telangana and will be brought to Chennai for assembly.The elevated walkway was slated for completion in September, but a shortage of workers delayed the project. Officials said workers engaged in fabrication of steel components had gone to their native places during the elections in April and did not come back immediately. At the Chennai site, construction is also restricted to about six hours at night, further limiting the window for work.Now the project is expected to be completed by the end of November. Motorists will have to contend with diversions due to construction and the Metro Phase-II works on Anna Salai till then.
