The Circle Line (CCL) is an underground Mass Rapid Transit line in Singapore. The 35-km, 30-station line runs from Dhoby Ghaut and Marina Bay in the Central Area to HarbourFront in the south.

It is one of the world's longest driverless rapid transit lines.

In 2013 the Circle Line stage 6 was announced, a 4-km extension to finally close the circle of the CCL by connecting HarbourFront station to Marina Bay station.

Three additional stations are under construction and expected to be operational in 2025.

Well-known expertise and quality in concrete reinforcement solutions were necessary to tackle this project, and Dextra’s Bartec couplers were chosen for several parts of the Circle Line structure, including starter bars, slabs, and column joints.

By the end of the project, approximately 200,000 couplers will be delivered on site.

Moreover, Dextra provided 3,000m of Glass Fiber Reinforced Polymer (GFRP) rebars, that can boast some key benefits with respect to metal rebars: a lighter weight, no risk of corrosion, and a lower susceptibility to attract lightning strikes.

On top of that, Dextra was entrusted with the reinforcement of the concrete structure of the tunnels: 8 Astec Soft-Eyes were used to facilitate the penetration of the Tunnel Boring Machines (TBM) through diaphragm walls, thanks to their innovative cuttable GFRP structure.