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.

The Doha Metro is a rapid transportation system, designed as an integral component to the larger Qatar rail network. This country wide mega-scale infrastructural project consists of 300km of rail and 100 stations. The rail network to reduce traffic congestion, and to connect the people of Qatar with the rest of the GCC region. At the city scale, currently under construction, the metro is projected to be operational by the end of 2019. It will serve Doha and its surrounding suburbs with stations located in all major nodes of the metropolis. Doha Metro will be operating both at grade and below grade, with the majority of the metro project being underground. Complex tunneling and soil retaining solutions by Dextra were utilized in the construction of this project.

Glass Fiber Reinforced Polymers (GFRP) as Tie-back anchors to retain soil

To eliminate concerns of encroachment, and obstacle for future construction projects, the Diaphragm Wall (D-Wall) at Al Sadd C-Ring Station were post-tensioned anchored with ASTEC Active Active Anchor. These high performance, fully cut-able GFRP anchors were chosen by ALSYJ JV contractors and the D-Wall anchors of choice. This innovative solution was chosen because it can be cut by Tunnel Boring Machines (TBM) or standard excavation equipment, it also doesn’t need to be removed from the ground even in temporary applications. For Al Sadd C-Ring Station 7,113 strands for GFRP rebars were used to make approximately 700 ground retaining anchors used in the D-WALL around that station.

The Second Ho Chi Minh City Environmental Sanitation Project consists of the construction of interceptor that will convey the wastewater collected from the Nhiêu Lộc-Thị Nghè Canal and District 2 areas of Ho Chi Minh City to the treatment plant.

Dextra has been involved in the construction of the large underground system by supplying 40 Soft-Eyes to assist in the tunnel breakthroughs.

The cuttable Glass Fiber Reinforced Polymer (GFRP) Soft-Eyes were applied to reinforce 21 shafts, allowing the penetration by the Tunnel Boring Machine (TBM) without the need of removing steel reinforcement and without the risk to damage the TBM’s head.

With its completion, planned to be in 2022, the wastewater services in HCMC will have a considerably more sustainable nature, and will be remembered as the first big step toward the alleviation of the environmental and sanitation issues of the Country.

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.

To reduce traffic congestion on Mexico – Toluca highway, as well as to ease connections between both cities, the Secreatariat of Commuciations and Transportaion (SCT) is undergoing the construction of the new Mexico city areas’ 55.7-kilometer rail line. Aiming to be an environment-friendly project, the commuter rail line includes 4.7-kilometer double-tube tunnel in highly complex terrain and natural protected areas.

The new train will connect Toluca Valley to Mexico City, and will provide a service to an estimated 270,000 commuters. The line included 6 stations: 2 terminals (Zinacantepec and Observatorio) and 4 intermediate (Cristobal Colon, Metepec, Lerma, and Santa Fe). It will also be a backbone for Mexico City area’s regional and urban transport.

The construction being initiated in 2015, the railway is scheduled for completion in 2019.

Light and productive rebar coupler solution for the construction project

For the reinforcement of the railways concrete structures, Dextra supplied more than 100,000 Rolltec splices. The system is a practical and economic alternative to laps. Rolltec is also supported by one rebar preparation equipment, and only one man is needed to operate the machine.

Plus, thanks to the performance of our machines, the thread is ready in less than 30 seconds!
Moreover, with Rolltec system, the same type of coupler can be used for both standard and position applications, resulting in an optimized inventory of the project.

For more information about our projects in Latin America, contact our Panama Office.

Since the first 29km segment of the Metro Line 1 opened in 1987, the Cairo Metro project has revolutionized the transit system in the capital.
Currently the whole network comprises 3 operational lines numbered from 1 to 3. Line 3 consists of four phases, and the first segment started operation in 2012.

Three new metro stations were opened as part of the fourth phase of the third line on June 15, 2019, a week before the kickoff of the 2019 African Cup of Nations (AFCON) in Cairo.

Dextra has continuously provided construction solutions since the operation of Line 2 in 2000, delivering since then more than:

-1,400,000 rebar couplers

-7,000 sonic tubes

-60 soft-eyes

Bartec rebar couplers are used for rebar reinforcement of tunnel and station structures on both underground and elevated metro lines as a way to reduce steel congestion and improve tensile connection.

Moreover, the integrity test of the metro foundations using the Cross Sonic Logging (CSL) testing method was facilitated by the usage of SONITEC sonic tubes, designed for easy assembly and installation in reinforcement cages.

Dextra’s ASTEC soft-eyes are made of GFRP rebar to reinforce D-Walls in underground tunnels, which can easily be cut by Tunnel Boring Machine (TBM), resulting in time and money savings.

The project is still ongoing and the fourth line of the Cairo Metro is expected to start operation in 2020.

Ho Chi Minh City Metro – Line 1 is the first part of the megacity’s 109-kilometer rail line project undertaken by the Management Authority for Urban Railways (MAUR).

When achieved, the mass-transit system will cover the HCMC areas with 6 metro lines, allowing inhabitants and tourists to commute easily and conveniently around the city, resulting in a better urban living quality.

The first phase of the project consists in construction of a 19.7-kilometer railway line, connecting Ben Thanh Market and Suoi Tien Park. It also includes the construction of 17.1 kilometer elevated railway with 11 stations, and 2.6 kilometer underground line with 3 stations.

For the construction of Vietnam’s biggest city, Dextra has been supplying both concrete reinforcement and bar system solutions.
To reduce steel congestion in heavily reinforced areas, the contractor Shimizu-Maeda Joint Operation opted for Dextra’s end anchors. Headed Bar is a simple alternative to rebar hooks.

The installation is done by only screwing the compact anchor plate onto the end of the reinforcement bar. The solution ultimately eases the process, resulting in a better concreting quality.

The Grand Paris Express is currently the largest transport project in development in Europe.

The new 200-km, 68-station automated railway network consists of a ring route around Paris (line 15) and three additional lines (16, 17 and 18) connecting adjacent neighborhoods.

These 4 new lines will circle the capital and link to 3 airports and many business districts. It will transport 2 million commuters a day. The lines are planned to open in stages, with the full completion of the project scheduled for 2030.

The construction of line 15 started in 2015, with its first section between Pont de Sèvres Métro station and Noisy – Champs RER A station.

Dextra was involved at that stage by providing 100,000 Fortec rebar couplers to connect the columns of the stations’ structure.

Additionally, Dextra supplied 15,000 meters of Sonitec sonic tubes to facilitate the structural integrity testing using the CSL (Cross Sonic Logging) method, thus ensuring the homogeneity of concrete within the deep piles and diaphragm walls that are being constructed for the future underground stations.

The first section of line 15 is scheduled to open in 2020.