The Delhi Metro is the largest and busiest rapid transit system in India, serving Delhi and its satellite cities of Ghaziabad, Faridabad, Gurgaon, Noida, Bahadurgarh and Ballabhgarh. It operates over 2,700 trips daily.

The system currently consists of 10 color-coded lines passing 253 stations with a total length of 348 km, including a mix of underground, at-grade, and elevated stations.

The development of the network was divided into phases. Phase 1 and Phase 2 were completed by 2006 and 2011, respectively. Phase 3 has 35 underground stations and 3 new lines, totaling 167 km, and is scheduled to be mostly completed by the end of 2020.

The total length of the underground corridors in Phase 3 is 54 km, more than 20 km longer than the total underground sections in Phases 1 and 2 combined, making it one of the most challenging construction phases.

More than 20 tunnel boring machines were used simultaneously to expedite the tunnel work through 10 Dextra soft-eyes installed in diaphragm walls. Thanks to the cuttable nature of GFRP (glass fiber reinforced polymer) bars, TBMs can get in or out of shafts/stations in few minutes.

Furthermore, 450 sets of active anchors were applied to retain walls during the excavation work. The anchors are also made of GFRP, hence the tendons can be excavated by any standard equipment, and no anchor removal is required.

Moreover, around 2.3 million Bartec couplers were installed to connect rebars in various parts of the concrete structures of the stations. Bartec is a bar-break performance system, designed to withstand an ultimate tensile performance of up to 800 MPa.

2,800 sets of Shear Key post-tensioning systems were also inserted into the concrete reservation as a permanent seismic restrainer for the connection of the elevated metro segments.

The Perth City Link is an transport and urban development project taking plate in Perth, Western Australia. It aims to reclaims more than 13.5 hectares of land previously used by connecting railways by sinking a train lane, hence making land available at the surface to reconnect two parts of the city with streets, commercial and residential buildings.

For this project, Dextra has been involved between 2012 and 2014 in the early foundation works:

• Supply of Dextra Rolltec mechanical rebar splicing solution, used for the vertical connection of rebar in D-Walls and Micropiles. Rebar couplers were used to reconnect cages which had been previously prefabricated by our rebar partner fabricator in Perth.
• Dextra also supplied its Sonitec sonic tubes used the Cross Sonic Logging (CSL) integrity testing of the foundations piles.

For more information about foundations solutions available in Australia, please consult our Bangkok office

Riyadh Metro is a massive urban transit system project under construction in Riyadh, Saudi Arabia. The project will feature 85 stations, built along 6 transit lines, for a total rail length of 176km. It is expected that the system will serve at least 1 million passengers daily at its inauguration in 2018.

For this large infrastructure project, Dextra has been involved on various stations and packages.

Excavation works

Before proceeding with general construction works, during early excavation phase, it is required to anchor retaining walls back into the stable ground in order to prevent any wall displacement. This will allow to keep excavating in a safe environment.

For that purpose, Dextra supplied steel ground anchors installed at the station perimeter. Each system is based on a high-tensile fully threaded bar, coming with nut and plate, and grouted to provide bonding with the soil.

For more information, please refer to Steel Ground Anchors page.

Raft & Vertical connections

Bartec rebar couplers were supplied for the works in the stations. Couplers were used for slabs, column and wall connections. A typicall application on this project is to cast rebar couplers in the concrete with reinforcement, and then proceed with second phase bar connection at a later stage.

Unitec bolted couplers can have also been use on various parts of the project. Typically Unitec is used when overlap is planned but lapping length appear to be too short to perform a safe splice. In that case Unitec provides a convenient and full performance connection.

Pune Metro is an under-construction mass rapid transit system that comprises of 3 lines with a total length of 55 km. The Metro is in Pune Metropolitan Region in Pune City, India.

Swargate Station is part of the 17-km Line 1 running from PCMC Building to Swargate. Lines 1 and 2 are expected to be operational in 2021 while the elevated Line 3 will be completed one year later.

For this project, Dextra supplied more than 1,700 steel active anchors for stabilization of vertical retaining walls around the excavation area.

Dextra’s Geotec Steel Active Anchor is the preferred solution for excavation works where post-tensioning is required.

The anchors are corrosion protected and based on high-tensile fully-threaded bars that help prevent deformation of the retained structure.

After the construction of Pune Metro UG04 is completed, the underground station at Swargate will be a strategic part of a multimodal transit hub connecting to the city bus services and parking facilities for private vehicles.

The Thomson-East Coast Line is a future Singapore MRT system line that will connect the Thomson Line and the Eastern Region Line. The 43-km link will add 31 new stations to the existing rail network, with 7 interchange stations.

For that project, Dextra supplied numerous packages, including for example the Marine Terrace Station, where 4 large diameter soft eyes have been installed in the diaphragm wall cages in August 2017.

Soft-Eyes are made of GFRP rebar, which is used to substitute the steel reinforcement in the D-Walls of construction shafts. When the Tunnel Boring Machine (TBM) breaks through the D-Walls, it easily cuts the GFRP bars, saving time on project schedule and money on equipment usage.

