Construction

Salient & Unique features of Phase II

1. PMIS

“Project Management Information System” to manage Schedule, Cost, Contracts, Design Deliverable, Quality, Physical Progress, Land Acquisition etc., for entire project life cycle.

• Cloud server for Data Management system for overall Control and transparency of project data.
• Track baseline budgets, actual costs, and manage forecasts either manually or automatically.
• Accessible to geographically diversified Project Team.
• Helps to prevent disputes and future litigations by capturing the data flows from various project phases.
• Real-time Dashboard Monitoring.
• Easy monitoring, visualization, and adjustment of plans based on financial forecasts.
• Enhanced Business Reporting: Better reporting tools with real-time information on Contract Management

2. Design

• Soil investigation @ every 25 m completed well in advance to avoid hinderances during execution, to enable optimized design & to avoid future disputes during construction.
• Completion of Detailed Design well before commencement of Civil works DDC engaged in 2018 because of this Station designs are optimized, Land Acquisition area reduced, Complete set of Good For Construction (GFC) Drawings issued to contractors on Award & Cost and Time over-run during execution is avoided.

3. Use of BIM technology during Design and Construction Phase

• Detailed drawings of all disciplines & stages are carried out by BIM (3D Virtual Design Construction Platform). BIM is included in the scope of DDCs as well as contractors.
• Clash detection/Interface checking with intra & inter discipline. Asset & Facility Management compatible

4. Civil works

Footprint of UG and Elevated stations reduced.

• Length reduced from 230m to 135m.
• Width reduced from 22/20m to 18/16m.
• System room sizes reduced/combined.
• Number of Entry/Exit structures reduced from 4 nos to 2 no’s.
• Ancillary Building eliminated.

Extensive use of pre-cast elements in Elevated section.

• Generally, in elevated viaduct construction, only U girders and I girders are precast members. In Phase II the following structural members: Pier cap (Approx: 2720 nos) U girders (Approx: 4340 nos ), I Girder( Approx :6570 nos) Cantilever Pier arms at Concourse, Cantilever pier arm at platform level and portal beams are precast elements with Portal columns.
• Less labours required when compared to conventional method i.e. Cast in situ.
• Precast members can be erected in daytime and night time without disturbing road traffic.
• Very cost-effective, Smooth operation, Highly safe method without disturbing road traffic during daytime facilitating 24 hrs of work.

5. Tunnel Boring Machine (TBM)

There is a total of 23 TBMs working in the Chennai city for building the extensive network of underground tunnels of Phase II which includes new TBMs imported and TBMs remanufactured in India. These TBMs shall be launched and retrieved multiple times till completion from the shafts at various locations. The tunneling work in Corridor 3 underground section of 26.7 km is being executed through two contracts with 15 TBMs and is being exclusively funded by the Government of Tamil Nadu. The Tunnelling work in Corridor 4 underground section of 10.1 km is being executed through two contracts with 4 TBMs and is being funded by ADB. The Tunnelling work in Corridor 5 underground section 5.8 km with 4 TBMs is being funded by JICA.

6. Phase-II – Elevated Section

CMRL will have a Double decker line & station standing in single pillar for a stretch of about 4 km. The double-decker stretch will have four stations developed at two levels, Alwarthirunagar, Valasaravakkam, Karambakkam and Alapakkam, and there will be common concourse (ticketing level) with two different platforms. To execute the same, a special Launching Girder is fabricated and ready for use.

Double Decker – 4 km (Alwarthirunagar, Valasaravakkam, Karambakkam and Alapakkam)

• Crossover at Karambakkam
• Street, Concourse, C4 level, C5 Level
• C4 platform rail level 13.9 m from ground level and C5 platform rail level 21.5m from ground level
• Station width – 195m x 17 m

Many Balanced Cantilever method spans are adopted as special spans to suit the site conditions. Out of all, the most challenging location is Kathipara Junction. 5-span continuous BCM (1 x 58m + 2 x 100m + 1 x 95m + 1 x 60m) with 125m radius curve. Corridor 5 crosses Corridor 1 (Elevated) and Corridor 2 (Elevated) at Kathipara. Corridor 5 viaduct height is 31 m from Ground level. Road Flyover at level One, Corridor 1 at level Two, Corridor 2 at level Three, Corridor 5 at level Four.

Kathipara Junction (BCM) – 413 m -125 m curve – 5 span

• 5 span – 125 m curve
• BCM (1 x 58m + 2 x 100m + 1 x 95m + 1 x 60m)- 413 m
• Corridor 5 viaduct height is 31 m from Ground level

Integrating with State Highway flyover at Thoraipakkam, Sholinganallur, Kattupakkam, Majambakkam & MIOT flyover location.

Integrated structure with State highway

Kattupakkam

• Length – 1.52 km
• Station – 2nos (kumanchavadi, karyanchavadi)
• Height – 22.7 m (metro rail level)

MIOT

• Length – 3.15 km
• Station – 3nos (Muglivakkam, Ramapuram, Manapakkam)
• Height – 23.7m (metro rail level)

Thoraipakkam

• Length – 1.8 km
• Height – 26.9m (metro rail level)
• Corridor 3 – 19.8 m (metro rail level)
• Future corridor – 26.9 m

Sholinganallur

• Length – 1.9 km
• Height – 27.6m (metro rail level)
• Corridor 3 – 20.5m (metro rail level)
• Corridor 5 – 27.6m (metro rail level)

7. Underground Section

Stacked station:

CMRL has planned to go with underground stations with a stacked-up platform design at locations where the width of the roads is as narrow as 10m. Pattalam, Thirumayilai, Kutchery, Alwarpet, and Bhardhidhasan road stations are with stacked tunnels. In Corridor 3, the Thirumayilai underground interchange station will be constructed at a depth of 38.79 m from street level (35 m up to rail level) and will have 4 levels. The size of the station box will be 155 m in length, and 11 m in width. There will be a total of 4 entries/exits to the station from street level. To facilitate passengers to reach the station smoothly, a total of 12 escalators and 3 lifts will be available from street level. In Corridor 4, Thirumayilai underground station will be constructed at a depth of 26m from street level and will have 3 levels. The size of the station box will be 152 m in length, and 19.7m in width. There will be a total of 2 entries/exits to the station from street level. To facilitate passengers to reach the station smoothly, a total of 12 escalators and 3 lifts will be available from street level.

Stacked Station- 5 nos (Pattalam, Thirumayilai, Kutchery, Alwarpet, Bharathidasan Road)

• Station Size: 155 x 11m
• Height of Thirumayilai station: 37 m from Street level
• Height of other stacked station – 19 m

Intersection of Tunnel:

At Kilpauk, Thousand Light, and Nandanam, Phase II tunnels are passing below the Phase I running tunnels. More challenging to execute the same.
Intersection of Tunnel at existing Phase 1 Corridor (Phase II tunnel below Phase I tunnel)

• Kilpauk, Thousand light and Nandanam,
• Minimum 1D (6.5m) cushion between two tunnels
• Below 18m (Phase 1) 30 m (Phase II) from Ground Level

Crossing of Adyar River:

Corridor 3 crosses the Adyar River near Adyar Junction (UG). The Crown of the Tunnel is 15 m below the bed level.
Crossing of Adyar River:

• Corridor 3 crosses Adyar River near Adyar Junction (UG).
• The Crown of the Tunnel is 15 m below the bed level

7. Multimodal Integration

As a part of Multi-Modal Integration, the Phase-II Network will be integrated with other public transport modes namely Suburban Rail, MRTS, City Bus service, etc. at 21 different locations to ensure hassle-free and seamless connectivity.

Last Updated On : July 15, 2024