The Six Stages to building an elevated MRT line - Preparatory Works (1)

 

We launched our new mini-series last week, a deep dive into the process of building an elevated MRT line which was last seen on the East-West Line when the Tuas West Extension was built. Join us as we explore the first of six distinct stages of bringing an elevated MRT line to life - the preparatory works stage.

Stage 1: Preparatory Works

Various work activities are carried out at this stage in order to prepare the site for the commencement of construction work. These may range from soil investigation to facility diversion works. Do refer to the table below for an idea of the types of work activities that are carried out & their purpose and function.

Typically, soil investigation works are conducted during the initial design stage of the line where engineers draft plans & come up with the drawings of the structures to be built. However, once contracts are awarded, contractors may opt to do another round of soil investigation tests as on occasion, the final proposed methods of construction may differ from those prescribed - especially if the proposed method allows for more efficient & effective construction.

As such, these tests allow the contractor to confirm the soil composition at the various sites before construction work begins. It allows for more detailed planning of work sequences and for the contractor to verify that the construction methods are sound. Often times, an external company is used to check engineering drawings & calculations to ensure that the structures being built comply to local guidelines & are sufficiently designed to support the expected loads.

29 November 2020 - Soil Investigation works between Tengah Park & Bukit Batok West stations.

29 November 2020 - Soil Investigation works between Tengah Park & Bukit Batok West stations.

2 October 2021 - Soil investigation works near Toh Guan station.

24 January 2021 - Soil investigation works along Choa Chu Kang
Avenue 3, at the site of Choa Chu Kang West station.

Utility diversion works typically involve identifying utility cables / pipes / networks in the vicinity of the project site, and their diversion so services remain uninterrupted by the civil (structural) construction works that will commence after. 

While the contractor may be provided (or directed to relevant agencies to secure) plans on nearby utilities, they have to supplement and confirm them through trial trenching. This is the process of digging shallow trenches to detect the presence of utility lines such as power cables, telephone lines, water mains or sewer and drainage networks. 

24 January 2021 - Trial trenching works in progress for utility detection.

24 January 2021 - Trial trenching works along Choa Chu Kang Avenue 3.

2 October 2021 - Notice on trial trenching works at Toh Guan station.

2 October 2021 - Notice on trial trenching works at Toh Guan station.

2 October 2021 - Trial trenches at Toh Guan station site appear as the darker portions of the road,
where the contractor has dug to detection any utilities.

The next work activity is tree felling or relocation, which is often necessary to clear the site for works to happen, or the road diversions needed to make space for the site. Where possible, efforts are made to relocate trees to another suitable site rather than felling. However, this is not always possible nor efficient, thus the tree will be felled to be replaced by future landscaping once the project is completed.

24 January 2021 - Tree felling along Choa Chu Kang Avenue 3.

8 November 2020 - Notice to residents in the vicinity of Boon Lay
station on upcoming works, which includes tree felling.

14 November 2020 - A view along Choa Chu Kang Avenue 3.

26 June 2021 - A view along Choa Chu Kang Avenue 3 with trees felled to make way for road
diversions & creation of the construction site.

Site clearing is another activity that may take place concurrently whilst tree felling work is on-going. This serves to clear the construction site so that works to build structures can begin.

14 November 2020 - The commencement of site clearing in Tengah,
near the junction of Brickland Road & Choa Chu Kang Avenue 3.

14 November 2020 - Site clearing in Tengah.

24 January 2021 - Progress of site clearing within Tengah.

26 June 2021 - The site clearing allows for further construction work
to take place on the cleared site.

In tandem with site clearing, hoarding is often put in place to segregate the construction site from public access areas. This helps to ensure the safety of pedestrians, motorists and construction workers alike. During this phase, high noise barriers may be constructed to reduce the amount of noise generated from the site affecting residents.

2 July 2020 - The multi-purpose court at Choa Chu Kang station prior to works.

14 November 2020 - Hoarding being put up around the construction site where a replacement
multi-purpose court will be built within the hoarded site.

26 October 2021 - Hoarding being put up outside Gek Poh Shopping Centre.

26 October 2021 - Hoarding being put up at the site of Gek Poh station.

26 October 2021 - Hoarding in front of Gek Poh Shopping Centre.

4 December 2021 - Noise barrier construction at Gek Poh station site.

4 December 2021 - A close up view of the noise barrier construction.

9 October 2022 - A view of the completed high noise barriers at Gek Poh.

Other facilities - such as bus stops and a nearby fitness corner in the case of works for Gek Poh station - may also be removed or relocated during this preparatory stage. There will occasionally be abandoned infrastructure that needs to be located and safely removed before the rest of construction can occur. 

7 February 2021 - A view of the former fitness corner at the site of Gek Poh station.

7 February 2021 - A view of the former cycling path at the site of Gek Poh station.

26 June 2021 - The demolished former fitness corner at Gek Poh station site.

26 June 2021 - An aerial view of the cycling path which has been removed.

26 June 2021 - Works in front of block 749 Jurong West Street 75, where the fitness corner
at the Gek Poh station site used to be.

4 December 2021 - Works to relocate the bus stop outside Gek Poh Shopping Centre.

As the name suggests, preparatory works are just the beginning of works and serves as a precursor to the actual construction works for the final structures of the line. These are enabling works, without which, the line cannot be completed. We hope that this has provided some insight to the types of work activities that are carried out before visible works for the line can be seen and allows you to better understand why construction of such a line through densely populated areas takes so long.

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