Doha Metro Phase 1 is Qatar’s mega infrastructure project of three metro lines with a total length of 164 km. The first phase involves the construction of red, green and gold lines and their major stations. It is a part of a US$36,000 million Doha Metro Rail Network Project, aiming to reduce the city’s road traffic congestion while facilitating the connection between Qatar and other Gulf countries.

The required completion period of this project is extremely short: with excavation starting in mid-2013 and operations expected by 2019. With the timeline of the project being constrained, high innovative solutions are required to complete the building of underground structures in a minimal amount of time.

Dextra’s FRP Active Anchors as temporary tie-backs in retaining walls

Composite materials have been used for over 20 years as temporary reinforcement in concrete structures. In Doha metro phase 1, both Dextra’s post-tensions carbon-FRP (CFRP) Active Anchors and glass-FRP (GFRP) Active Anchors have been used in retaining walls. When used as temporary tie-backs, CFRP material is offering the most advanced technical solution thanks to its superior properties in tensile, creep and durability, while the GFRP Anchors offers a cost-effective solution without technical compromise.

GFRP anchors can advantageously replace steel removable anchors to prevent encroachment of neighboring plots. This is why nowadays, GFRP anchors account for more than 90% of the FRP anchors installed in the region.

For the first phase of the Doha Metro Rail Network project, Dextra has been supplying 150 CFRP Active Anchors and 700 GFRP Active Anchors to date.

ASTEC Soft-Eye for a better penetration of TBMs

Dextra’s ASTEC Soft-Eyes is a unique technology using cut-able GFRP reinforcement as a replacement of conventional steel rebars. Since 1996, this solution has become a standard concept in the design of shafts and subway stations. More than 10 sets of Dextra’s ASTEC Soft-Eyes have been supplied and used in Doha Metro construction project as per May 2018.