Scheduling of Elevated Metro Rail Structure: A Detailed Guide for Planners

 Planning and scheduling are at the heart of every successful metro rail project. In elevated metro projects, each activity—starting from piling to girder erection and station construction— requires careful sequencing to ensure timely completion. This blog provides a detailed breakdown of the construction process and typical durations for each activity involved in building both the elevated structures and metro stations, covering piling, pile cap, piers, pier caps, and more specialized elements like concourse levels, platforms, and station amenities.


1. Elevated Structure Construction Activities

a) Piling (Duration: 2-3 Days per Pile)

Piling forms the foundation of elevated structures. It involves drilling deep into the ground and placing reinforcement cages, followed by concrete pouring.

  • Step 1: Boring/Drilling: Using rotary or bored piling machines.
  • Step 2: Reinforcement Placement: Installation of steel reinforcement cages into the drilled holes.
  • Step 3: Concreting: The final step involves pouring concrete into the bored pile.


b) Pile Chipping (Duration: 1-2 Days per Pile)

Once the piles are cured, chipping is carried out to remove excess concrete from the top to expose reinforcement bars.

c) Pile Cap Reinforcement & Shuttering (Duration: 4-6 Days)

The pile cap ties together the group of piles.

  • Reinforcement: Steel bars are placed to connect all the piles.
  • Shuttering: Formwork is erected around the reinforced pile cap, ensuring it holds the concrete.

d) Pile Cap Concreting (Duration: 1-2 Days)

Concrete is poured into the formwork to create a solid pile cap, distributing the load from the pier.




e) Pier Reinforcement (Duration: 2-3 Days per Pier)

The pier is a vertical column that supports the viaduct. Reinforcement bars are tied based on structural requirements.

f) Pier Shuttering & Concreting (Duration: 4-5 Days)

  • Shuttering: Formwork is erected around the reinforcement to give the pier its shape.
  • Concreting: High-strength concrete is poured into the formwork.
  • Pier Protection: After curing, protective layers, such as anti-carbonation coatings, are applied to protect the pier from environmental elements.

g) Pier Cap Construction (Duration: 4-6 Days)

  • Pier Cap Reinforcement: This connects the pier to the U-girders or I-girders.
  • Pier Cap Shuttering: Formwork is erected.
  • Pier Cap Concreting: Concrete is poured into the formwork to create the pier cap.





h) Erection of U-Girders (Duration: 1-2 Days per Span)

The U-girder forms the horizontal section of the elevated structure, upon which the tracks are placed. Precast U-girders are transported to the site and lifted into place using heavy-duty cranes.

  • Temporary Supports: While lifting, temporary supports ensure the girder is in the correct position.
  • Fixing and Post-tensioning: Bearings and post-tensioning ensure that the U-girders are securely fixed in place.


2. Station Construction Activities

Metro station construction involves multiple levels, including concourse, platform, and amenities like staircases, lifts, and PEB structures.

a) Hammerhead Construction (Duration: 8-10 Days)

Hammerheads provide the structural support for elevated platforms. The construction involves:

  • Reinforcement: Tying of steel bars.
  • Formwork Setup: Shuttering for hammerhead shape.
  • Concreting: Hammerhead is cast with high-strength concrete.

b) Pier Arms Construction (Duration: 7-8 Days per Arm)

Pier arms extend from the piers to support the concourse and platform levels.

  • Reinforcement: Placement of reinforcement bars in a predefined pattern.
  • Shuttering & Concreting: Formwork is placed, and concrete is poured to form the arms.

c) Concourse Level Construction (Duration: 12-15 Days)

The concourse level is where ticketing and passenger flow management occurs.

  • Column Reinforcement: Steel bars are tied to form columns supporting the concourse.
  • Beam and Slab Concreting: Reinforcement for beams and slabs is prepared, followed by concreting.

d) Platform Level Construction (Duration: 15-18 Days)

The platform level is where passengers wait for trains. It requires careful planning for structural integrity and space for amenities.

  • Precast or Cast-in-situ Slabs: Construction of slabs using either precast elements or cast-in-situ concrete.
  • Platform Fittings: Installation of platform screen doors, benches, etc., once the structure is completed.



e) Staircase & Lift Construction (Duration: 7-10 Days)

Staircases and lifts are essential for passenger access between concourse and platform levels.

  • Reinforcement and Formwork: Concrete staircases are reinforced with steel bars, while lifts require reinforced lift shafts.
  • Concreting and Finishing: Concreting and subsequent finishing works like tiling are completed.

f) Underground Water Tank (UG Tank) (Duration: 12-14 Days)

Stations often require UG Tanks for fire-fighting systems and other utilities.

  • Excavation: The area is excavated for tank placement.
  • Waterproofing: Special coatings are applied to prevent water seepage.
  • Reinforcement and Concreting: The tank is reinforced and cast with concrete.

g) PEB (Pre-Engineered Building) Column Erection (Duration: 7-8 Days)

PEB structures are used for station roofing and external coverings.

  • Bolt Fixing: Foundation bolts are fixed in the base to support PEB columns.
  • Column Erection: Pre-fabricated columns are erected using cranes.
  • Roofing and Cladding: Once columns are up, roofing sheets and external cladding are installed.





3. Key Considerations for Effective Scheduling

  1. Parallel Execution: Many activities such as pier reinforcement, pile cap casting, and station slab construction can run concurrently. Proper scheduling of such parallel tasks optimizes project timelines.

  2. Use of Primavera: Advanced project management tools like Primavera P6 or MS Project help monitor critical paths, resource allocation, and track project progress in real-time.

  3. Risk Mitigation Plans: Weather delays, material shortages, or equipment breakdowns are common in large projects. Having contingency plans integrated into the schedule ensures timely resolution without affecting the overall timeline.

  4. Regular Reviews: Weekly or bi-weekly review meetings with contractors, engineers, and stakeholders help in tracking the progress and making necessary adjustments to the schedule.


Conclusion

Building elevated metro structures and stations is a meticulous process that demands accurate scheduling for each task. From pile construction to the erection of U-girders, and from the concourse level to platform finishing, each phase plays a crucial role in the overall project completion. Following best practices in scheduling, including the use of advanced tools and parallel task execution, ensures timely delivery while mitigating delays and unforeseen challenges.




#ElevatedMetroConstruction #MetroStationConstruction #ProjectManagement 

#MetroRailInfrastructure #PreEngineeredBuildings #UGirderErection

Metro rail project scheduling, Construction scheduling for metro stations, Pile cap reinforcement and concreting timelines, U-girder and I-girder erection methodology, Pre-engineered building erection in metro projects


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