70% Done, Yet Chennai Flyover Needs Redesign; Opening Pushed To 2027 | Chennai-news News
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Chennai’s Rs 621-crore flyover is 70% complete, but an engineering problem has forced a redesign. The project deadline has now moved from September 2026 to February 2027
Officials are attempting to complete the revised section without increasing the project’s approved cost. (Representative Image)
CHENNAI NEWS: A Rs 621-crore flyover being built along Chennai’s busy Anna Salai has hit an unexpected engineering hurdle, forcing authorities to redesign part of the project even after construction had progressed significantly.
The 3.2-km Teynampet-Saidapet flyover is around 70% complete, with more than 80 pillars and girders and 50 spans already constructed or placed. According to a report in Money Control, the project was originally scheduled for completion in September 2026. Following the design change, the deadline has been pushed to February 2027. Officials have indicated that meeting the revised deadline may also prove challenging.
Metro Foundations Found To Be Misaligned
The problem emerged on the Nandanam-Teynampet stretch of the flyover. The original design envisaged using existing Metro foundations to support the flyover’s central pillars. However, during construction, engineers found that the Metro foundations in this section were not aligned in a straight line as expected.
Building the flyover pillars on the existing foundations would have forced the elevated road to deviate from its planned alignment and create an unwanted curve.
The discovery came after substantial construction had already been completed, making a redesign of the affected section necessary.
Existing Underground Metro Adds To Engineering Challenge
The flyover is being built over an operational underground Metro corridor, creating additional structural constraints. Of the 3.2-km flyover, around 2.4 km will run at ground level above the Metro tunnel, while another 460 metres will pass above the Teynampet and Nandanam Metro stations.
The Metro tunnel is located around 14-15 metres below Anna Salai. To protect the underground infrastructure, foundation drilling for the flyover has been restricted to around seven metres from the road surface.
This leaves a substantial buffer between the flyover foundations and the Metro tunnel, limiting the options available to engineers.
45 Portal Pillars Planned Under New Design
The state highways department has approved a change in scope for the affected section. Instead of conventional central pillars, the redesigned portion will use portal pillars. Under the revised plan, 45 pillars will be constructed around the Teynampet and Nandanam Metro stations.
Chennai Metro Rail Ltd will provide foundation support through the station walls. The redesign also takes into account the varying width of Anna Salai, which becomes narrower along some parts of the flyover’s route.
The road is around 28 metres wide near Cenotaph Road and 32 metres near Arivalayam, compared with approximately 36 metres at DMS and 40 metres at Saidapet.
Installing central pillars along the narrower sections could significantly obstruct traffic movement, making the revised portal-pillar design necessary.
Major Construction Already Completed
The project began in January 2024, with the design change being approved after construction had already progressed considerably. More than 80 pillars and girders and 50 spans have already been constructed or placed on the Saidapet-Nandanam side.
Authorities are now working to incorporate the revised structural arrangement while keeping the project within its approved Rs 621-crore cost.
Why The Anna Salai Flyover Is So Challenging
The Teynampet-Saidapet flyover presents an unusual engineering challenge because it is being constructed along one of Chennai’s busiest corridors while having to work around infrastructure both above and below the road. The project uses prefabricated steel structures that can be assembled with support from Metro station foundations. The approach is intended to speed up construction while reducing disruption to traffic below.
However, engineers have to account for several constraints simultaneously, including the underground Metro tunnel, existing foundations, utility lines, varying road widths and heavy traffic on Anna Salai.
The latest design issue highlights the difficulties of constructing new infrastructure in an already developed urban corridor, where actual ground conditions can differ from assumptions made during the planning stage.
Completion Target Pushed To February 2027
The flyover was initially expected to be completed by September 2026. Following the redesign, the target has now been shifted to February 2027. Officials are attempting to complete the revised section without increasing the project’s approved cost. However, the new deadline could prove difficult to meet as construction has to be reorganised around the revised structural design.
Until the work is completed, commuters using Anna Salai are likely to continue facing traffic diversions and construction-related disruption.
Quick Answers
Ask News18The Metro foundations were found to be misaligned on the Nandanam-Teynampet stretch, meaning they were not straight as expected. The original design intended to use these existing Metro foundations to support the flyover’s central pillars.
Ask News18August 19, 2026, 13:18 IST
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