Dextra has been the pioneer of this application since its first use in the Bangkok metro project in 1998 and has extensive experience for in-house design and manufacturing of Soft-Eyes.

The D-Walls installed on Terrace Station also feature Bartec® rebar couplers, a common application for most station packages in order to reconnect slabs horizontally in underground stations. Bartec couplers are also used more generally for vertical connections in foundation piles and slabs.

Dhaka Metro Rail is a mass rapid transit system under construction in Dhaka, the capital and the busiest city of Bangladesh.

MRT Line 6 consists of 16 elevated stations that are each 180 meters long and 20.1 kilometers of electricity-powered light rail tracks. Except for the depot and some of the LRT (Light Rapid Transit) that would run beside it, Line 6 will be elevated over current roadways, largely above road medians, to let traffic to flow beneath it, with stations likewise elevated.

Dextra supplied various solutions to the project.

Construction of Line 6 is anticipated to be completed in 2022.

Ho Chi Minh City Metro is Vietnam’s first rapid transport system, serving the country’s business and financial capital.

There will be eight lines in the metro system. The first, second, and fifth lines are in the implementation stage, while the remaining lines are in the investment planning stage.

The project’s Line 1 is 19.7 kilometers long, with a 2.5-kilometer underground segment and a 17.2-kilometer elevated section. Line 1 will run from Ben Thanh Market in the central area to Suoi Tien amusement park in District 9. There are three underground stations throughout the underground section. Line 1 also includes a Saigon River crossing.

The Line 1 Package 1b comprises of construction of the underground section from Opera House station to Ba Son station, including two underground stations and a 1,315-meter subway tunnel.

Shimizu-Maeda Joint Operation selected Dextra’s concrete reinforcement solutions to minimize steel congestion in heavily reinforced areas. 230,000 headed bars were delivered and installed for shear link reinforcement.

Río Subterráneo a Lomas tunnel is a 13.5-kilometer-long tunnel in Buenos Aires, Argentina, which will transport drinking water from the newly expanded General Belgrano Water Treatment Plant in Bernal’s Quilmes area to the city of Lomas de Zamora.

Being the main element of the Agua Sur system, a water supply project in Argentina, the tunnel is the country’s largest water infrastructure project in the last 40 years. This new system will provide 2.5 million inhabitants in the Buenos Aires metropolitan area’s southern region access to freshwater.

For this significant project, Dextra supplied soft eyes reinforced with GFRP (Glass Fiber Reinforced Polymer) bars to facilitate the penetration of Tunnel Boring Machines (TBM) through a reinforcement cage.

The project required two boring machines to be launched and received from shafts. The tunnel was excavated at an average depth of 25 meters, starting with a curve with a radius of about 400 meters, and moving along a largely straight alignment, with a maximum slope of +/- 2 percent.

The first launch shaft is composed by 4 circular sectors that interconnected with each other in the bottom area. The total length of the shaft is around 45 meters long, 12 meters wide, and 25 meters high.

The whole project is anticipated to take approximately 10 years to complete.

The Dubai Metro is a urban transit rail system operating in Dubai, United Arab Emirates. Two lines are currently operational, the Red Line and Green Line. Additional lines are also planned for coming years.

For the construction of the Red Line, Dextra has been involved between 2005 and 2010 together with the contractors making J T Metro (Obayashi Corporation – Kajima – YapiMerkezi) for the supply of numerous Dextra solutions for various packages and stations.

For the station construction, especially for the foundation works (piles and perimeter d-walls), Dextra supplied its Bartec rebar splicing solutions. Rebar couplers were used for vertical connections in piles D-Walls, columns and piers. Rebar couplers were also used for reconnecting slabs onto the D-Walls. A total of 800,000 Bartec rebar couplers have been supplied for this project, supported by several Bartec equipment sets maintained by local Dextra Aftersales team.

For minor repair applications, RepairGrip couplers were also supplied to splice rebar which had not be prepared with a thread and which had unsufficient produding length to be spliced.

For foundation works as well. Dextra supplied more than 60km of Sonitec sonic tubes, used the CSL integrity testing of piles and walls. Sonitec can be easily assembled at site thanks to their push-fit mouth system, boosting teams productivity and avoiding the tedious task of welding tubes together.

Finally, to accelerate tunneling breakthrough phases and minimize TBMs (tunnel boring machines) time when exiting/entering shafts and stations, Dextra engineered the design of GFRP Soft Eyes and supplied more than 400 km of composite rebar for numerous station packages.

Coimbra B-Portagem Mondego Metro project is part of the mass transit public transport system of Coimbra, Portugal. Dextra has played a significant role by providing Sonitec tubes for pile testing.

Dextra has supplied Sonitec tubes for testing a total of 67 piles ranging from 12 to 19 meters in depth. The tubes have been instrumental in conducting these tests with the Cross-Hole Sonic Logging (CSL) methodology.

The innovative push-fit connection system of Sonitec has greatly reduced labor time during installation. Thanks to this user-friendly system, the contractor has experienced smoother and more efficient pile testing processes. By eliminating the need for additional labor-intensive procedures, the contractor has saved valuable time and resources. It also ensures a secure and reliable connection between piles.