Interface Management for Station Construction

Interface Management for Station Construction

 Metro Rails are playing a vital role in the development of progressive cities. For its inhabitants, it is reducing the commute time and thereby lessening the stress. Metro rails have virtually made the cities small by providing comfortable travel to the citizens.

And, understanding the advantages of rapid mass transit, Tier-2 cities are also following suit. Metro projects are being launched in full swing in these cities. Like any other construction project, time is of great essence for Metro projects as well. But, there are few elements in Metro projects which differentiate them from other construction projects.

First and foremost, 90% of the metro infrastructure is along the main roads of the city. This is particularly troublesome to commuters during the construction period. Hence, it is very critical for Metro projects to minimize the construction duration as, apart from the monetary losses, the delay might lead to huge pain to the public.

Secondly, the metro alignment, which is the basis of all design, needs several alterations to accommodate the issues related to property acquisition, traffic management and underground utilities. All these issues occur mainly during the execution phase, which makes it tougher to accommodate and delays the execution.   

If we see broadly, the metro projects have 3 major components: Stations, Track (elevated / underground tracks) & Depots.

Depot are located at the end of metro line and house the maintenance and control room for Metro operations.

Tracks are elevated / underground permanent way consists of rails of section connecting two Stations. Usually, the tracks are placed on precast RCC sections spanning 45m to 60m. The execution time is less due to larger spans.

Stations are always on the critical path, having longer design / construction durations and complexity related to Entry Exits planning and execution.

Based on my experience of working on Hyderabad Metro Rail Project, I derived a few conclusions which can help in optimizing the execution timeline:

1. The location of the footprint and available RoW - Finalization of station location depends on the catch pool of the area, connectivity with other mode of transportations and minimum interference with the existing structures in its vicinity. Usually, the “Right of Way” (available width on both side of center line of the road) is defined along the metro alignment at the start of concept design. The Station footprint is designed considering the available RoW. However, based on the property acquisition strategy, the Station footprint goes under several alterations.

During the execution phase as well, the station footprints may undergo revision due to various underground utilities (electrical cable / sewage and water supply lines), which are usually missed during the utility surveys. There is always a trade-off between rerouting of utilities vis-a-vis redesign of Station footprint i.e., Entry & Exit.

2. Interface Matrix – The Battery limits of all the subcontractors shall be defined at the start of the project itself. Further, space / technical room owners shall be assigned to lead the discussions for respective space.

The different systems shall also be prioritized based on the complexity. This will enable to resolve the conflicts during planning and execution. Example: For space co-ordination purpose, sprinkler location takes precedent over HVAC diffuser. 

3. Planning for system co-ordination – Station Control and S&CT / COMs rooms are the heart of station design. It houses equipment for all specialized packages such as Automatic Fare Collection System (AFC), Signaling & Train Control, Telecom System, Power Supply, Traction and SCADA System, Electrical Low voltage system.

The best way to finalize the design is to generate coordinated layouts, after incorporating the inputs from all subcontracts. It is very important for the well-functioning of a station that LED display, double sided TFT, Master clock, Public Address systems, access control systems, wicket gates, etc. are well in sync with station layout.

4. Detailed Design Schedule for Sub contractor Co-ordination – Detailed schedule shall be prepared comprising the information for each package, subcontractor on board, first cut design inputs from all sub-contractors, Interface management among sub cons, and finalization of design.

In absence of proper planning, the design will undergo several alterations and lose time.

5. Standardize the Station Layout - Arrive on a standard Station Box size comprising all the required rooms. It is of utmost importance to discuss the technical room sizes with all stakeholders and optimize it. Any spare space will have a multiplier effect on cost (as the spare space will be replicated across the number of Typical Stations)

6. Built-in feasibility to accommodate Entry and Exits – Now, this may appear a little contradictory to the above point and it is definitely a little tricky to have standardization and customization feasibility go hand-in-hand. It boils down to the smartness of the architect to accommodate flexibility for Entry and Exits which are unique for each typical station in the standard station box design, with minimum efforts.

7. Modularization to the last extent – It is worth to spend a little more time while developing the details and reduce gaps for interpretation on site. Modularize the flooring, Handrails, False ceiling, Dry wall and reduce the onsite construction duration.

Same is applicable for MEP services. If the support for cable trays, HVAC ducts and Fire protection pipes are built in the structure, the onsite installation will be faster.