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.

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.

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.

London Crossrail (given the name Elizabeth line in 2016) is the largest engineering project in Europe. It is a major part of Transport for London’s investment programme and the largest addition to the transport system for 50 years.

The project consists in a 118-km east-west rail link across Greater London which will run from Reading and Heathrow in the west to Shenfield and Abbey Wood in the east.

Since 2009, Dextra has delivered more than 600,000 Griptec connections on more than 20 packages including stations such as :

• Liverpool Street
• Paddington
• Bond Street
• Canary Wharf
• Royal Oak portal
• Pudding Mill Lane

Griptec couplers have been used on D-Wall (vertical and horizontal connections), columns and piles (vertical connections).

Segments of Crossrail are expected to start operating progressively, with full completion scheduled for December 2019.

The Rio de Janeiro Line 4 is a subway line. It is part elevated and part underground (2 segments). The line has been planned to open for the 2016 Rio de Janeiro Summer Olympics.

Dextra has been involved since between 2013 and 2015 in the design, engineering and supply of four large FRP Soft Eyes for the station entry/exit points. Those Soft-Eyes were the first ever delivered in the South American continent.

Prior to D-Wall construction, Dextra engineers the FRP cage design taking into account size of the TBM, margin for error, soil forces and more design parameters.

Thanks to the properties of FRP material, Tunnel Boring Machines cut through the D-Wall in a minimum time, saving time on schedule and ensuring the perfect condition of the TBM’s head. The time factor is especially important in humid environments such as Rio to limit the water entry into the station excavations.

On this project, Dextra also supplied Rolltec Rebar Couplers, used as vertical connections in the station diaphragm walls as vertical connectors to reconnect cages.

Couplers were also used horizontally to provide a reconnection point for slabs (at station level and at the surface) in the D-Walls.

Nagpur, the second capital of Maharashtra and one of the fastest developing city in India is witnessing major growth in terms of Infrastructure. The development encompasses primarily the connectivity, of which Metro rail becomes a major part.

Incepted in 2016, the metro project is being a subject of acclaimed discussion for its speed of execution and the quality of construction.

Within the city boundaries, it requires the highest standards of safety considerations including the seismic analysis of structure in service life.

Project Requirement

The fast track project has typical structure for its Line 1 alignment, where the viaducts are supporting 2 levels of pathways, lower one for NH-7 and upper one for the metro rail. As the impact loading is a big concern due to train movement.
Being the stretch of always busy traffic, a solution was required which does not have to revise the existing design. Plus a major concern was the impact on speed of the otherwise fast moving project. The issue was concerning to all the stakeholders especially the GC for the project, who were looking to maintain the agility as well as find a sustainable solution.

Solution

Dextra Introduced Shear Key Bars for the priority section allowing the structure to neutralize the seismic forces. This not only helped the contractor to get the work done faster, but also enabled the client to go for the trial run earlier than expected.